Chapter 10 Physical Activity and Diabetes. Types of Diabetes Type 1 Diabetes Type 2 Diabetes...

Chapter 10

Physical Activity and Diabetes


Types of Diabetes

Type 1 Diabetes Type 2 Diabetes Gestational Diabetes

Source = WHO (World Health Organization)



Diabetes Defined

Type 1 Diabetes

Type 1 diabetes is a chronic (lifelong) disease that occurs when the pancreas does not produce enough insulin to properly control blood sugar levels.




Type 1 Diabetes In this type of diabetes, cells of the pancreas produce little or no insulin, the

hormone that allows glucose to enter body cells. Without enough insulin, glucose builds up in the bloodstream instead of

going into the cells. The body is unable to use this glucose for energy despite high levels in the bloodstream. This leads to increased hunger.

In addition, the high levels of glucose in the blood cause the patient to urinate more, which in turn causes excessive thirst. Within 5 to 10 years, the insulin-producing beta cells of the pancreas are completely destroyed and the body can not longer produce insulin.

Type 1 diabetes can occur at any age, but it usually starts in people younger than 30. Symptoms are usually severe and occur rapidly.

Source = NIH / Medline



Signs and symptoms of Diabetes (All Types): unusual thirst (polydipsia), excessive hunger (polyphagia), frequent urination (polyuria), unusual weight loss (emaciation), extreme fatigue or lack of energy, blurred vision, frequent or recurring infections, cuts and bruises that are slow to heal, tingling &/or numbness in hands &/or feet.

Source = TCM Health



Diabetes Defined

Type 2 Diabetes

Type 2 diabetes is a life-long disease marked by high levels of sugar in the blood. It occurs when the body does not respond correctly to insulin, a hormone released by the pancreas. Type 2 diabetes is the most common form of diabetes.




Type 2 Diabetes This type of diabetes is accompanied by insulin resistance. Insulin resistance

means that insulin produced by your pancreas cannot get inside fat and muscle cells to produce energy. Since the cells are not getting the insulin they need, the pancreas produces more and more. Over time, abnormally high levels of sugar build up in the blood. This is called hyperglycemia. Many people with insulin resistance have hyperglycemia and high blood insulin levels at the same time. People who are overweight have a higher risk of insulin resistance, because fat interferes with the body's ability to use insulin.

Type 2 diabetes usually occurs gradually. Most people with the disease are overweight at the time of diagnosis. However, type 2 diabetes can also develop in those who are thin, especially the elderly.

Family history and genetics play a large role in type 2 diabetes. Low activity level, poor diet, and excess body weight (especially around the waist) significantly increase your risk for type 2 diabetes.




Gestational Diabetes

Gestational diabetes is a glucose intolerance of variable severity that starts or is first recognized during pregnancy.




Gestational Diabetes Gestational diabetes is usually diagnosed during the 24th to 28th weeks of

pregnancy. In many cases, the blood glucose level returns to normal after delivery.

It is recommended that all pregnant women be screened for gestational diabetes during the 24th and 28th weeks of their pregnancy. The symptoms are usually mild and not life-threatening to the pregnant woman.

However, the increased maternal glucose (blood sugar) levels are associated with an increased rate of complications in the baby, including large size at birth, birth trauma, hypoglycemia (low blood sugar), and jaundice. Rarely, the fetus dies in the womb late in the pregnancy.

Maintaining control of blood sugar levels significantly reduces the risk to the baby.

Gestational diabetes occurs in up to 10% of pregnancies and costs an estimated $623 million in 2007

Additional Source = NIH / Medline



Gestational Diabetes A diagnosis of gestational diabetes requires at least two

of the following plasma glucose values: •Fasting: ≥92 mg/dL (5.1 mmol/L) •Or the following glucose levels after a glucose tolerance

test •1 h: ≥180 mg/dL (10.0 mmol/L) •2 h: ≥153 mg/dL (8.5 mmol/L)



Health Complications of Diabetes Emergency complications include:

Ketoacidosis (burning fat for fuel) Hypoglycemia (low blood sugar)

Long-term complications include: Vascular disease, including blocked arteries and heart attacks -- risk can be

reduced by treating high cholesterol and blood pressure, exercising regularly, and avoiding or quitting tobacco products

Eye problems, including diabetic retinopathy , retinal detachment, glaucoma, and cataracts

Kidney disease (diabetic nephropathy) Nerve damage (diabetic neuropathy) Foot problems, including skin changes Infections of the skin, female genital tract, and urinary tract




Clinical Tests for Diabetes Glucose tolerance test: Detects elevated serum glucose usually 2 h after oral ingestion of typically 75

mg of glucose. a positive test indicates inadequate insulin response or insulin insensitivity, but this test is not always accurate because it is influenced by pre-examination diet.

Home glucose monitoring: Is usually done over four to seven days and is more reliable than a

glucose tolerance test. •Glycosylated hemoglobin: Measures the binding of glucose with the iron in red blood cells—that

is, glycosylated hemoglobin (HbA1c). this is the most accurate test because it is not affected by acute plasma changes and is related to long-term exposure (i.e., two to three months) of red blood cells to glucose during their 120-day life span in the circulation.





Magnitude of the Problem: National Diabetes Statistics Demographics of Diabetes The Centers for Disease Control and Prevention (2011)

estimated that in 2010 the prevalence of diabetes in the United States was about 12.6 million women, 13 million men, 215,000 children and adolescents, and 10.9 million older adults 7.1% of non-Hispanic whites 8.4% of Asian Americans 12.6% of non-Hispanic blacks 11.8% of Hispanics 7.6% for Cubans 13.3% for Mexican Americans 13.8% for Puerto Ricans


Magnitude of the Problem: National Diabetes StatisticsCOSTSThe economic burden of diabetes in the United States is great, $174 billion in 2007: $116 billion in direct medical costs and another $58 billion for disability and work loss ($39 billion) and premature death ($1 If ancillary costs associated with undiagnosed diabetes, pre-diabetes, and gestational diabetes are added, the total cost of diabetes in the United States in 2007 approximated $218 billion annually 9 billion).


Magnitude of the Problem: National Diabetes StatisticsPrevalenceThe United States has the third highest number of cases (about 26 million) and the second highest prevalence rate of diabetes among adults 20 to 79 years old in the world.According to estimates by the U.S. Centers for Disease Control and Prevention, nearly 19 million American children and adults say they have been told by a doctor that they have diabetes, but another 7 million people who have diabetes have not yet been diagnosed


Complications of Diabetes

Diabetic Neuropathy Neuropathies are the most common complication

of diabetes mellitus (DM). Neuropathies related to DM affect up to 50% of patients both with type 1 and type 2 DM. Neuropathies also cause great morbidity because the symptoms severely decrease patients' quality of life (QOL). While the primary symptoms of neuropathy may be highly unpleasant, the secondary complications such as falls, foot ulcers, cardiac arrhythmias can lead to chronic morbidity and even mortality

Source = eMedicine.com



Diabetic Retinopathy (increases risk for glaucoma and cataracts)

Diabetic retinopathy is result of microvascular retinal changes. Small blood vessels – such as those in the eye – are especially vulnerable to poor blood sugar control. An over accumulation of glucose and/or fructose damages the tiny blood vessels in the retina.

As the disease progresses, severe non-proliferative diabetic retinopathy enters an advanced, or proliferative, stage. Without timely treatment, these new blood vessels can bleed, cloud vision, and destroy the retina.

Source = wikipedia.org



Renal Disease Hyperfiltration causes protein albumin begin to leak

into the urine. As the amount of albumin in the urine increases,

filtering function usually begins to drop. The body retains various wastes as filtration falls. As kidney damage develops, blood pressure often

rises as well. Overall, kidney damage rarely occurs in the first 10

years of diabetes, and usually 15 to 25 years will pass before kidney failure occurs. For people who live with diabetes for more than 25 years without any signs of kidney failure, the risk of ever developing it decreases.

Source = kidney.niddk.nih.gov



Pregnancy Complications About 1 to 3% of pregnant women develop

diabetes during pregnancy. This disorder is called gestational diabetes. Unrecognized and untreated, gestational diabetes can increase the risk of health problems for pregnant women and the fetus and the risk of death for the fetus. Gestational diabetes is more common among obese women and among certain ethnic groups, particularly Native Americans, Pacific Islanders, and women of Mexican, Indian, and Asian descent.

Source = www.merck.com


Risk Factors for Diabetes

You have a higher risk for diabetes if you have any of the following:

Age greater than 45 years Diabetes during a previous pregnancy Excess body weight (especially around the waist) Family history of diabetes Given birth to a baby weighing more than 9 pounds HDL cholesterol under 35 High blood levels of triglycerides, a type of fat molecule

(250 mg/dL or more) High blood pressure (greater than or equal to 140/90

mmHg) Impaired glucose tolerance Low activity level Poor diet

Source = www.nlm.nih.gov/medlineplus


Risk of Diabetes

Persons from certain ethnic groups, including African Americans, Hispanic Americans, and Native Americans, all have high rates of diabetes

Everyone over 45 should have their blood glucose checked at least every 3 years. Regular testing of random blood glucose should begin at a younger age, and be performed more often if you are at higher risk for diabetes.

Source = www.nlm.nih.gov/medlineplus


Etiology of Diabetes Mellitus Type 2

Is a metabolic disorder that is primarily characterized by insulin resistance, relative insulin deficiency, and hyperglycemia.

If high insulin levels compensate for the increased insulin resistance, then the person maintains normal glucose tolerance, otherwise the early stages of impaired glucose tolerance [IGT] (a pre-diabetic state of dysglycemia ) begin.

The transition from IGT to diabetes occurs when insulin resistance becomes severe and pancreas dysfunction of insulin production occurs

Reduction of IGT occurs via weight loss and exercise


Effects of Physical Activity on Diabetes: The Evidence

Summary Physical activity could potentially contribute to

primary (reducing the initial occurrence), secondary (reversal), and tertiary (delay of medical complications) prevention and treatment of diabetes.

Exercise improves: Glucose transport Insulin sensitivity Chronic complications in Type 2 Diabetes



Cross Sectional Studies Kiribati

Study of Micronesians Urban population (Lower activity profile and

heavier) had 3x the prevalence of Type 2 diabetes compared to the rural population.

Mauritius Fasting blood glucose levels and 2-hr plasma

glucose and serum insulin levels after glucose tolerance test (GTT) lower in active subjects of both sexes, independent of BMI.



Cross Sectional Studies Pima Indians

The Pima Indians have the highest known incidence of Type 2 Diabetes in he US.

Physical activity was inversely related to fasting glucose levels and 2-hr glucose levels following GTT.

After adjustments for BMI 2-hr glucose levels were still lower in physically active

Those in the lower activity groups had higher rates of Type 2 Diabetes



Prospective Cohort Studies (see also Figure 10.8, next slide)

University of Pennsylvania Alumni Study 14 year observational study of male alumni Dose-dependent reduction in risk of developing

Type 2 Diabetes was associated with increasing levels of activity

Age-adjusted risk of Type 2 Diabetes decreased 6% for every 500 kcal/wk increase in activity up to 3500 kcal/wk.

The risk reduction remained after adjusting for obesity.



Figure 10.8 - University of Pennsylvania alumni study examining leisure physical activity with relative risk for type 2 diabetes. the study included 5990 males who were followed for 14 years; age-adjusted risk for type 2 diabetes decreased by 6% for each 500 kcal/week increase in leisure-time physical activity \up to 3500 kcal/wk



Prospective Cohort Studies Nurses’ Health Study

Eight year study of nurses Nurses who exercised at least 1x week had and

age adjusted RR that was 1/3 less than those inactive

The protective effect of exercise intervention (vigorous) was still 0.84 after adjusting for BMI

In the current eight year follow-up of the initial study a linear reduction in risk of Type 2 Diabetes has been found between the least active to the most active groups



Prospective Cohort Studies Physicians’ Health Study

Five year study of physicians Men who exercised at least 1x week had and age

adjusted RR that was 1/3 less than those inactive RR for diabetes decreased to 0.62 for 2-4x

exercise per week; and 0.58 for 5x week The protective effect of exercise intervention

remained after adjusting for BMI



Prospective Cohort Studies British Men

Sixteen year study of men Physical activity was inversely related to risk of

Type 2 Diabetes, and blood insulin levels Because the study examined the insulin

resistance of the liver, it could be concluded that physical activity reduced the risk of Type 2 Diabetes mainly by improving insulin sensitivity .



Prospective Cohort Studies Aerobics Center Longitudinal Study

Eight year study of men Findings of the study suggested that the risk of

early death increases with less favorable blood glucose levels and that improved fitness levels might reduce all-cause mortality associated with impaired glucose metabolism.



Prospective Cohort Studies Malmo Sweden

Six year study of men Those who contracted Type 2 Diabetes had:

Higher BMI’s Positive Family History Lower levels of physical activity / aerobic fitness 3x higher 2-hr GTT values

Hyperinsulinemia, BMI, and fasting blood glucose levels were independent risk factors for Type 2 Diabetes

Both physical fitness and the level of physical activity were associated with lowered risk of developing Type 2 Diabetes.



Prospective Cohort Studies Women’s Health Initiative Study 86,000+ Cohort of Women White women had a 20% to 33% reduction in

risk if they were in the top 60% of total physical activity and a 25% reduction in risk if they were in the top 40% of walking when compared with the 20% least-active women

Similar trends of lower risk with higher physical activity were found among African American and Hispanic women


Prospective Cohort Studies Women’s’ Health Study of 37,878 U.S. female

health care professionals without CVD, cancer, or diabetes at baseline, 1361 incident cases of self-reported diabetes were observed during nearly seven years of follow-up.

Women who were classified as active expended more than 1000 kcal per week in leisure-time physical activities and had a 15% reduction in diabetes risk

The benefit of physical activity was not independent of obesity - Walking 2 to 3 h each week reduced risk by more than one-third in overweight and obese women, but not in women who were normal weight.



Prospective Cohort Studies Losartan Intervention for Endpoint Reduction

in Hypertension (LIFE) Study - Physical activity was measured in 4961 women and 4232 men aged 55 to 80 years from multiple countries.

Patients who said they got more than 30 min of exercise twice per week (52% of the patients) at entry into an antihypertensive drug intervention had 25% to 40% lower risk of incident diabetes during nearly five years of treatment, regardless of which drug they took.



Prospective Cohort Studies Walking and Mortality Risk in People With

Diabetes A cross-sectional study of adults with diabetes

from the National Health Interview Survey showed that compared with inactive adults, people who walked at least 2 h/week had a 39% lower all-cause mortality rate.

It was estimated that one death each year might be prevented for every 61 people who were previously inactive but then walked 2 or more hours each week.

Effects of Obesity Versus Physical Activity on Risk A recent review (2010) concluded that having high BMI

(30-35 kg/m2) even with high physical activity was a greater risk for the incidence of type 2 diabetes and diabetes risk factors than having normal BMI and low physical activity

A review of five cohort studies published between 1999 and 2008 that examined the joint effects of obesity and physical activity on the risk of type 2 diabetes concluded that the joint effect of obesity and low physical activity was, on average, additive and sometimes more than the sum of their individual effects




Clinical Studies Da Qing, China Randomized Control Trial

Six year follow-up study Those who exercised had ½ the rate of Type 2

Diabetes Intervention groups of diet, exercise, and diet +

exercise, all had significantly lower levels of incidence of Type 2 Diabetes than the control group

Exercise was as effective as diet alone in controlling the incidence of Type 2 Diabetes.


Clinical Studies The Finnish Diabetes Prevention Study Middle-aged, overweight men and women with IGT (n = 522)

were randomized into an intensive lifestyle modification intervention that included leisure-time physical activity, weight reduction, and dietary counseling or into a minimal intervention control group

People who had the biggest increases (top third) in moderate-to-vigorous physical activity or strenuous, structured exercise were 50% to 60% less likely to develop diabetes than people in the bottom third

The amount of risk reduction was about 50% for people who met the weight loss goal and nearly 40% for people who met the physical activity goal.



Clinical Studies U.S. Diabetes Prevention Program

45% of participants were ethnic minorities RR of Type 2 Diabetes decreased with

administration of oral hypoglycemic, but not as much as with diet and exercise therapy

The diet and exercise led to an average weight loss of 15 lbs. in the first year of study.



Clinical Studies Enhanced Glycemic Control in People With

Type 2 Diabetes Multiple meta-analysis studies / follow-ups all

demonstrated significant reductions HbA1c levels in the exercise groups (aerobic and resistance training programs), when compared with control patients

Reductions were larger in subjects who exercised longer



Clinical Studies Look AHEAD Trial - The Look AHEAD (Action for

HEAlth in Diabetes) study was a multicenter, randomized controlled trial of 5145 overweight adults (45-74 years old) with type 2 diabetes designed to compare a lifestyle intervention to achieve and maintain weight loss through diet and increased physical activity with a diabetes support and education condition.

After one year of the intervention, people in the weight loss group lost an average 8% of their weight and had reductions in diabetes, hypertension, and lipid-lowering medicines. Mean HbA1c dropped from 7.3% to 6.6%. Triglycerides and high-density lipoprotein cholesterol also improved.


Effects of Physical Activity on Diabetes: Strength of the Evidence

Temporal Sequence Physical activity reduces the risk of Type 2

Diabetes and improves glucose control in people with IGT or Type 2 Diabetes

Strength of the Association Regular, vigorous physical activity is associated

with a 25-50% reduction in the risk of the development of Type 2 Diabetes.

Consistency Exercise decreases the risk of Type 2 Diabetes

across ethnic groups, and age groups regardless of the initial fitness level


Dose Response There is not enough controlled clinical studies to permit a

clear consensus about the amount or intensity of physical activity the improves glucose control among Type 2 Diabetics

There are improvements in insulin sensitivity with increasing levels of physical activity

Figure 10.13 (next slide) shows that after adjustment for age, sex, ethnicity, dietary fat, alcohol intake, and smoking, insulin sensitivity among people who reported vigorous physical activity five or more times a week was significantly higher than that of people who reported that they rarely or never participated in vigorous physical activity


Figure 10.13 - Insulin sensitivity according to frequency of self-reported participation in vigorous physical activity. adjusted for ethnicity, clinic, age, sex, alcohol intake, smoking, dietary fat, and hypertension.



Biological Plausibility Acute Effects of Exercise

Increased hepatic glucose uptake Increased glucose uptake in the muscle Increased lipolysis of Free Fatty Acids from Adipose

Tissue Decreased insulin secretion:

Increased epinephrine secretion Increased glucagon Increased growth hormone Increased cortisol



Biological Plausibility Chronic Effects of Exercise

Decreased circulating insulin Improved glucose tolerance Increased insulin receptors in skeletal muscle Increase insulin sensitivity


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Chapter 10 Physical Activity and Diabetes. Types of Diabetes Type 1 Diabetes Type 2 Diabetes...

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