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THE RELATIONSHIP BETWEEN YEAR THE RELATIONSHIP BETWEEN YEAR OF PROGRAM COMPLETION AND OF PROGRAM COMPLETION AND
FREQUENCY OF EXERCISE IN FREQUENCY OF EXERCISE IN CARDIAC REHABILITATION CARDIAC REHABILITATION
PATIENTSPATIENTS
Robert C. Lowe, MA, FAACVPR
Wellness Research Center
University of Central Florida
IntroductionIntroduction• We previously reported that physical
activity (PA) returned to near baseline by 6 and 12 mo. following an intensive cardiac risk intervention program (Lowe, et. al, 1998).
• In addition, there was a shift in exercise patterns (EP) from high to moderate intensities (Lowe & Williams, 2000).
• Both increased PA and EP have been implicated in the primary and secondary prevention of coronary artery disease (CAD).
PurposePurpose
The purpose of this study was to determine if the years since program completion (YEARS) influence frequency of “vigorous” aerobic exercise (FREQ).
Null HypothesisNull Hypothesis
YEARS since graduation will not influence the FREQ of “vigorous” physical activity.
MethodsMethods• Annual cardiac rehab survey yielding
731 responses between the years of 1994 – 1998.
• Variables of interest:• YEARS since program completion• FREQ of exercise per week
“In the past 3 months how often did you exercise aerobically for 20-30 minutes in your training heart rate zone per week?”
Subject CharacteristicsSubject Characteristics• Age, 62±11 yr.• Completed cardiac rehab program
• Exercise• Diet• Classes
• Average YEARS since completion of program, 4.3±2.3 yr.
• Average FREQ of 2.5±1.1 exercise sessions per week
StatisticsStatistics
• The relationship between FREQ and YEARS was explored by linear regression.
• Data was analyzed by one-way ANOVA and Sheffé post-hoc tests.
• The level of significance was set at p < 0.05.
ResultsResults
• The linear relationship between FREQ and YEARS was significant (F= 20.97, df=730, p < 0.05).
Prediction Equation
• FREQ = 2.16 + 0.167[YEARS]• Where YEARS = 1,2,3,4,5,6,7,8
ResultsResults
ANOVA
FREQ
38.605 7 5.515 4.470 .000
20.534 1 20.534 16.643 .000
26.027 1 26.027 21.095 .000
12.578 6 2.096 1.699 .118
892.021 723 1.234
930.627 730
(Combined)
Unweighted
Weighted
Deviation
Linear Term
BetweenGroups
Within Groups
Total
Sum ofSquares df Mean Square F Sig.
YEAR 1 2 3 4 5 6 7 8
FREQ 2.15a 2.37 2.67 2.56 2.37 2.74 2.62 2.85b
a different from YEARS 2-8; b different from YEARS 1-7
ResultsResults
124 9458109 93907093n
ResultsResults
TIME since completion
87654321
Me
an
of
FR
EQ
of
vig
oro
us
exe
rcis
e p
er
we
ek
3.0
2.8
2.6
2.4
2.2
2.0
ConclusionsConclusions
• The results indicated that YEARS since program completion significantly predicted FREQ.
• Further, FREQ was significantly greater 8 years post-cardiac rehab compared to 1 year post-cardiac rehab.
CaveatsCaveats
• Data is by self-report.• No information regarding diagnosis at
entry. • New medications, treatments,
diagnoses.• Seasonal fluctuations in PA• Did not construct the survey.• Not a random sample.
DiscussionDiscussion
• The amount and intensity of physical activity of this group of post-cardiac rehab patients is likely to be less than has been shown to reverse CAD.• 5 sessions x 30 minutes = 150 minutes per
week• On the average subjects performed 2.5
sessions x 30 minutes = 75 minutes per week
DiscussionDiscussion
• Lifestyle Heart Trial: 1990• Low fat diet: 10% Fat• Moderate exercise: > 30 minutes• Daily stress managementResults:• Treatment group showed 3.1% decreased
coronary blockage over 5 years versus 11.8% increased blockage in the control group
• Subjects who showed the most improvements exercised 5-7 hours per week
Ornish D, Brown SE, Lancet. 336: 129-133, 1990.
DiscussionDiscussion
Tests of Between-Subjects Effects
Dependent Variable: INTERVEN
35.541b 40 .889 2.265 .000 .117 90.616 1.000
3.316 1 3.316 8.456 .004 .012 8.456 .827
17.880 7 2.554 6.513 .000 .062 45.588 1.000
2.897 5 .579 1.477 .195 .011 7.387 .522
8.910 28 .318 .811 .744 .032 22.717 .756
268.272 684 .392
349.000 725
303.812 724
SourceCorrected Model
Intercept
GRAD
FREQ
GRAD * FREQ
Error
Total
Corrected Total
Type III Sumof Squares df Mean Square F Sig.
Partial EtaSquared
Noncent.Parameter
ObservedPower
a
Computed using alpha = .05a.
R Squared = .117 (Adjusted R Squared = .065)b.
DiscussionDiscussionRevascularization by PTCA or CAB
Years Since Completion
87654321
Estim
ate
d M
arg
ina
l M
ea
ns
1.4
1.2
1.0
.8
.6
.4
.2
0.0
-.2
Exercise FREQ
1
2
3
4
5
DiscussionDiscussion• It is recommended that future research
focus on interventions designed to increase PA.