How to Exercise Safely during Pregnancy

By Dr. Anna Burns, PT, DPT
South Shore Pelvic Health

There are so many things to consider when pregnant, and physical activity is one of them. In the old days, women were advised to “take it easy” while pregnant. However now, the Center for Disease Control and Prevention recommends that pregnant women get at least 150 minutes of moderate-intensity aerobic activity every week. A growing body of research has shown that exercise is associated with decreased fetal distress during delivery, higher APGAR scores, decreased risk for gestational diabetes, and decreased risk for preeclampsia. In a recent study of runners, strength training during pregnancy led to decreased musculoskeletal pain and postpartum stress urinary incontinence. Recovery begins in pregnancy!
Body Changes
A woman’s body changes significantly during pregnancy. Her blood volume increases
by 50%. Her resting heart rate increases by 15-20 beats per minute. Her respiration
rate increases by 10-20%. Her joints become more lax due to pregnancy hormones.
Her body temperature is slightly higher. Her posture changes with an increase in the
curve of her low back, forward tipping of her pelvis, backward shifting of her rib cage to
compensate for an altered and growing center of mass. As a result, gait mechanics
change and balance can become more challenging.
Ideally, a pregnant woman should be able to do any exercise she had been doing prior
to pregnancy with a few modifications. If you were previously sedentary, adopt a mild to
moderate intensity routine. If you were previously active, you can adopt moderate to
high intensity routine. Exercise should be performed at least three times a week. You
should always talk to your obstetrician or midwife before starting an exercise
routine.
If you have a heart rate monitor, you can use the following heart rate guidelines for
activity level:
If you are younger than 30 years old, heart rate range targets are (in beats/minute):
LIGHT INTENSITY: 102-124
MODERATE INTENSITY: 125-146
VIGOROUS INTENSITY: 147-169
If you are 30 years or older:
LIGHT INTENSITY: 101-120
MODERATE INTENSITY: 121-141
VIGOROUS INTENSITY: 142-162

There are just a few things to AVOID during exercise while pregnant:
Laying on your back for more than 3 minutes after 20 weeks
Exercising in a hot, humid environment, whether it’s outside or at hot yoga
Performing inversion poses or any position where the hips are above the shoulders
(handstands, prolonged bridges, etc.)
Exercises that put pressure on the abdomen during mid-to-late pregnancy
Over-stretching muscles

If you lift weights, here are a few guidelines and suggested modifications:
Decrease your lifting load to 60-75% of your pre-pregnancy “one rep max.”
Modify asymmetrical movements such as a split snatch or a split jerk. Decrease the
width of the stance or perform these without the split positioning at all.
If your belly gets in the way with lifting, lift from blocks instead of the floor.
Switch out front squats for back squats, as the front squats increase your intra-
abdominal pressure (which is already increased by the presence of the fetus).

Regardless of the type of exercise you participate in, watch for symptoms that signal
you should STOP exercising and contact your healthcare provider immediately:
Bleeding or leaking fluid from the vagina
Feeling dizzy or faint
Shortness of breath before starting exercise
Chest pain
Headache
Muscle weakness
Calf pain or swelling
Regular, painful contractions of the uterus
Don’t let pregnancy leave you sitting around eating bonbons! The more active you can
stay, the better you and your baby will feel, both during pregnancy and after delivery!

References:
Blyholder, Liga & Chumanov, Elizabeth & Carr, Kathleen & Heiderscheit, Bryan. (2016).
Exercise Behaviors and Health Conditions of Runners After Childbirth. Sports Health: A Multidisciplinary Approach. 9. 10.1177/1941738116673605.
​
Clapp, J.F. III. The Course of labor after endurance exercise during pregnancy. Am J
Obstet Gynecol. 1990 Dec;163(6 Pt 1):1799-805.

Mack, C.F., Morgan, C., & Rohde, M. (2019, January). Science Meets Practice: Running
vs. Sports Performance Training in Pregnant and Postpartum Females. Presented at
the Combined Sections Meeting of the American Physical Therapy Association,
Washington, DC, USA.

Rohde, M., and Mack, C.F. (2019, January). Sports Performance Programming for the
Pregnant and Postpartum Female Athlete. Presented at the Combined Sections
Meeting of the American Physical Therapy Association, Washington, DC, USA.

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