If you’ve ever searched for pregnancy exercise advice online, you have likely felt frustration. One source says to keep your heart rate below 140 beats per minute. Another warns against doing core work. Your friend advises not to start exercising during pregnancy, while your neighbor lifted heavy weights through her third trimester.
The conflicting information can leave you feeling confused, anxious, and unsure about how to move your body safely during pregnancy. What if we told you that much of this “common knowledge” about prenatal exercise is based on outdated guidelines, fear, and misconceptions rather than current evidence?
It’s time to separate fact from fiction so you can exercise with confidence during pregnancy.
Read on to learn:
- Myth 1: If you haven’t been exercising, pregnancy is not the time to start
- Myth 2: Keep your heart rate below 140 BPM
- Myth 3: Avoid all core work during pregnancy
- Myth 4: Don’t lift heavy during pregnancy
- Myth 5: You don’t need to modify until the second trimester
Quick Answer: Most common prenatal exercise myths stem from outdated information and fear-based thinking. Current research shows that exercise during pregnancy is safe and highly beneficial for both parent and baby. Rather than avoiding activities or simply “modifying” workouts, the most effective approach is to focus on training that prepares the body for the unique, high-stress demands of pregnancy, birth, and postpartum recovery.
Myth 1: If You Haven’t Been Exercising, Pregnancy Is Not the Time to Start
This myth suggests that pregnancy is too delicate a time to begin a new exercise routine, especially if you haven’t been active before. The concern is that starting exercise during pregnancy might harm the baby or create unnecessary stress on the body.
The Reality: Exercise during pregnancy is safe and highly beneficial for both parent and baby, regardless of your pre-pregnancy fitness level.
Key Benefits Include:
For the pregnant person:
- Reduced risk of gestational diabetes, excess weight gain, and pregnancy-induced hypertension
- Fewer common pregnancy discomforts (nausea, constipation, swelling, varicose veins)
- Improved sleep, mood, and energy
- Better labor experience with fewer medical interventions
- Easier postpartum recovery
For the baby:
- Improved placental function and health at birth
- Better ability to manage labor stresses and recover afterward
- Enhanced cardiorespiratory health extending into childhood
- Higher likelihood of healthy weight in adolescence and adulthood
- Potential positive impact on childhood cognitive development
In short, nine months of exercise can have a lifetime impact.
For a complete breakdown of the research-backed benefits and sources, read this article on the surprising benefits of prenatal exercise.
The benefits are so substantial that the American College of Obstetricians and Gynecologists (ACOG) recommends that those with uncomplicated pregnancies engage in both aerobic and strength training before, during, and after pregnancy.
The Bottom Line: It is safe and recommended to start exercising at any point during pregnancy. If you haven’t been active before, ease in gradually and let comfort guide you as you progress. Any amount of training is preferable than none.
Myth 2: Keep Your Heart Rate Below 140 BPM
Unfortunately, the guideline to “keep your heart rate below 140 beats per minute” remains one of the biggest prenatal exercise myths (and, regrettably, we hear it most often from doctors).
The Reality: This is an outdated ACOG guideline from 1985, which was developed when almost no research existed about exercise during pregnancy. ACOG eliminated the heart rate guideline in 1994, due to research findings on heart rate variability during pregnancy (summarized below).
Why heart rate isn’t reliable during pregnancy:
- Your resting heart rate naturally increases throughout pregnancy
- Individual responses to exercise vary significantly
- The same workout can produce different heart rates on different days
- Heart rate doesn’t reflect actual effort level during pregnancy
Official Guideline for Gauging Exertion During Pregnancy
The current ACOG guideline is to use Rate of Perceived Exertion (RPE) instead of heart rate monitoring. RPE relies on listening to your body and gauging your exertion by how you feel, which is a more reliable method. For details on how to utilize the RPE scale to find the right intensity for you, read this article on What’s a Safe Intensity to Work at During Pregnancy?
The Bottom Line: Heart rate is not an accurate gauge of exertion during pregnancy. Use RPE instead, which involves listening to your body and gauging your exertion based on how you feel.
Myth 3: Avoid All Core Work During Pregnancy
Many people believe they should avoid all core work during pregnancy to prevent issues like diastasis recti or to protect their baby.
The Reality: Optimizing deep core function is one of the most significant things you can do for your own health during pregnancy (and the health of your growing baby). Moreover, the core must be strong enough to handle the physical stresses of pregnancy.
The benefits of a well-functioning core
A strong, functional core during pregnancy leads to a cascade of benefits across the entire body, including:
- A stronger core
- Fewer pain or injuries
- Reduced severity of diastasis recti
- Reduced risk of pelvic floor dysfunction
- Improved posture
- Easier movement
- Better immunity
- Less stress
- Improved digestion
- Increased energy
- Better focus
- Easier labor
- Healthier fetal growth environment
The key to reaping all these benefits comes down to the way you breathe. Specifically, you want to breathe in a manner that activates your deep core system. We call this style of breathing 360° Breathing. To learn more about it, and how to perform it, read The #1 Most Effective Core Exercise.
Why pregnancy demands strong core work
Several physical changes place extra stress on your core:
- Alignment shifts create new demands on core muscles
- Weight gain increases the load your core must support
- Pressure within the core increases as the baby grows
- Breathing patterns change in ways that impact core strength
Without appropriate core work, these changes can lead to injuries, pain, and movement compensations. Therefore, you want to strengthen your core to better withstand these additional stresses. See these 12 moves to build core strength for some highly-beneficial core exercises during pregnancy (or any other time, for that matter).
The Bottom Line: Core work isn’t just safe during pregnancy, it’s essential. Optimizing deep core function is one of the best things you can do for your health. In addition, a strong core during pregnancy is essential to manage the additional stresses placed on it.
Myth 4: Don’t Lift Heavy During Pregnancy
This myth suggests that lifting heavy weights during pregnancy puts too much stress on the body and could harm the baby or lead to injuries. Therefore, it’s best to minimize loads, or focus on bodyweight exercises only to reduce stress on the body.
The Reality: Your body must be strong enough to handle pregnancy weight gain and other changes. Without a focus on building strength, the body could be at its weakest when at its heaviest.
The altered strength-to-weight ratio
During pregnancy, your weight gradually increases. If you follow the conventional wisdom of “reducing loads” to limit stress, then strength will consequently decrease. The theory of progressive overload says that muscles need to be stressed in order to adapt and tolerate greater levels of stress.
This creates an unfavorable strength-to-weight ratio, which could lead to movement compensations and other pregnancy-related pains or injuries.
For more guidance on the benefits of strength training and how to approach strength training safely and effectively, read our Guide to Strength Training During Pregnancy.
The Bottom Line: Strength training needs to be a primary focus of prenatal exercise programs. It’s essential for keeping your body moving well and minimizing injuries. Rather than avoiding lifting, focus on building and maintaining strength to support your changing body throughout pregnancy and into the postpartum period.
Myth 5: You Don’t Need to Modify Until the Second Trimester
This myth suggests that the first trimester requires no changes to your routine, modifications start in the second trimester, and by the third trimester, you should be significantly scaling back.
The Reality: The pregnancy journey places specific, high-stress demands on the body – comparable to that of a major athletic event. Instead of “modifying” an existing routine, the most effective approach is to prepare your body for the unique demands ahead – similar to how athletes prepare for their specific sport.
Why “modifications” miss the point
Think about it this way. If you decided to run a marathon, would you prepare for it by simply “modifying” your existing routine in order to stay safe leading up to the race? Probably not. More likely, your focus would be on preparing your body for the specificdemands of that marathon so that you’re able to successfully complete it (with minimal risk of pain or injury).
Similarly, the pregnancy journey places specific, high-stress demands on the body, including increased weight, shifts in alignment, changes in center of gravity, increases in intra-abdominal pressure, and hormonal changes. Then, we get to childbirth – an event many consider the greatest physical feat of their lives. After the joys of completing this extraordinary event, unfortunately, there is no rest. Then begins the 24/7 (highly-physical) demands of parenthood – typically on little sleep.
We say all this not to scare you, but to help shed light on the fact that the pregnancy journey is similar in nature to other major athletic events. Yet, we don’t often approach training for it in the same way.
The Bottom Line: Instead of focusing on all the things you should stop doing, or “modify,” focus on how to prepare your body for the unique stresses of the journey ahead. This is the core of the ProNatal Fitness Performance Training Approach.
Moving Forward with Confidence
These five myths are among the most common misconceptions about prenatal exercise, but they all stem from the same root: outdated information and fear-based thinking rather than current evidence.
The truth is that pregnancy is not a time to avoid exercise, limit yourself unnecessarily, or simply “modify” your way through nine months. Instead, it’s an opportunity to train specifically for one of the most physically demanding experiences of your life.
When you approach prenatal exercise with accurate information and proper programming you can move with confidence, feel strong in your changing body, and prepare yourself for the challenges of pregnancy, birth, and postpartum recovery.
Want a performance-based training program for your pregnancy journey? Check out our Prenatal Workout Programs.
Want to learn how to train pregnant and postpartum clients utilizing the Performance Training Approach? Explore our Pre & Postnatal Fitness Certification, the #1 recommended pre & postnatal fitness certification in the U.S. by the top health clubs and fitness studios.
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