1. Identify the physiological demands of exercise for endurance training in pregnancy.
2. Identify and address any contraindications to endurance training in pregnancy.
3. Discover ways to empower women to exercise during pregnancy.
Fit Pregnancy Guidelines
The American College of Obstetricians and Gynecologists (ACOG) as well as the US Department of Health and Human Services encourage the participation of exercise during pregnancy. By following evidence-based guidelines, we can ensure a beneficial and safe training plan for our pregnant clients. We know physical activity is important, but how can we gain trust with our pregnant clients to help them best understand their bodies during this time of change? By understanding the physiological demands of endurance training during pregnancy, the better we can serve this population.
Similar to the general population, ACOG recommends at least 150 minutes of moderate-intensity aerobic activity for healthy pregnant women, and agree that the benefits of exercise at this time greatly outweigh the risks. Helping our clients to establish healthy habits and routines may continue to benefit them long after baby is born.
The acute physiological responses to exercise (heart rate, cardiac output, stroke volume, etc.) are increased during pregnancy. If a woman does not have any medical contraindications, it is appropriate to monitor exercise intensity using the rate of perceived exertion. According to ACOG, “Minute ventilation increases up to 50 percent, primarily as a result of the increased tidal volume.” This makes it harder for pregnant women to reach an anaerobic threshold with less available oxygen. They also note that, “Aerobic training in pregnancy has been shown to increase aerobic capacity in normal weight and overweight pregnant women.”
"Similar to the general population, ACOG recommends at least 150 minutes of moderate-intensity aerobic activity for healthy pregnant women"
In addition to respiratory changes, circulation and blood pressure also may respond by decreasing, in order to sustain mom and baby from a circulatory standpoint during pregnancy. This is why it is recommended that pregnant women avoid or modify any supine positions after week 16 of pregnancy. Also, the baby’s weight in this position can decrease venous return as well as cardiac output, resulting in hypotension.
In addition to the physiological changes a woman experiences during pregnancy, it’s crucial to recognize the anatomical changes as well, especially the shift in center of gravity as pregnancy progresses. Lordosis may result in increased joint and/or discomfort in other areas. Metabolic demands also increase by approximately 300 kilocalories per day. Consider working with a Registered Dietitian Nutritionist to discuss individual energy needs.
ACSM’s Guidelines for Exercise Testing & Prescription: Contraindications for Exercising during Pregnancy
- Severe anemia
- Unevaluated maternal cardiac dysrythmia
- Chronic bronchitis
- Poorly controlled Type 1 diabetes mellitus
- Extreme morbid obesity
- Extreme underweight
- History of extremely sedentary lifestyle
- Intrauterine growth restriction in current pregnancy
- Poorly controlled hypertension
- Orthopedic limitations
- Poorly controlled seizure disorder
- Poorly controlled hyperthyroidism
- Heavy smoker
- Hemodynamically significant heart disease
- Restrictive lung disease
- Incompetent cervix/cerclage
- Multiple gestation at risk for premature labor
- Persistent second or third trimester bleeding
- Placenta previa after 26 week of gestation
- Premature labor during the current pregnancy
- Ruptured membranes
- Preeclampsia/pregnancy-induced hypertension
How can I help?
Pregnancy can make a woman feel inspired and motivated to adopt healthy habits for the well-being of her baby. Consider using motivational interviewing to help set goals for training during exercise. Use training sessions to educate your pregnant client on the changes she is experiencing while training in a new body. Helping her better understand these changes can lead to increased communication between trainer and client, and a more positive overall experience with a fit pregnancy.
is a registered dietitian nutritionist and an ACSM certified personal trainer. In addition to her private practice, Katie Hake Health & Fitness (KatieHake.com), LLC, she works as a metabolic dietitian for children and adults with rare genetic metabolic disorders. She loves teaching group fitness classes and empowering women to find their fierce through the joy of eating and moving.
Read more from Coach Katie
6 Fit Pregnancy Tips | For Clients, Coaches and Trainers
The views expressed are those of the author and do not necessarily reflect those of the ACSM.