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Running During Pregnancy: Guidance by Trimester

Running during pregnancy is a topic that often causes uncertainty, which may lead you to think that it isn’t advisable or safe. However, if you were a runner prior to pregnancy, and haven’t been told by a medical provider that you should stop, there is no reason why you can’t continue well into your pregnancy.

That said, there are some key physical and physiological changes that may impact running at different stages of pregnancy. We will cover these key changes by trimester, then provide some beneficial training strategies to help you continue to run safely and pain-free.

General Prenatal Running Recommendations

Running is perfectly safe to continue if you had been running prior to pregnancy — even long distance running. However, it is not advised to start running during pregnancy. That is because your body needs to be conditioned to handle the impact forces to minimize the aches and pains that some people experience with such a dynamic activity.

One of the most important elements for pain-free running during pregnancy is strength training — especially on one leg — so that you’re able to absorb the forces generated during impact. In other words, every time you land (when you aren’t pregnant), you must absorb roughly 4-6x your body weight. This places a great deal of stress on your soft tissues.

As weight gain increases during pregnancy, so too does the force that must be absorbed with each step. In addition, the bigger the body, the more force needed to propel it forward each step. The more you can absorb and dissipate impact forces, the less stress running will cause your joints (ankles, knees, hips, lumbar spine) and pelvic floor. Make sure to incorporate moves such as squats, deadlifts, step-ups, and lunge patterns.

Now that you understand the importance of lower body strength training, let’s look at the specific trimester-based changes and training implications.

Trimester-Specific Guidelines

First Trimester Changes

Aside from any fatigue or nausea that you may experience, running won’t feel markedly different because weight gain, and the resulting alignment shifts, have not become a factor yet. However, there are two key things to be aware of in the first trimester:

  1. Potential instabilityDuring pregnancy, hormonal changes – including the increase in the hormone relaxin – soften the joints, ligaments, and connective tissue to allow the body to adapt to carry a growing baby and to provide laxity and mobility needed to push a baby out. A consequence of this soft tissue laxity is that it often increases mobility and decreases stability. This is most often felt in the pelvic/hip region, but the effect varies highly by individual, so just be mindful of it.
  2. Risk of getting overheated: During the first trimester (especially the first month), it is important to avoid overheating (body temperature above 102° F), as this could interfere with the critical process of the fetus’s brain and organ development. The pregnant body does adapt to allow greater heat dissipation, but it is important to avoid those situations that can make it difficult to dissipate heat, like running in high-heat and humidity. It is also very important to stay hydrated to enable your body to continue to sweat.
First Trimester Training Strategies
  • Assess your stability at rest: To gauge your level of baseline stability in single-leg stance, stand on one leg with the opposite knee to chest and note how long (and how well) you can balance on one leg. Also notice if you are more successful on one leg vs. the other. You can re-assess every month or so to determine if the hormonal changes may be affecting your balance. For help in increasing your stability, check out these 5 moves to build lower body stability.
  • Avoid high heat and humidity: Focus on hydration before, during, and after running sessions.
  • Ingrain proper breathing mechanics: Learn how to perform 360° Breathing. This important for several reasons, but specific to running, it improves your cardiac efficiency (delivery of oxygen to working muscles) — allowing you to run longer distances before tiring, or to recover more quickly in between intervals.
  • Begin pelvic floor training: Begin early to strengthen your pelvic floor (PF) so that, when you begin to get heavier, your PF tissues will be strong enough to continue to support you. It is important to develop both strength and length in the PF tissues during pregnancy. Learn how to do this by practicing Pelvic Floor Activations (PFAs).
Second Trimester Changes
  1. Nausea and Fatigue (typically) subside: The second trimester is often called the “honeymoon of pregnancy” because typically the first trimester nausea and fatigue dissipate, and you haven’t yet begun to experience the common discomforts of the third trimester.
  2. Increased cardiac output: This change is pretty cool! A pregnant person’s heart pumps more blood with each beat AND beats more times per minute. This confers a cardiac advantage similar to “blood doping.” Of course, increased weight gain and alignment shifts can mitigate this advantage as pregnancy progresses.
  3. Weight gain: Second trimester is when weight starts to increase. This will likely cause more noticeable changes in your running.
  4. Alignment shifts: Compounding the changes caused by weight gain, the growing belly tends to pull the pelvis forward into an anterior pelvic tiltwhich compresses the tissues in the lower back and increases pressure on the pelvic floor muscles. When we combine this with the added impact of running, it could result in the common pregnancy complaints of lower back pain and incontinence (accidental urine leakage).
Second Trimester Training Strategies
  • Take advantage of your “honeymoon” (if it feels ok): The second trimester is often considered the time when you will feel most energetic and motivated to train. Also, remember that you do have that cool advantage of the increased aerobic capacity. So, if you’re feeling good, you can push yourself if you wish to do so. Increase your distance and/or speed, while keeping in mind the next point.
  • Use Rate of Perceived Exertion (RPE): Knowing the level of intensity to work at can be more challenging during pregnancy because heart rate is no longer an accurate gauge of how hard you are working. Therefore, it is recommended that you use a simple RPE scale of 1-10, where 1 = minimal exertion (like gentle walking) and 10 = maximal effort (like a full sprint). Generally, you want to stick to an RPE of 6-8. If you are a more experienced runner, you can push to an 8.5. Remember though, RPE is all about how you feel. It will vary highly by individual and also for each individual as pregnancy progresses (and even from day to day).
  • Emphasize neutral alignment: Because greater weight gain and hormonal changes can alter your body position, which could lead to pain in the low-back and hips (among other areas), you want to make sure you are maintaining neutral alignment as much during running as possible.
  • Focus on lower-body strengthening: As mentioned earlier, strength is critical to absorb and dissipate impact forces. Therefore, focus your strength work on single-leg moves because running is a single-leg activity.
  • Watch for signs of PFD: If you experience accidental leakage (urinary or fecal) while running, you may be experiencing pelvic floor dysfunction (PFD). This means that there is an imbalance between the loads you are putting on the body and your body’s ability to control those loads through the pelvis, creating unintended or spontaneous leakage of urine or feces. If this sounds familiar, then it would be prudent to stop running (along with any other activities that trigger this leakage).
  • Use of running “accessories”: As the breasts and belly get bigger, they may become uncomfortable, but they don’t have to curtail your running. Consider doubling your sports bra and possibly using a belly support (NOT a wrap or corset). In addition, changes to your feet may necessitate an increase in shoe size. Why? Hormonal changes, coupled with the weight gain, may cause your feet to spread and flatten, which can result in discomfort if your shoes are too tight (and don’t have enough arch support). If you are a more serious runner, you may consider making the purchase of a larger shoe (which will likely last you into postpartum, as prenatal changes to the feet may become permanent).
Third Trimester Changes
  1. Increased Weight Gain and Alignment Shifts: The changes that began in the second trimester will be most pronounced now.  For many people, their bodies will tell them they need to lower the intensity and reduce (or stop) running.
  2. Altered Running Mechanics: The pelvis widens a bit during pregnancy and, as a result, the feet get wider. This can lead to a change in your stride. Expect a shorter stride with the potential for more side-to-side shifting. This places a high demand for strength on the legs, especially on the outer hip muscles.
  3. Constricted Breathing: As the belly gets larger, it may push into the chest area, thereby limiting how much the lungs can expand. Therefore, you might find it more difficult to take a deep breath, which may cause a change to your breathing pattern and rhythm — increasing the difficulty of running.
Third Trimester Training Strategies
  • Reinforce 360° Breathing: As breathing can become challenged at this stage, you want to ensure you are expanding the ribs in all directions to maximize air intake. Be sure you have mastered 360° Breathing — learning how to expand your ribs three dimensionally when you inhale.
  • Focus on lower-body strengthening: As mentioned in the second trimester training focus, continue incorporating lower-body moves, especially single-leg work to maintain your strength.
  • Soft tissue care: Doing some foam rolling prior to running can help keep your tissues supple, especially when getting loaded by more bodyweight. Focus on the glutes, hamstrings, hip flexors, and quads. After running, it’s a good idea to stretch those same areas (and include the calves) to lengthen muscles that became shortened during your session.
  • Watch for signs of PFD: If you experience any symptoms of urinary or fecal leakage during runs, this is a sign that it is best to stop running.
  • Routinely “check in”: Above all else, running really comes down to: Does it feel good? If you hesitate in answering that question, then it is probably time to scale back (or eliminate) running and focus on more comfortable movements.

Alternative Cardio Options

If you decide you need to scale back (or eliminate) running, there are several alternatives to still get a great cardio workout. Here are just a few suggestions for scaling back running, or finding different cardio options altogether:

  • Continue running, but reduce your speed and/or your distance
  • Combine running/walking
  • Switch to incline walking
  • Change cardio piece altogether (i.e. stationary upright bike, elliptical)
  • Decrease your rest time during your strength training sessions to keep your heart rate elevated for longer periods
  • Try our highly beneficial cardio interval practice, LIIT (Labor Intensity Interval Training), to help you prepare physically and mentally for the “intervals” of Stage 1 Labor (contractions). You’ll get a great cardio workout and some excellent preparation for your BIG day.

Want Additional Resources?

For additional resources to help you exercise safely and effectively during pregnancy, explore our training programs and services. You’ll find a variety of offerings tailored to different needs — from education, to self-guided programs, to the ability to work with an expert coach.

Or, if you’re a health & fitness pro interested in coaching pre & postnatal clients, check out our ProNatal Education & Certification.