Exercise Diabetic Pregnancies

E. Albert Reece, M.D., Ph.D., M.B.A.Dean and Vice Chancellor

College of MedicineUniversity of Arkansas for Medical Sciences

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Benefits of Exercise 30 minutes of moderate

activity a day has many health benefits:

• Exercise increases muscular strength

• Exercise improves lung capacity

• Exercise helps to control weight

• Exercise helps to maintain and may increase bone density

Benefits of Exercise - 2

• Exercise protects against a variety of diseases:- Heart disease- Stroke- High blood pressure- Osteoporosis- Diabetes

• Exercise has several mental health benefits:- Lowers stress- Boosts mood- Improves self-esteem

Metabolic Effects of Exercise

• Each day, 60-75% of total caloric expenditure is used to maintain our resting metabolic rate

• Only about 15-30% of energy expenditure is used for physical activity

• Exercise facilitates glucose utilization secondary to increase in insulin binding and affinity to its receptor

Metabolic Effects of Exercise - 2

• Effects of exercise on lipids:

- Cholesterol drops 4-72 hours after intensive prolonged exercise

- Plasma triglyceride falls acutely after isolated exertion, possibly secondary to increase in lipoprotein activity with secondary catabolism of triglyceride

Oscai et al., Am J Cardiol 1981

Metabolic Effects of Exercise - 3

Protein Synthesis

Stored in:

Lipid Synthesis

Lipolysis

Gluconeogenesis

Skeletal Muscle

Liver

Adipose Tissue

Pancreas

Islets of Langerhans

Beta CellProinsulin

Amino AcidsGlucose

Circulatory System

Insulin

GlucoseInsulin Amino Acids

Insulin Production

and Effects

Metabolic Effects of Exercise - 4

• Effects of exercise on plasma glucose uptake:

- Glucose uptake remains unchanged during brief, moderate exertion

- Glucose uptake rises 15-20% during intense exertion and falls gradually during prolonged moderate work

- Glucose uptake continues to rise transiently after exhaustive exercise and remains elevated

up to 30 minutes later

Wahren, et al., JCI 1971Wahren, Diabetes, 1979

Metabolic Effects of Exercise - 5

- Plasma glucose is maintained by 2-5-fold increase in hepatic glucose production, which is secondary to gluconeogenesis as duration of exertion increases

- Glucose uptake by muscle increases linearly with exercise duration and intensity, reaching 50 times resting values at maximum effort

- Increase in glucose uptake occurs at very low insulin concentration, but not in the absence of circulating insulin

Calles, et al., Diabetes 1983Katz, et al., AJP 1986Berger, et al., JAPPL Physiol, 1989

Metabolic Effects of Exercise - 6

- Glucose uptake increases after exertion in exercised muscle vs. non-exercised muscle for 4 hrs

- Glucose uptake is not studied in insulin- resistant pregnant diabetic women

Katz, et al., AJP 1986Berger, et al., JAPPL Physiol, 1989

Physiologic Changes Associated with

Pregnancy• Hemodynamic changes include increase in

cardiac output, ventilation and oxygen consumption

• Hyperventilation occurs normally; arterial CO2 is 10 mmHg lower postpartum

• Edema of lower extremities and shift in center of gravity

Physiologic Changes Associated with Pregnancy - 2

• Ligaments that support the joints become more relaxed – joints become more mobile and are at greater risk for injury

• Center of gravity shifts and places stress on joints and muscles, especially in the pelvis and lower back

Benefits of Exercise During Pregnancy

Almost all women should be physically active during pregnancy. Thirty minutes of moderate exercise a day can provide many benefits:

• Exercise during pregnancy may help to prevent gestational diabetes

• Exercise can help pregnant women to have easier, shorter labor

ACOG, “Exercise During Pregnancy” pamphlet, 2003

Benefits of Exercise During Pregnancy - 2

• Exercise can promote faster recovery from delivery

• Exercise can help to reduce pregnancy-related discomforts:- Back aches- Leg cramps- Constipation- Bloating and swelling

• Exercise can help to improve mood and energy levels

ACOG, “Exercise During Pregnancy” pamphlet, 2003

Safety of Exercise in Pregnant Women

• Studies suggest exercise may trigger premature labor, mediated through enhanced uterine activity

• Some investigators found no effect on prevalence of uterine contractions during exercise

Safety of Exercise in Pregnant Women - 2

• One report suggests increased incidence of prematurity and IUGR among mothers who stood while working vs. sedentary workers

• U.S. collaborative perinatal project reported reduction in mean birth weight in infants of women who had jobs that required standing

Veille, et al., AJOG, 1985

Safety of Exercise in Pregnant Women - 3

• Most researchers use fetal heart rate as an indicator of fetal distress and as a criterion for disturbances in fetal gas exchange

• Some researchers have observed marked fetal bradycardia during or after exercise; others have not

• Controversy exists about analysis and interpretations of fetal bradycardia

Artal, et al., Lancet 1984Collings, AGOG 1985Dale Can JAPPSports SCI 1982

Safety of Exercise in Pregnant Women - 4

Jovanovic Study on Safety• Healthy women were recruited to exercise on 5

types of equipment that monitored blood pressure, fetal heart rate and uterine activity

• Bicycle exercise caused uterine contractions (50% of 25 sessions)

• Walking on treadmill produced contractions when pace quickened to a jog (40% of 10 sessions)

Durak and Jovanovic, AJOG, 1990

Safety of Exercise in Pregnant Women - 5

Jovanovic Study on Safety• Rowing associated with fewer problems if seat

was fixed and arms did most of the work (10% of 68 sessions)

• Recumbent bicycle exercise did not cause contractions (0% of 20 sessions)

• Conclusion: upper arm exercises proved to be the safest and most accepted mode of exercise in pregnancy

Durak and Jovanovic, AJOG, 1990

Guidelines for Exercising

During Pregnancy• Maternal heart rate should not exceed

140 beats per minute

• Strenuous activities should not exceed 15-min duration

• No exercise should be performed in the supine position after the first trimester of gestation

• Avoid standing still for long periods of time

Guidelines for Exercising During Pregnancy - 2

• Pregnant women should be evaluated individually with respect to exercise program

• Diabetes is a relative contraindication to vigorous physical activity

• Other contraindications include risk factors for preterm labor, vaginal bleeding and premature rupture of membranes

• Little data exist regarding efficacy of exercise in pregnancy complicated by Type 1 diabetes

Choosing Safe Exercises During Pregnancy

According to ACOG, many forms of exercise are safe during pregnancy.

• Each woman should consult her doctor for appropriate exercises

• Beginners may start with as little as 5 min. a day

• Do not exercise until exhaustion.

ACOG, “Exercise During Pregnancy” pamphlet, 2003

Choosing Safe Exercises During Pregnancy – 2

• Warning signs of overexertion:

- Vaginal bleeding

- Dizziness

- Increased shortness

of breath

- Chest pain

- Headache

ACOG, “Exercise During Pregnancy” pamphlet, 2003

- Muscle weakness

- Calf pain or swelling

- Uterine contractions

- Decreased fetal

movement

- Fluid leaking from

the vagina

Choosing Safe Exercises During Pregnancy - 3

• Exercises generally considered to be safe- Walking: gives a total body workout- Swimming: water supports body weight, avoids

muscle strain- Cycling: provides good aerobic workout; stay with stationary or recumbent biking in late pregnancy- Aerobic classes: low-impact and water aerobics

ACOG, “Exercise During Pregnancy” pamphlet, 2003

Exercise in Women With Type 2 Diabetes

Moderate, sustained exercise can:• Decrease blood glucose concentrations• Lower plasma insulin concentration in

both fasting and postprandial states• Increase insulin sensitivity• Improve lipid profile• Reduce hypertension, independent of

weight loss or change in body composition

Results from two studies differ, describing glucoselevels following exercise:

• Artal and colleagues report a reduction in glucose and free fatty acid levels, but heightened epinephrine and norepinephrine response

• Hollingsworth reports no significant improvement in HBA1 levels

Artel, 1986Hollingsworth, et al., AJOG 1987

Exercise in Women With Type 2 Diabetes - 2

Exercise in Women With Type 2 Diabetes - 3

• Exercise appears to be effective only as long as training is continued

• Physical activity may be effective adjuncts to other weight reduction strategies

• Metabolic effects may be less likely to occur during pregnancy

Gestational Diabetes and Exercise

• Gestational diabetes: carbohydrate intolerance of variable severity with onset or first recognition during pregnancy

• Similarities to Type 2:- Abnormalities of insulin secretion and action- Obesity- Insulin resistance- Abnormal first phase insulin release

• Is a strong predictor (approximately 50%) of later IGT or Type 2

Horten, et al., Diabetes Suppl 1991

Gestational Diabetes and Exercise - 2

Two studies show positive results:

First study:• 20 patients were randomized 2 groups

• One underwent 6 weeks of intensive dietary therapy

• The other followed 6 weeks of dietary therapy with 20 min. of supervised exercise 3x/day for 6 weeks

• All women exercised on arm ergometerJovanovic-Peterson, et al, AJOG, 1989

Gestational Diabetes and Exercise - 3

• Glycemic levels in 2 groups diverged by week 4• By week 6, women in exercise group had

normalized hemoglobin A1, fasting postprandial plasma glucose levels on 50 gm oral glucose challenge

• Women in diet group improved but had severe fasting and postprandial hyperglycemia

Jovanovic-Peterson, et al, AJOG, 1989

Gestational Diabetes and Exercise - 4

Second study• Compared 6 weeks of arm crank exercise to

dietary therapy in gestational diabetes patients with plasma glucose 84-106 mg/dL

• Exertional heart rate was kept at less than 140 and exercise occurred 3 times a week for 20 minutes

• In controls, fasting and plasma glucose fell from 98 to 88, and 1-hr post 50 gm glucose challenge fell from 226-188.

Bung, et al., Diabetes 1991

Gestational Diabetes and Exercise - 5

• Improved glycemia occurred in exercise group• Fasting glucose fell from 100 to 70• 1-hr post 50 gm challenge fell from 231 to 106

mg/dL• Conclusion:

- Exercise results in lower levels of glycemia than diet alone- Significant effects of exercise after only 4 weeks suggests that it could be started even at 28 weeks and still have therapeutic benefit on fetal macrosomia

Complications of Exercise

in Diabetic Pregnant Women• Glucose intolerance of Type 2 is reinforced by

the diabetogenic effects of pregnancy• Effective reduction of fasting and postprandial

glucose levels has not been consistently demonstrated

• Effects of exercise during pregnancy and progression of diabetic vasculopathy is unknown

• ACE inhibitors retard progression of proteinuria without worsening azotemia in patients with nephropathy

Complications of Exercise in Diabetic Pregnant Women - 2

• ACE inhibitors are contraindicated pregnancy secondary to risk of IUGR, fetal loss and neonatal hypotension

• In late pregnancy, venous return and cardiac preload may be reduced after exertion leading to reduced stroke volume and reduced cardiac output

• The effect of autonomic neuropathy on exercise safety is uncertain, especially at moderate exercise intensities

Morton et al., AJOG 1985

Conclusion• One-third of adult women in the U.S. are obese

• Only 1 in 6 pregnant women meet the current physical activity recommendations of 30 or more minutes of moderate physical activity a day

• During pregnancy, obese women are at increased risk for adverse perinatal outcomes- Spontaneous abortion- Gestational hypertension- Preeclampsia- Gestational diabetes- Fetal macrosomia

Johnson K. Ob. Gyn. News, Dec. 2005ACOG Committee Opinion no. 315, Sept. 2005

Conclusion - 2

• Cesarean delivery rate was 20.7% for women with BMI of 29.9 or less; 33.8% w/BMI of 30-34.9; 47.4% w/BMI of 35-39.9

• Studies show that exercise is not associated with: - Early pregnancy loss- Late pregnancy complications- Adverse neonatal outcomes

Johnson K. Ob. Gyn. News, Dec. 2005ACOG Committee Opinion no. 315, Sept. 2005

Conclusion - 3

• Exercise is advocated as treatment for women with GDM

• Those who are inactive or have complications should be evaluated before initiating exercise

• Medical supervision is recommended for all women with diabetes who exercise during pregnancy

Metzger, Diabetes 1991

Dye et al., Am J Epidemiol 1997

Thank You