Exercise And Pregnancy_zanovec

What are the recommendations for physical activity and exercise during pregnancy? Michael Zanovec April 15, 2008

Artal & O’Toole. Br J Sports Med, 2003; 37:6-12.

Overview • • • • • • • • • • •

Key Points Physiological adaptive changes Maternal Benefits from Exercise Research Advising exercise in pregnancy Conditions requiring medical supervision Warning signs to terminate exercise General Guidelines Exercise Prescription Other considerations / activities to avoid Take Home Points

Key Points From the American College of Obstetricians and Gynecologists (ACOG) Committee (2002).

• All women should be encouraged to participate in aerobic and strength-conditioning exercise as part of a healthy lifestyle during pregnancy

• Reasonable goals - maintain maternal fitness levels • Choose activities to minimize risk to developing fetus

• Guidelines tailored to each individual woman • As a woman’s pregnancy changes, so must her exercise regimen • Primary concern with exercise during pregnancy is safety Artal & O’Toole. Br J Sports Med, 2003; 37:6-12.

Physiological adaptations • Weight gain – effects joints and balance • Lumbar lordosis • Increased ligamentous laxity • Increased uterine activity? • Increased risk of preterm labor?

Physiological adaptations • BMR and core temp. ↑ – ↑ risk of hyperthermia • Increased maternal blood volume by 50%

• Cardiac output increases by 30-50% • Decreased systemic vascular resistance

• Total lung capacity decreases by 5% • 30-40% increase in tidal volume and minute ventilation = chronic state of hyperventilation Results in a circulatory reserve necessary to provide nutrients and oxygen to mother and fetus at rest and during moderate-intensity exercise

Benefits of Exercise during Pregnancy • Reduces fatigue and helps manage stress • Increases endurance and strengthening muscles • Help relieve back pressure • Improve posture and balance • Improve circulation & lowers blood pressure • Helps prepare for the strain of labor • Improve self image • Regain figure faster

Exercise Guidelines: Then & Now

Old

vs. New

ACOG 1985: • Limit HR to 140 • No vigorous activity > 15 min

Research – Exercise and Pregnancy • Aerobic fitness can be maintained throughout pregnancy • Women wishing to resistance train need to avoid supine exercises • No relationship demonstrated between activity levels and birth weight

• No human studies have shown that hyperthermia associated with exercise is teratogenic • Fetal heart rate may transiently increase or decrease with maximal exercise but no adverse birth outcomes • Anatomic changes may predispose to musculoskeletal injury

Advising exercise during pregnancy: Steps to beginning an exercise program • Clinical Evaluation ▫ Routine prenatal care is sufficient for monitoring exercise program

• Medical Screening before exercise ▫ Overall health, obstetric, and medical risks reviewed ▫ Physical limitations / contraindications – evaluate throughout pregnancy

• Exercise prescription - physical activity plan ▫ Consideration should be given to patient’s goals, initial fitness level, and to balance frequency, intensity, duration, and type of exercise so that the risks do not exceed the benefits ▫ Additional attention should be given to progression in intensity over time

Conditions requiring medical supervision ABSOLUTE CONTRAINDICATIONS

• Cardiac disease • Restrictive lung disease • Persistent bleeding (2nd & 3rd trimester) • Preeclampsia / PIH • Preterm labor (previous/present) • Cervical weakness • Placenta previa after 26 wks • Preterm pre-labor rupture of membranes • Multiple gestation

Conditions requiring medical supervision RELATIVE CONTRAINDICATIONS

• Severe anemia (Hb < 100 g/L) • Intrauterine growth restriction • Poorly controlled hypertension, diabetes, thyroid disease, or seizures • Unevaluated maternal cardiac arrythmia • Chronic bronchitis • Extremely sedentary lifestyle • Morbid obesity (BMI > 40) • Malnutrition or eating disorder (BMI < 12) • Orthopedic limitations • Heavy smoker

General Guidelines – Where to start? • In the absence of either medical or obstetric complications, follow the current CDC-ACSM guidelines (Artal & O’Toole, 2003). • For general health and well-being, accumulate at least 30 minutes of moderate-intensity aerobic and/or muscle-strengthening exercise at least 5 days/week (Haskell et al., 2007). ▫ Moderate intensity = 3-5 METs (equivalent to brisk walking)

• Stop if you feel pain. • Finish eating at least 1 to 1 ½ hours before working out. • Drink water before, during, and after your workout -- even if you aren't thirsty. • Don't go on a calorie-restriction diet during pregnancy. Eat a nutritious, balanced diet. • Basically, use common sense!

Warning signs to terminate exercise • Excessive fatigue or shortness of breath • Chest pain or palpitations • Dizziness or fainting • Abdominal pain • Painful uterine contractions • Leakage of amniotic fluid • Vaginal bleeding • Reduced fetal movement • Muscle weakness • Calf pain or swelling

Exercise Prescription (FITT principle) • For sedentary women ▫ ▫ ▫ ▫

Frequency = 3 x per week (minimum) Intensity = moderate RPE (12-14) Time = 30 minutes Type = low impact

• For regular exercisers ▫ ▫ ▫ ▫

Frequency = 3-5 x per week Intensity = moderate-to-hard RPE Time = 30-60 minutes Type = low impact and any prior safe activities

• For elite athletes ▫ ▫ ▫ ▫

Frequency = 4-6 x per week Intensity = 70-80% max HR or hard RPE Time = 60-90 minutes Type = competitive activities as tolerated during pregnancy

Adapted from Paisley et al. (2003)

Energy expenditure and intensity of specific activities for a 140 lb. female

Energy Expenditure (kcal/h)

700 Running, 10 min/mile, 6 mph

600 Running, 12 min/mile, 5 mph

500 400

Vigorous intensity (>6 METs)

Swimming – leisurely, general

300 Water aerobics

200 100 0

Yoga Typing Sitting quietly

Vacuuming Walking, 3 mph Cleaning house

Moderate intensity (3-6 METs) Light intensity (<3 METs)

Recommended Exercises During Pregnancy • • • • • • • •

Low impact aerobics Water aerobics Walking Kegels Pilates Yoga Cycling Swimming

Activities to avoid during pregnancy • Avoid

▫ Scuba diving

▫ High altitude activities ▫ Activities with risk of fall  Skiing, horseback riding, skydiving

▫ Activities with risk of abdominal trauma

 Hockey, basketball, soccer

Other Considerations • Dehydration and hyperthermia:

▫ Avoid exercise in hot humid environments ▫ Drink plenty of liquids – prior, during, after ▫ Appropriate clothing may help dissipate heat ▫ Hot tubs/saunas

• Poor Balance:

▫ Centre of gravity shifts as pregnancy progresses ▫ Exercise cautiously ▫ Pay attention to changes to terrain

• Muscle cramps and soreness:

▫ Stretch muscles and warm-up before exercising ▫ Wear supportive well cushioned shoes

Take Home Points • Avoid exercise in the supine position after first trimester • Avoid prolonged periods of motionless standing • Adequate nutrition • Maintain hydration • Avoid ballistic exercise • Avoid exercise in hot humid environments • Balance issues in third trimester • Avoid contact sports/sports with risk blunt trauma after first trimester/16-20 weeks • Track fetal activity and uterine contractions

Take Home Points • No standard heart rate maximum • Exercise regimen based woman’s symptoms • Exercise recommendations vary with each individual pregnant woman • Discuss risks and benefits of exercise • Use common sense

References • Artal, R. & O’Toole, M. (2003). Guidelines of the American College of Obstetricians and Gynecologists for exercise during pregnancy and the postpartum period. Br J Sports Med, 37, 6-12. • Haskell, W. L., Lee, L. M., Pate, R. R.,Powell, K. E., Blair, S. N., Franklin, B. A., et al. (2007). Physical activity and public health: updated recommendation for adults from the American College of Sports Medicine and the American Heart Association. Med Sci Sports Exerc, 39(8), 1423-1434. • Pivarnik, J. M., Chambliss, H. O., Clapp, J. F., Dugan, S. A., Hatch, M. C., Lovelady, C. A., et al. (2006). Impact of physical activity during pregnancy and postpartum on chronic disease risk. Med Sci Sports Exerc, 38(5), 9891006.