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IS THERE A BEST OR SAFEST TIME TO TRAIN TO MAXIMISEYOUR
AbstractThe following article, in a proposed series will provide another best practice-research based solution fordefining the best time of day for athletes to train. Contrary to conventional and contemporary wisdom, thebest time for athletes to train is between 5 PM and 7PM. The rationale for this preferred training timeframe is based in scientific research that suggests that at this time, the human organism is in an optimalstate of homeostasis. Accordingly, both an athletes biological and neurological functions will be at theirpeak thereby allowing for the best chance for the targeted training performance and results to occur. Asevidence to these conclusions, the article will site recent scientific research that will describe theparameters for aligning training prerequisites, and the optimal times when the training perquisites shouldbe applied within the optimal biochemical, neurological, and biomechanical timing for training outputcapacity of the human body.
To this end, the article will describe in depth cause and effect analysis of requisite training input balances
and requirements of proper hydration, rest cycles, physical therapy, anaerobic and aerobic training,strength training, plyometrics, and sport psychology. In particular interest there is discussion on the impactof training times with respect to the relationship between circadian rhythms and human core temperature,biomechanical effects for performance output and the inverse relationship with respect achievement ofoptimal motor memory and motor skill adaptations. The article goes on to describe the impact an influenceof life style tendencies and behaviours on training for peak performance and in particular as they relate toan athletes genetics, hormonal balances, physiological body mass indices, and the overall impact onpsychophysiological components as they relate to peak performance. The article concludes with aretrospective summary of elite athlete competitive performances achieved in world-class competitions andtheir demonstrative effect and endorsement of the best practice training methods prescribed herein. Alsoincluded are comprehensive listings of the longitudinal scientific research used by the author to supportthe enclosed conclusions and recommendations offered to the reader.
Does the time of day at which you exercise matter? And more importantly, can you improve your performance bypicking the right time for a workout? There is certainly evidence to suggest that the body is more geared up forphysical activity at some times of the day than others. This article is not just confined to the throwing events, it will beapplicable to all sports and their various body types. From Running to Rugby, Swimming to Shooting, Basket Ball toBoxing etc
According to Dr Steve Ingham, EIS physiologist, the best time of the day to train is between 5pm and 7pm. This iswhen your body is at its physical peak. Training at that time of day is when you are likely to get the greatest positiveincrease in performance level. The main reason for this is that at other times of the day, your body is less prepared forphysical exertion. In the morning, your core temperatures (and environmental temperature) are close to their lowestpoint. Your muscular skeletal structures are also colder, and your joints aren't in a ready state for heavy lifting orstretching first thing this can increase the risk of injury.
Furthermore Ally McDonald EIS physiologist also points out that our concentration levels are typically lower in themorning which can lead to mistakes or incorrect training. Your blood sugar levels will also be lower than at any othertime of the day because you haven’t had a substantial food intake for about ten hours, a long period of time. Duringthe late afternoon between 5pm and 7pm, you are likely to have had 2 good meals if you are in training, be physicallyand mentally more ‘awake’ and your body warmer, allowing you to be in the optimum state for effective training. Doremember, that as the temperature of the day increases, thermoregulatory considerations become increasinglyinfluential on performance. Training in too much heat can lead to a negative and potentially dangerous training
session.
Here is an extraordinary example of why trainers, coaches, managers etc should have a working knowledge of howthe body works. In the UK the general public is force fed a diet of football. One of the worst aspects of this, as far as Iam concerned, is that after the games, the broadcasting powers that be think the public wish to hear the ridiculousrepetitive comments from the managers. I’m sure many viewers use the mute button.
Unfortunately just recently for me this was not possible. This is what I heard on a BBC football report in a discussionwith the manager of a particularly struggling club “Took em warm weather training, on the bus for training by 8.30amevery morning, never went out for an evening all week”.
Anyone aware of how the body works would be most surprised. As far as I am aware football in the UK is almostalways played between 3pm – 5pm, not 8.30 am. We are not told as to whether they went to the East or to the Westof the UK for their ‘training’ as there was no mention of jet lag or lead. In the UK on match day at 3pm the player has
been correctly fed and watered, food digested & is ready to play. The player with the 8.30am kick off probably still hasa stomach full of breakfast. There again it could be that this is a very clever manager and he has got the players out oftheir beds at 2.00am in the morning to fool their bodies into thinking that by 8.30am is was actually 3pm. Is that whyhe claims they never went out on an evening? Yes the team have dropped from the middle of the table, when themanager took over, and are now near the bottom of the table, thanks to the manager’s training them to be there!! Afterall their training dictates that they are having their afternoon siesta at 3pm!!, certainly not running around a footballpitch chasing a ball.!!
The need to be your fittest on the right day at theright time
History tells us that world and Olympic records insports events are usually broken by athletescompeting in the early evening, 4pm – 7pm, the timeof day when body temperature is highest. Only a few
world records, since 1900, have been broken in themorning. (for the stats freaks see end of article, theyare also given with the time of day).
Moreover, if high performance is required at a specifictime of day -- e.g., Olympic final – for optimum resultsthe athlete and coach need to anticipate this well inadvance and to structure training sessions around thetime of day that the final will be held. This should bethe same criteria for all sports. Train when you play.
When one considers that the morning/afternoonperformance variation may amount to as much as 3-7percent (1), it becomes very clear that failure toconsider this fluctuation in high-intensity performancehas the potential to drastically affect achievement ofgoals.
Athletes in high-intensity sports who are training topost specific qualifying performance marks -- e.g.,Olympic trials standards -- would therefore be welladvised to note this article and make these attemptslater in the day or in the evening.HydrationMost of us go to bed each night lying down to sleep for8 hours or over. During this time the spine is relievedof pressure. As the discs hydrate they are able to holdmore spinal fluid. This makes them larger and it alsoputs more space between each vertebra. Under
normal circumstances disc hydration and height isgreatest in the morning says Dr. Sudhakar Rajulu aresearcher at Johnson Space Centre’s Habitability andEnvironmental Factors Office.
Coaches need to be very aware of this 24 hourlyhydration cycle, particularly when dealing with contactsports, taller and heavier players/athletes. The initialheight loss after morning rising is quite dramatic, butthe rate of reduction drops off as upright posturecontinues. Normal daily height variation is 1.1 percentof its average value (2).
Credit to NBAE/ Getty Images
Dr. S. Rajulu’s work is supported by Prof Stuart McGill
University of Washington, Ontario in his book ‘LowBack Disorders’ where he warns “do not performdemanding exercises first thing in the morningbecause discs are hydrophilic.
Overnight, they tend to soak up water and swell. It'seasier to herniate a swollen, water-filled spine if youattempt bending and lifting exercises”. He warnsagainst doing weight training early in the morning. Hepoints out that after rising, hydrostatic stresses of justwalking around and using the muscles during the daycompress your spine and the fluid is squeezed out,decreasing the annular tensions in the disc.
So, when you wake up the extra height in the discsareanalogous to a full water balloon ready to burst andif you bend, you build up much higher stresses in thedisc. In fact, the stresses are three times higher thanwhen you perform the same bend two or three hourslater.
He highlights that he is not talking about getting upand going for a walk or perhaps a boxer going for alight jog first thing in the morning. He is talking aboutheavy bending and lifting exercises, like for example asquat, the good-morning exercise or doing sit-ups.Somehow people thought that this would be a goodthing to do in the morning?. It’s the worst possible thing you could do to your back first thing in themorning. Full spine bending first thing in the morningis a great way to damage your back—an unwise thingto do. Wait until you've been up for a reasonableamount of time and the discs have lost some water,reducing their stress.
1. Bernard, T., M. Giacomoni, O. Gavarry, M. Seymatand G. Falgairette. "Time-of-day effects in maximalanaerobic leg exercise." Eur. J. Appl. Phsiol. 77.1-2(1998): 133-138.2. Reilly, T. "Human circadian rhythms and exercise."Crit. Rev. Biomed. Eng. 18 (1990): 165-180.
Let us go back to what was probability a catalyst to theresearch that is now serving our sports people so well.When the 1968 Olympic Games were awarded toMexico City problems of competing at altitude came tothe fore. It is situated some 7,500 feet above sea
level, where the partial pressure of oxygen is reduced,due to decreased barometric pressure. It is importantto note that up to 20,000 feet, there is in fact no lack ofoxygen, and the chemical composition of theatmosphere does not change. However, because ofthe reduced barometric pressure, the oxygen in theatmosphere is not as freely assimilated by the body asit is at sea level.
This article has deliberately not ventured into anydepth about the acclimatising models required tostabilise the homeostasis of the body, to ready thebody for competition due to altitude, temperature andthe time change. Except to say that from the UK if wetravel sufficiently far in an Easterly or a Westerlydirection, for every 1 5 degrees of longitude a 'timechange' of one hour occurs. Inevitably, when travellinglong distances this change is sufficiently large to havea debilitating effect. 'Jet-lag' has become a commonterm in modern times to denote the efforts of a rapidtime change. (for some notes on this subject pleasesee later in this article P6, Col 2, para 3, and P13, Col1, para 3) However a few notes on the subject doappear at the end of this chapter.
For many years a significant number of fitness trainingresearchers have investigated time-dependentchanges in physiological variables, Aerobic andAnaerobic exercise Chronobiology – how timing could
give you the edge, as they appear to do, and have far-reaching implications for athletes/players. We may livein a hightechnology 24/7 world, but the daily orcircadian rhythm remains deeply ingrained in ourphysiological make-up.There’s now plenty of recent research to suggest thatcoaches and athletes ignore this circadian rhythm attheir peril when conducting aerobic and anaerobicexercises
They found that rhythms exist that affect our physical,mental and behavioral changes, and that they follow aroughly 24-hour cycle, responding primarily to lightand darkness in an organism’s environment. They are
found in most living things, including animals, plantsand many tiny microbes. The researchers refer tothem as ‘Circadian rhythms’ particularly noting thevariations that recur every 24 hours.
The circadian rhythm is the most powerful rhythmaffecting humans; as well as the sleep/waking cycle, itaffects hormone secretions, body temperature, mentalalertness and physical performance capacity.Due to these rhythmic fluctuations, many peopleexperience maximum mental alertness, fastestreaction times and highest core temperature in the lateperiod leads to maximum fatigue/sleepiness andlowest alertness.afternoon/early evening period, while the peak in
melatonin concentrations in the middle of the night
They found, under strict control of possible variables,that the majority of components of sports performanc
e.g. flexibility, muscle strength, short term high poweroutput, vary with time of day in a sinusoidal mannerand peak in the early evening close to the dailymaximum in body temperature. There’s also evidencethat the amplitude of these rhythms may be altered byvarying exercise intensity, and that other rhythms caninterfere with the circadian rhythm (especially themonthly menstrual rhythm in women(3). 3. Clin Ter
2006 May-Jun;157(3): 249-64They also found that higher work-rates are selectedspontaneously in the early evening.(3)
(Please note that there will be further informationspecifically to assist the understanding of coachingfemales in this area)
So it seems as far as most physiological variables areconcerned, late afternoon to early evening is primetime for a workout. ‘In the morning, virtually all bodilyfunctions are at their worst, body temperature is low—meaning your muscles, ligaments, joints and tendonswill feel stiff—lung function is poor, the nervoussystem sluggish,’ As Professor Tom Reilly, arenowned expert on Circadian Rhythms at theResearch Institute for Sport and Exercise Science atLiverpool John Moores University points out, thismeans the same level of exertion is likely to feel muchharder at this time of day than later on.
To top things off, James Waterhouse, Professor ofBiological Rhythms also at John Moores University,Liverpool points out that ‘exercising early in themorning will leave you more prone to injury or worse.Research shows this is the most common time of dayfor heart attacks and strokes.’
It is the influence of circadian rhythms on body
temperature that seems to yield the most control overthe quality of a workout. When body temperature is atits highest, your workouts will likely be moreproductive; when your body/core temperature is low,chances are your exercise session may be less thanoptimal.
It is well known that body temperature is at its lowestabout one to three hours before most of us wake up inthe morning, in contrast to late afternoon when bodytemperature reaches its peak. (Fig 1)
36
36.5
37
37.5
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0000h 0200h 0600h 1000h 1400h 1800h 2200h
Time of Day
R e c t a l T e m p e r a t u r e ( ° C )
Figure 1 – Circadian variation of human core
temperature (Adapted from Reilly & Cable, 2001)
Studies have consistently shown that exercise duringthese late-in-the-day hours produces betterperformance and more power. Muscles are warm andmore flexible, perceived exertion is low, reaction timeis quicker, strength is at its peak, and resting heartrate and blood pressure are low. The effects ofcircadianrhythms and performance has been noted ina number of sports, for instance swimming.
Numerous papers have identified that swimmersperformed significantly faster in the late afternoon(5:30pm) than early in the morning (6.30am). (4, 5, 6)
As previously mentioned, the most pronouncedphysiological body rhythm is that associated with bodytemperature. Core temperature is at its lowest whenyou first wake up in the morning (7am-9am) and thengradually increases throughout the day until it peaks ataround 7pm hours. Thereafter the temperaturegradually decreases to absolute resting levels. How dothese changes in body temperature over 24 hoursaffect sports performance? (Fig 1)
According to motor learning and performance theory,there exists an inverse relationship between the levelof skill required in any given task and optimal arousallevels (7). The available data suggest that for mostindividuals fine motor tasks and balance skills may bebetter learned and mastered in the morning (8). Weare aware that simple reaction time (either auditory orvisual) is a major component of performance.
Reaction time peaks in the early evening at the sametime as the maximum in body temperature. For every1 deg. rise in body temperature, nerve conductionvelocity increases by 2.4 in/sec (Winget et al, 1985).
Often there is an inverse relationship between thespeed and the accuracy with which a simple repetitivetest is performed. Research shows that people learnnew motor skills more readily in the morning than inthe evening. (so accuracy may be worse in the earlyevening)
In one study, subjects improved most in a newlylearned task at 9am. Short-term memory and finemotor control (the ability to do precise or fiddly tasks)are also superior in the morning compared to later inthe day –which may play a part in overallperformance. This shows the importance of definingdemand accuracy without speed, such as archery,shooting, darts, snooker, putting etc.Whereas fencers tend to perform best in the middle ofthe day, perhaps because their sport depends onmental skills, which peak about that time.
Therefore for athletes wanting to perform at their bestit is clear that morning is definitely not the time toattempt feats of explosive strength, power oranaerobic capacity(1).
Circadian rhythms seem especially prone to a “postlunch dip” (Reilly. 1990). This phenomenon describes,atransient decline in alertness and performanceoccurring early in the afternoon. Some aspects ofperformance deteriorate at this time without acorresponding decrease in body temperature andeven if no food is ingested at lunchtime. (Winget et al,1985).
A number of studies have concluded that a shortperiod of sleep during the day, a power-nap, does nothave any measurable effect on normal circadianrhythms, but can decrease stress and improve
productivity. (9, 10)
Wright et al (1969) found that the circadian variation instiffness (resistance to motion) of the knee joint issimilar to that of body temperature, with lowest levelsof stiffness recorded in the early evening.Flexibility is greatest from late afternoon until midnightand lowest from 6am-10am (11) Similarly, rectaltemperature in humans reaches a high at around 6pmand a low at around 6am (12). (Fig 1) Thus, it isgenerally more productive to perform developmentalstretching in the late afternoon or early evening.Increased body temperature at these times createsgreater tissue pliability and permits much better rangeof motion with far less discomfort, particularly whenrestrictions are due to fascial tension.
Some brief notes to understand the needs foracclimatisation of the modern athlete competingworld wide.For the Moscow Olympic Games there was a threehour time change, and for Edmonton CommonwealthGames there was an eight hour time change. Eventsin the Antipodes are affected by a 12 hour timechange. The existence of continental 'time zones' andthe operation of local 'summertime' can either increaseor diminish the overall effect.
The general effect of long distance flying makes itselffelt in several ways. As a result of the time changethere is an upset in the Circadian Rhythms, whichmanifests itself in an upset of those body functionswhich are time-linked, e.g. sleeping, waking, eating,bowel and bladder functions. Although an aircraftcabin is pressurised, this is not to sea levelnormalities, but to about 5,000 - 6,000 feet. The resultof this is that digestion tends to be upset with adistension of the gases in the intestine and also someswelling effect of the feet. There is also somedehydration due to dryness of the air in the cabin.These adjustments add to the general upset in thebody rhythms.
The most common effect to athletes experiencing alarge time change, is the disturbance of the body's'time clock'. It usually takes quite a while for the 'timeclose' to re-adjust to the new environment. Frompersonal experience, a time change of more thanthree hours has the most serious effect. For changeslonger than that period, there is a complete disruptionof routine, with a desire to fall asleep during the day,and an inability to sleep at night. Athletes foundgreater difficulty in sleeping soundly later than 3 a.m.in Edmonton, until their bodies had begun to adjust.During this period a lighter than normal training loadshould be undertaken. After four to five days,adjustment began to make itself felt. Variousauthorities have recommended suitable periods ofacclimatisation to time change.
If the competition is on a single day, the athlete haslittle choice but to fly in, compete, and fly out. This isusually a satisfactory method.Certain authorities have successfully retained the dailyroutines of the country of departure for such shortstays. This has the advantage of causing leastdisruption of training routines on return.
If the athlete is competing in a major games, aminimum of one days stay for one hour’s time~change is regarded as a basic necessity, someauthorities have recommended two day’s stay for onehour’s time change. Whilst the latter is more suitable itcarries other problems of boredom and homesickness,and will undoubtedly be very expensive. The formersolution of one day for one hour’s time change hasproved acceptable in the past.
References1. Bernard, T., M. Giacomoni, O. Gavarry, M. Seymatand G. Falgairette. "Time-of-day effects in maximal
anaerobic leg exercise." Eur. J. Appl. Phsiol. 77.1-2(1998): 133-138.
3. Sports Med. 1996 Apr;21(4):292-312. Circadianvariation in sports performance. Atkinson G, Reilly TCentre for Sport and Exercise Sciences, School ofHuman Sciences, Liverpool John Moores University,England.
4. Rodahl, A., O’Brien, M., & Firth, P. G. (1976).Diurnal variation in performance of competitiveswimmers. Journal of Sports Medicine and PhysicalFitness, 16, 72-76.
5. Baxter, C., & Reilly, T. (1983). Influence of time ofday on all-out swimming. British Journal of SportsMedicine, 17, 122-127
6. Reilly, T., & Marshall, S. (1991). Circadian rhythmsin power output on a swim bench. Journal ofSwimming Research, 7.2 11-13.
7. Schmidt, R.A. and C.A. Wrisberg. Motor Learningand Performance. Human Kinetics, 2000.
8. Gutenbrunner, C. “Circadian variations of physicaltraining.” Chronobiology and Chronomedicine: BasicResearch and Applications. Eds. C. Gutenbrunner, G.Hildebrandt and R. Moog. Frankfurt: Lang-Verlag,1993. 665-680.
9. Pilcher, J.J.; Michalowski, K.R.; Carrigan, R.D.(2001). “The prevalence of daytime napping anditsrelationship to nighttime sleep”. Behavioral Medicine27 (2): 71–6.
10 Emily Rolston, Judy R. Sandlin, Michael Sandlin,and Rosanne Keathley (2007). “Power-Napping:Effects on Cognitive Ability and Stress Levels AmongCollege Students”. Liberty University.
11 Atkinson, G., A. Coldwells, T. Reilly and J.Waterhouse. “A comparison of circadian rhythms in
work performance between physically active andinactive subjects.” Ergonomics 36 (1993): 273-281.
12. Reilly, T. “Circadian Rhythms.” Oxford Textbook ofSports Medicine. Eds. M. Harries, C. Williams, W.D.Stanish and L.J. Micheli. New York: Oxford UniversityPress, 1994. 281-297.
The study and application of research into ‘CircadianRhythms’ is reliable evidence to suggest that power isoptimal from late afternoon onwards (11). Nerveconduction velocities and reaction time peak with bodytemperature (12), while standing long jump andvertical jump peak at around 6pm (13). Muscularstrength, is maximal from late afternoon onwards.There is a strong relationship between this rhythm andthe rhythm of core temperature, although it is relevantto note that a reduction in strength occurs during aPost Lunch Dip. (14). Back and leg strength peaks inthe late afternoon/early evening (15)
The further implications of this information for theexercise specialist are that in order to optimize powerand strength early in the morning, far greater time andattention must be devoted to warm-up. It should alsobe noted that performance in fine motor tasks and
balance is better in the morning when arousal levelsare lower (16). (See also Para 3, col 2, page 5)
Coldwells et al found that muscle strength,independent of the muscle group measured or speedof contraction, consistently peaks in the early evening.Back strength is also higher in the evening than in themorning. Both concentric and eccentric strength havebeen measured at different times of the solar dayusing isokinetic dynamometry (Atkinson et al, 1996).The results have been consistent.
A time-of-day effect in these variables has been noted,with peak values occurring in the early evening. Hill &Smith (1991) measured anaerobic power and capacitywith a modified version of the Wingate test at 3am,9am, 3pm and 9pm. Peak power in the evening wasfound to be 8 per cent higher than at 3am.
To get the most out of anaerobic training, do it in theafternoon or early evening not in the morning. A studyby Bernard et al (1998), looked at differences betweenthe results of three different anaerobic power tests: a50m dash, vertical jump and max cycles sprint at threedifferent times of day. A group of 23 men undertookeach of the three tests on three separate days at 9am,2pm and 6pm.
Results showed that anaerobic power and max
running speed were significantly lower in the morningcompared with the afternoon, with 5 to 7% greaterpower achieved in the afternoon. In addition, thisfinding suggests that the best time of day for
anaerobic training is in the afternoon or early evening.This is consistent with other research into circadianrhythms which shows heart rate, body temperatureand muscular strength are all higher in the afternoonthan in the morning.
In an area of associated research, the results of astudy of the immune system by Dr Lygeri Dimitriou, ofBrunel University shows that there is a morningcircadian lowering of Immunoglobulin A (IgA), aprotective chemical produced by the immune system(17) and saliva secretory rate. There is also anincrease in the levels of the stress hormone cortisol,which suppresses the immune system. These levelsare higher in athletes who train early rather than late inthe day, indicatingthat athletes should avoid early morning training,particularly after an injury or illness or before a bigcompetition. The findings suggest that a person'sinternal body clock, or circadian rhythms, have animpact on the immune system, added Dimitriou.
Other research at the Hunter Immunology Unit and theRoyal Newcastle Hospital in Australia into theprotective effects of Immunoglobulin A (IgA), foundthat although the immune-system competency andperformance potential may not necessarily peak ortrough simultaneously, it is very clear that an athlete ismore susceptible to infections when immune-systemfunction declines, and infections can produce majorsetbacks in an athlete’s overall training. This furtherseems to confirm the case for not training in themorning, particularly early morning.
The results of continued testing by the Hunter unitshowed that IgA did follow a pronounced circadianrhythm, with low levels of IgA secretion (saliva)observed in the morning and significantly higher ratesof secretion occurring in the late afternoon. The overall‘flow rate’ of saliva was also greater at 6pm, comparedwith 6am. In contrast, levels of cortisol – a hormoneknown to compromise immuno competency – werehigher in the morning and slack in the evening.Although cortisol tends to hamper the immune system,it does promote the formation of glucose within thebody, and also stimulates appetite, explaining why ittends to be elevated during the morning.
What does this mean to the coach and athlete?
Both the Hunter data and that from the Brunel-Lutonresearch suggest that the optimal time for trainingfromthe standpoint of health (i.e., the time of dayassociated with the least suppressive effect on theimmune system) would have to be the evening(around 1800 hours). The reason for this is thatcortisol levels are low at this time, while the flow rateof saliva is high and the secretory rate of IgA is alsoelevated, both before and after workouts.
Thus, the decreases in overall salivary flow as well asin the rate of secretion of IgA at around 6am makesearly morning appear to be a relatively risky time totrain, from the standpoint of maintaining good health.(18)
Some athletes who have recurrent infections or whohave suffered from infections at very inopportune
times(before very important competitions, forexample), mayneed to take special heed of the new evidence. Suchathletes might want to decrease their frequency ofmorning workouts, especially prior to majorcompetitions or during the recovery from illness orinjury. A study published in the British Journal ofSports Medicine (2002) found that early morningexercise left swimmers’ immune systemscompromised
Endurance SportsPerformance in endurance sports is influenced byseveral variables. A small number of studies haveshown that endurance training in the afternoon orevening produces better increases in VO2 max (19)and performance on a swim bench seems to reflectthe faster times posted in evening swim races (20).Further references on the extensive reading ofresearch material into this vast subject of ‘endurancein sports’ are indicated in the references at the end ofthis article.(6, 21, 22, 23). (24, 25 26) (27 28). "Body,
Mind and Sport" by Douillard
References6. Reilly, T., & Marshall, S. (1991). Circadian rhythmsin power output on a swim bench. Journal ofSwimming Research, 7.2 11-13.
11. Deschenes, M.R., W.J. Kraemer, J.A. Bush, T.A.Doughty, D. Kim, K.M. Mullen and K. Ramsey.“Biorhythmic influences on functional capacity ofhuman muscle and physiologic responses.” Med. Sci.Sports Ex. 30.9 (1998): 1399-1407
12. Winget, C.M., C.W. Deroshia and D.C. Holley.“Circadian rhythms and athletic performance.” Med.Sci. Sports Ex. 17.5 (1985): 498-516.
13. Reilly, T. and A. Down. “Circadian variation in thestanding broad jump.” Perceptual and Motor Skills 62(1986): 830
14. Reilly, T., G. Atkinson and J. Waterhouse.Biological Rhythms and Exercise. Oxford UniversityPress, 1997
15. Coldwells, A., G. Atkinson and T. Reilly. “Sourcesof variation in back and leg dynamometry.”Ergonomics 37.1 (1994): 79-86.
16. European Journal of Applied Physiology, 77, pp.133-138)
17. ‘Salivary IgA Levels and Infection Risk in EliteSwimmers’, Medicine and Science in Sports andExercise, Vol 31 (1), pp67-73, 1999
18. ‘The Effects of High-Intensity Intermittent Exerciseon Saliva IgA, Total Protein and a-Amylase’, Journalof Sports Science, Vol 17, pp1-6, 1999
19. Hill, D.W., K.J. Cureton and M.A.Collins.“Circadian specificity in exercise training.” Ergonomics32.1 (1989): 79-92.
20. Piercy, J. and L. Lack. “Daily exercise can shift theendogenous circadian phase.” Sleep Res. 17 (1988):393. Abstract.
21. Hill, D.W., J.A. Leiferman, N.A. Lynch, B.S.Dangelmaier and S.E. Burt. “Temporal specificity inadaptations to high-intensity exercise training.” Med.Sci. Sports Ex. 30.3 (1998): 450-455.
22. Dalton, B., L. McNaughton and B. Davoren.“Circadian rhythms have no effect on cyclingperformance.” Int. J. Sports Med. 18.7 (1997): 538-542.
23. Marth, P.D., R.R. Woods and D.W. Hill. “Influenceof time of day on anaerobic capacity.” Percept. MotorSkills 86.2 (1998): 592-594.
24. Reilly, T. and R. Garrett. “Investigation of diurnalvariation in sustained exercise performance.”Ergonomics 41.8 (1998): 1085-1094.
25. Atkinson, G. and T. Reilly. “Effects of age and timeof day on preferred work rates during prolongedexercise.” Chronobiol. Int. 12.2 (1995): 121-134.
26. Reilly, T. and R. Garrett. “Effects of time of day onself-paced performances of prolonged exercise.” J.Sports Med. Phys. Fitness 35.2 (1995): 99-102.
27. Douillard, J. Body, Mind and Sport. Three RiversPress, 1994.
28. Van Cauter, E., J. Sturis, M.M. Byrne, J.D.Blackman, N.H. Scherberg, R. Leproult, S. Refetoffand O. Van Reeth. “Preliminary studies on theimmediate phase-shifting effects of light and exerciseon the human circadian clock.” J. Biol. Rhythms 8(1993): S99-S108.
REFERENCES FOR FURTHER READINGTowards an Understanding of Human Performance —BURKE E.J. Movement Pubs. 1977.
Sports Physiology - FOX E.L. - Saunders Co. 1979.
Science and Medicine of Exercise and Sport —BUSKIRK E.R. AND BAN D.E. - Harper and Row1974.
Climate and Exercise - BUSKIRK E.R. AND BAN D.E. — Harper and Row 1974.
Are you a morning or an evening person?There is general agreement in the literature thatpeople have distinct natural tendencies towards‘morningness’ or ‘eveningness’. The reason thatpeople tend to display one or the other of thesetendencies is not clearly understood. For instance, anindividual who feels at his or her best first thing in themorning will often exercise at that time. Since exercisehas the potential to affect human circadian rhythms (6,28) and bright light is considered to be one of the mostpotent zeitgebers (time givers) of all (14), it isreasonable to assume that individuals who exerciseoutside at sunrise are reinforcing this behaviouraltendency.
Summarising the available expert data,Reilly et al. assert that human performance inindustrial tasks is better in the morning for morningtypes and vice versa (1). They also note that PostLunch Dip (PLD) tends to be more pronounced in
morning types.
It can be concluded that individuals who displayexcellent technical skill with their exercises willprobably get more benefit from strength and powertraining later in the day as body temperature nears itspeak. In further support of this Gutenbrunner showedthat strength gains were greatest when trainingoccurred between 6pm and 9pm (8). He also foundthat training in the evening produced significantly lesspost-exercise muscle soreness than training at anyother time of day.Training at 9pm may have a phase delaying effect onmany individuals (22). For this reason it is generallypreferable to train at around 5-7pm instead. Thiscompromise would enable athletes to take advantageof the circadian peak in strength and power thatoccurs in the evening without phase delaying theendogenous circadian pacemaker.
As most players/athletes under 40 display eveningtendencies and for whom heavy workouts areplanned, it will usually be more productive to exerciselate afternoon early evening. At the end of the day itmakes obvious sense to practice at the time you willcompete. With a good understanding of individualcircadian characteristics, it is possible for the strengthand conditioning specialist to produce better results ina shorter time frame than less well-informedcolleagues.
According to Andrew Hamilton, BSc, MRSC aconsultant to the fitness industry and an experiencedscience writer, there’s plenty of recent and ongoingresearch to suggest that coaches and athletes whoignore their daily or circadian rhythms do so at theirperil. We may live in a high-technology 24/7 world, butthe daily or circadian rhythm remains deeply ingrainedin our physiological make-up. He tells us , there’splenty of recent research to suggest that athletesignore this rhythm at their peril when conductingaerobic and anaerobic exercises.
With thanks to Peak Performance and AndrewHamilton BSc MRSC I can include some examples ofthe latest research into how circadian rhythms affectperformance. These are not limited to anaerobic
power/lactate studies. A 2002 UK study on the effectsof circadian rhythm on strength found that the time ofday affected maximal lifting strength in young femalesubjects with an 8% increase in maximal strength at6pm compared to 6am (29). However, this effect wasonly observed in the luteal phase of the cycle; in thefollicular phase, there was no discernible effect.
10 years previous to that there was evidence fromstudies that circadian rhythm affects strength. Forexample, researchers from the University of Dijon onthe variation of maximum isometric elbow torque in PEstudents at different times of day found that peaktorque tended to occur at 5.58pm, and was nearly 7%higher than the averaged peak torque figure over thewhole day. Moreover, when the experiment wasrepeated and spread out over a period of six days, thepeak torque figure was calculated to occur at 5.55pm
– just three minutes earlier. This led the researchers toconclude that the circadian rhythms affecting muscularactivity are remarkably constant (30).
A more recent Iranian study, published 16 monthsago, looked at isometric and isokinetic leg strength ineight women during the follicular phase only of themenstrual cycle (to prevent any masking effect), underconditions of both adequate sleep and partial sleeploss (31). The researchers also assessed the strengthof involuntary contractions in the quadriceps producedby electrical stimulation (this technique is used to helpscreen out any effects of varying levels of motivationat different testing times). The results showed that thepeak torque generated by the leg muscles was 4.5-5.9% higher at 6pm compared with 6am and that theperformance rhythms were synchronised with rectaltemperature (i.e. circadian rhythm).
Furthermore, partial sleep loss did not alter themagnitude or variations in muscle strength withchanging time of day. These results were supportedby a French study on circadian variations in strength inmen and women published at the same time and inthe same journal(32).
From a number of papers the summary of resultswere as follows: The changes in power output andcore temperature were strongly associated (indicatingthat this was a circadian rhythm effect). Theresearchers concluded that athletes could benefit byrecording their temperature and timing their bouts ofsubsequent anaerobic training to coincide with peaksin their circadian rhythm.
Researchers suggest that athletes trying to buildstrength should time workouts to coincide with theircircadian peak; that is late afternoon. Weight trainingat that time produces a more favourable post-exerciseanabolic hormone profile, with higher levels oftestosterone and lower levels of cortisol (a hormoneassociated with physiological stress and muscle tissuebreakdown) (33);
Circadian peaks (highest core temperatures) occurredat 5.29pm and 4.40pm for males and femalesrespectively.
Maximum voluntary leg strength occurred at 5.06pm inmales (increase of just over 2.5%) and 3.35pm infemales (increase of just under 3%);
In a study on male rowers, maximum peak powertended to occur just before 5.30pm (7.6% higher thanaverage peak power); maximum mean poweroccurred at 6pm (11.3% higher);
It is recommended, that whenever possible, scheduleimportant and/or strenuous workouts within an hour orso of circadian peak; you will almost certainly gainquality over attempting the same workout earlier in theday;Remember, early morning workouts should beperformed at a gentle pace and a more thoroughwarmup performed to reduce the risk of injury;
Getting up much earlier than usual (i.e. when thecircadian rhythm is in a trough) to ‘squeeze’ inaworkout may be counterproductive; the quality of theworkout is likely to be reduced, the risk of injury isincreased and the athlete will of course be losingsleep into the bargain! Over a period of time this willalso alter their circadian rhythm (Please also refer toimmunology re saliva levels for higher infection risks.
MJM)
For competition (where the time of the event is usuallyfixed), you may wish to experiment with manipulatingyour circadian rhythm so that you’re nearer your peakat the time of the event. The same applies whencompeting abroad in different time zones; TRAIN ATTHE TIME THAT YOU COMPETE!
Circadian rhythmThe circadian rhythm is the most powerful rhythmaffecting humans: as well as the sleep/waking cycle, itaffects hormone secretions, body temperature, mentalalertness and physical performance capacity. Fig 2below shows the typical daily variations of melatonin,core temperature, triacylglycerol, alertness andreaction time as a result of the circadian rhythm.
Due to these rhythmic fluctuations, many peopleexperience maximum mental alertness, fastestreaction times and highest core temperature in the lateafternoon/early evening period, while the peak inmelatonin concentrations in the middle of the nightperiod leads to maximum fatigue/sleepiness andlowest alertness.
MelatoninA hormone produced in the pineal gland of the brain,which is involved in the regulation of the sleep/wakecycle. Melatonin synthesis is inhibited by light andpermitted in darkness. Melatonin has hypothermicproperties, and its nocturnal secretion generates about40% of the amplitude of the circadian bodytemperature rhythm. Melatonin has sleep inducingproperties, and exerts important activities in theregulation of circadian rhythms. Melatonin is capableof phase shifting human circadian rhythms, ofentraining free-running circadian rhythms, and ofantagonizing phase shifts induced by night timeexposure to light.
TriacylglycerolA compound that combines glycerol with three fatty
acids, which is used for transporting fats in thebloodstream. Melatonin and Triacylglcerol are at theirhighest at 3am - 4am. Whereas the body’s coretemperature is at it’s lowest 3.3am - 4.30am
HormonesHormones such as testosterone (an"anabolic"hormone) and cortisol (a "catabolic"hormone) also vary during the day. Testosterone, forexample, peaks in the morning and drops at the end ofthe day. However, while resting testosterone levelsreach a low point in the evening, the rise intestosterone after exercise appears to be greater inthe evening than it is in the morning (34)
Resting levels of the hormone cortisol are also higherin the morning and lower in the evening. But thecortisol response to exercise is lower in the earlyevening (7.00pm) compared with the morning(7.00am) (35). In other words, the testosterone-cortisolratio (when testosterone levels are highest relative tocortisol levels) is higher in the early evening than it isin the morning. This, in theory at least, makes theevening the least "catabolic" time to train (36).
References29. Chronobiol Int 2002 Jul; 19(4):731-42
Physiological Components andpsychophysiological systemsThere has been a great deal of research conductedconcerning circadian rhythms in many physiologicaland psycho-physiological systems (displayed in table1) that can all affect the performance of a rugby player(but also anyone attempting serious or sociabletraining. MJM)
For example, Reilly et al. (2000) reported that,independently of muscle group measured, musclestrength peaks in the early evening. Trunk flexibilitywas reported to peak at 1.30pm (Baxter andReilly,1983), but lower limb measures in knee flexionand extension have been higher in training sessionsconducted at 6pm – 7pm (Wyse et al., 1994).
Improvements in muscle strength after trainingsessions scheduled in the early evening have beenfound to be 20% higher than those conducted in themorning (Manfredini et al.,1998). Resultant datasuggests that any comparisons of strength should beconducted at similar times of the day (± 30 mins.) Toriiet al. 1992) studied the effects of aerobic training atdifferent times of the day and suggested that, whenaiming to increase VO2max and decrease heart rateand blood lactate levels, then training should occurbetween 3pm and 3.30pm hours.
Rhythms in cognitive variables have relevance ininfluencing strategies, decisions and recollectionofcomplex coaching instructions (Reilly et al., 2000).Reaction time was found to peak in the early evening(3pm – 6pm) but information processing abilities peakover a longer period between 2pm and 9pm.Theimpact of these “windows” that enable optimalperformancecan be seen in relation to training andscheduling in table 1
Table 1: The influence of circadian rhythms on physiological and psychological components (Adapted fromWinget et al. (1993) and Cappaert (1999))
Key references: Used by James Morris Bsc MscManfredini, R., Manfredini, F., Fersini, C., andConconi, F. (1998). Circadian Rhythms, AthleticPerformanceand Jet Lag. British Journal of SportsMedicine, 32,101-106.Reilly, T., Atkinson, G., and Waterhouse, J. (2000).Chronobiology and Physical Performance.W.E.Garrett, J.R. and D.T. Kirkendall. (Eds.), Exercise andSports Science. Philadelphia: Lippincott Williamsand Wilkins.
NoteConcurrent Strength and Endurance Training (Crosscontamination or Complex Interference Effect) needsto be understood. (See table)Several studies have indicated that there is anincompatibility between simultaneous high-intensitystrength and endurance training such that maximalstrength and power appear to be limited. A shortarticle will appear later that will look at the researchinto this area.
I think an extract from an article on the body’s naturalrhythms by James Morris BSc, MSc, BASES carryingthe RFU badge, summarises this article very well.
These results are further confirmed by the followingcomments from Dr Calvin Morriss Head NationalFitness Coach with British Rugby Football Union on06.08.07“We are aware that some people advocate earlymorning training, UK Rugby Union do not. An earlystart is 10am. The players will have been awakebreakfasted and alert for over two hours by that time.The workout they will do will be very light. Such asshoulder mobility and stability work, nothing stressful.Their strength work in the gym is carried out in the lateafternoon” *
From a short news item on BBC Breakfast TV on18.10.07. In a discussion about the England rugbyWorld Cup team it was mentioned that they arealtering their circadian rhythm to fit in with an 8pmkickoff. They are going to bed later and rising later inorder to move their chances of peak performance 3hrslater than normal. The commentators also noted thatOlympic athletes do this and that most World Records
World records set outside the early evening timeframe.My thanks to Ian Tempest of NUTS for this informationGorchakova Women’s JT 62.40 in OG qual 64(10.20am), Gentile TJ 17.10 OG qual 68 (11.10am),Jamaica 4x100 38.6 ht 2 OG 68 (11.05am), TamaraPress 59.70 Women’s DT RUS Champ qual 65(11.30am), Bondarchuk 75.48 HT small meet atRovno 69 (11.30am), Ter-Ovanesyan 8.35 LJ in 67(11.00am) Fatima Whitbread JTQ (9.19am) Plus anumber of marathon records. Obviously there areother contributors to the endurance needs, but theywill notbe discussed here.
Although some early studies had reported little effectof circadian rhythm on athletic performance (37), theweight of more recent research suggests that for highintensity aerobic/anaerobic and in particular strengthtraining, circadian rhythms significantly affects
performance potential. The obvious question forathletes and coaches therefore is how they can theycan train in harmony with this rhythm to maximiseperformance, in the safest manner.
Here are some suggestions:Initially you could measure your own circadian rhythm;this is best done by taking your temperature every twohours during a rest day following several days of anormal, regular sleep pattern. Plot the figures andobserve when the peak occurs (normally lateafternoon/early evening);
Try where possible to schedule important and/orstrenuous workouts within an hour or so of circadianpeak; you will almost certainly gain quality overattempting the same workout earlier in the day;
Early morning workouts should be performed withcaution at a gentle pace and a more thorough warm-up being performed to reduce the risk of injury;
Getting up much earlier than usual (i.e. when yourcircadian rhythm is in a trough) to ‘squeeze’ in aworkout may be counterproductive; the quality of theworkout is likely to be reduced, the risk of injury isincreased and you will of course be losing sleep intothe bargain!
Adaptation to hot conditions during a workout seemsto be more efficient during circadian peak; ensureplenty of fluid/hydration during hot morning workouts;Athletes trying to build strength should time workoutsto coincide with their circadian peak; researchsuggests that late afternoon weight training producesa far more favourable post-exercise anabolic hormoneprofile, with higher levels of testosterone and lowerlevels of cortisol (a hormone associated withphysiological stress and muscle tissuebreakdown)(38)
For competition (where the time of the event is usuallyfixed), you may wish to experiment with manipulating
your circadian rhythm so that you’re nearer your peakat the time of the event. This may seem obvious butthere are many major sports that appear to beunaware that circadian rhythms exist let alone what
the are. It has been previously mentioned in this articlethat the same logic applies when competing abroad indifferent time zones ; Unless you’re trying to manipulate your circadianrhythm, try to maintain regular bedtime and wakinghours; irregular hours can disrupt circadian rhythm,leading to a generalised drop in performance.With thanks to Andrew Hamilton BSc, MRSC, aconsultant to the fitness industry and an experiencedscience writer
References37. Int J Sports Med 1997 Oct; 18(7):538-42
38. Chronobiol Int 2004 Jan; 21(1):131-46
My thanks to all who gave their time to discuss thissubject with me and my dear wife Linda for proofreading. Mike Lauro, USA, for his continued supportand encouragement.
With Notes from America, (Apologies to Alistair
Cook)
What is Circadian Rhythm and what does it have to dowith football?A paper on Circadian Rhythms by, Thispaper confirms the many observations in this paper.They confirm that it is our daily clock, which tells usnot only when we wake and when we sleep, but alsoincludes frequency of eating and drinking, bodytemperature, blood pressure, release of certainhormones, and even sensitivity to certain medications.
A quick summary tells us: The typical adult humancycle is about 24 hours. Starting in the morning, ourlowest body temperature is around 4:30 a.m., andpeaks around 7 p.m. We are highly alert around 10a.m., our best coordination is mid-afternoon around2:30 p.m., followed by peak reaction time at 3:30 p.m.and, here’s the important one—greatestcardiovascular and muscle strength is around 5 p.m.
Using circadian rhythms has been a better predictor ofMonday night NFL wins than Las Vegas odds. Onestudy evaluated 25 NFL seasons to see ifperformance on Monday night was affected by timezone. Because game start time was typically 9 p.m.ET during this review, the East Coast team wasplaying much later than their peak cardiovascular andstrength time of 5 p.m., while the West Coast teamshad the clock advantage. Even when the West Coastteams traveled to the East’s field, the home team stilllost to the circadian clock advantage.
1. Smolensky M, and Lamberg L., ‘The Body ClockGuide to Better Health: How to Use your Body’sNatural Clock to Fight Illness and Achieve MaximumHealth’ 1 st edition. New York: Henry Holt and Co; June14, 2000.
2. Smith Roger S., Guilleminault Christian, EfronBradley. Sport, Sleep, and Circadian RhythmsCircadian Rhythms and Enhanced AthleticPerformance in the National Football League. Feb.1997. Date accessed 7 Oct. 2012
