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Facts About Prenatal Exercise That Will Turn Your World Upside Down

Exercise can be the most invigorating and relaxing experience of your day. It boosts energy, enhances health, and aids in a restful nights sleep, three very important needs of a pregnant woman. The benefits of prenatal exercise go well beyond energy and sleep yet many women are still reluctant to continue or start a program during pregnancy. This is likely due to the outdated or misguided information making its rounds.

Fortunately, there are some amazing governing medical bodies that create guidelines and standards for medical and fitness professionals to use with their prenatal clients (if only every practitioner knew about these!). These guidelines are based off of an ever growing mountain of research that supports exercise during the most sensitive time in a woman's life.

ACOG Guidelines

The American College of Obstetrics & Gynecology (ACOG) sets the standard for medical practices when it comes to women. ACOG explains that continuing or starting an exercise program is not only safe during a normal, healthy pregnancy but it is also recommended. They advise at least 150 minutes of moderate-intensity aerobic activity every week. They even go as far as combating rumors that are causing some women to refrain from exercise. They state, "Physical activity does not increase your risk of miscarriage, low birth weight, or early delivery."

Benefits of Prenatal Exercise

The benefits of prenatal exercise are abundant. Exercising regularly during early and mid-pregnancy increases the growth and function of your placenta, enhancing oxygen and nutrient transfer to your baby. Exercise also improves the body's ability to get rid of heat, decreases fat accumulation, improves sleep quality, decreases postpartum depression, and more. There are even significant beneficial effects that extend through labor. Our charts give you a better view of the improvements exercise can bring to you, your baby, and your birth. Check them out below! Keep reading to find out what the top 5 myths are regarding prenatal exercise and when you should refrain from it.

Top 5 Prenatal Exercise Myths Busted

1. Myth: You must always keep your heart rate below 140 beats per minute during exercise.

  • Fact: This myth comes from old guidelines that were established long before there was any research on the safety of exercise during pregnancy. It was more of a "to be on the safe side" kind of thing. Broadly telling women to keep their heart rates below 140 bpm is actually useless. Because of a lack of consistency when it comes to heart rates, there is no one size fits all. Genetics, age, exercise experience, hydration, and activity can all influence beats per minute. Research has shown that rating of perceived exertion, or the talk test, is a more reliable predictor of exertion and pregnant women are encouraged to follow that instead.

2. Myth: Absolutely no running or high impact exercises during pregnancy.

  • Fact: Pregnancy is not the time to try to run your first marathon however if you were an avid runner before pregnancy there is no reason to automatically stop. Starting a light running routine in the first trimester is safe, assuming you have a healthy pregnancy. Remember to start slow and listen to your body. As the weeks go on you may feel the need to scale it down due to the added weight, decreased lung space, or increased pressure on your pelvic floor. Using a pregnancy support belt can help hold the belly up and decrease pressure on the pelvic floor. Once you get into the second and third trimester it is not recommended to start high impact routines. Starting a new walking routine would be more ideal in the late phases of pregnancy.

3. Myth: Ab work is not safe during pregnancy.

  • Fact: Ab work is safe and highly recommended during pregnancy. Maintaining a strong core during pregnancy is important to help support posture, minimize low back pain, aid in birth, and assist in postpartum recovery. There is a catch though, not all ab work should be done during pregnancy. Generally speaking, any exercise that requires you to lay flat on your back after 20 weeks should not be preformed. Sit-ups, crunches, and rotational core exercises should also be avoided after the 1st trimester.

4. Myth: Lifting more than 10 pounds is dangerous.

  • Fact: This is a mixture of legend and misconception. Another one of those "to be on the safe side" kind of things mixed with some misleading truth. Women who are in a high risk pregnancy may be advised to limit the weight that they lift to 10 pounds as a precaution to their condition. An otherwise healthy pregnancy with no complications shouldn't be limited with the same restrictions. Lifting more than 10 pounds is safe for the majority of pregnant women. If you are given these restrictions in a healthy pregnancy don't be afraid to ask why and then ask for the supporting evidence. Some practitioners are not up to date with guidelines and research in exercise science.

5. Myth: Exercise will decrease oxygen transfer to the baby.

  • Fact: Breathing is actually enhanced through exercise. It improves the transportation of oxygen to various cells. This process makes oxygen and nutrients more available at the cellular level. It increases the body's ability to use this oxygen as well. It also aids in the removal of metabolic waste. The combination of pregnancy and exercise improves aerobic capacity by 5-10%, increasing VO2 max and enhancing performance all the way through postpartum. This is why it is especially harder for avid exercisers to get their heart rates up during pregnancy. The increase in oxygen from exercise accelerates the growth and function of the placenta to meet the baby's needs (as discussed earlier). This growth increases the blood flow to the baby and therefore increases the transfer of oxygen and nutrients. In conclusion, exercise enhances both mother and baby's oxygen consumption and utilization.

When Exercise is Contraindicated

There are times in a pregnancy where exercise is not recommended. These scenarios are not absolute disqualifiers though they should be addressed with a healthcare professional. Discuss any of these signs or symptoms with your provider before returning to exercise:

  • Injury or illness

  • Vaginal bleeding

  • Dizziness

  • Shortness of breath

  • Chest pain

  • Persistent headache

  • Muscle weakness

  • Calf pain or swelling

  • Regular, painful contractions

  • Fluid gushing or leaking from vagina

Physical activities that should be avoided during all pregnancies include:

  • Any activity that puts you at risk for getting hit in the abdomen (football, hockey, soccer, basketball, etc)

  • Activities performed above 6,000 feet

  • Activities that may put you at risk for a fall (skydiving, skiing, surfing, off-road cycling, horseback riding, etc)

  • Hot Yoga & Hot Pilates (or other activities that can cause you to become overheated)

  • Scuba Diving


In short, if you were exercising before pregnancy, and you are healthy and low-risk, there is no reason for you to stop or alter your current routine. As the weeks go by and the baby gets larger, you may feel the need to slow down or decrease your weights. Listen to your body. If you are new to exercising, it is perfectly safe to start a new exercise routine in a healthy pregnancy. Remember to start slow. Gradually increase the amount of time spent exercising. If you are still unsure or want additional guidance don't be afraid to ask for help. When you hire a fitness professional be sure that they have additional training in pre/postnatal fitness. Standard personal training certifications cover pregnancy in one to two paragraphs. This is no where near enough information to effectively train women through their childbearing years.

Need some accountability, motivation, or instruction? Contact us today to schedule your consultation.


ACOG. (2019). Exercise During Pregnancy. FAQ119

Clapp, J., & Cram., C. (2012). Exercising Through Your Pregnancy. Omaha, NE: Addicus Books.

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