Illinois State University Exercise and Pregnancy What are the common responses and adaptations we see in the pregnant exerciser?

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Cardiovascular system: l Cardiac output –rapid increase in 1st two trimesters –levels off in 3rd –30-50% above normal –increased stroke volume –greater strain on heart during exercise

Illinois State University Cardiovascular system: l Blood flow distribution –increased flow to surface –increased renal, pulmonary, and uterine blood flow –decreased total peripheral resistance and increased peripheral blood flow –decreased venous return –exercise helps with venous return

Illinois State University Cardiovascular system: l Blood pressure –decreased SBP and DBP during 1st two trimesters

Illinois State University Cardiovascular system: l Blood volume –increases 50% by end of 2nd trimester –increased plasma volume

Illinois State University Pulmonary System l Diaphragm elevates –FRC decreases by 25% due to decreased ERV and RV –hyperventilation occurs at rest due to increased progesterone levels and changes in the threshold of the respiratory centers.

Illinois State University Metabolic System: l Slight increase in blood acidosis l Increase in resting VO 2 and VCO 2

Illinois State University Metabolic System: l Metabolic rate is increased l Increased use of carbohydrates as fuel l result – increased VO 2 at any given workload – increased O 2 debt (EPOC)

Illinois State University Musculoskeletal System: l Increased joint laxity (relaxin) l Stretching and thinning of abdominal wall

Illinois State University Musculoskeletal System: l Forward shift in c of g and anterior rotation of pelvis l Proprioception and coordination are adversely effected

Illinois State University Benefits of Exercise to the Pregnant Woman l 1. Facilitate a general feeling of well-being. l 2. Control of body composition. l 3. Maintenance or development of optimal posture. l 4. Decrease in the minor discomforts of pregnancy. l 5. Promotes pelvic floor strength.

Illinois State University Benefits of Exercise to the Pregnant Woman l 6. Maintain or improve aerobic conditioning. l 7. Maintain or improve strength and/or flexibility. l 8. Facilitate general recovery after delivery. –Decrease by 1/2 post partum recovery days. l 9. Improved tolerance during delivery.

Illinois State University Benefits of Exercise to the Pregnant Woman l 10. Improved physiologic adaptations to pregnancy. l 11. Improved ability to dissipate heat. l 12. Limits the pregnancy related increase in peripheral insulin resistance.

Illinois State University Risks to the Mother: l 1. Risks of injury due to overuse. l 2. Increased potential for fatigue. l 3. Joint injury. l 4. Redistribution of cardiac output. l 5. Thermoregulatory problems.

Illinois State University Latest Research l Most women increase body mass by 20% during pregnancy.

Illinois State University Latest Research l Supine exercise doesn’t create abdominal hernias. –Abdominal recover within 6 weeks.

Illinois State University Latest Research l Cardiac remodeling occurs. –VO2 Max higher weeks post-partum.

Illinois State University Latest Research l Birth occurs 5-7 days earlier. –No increased incidence of premature birth.

Illinois State University Latest Research l Higher rate of normal delivery. –Quicker recovery post-partum.

Illinois State University Latest Research l Decreased feelings of stress.

Illinois State University Latest Research l Increased fitness and muscle tone.

Illinois State University Latest Research l Improved bladder control.

Illinois State University Risks to the Baby: A. Heat Stress: l 1. Heat stress and malformation (animal studies). l 2. Heat stress and malformation in saunas in humans during early pregnancy.

Illinois State University Risks to the Baby: l 3. With exercise there is an increase in skin temperature with minor increases in core temperature. l 4. Exercising studies have not shown the correlation between heat stress and malformation.

Illinois State University Risks to the Baby: B. Oxygen Delivery: l 1. Animal studies show conflicting results. l 2. Body can adapt to make-up for decreased blood flow - increase hemoconcentration and better extraction.

Illinois State University Risks to the Baby: C. Fetal Heart Rate Changes: l 1. Conflicting results. l 2. Increased HR during start of exercise then it levels off.

Illinois State University Risks to the Baby: l 3. No adverse effects. l 4. Trained women show less uterine blood flow.

Illinois State University Risks to the Baby: D. Decreased Blood Flow: l 1. Animals suggest there is a relationship between exercise and low birth weight.

Illinois State University Risks to the Baby: l 2. This does not seem to be a problem in rationally trained women. l 3. No relationship between exercise and miscarriage.

Illinois State University Guidelines for Exercise l 1. Medical and exercise history of the individual. l 2. Questions or unusual symptoms –bleeding, dizziness, – cramping, joint pain – faintness, elevated blood pressure, – STOP exercising and consult physician.

Illinois State University Guidelines for Exercise l 3. Listen to your body. l 4. Expect some discomfort.

Illinois State University Guidelines for Exercise l 5. Exercise regularly. l 6. Do not exercise vigorously in hot humid weather.

Illinois State University Guidelines for Exercise l 7. Do not exercise at all during an illness with fever.

Illinois State University Guidelines for Exercise l 8. Avoid high impact activities. l 9. Drink plenty of fluids.

Illinois State University Guidelines for Exercise l 10. Rise slowly from down positions. l 11. ACOG recommends that the HR not exceed 140 bpm.

Illinois State University Guidelines for Exercise l 12. Avoid the valsalva maneuver.

Illinois State University Guidelines for Exercise l 13. Do not begin a new fitness program. l 14. Follow basic fitness principles.

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