A Runner’s Guide to Training Through Pregnancy

I’VE WRITTEN several columns on running and pregnancy, but there have been none more controversial than this: Should Women Run Marathons While Pregnant?

The feedback has been split down the middle. For the not-so-positive half, I get it. I really do. Racing, particularly marathons, is your passion and a significant part of your lifestyle. The loss of that seems unfair.

All my articles – like this one – are dedicated to my critics and written with love. Since I’m a running and fitness coach, the last thing I want to do is hold women back. My goal is to help you achieve your goals and improve health and wellness during pregnancy and beyond, refocussing the attention away from what can’t be done and onto what matters most – performance. Before we get to the strategy, let’s look at some positive things first.

For women who run, it has never been a better time to be pregnant, especially when you consider the first exercise guidelines from the ACOG (American Congress of Obstetricians and Gynecologists) Guidelines for exercise during pregnancy in 1985:

  • Maternal heart rate should not exceed 140 beats per minute.
  • Strenuous activities should not exceed fifteen minutes in duration.
  • Maternal core temperature should not exceed 38 degrees Celsius.

These guidelines were based on early studies, many of which were conservative and performed on animals. If you look back to my mother’s era in the ’60s, exercise wasn’t recommended at all!

The ACOG updated its guidelines in 2002 and reaffirmed them in 2009:

  • Pregnant women without contraindications should be encouraged to engage in regular, moderate-intensity physical activity 30 minutes or more, on most, if not all days of the week.
    Women who engage in strenuous exercise during pregnancy require close supervision.
  • All expectant women (especially inactive women or those with medical complications) should undergo a thorough medical evaluation before beginning an exercise program.
  • After the first trimester, pregnant women should avoid the supine (on your back) position and motionless standing as much as possible.

We also know now that regular moderate-effort exercise has many benefits:

  • Increases energy and mood.
  • Improves posture as center of gravity shifts.
  • Promotes muscle tone, strength and endurance.
  • Improves sleep.
  • Improves circulation and blood flow, which reduces bloating, swelling and risk of blood clots.
  • May prevent gestational diabetes.
  • Reduces the risk of back pain.

That’s all fine and dandy, but I know I’m writing to competitive female athletes who want to perform their best. And although these benefits are great, they aren’t enough.

When I work with runners, my aim is to create a training plan that flows with their lifestyle, is in tune with their fitness and experience levels, and is targeted to meet their goals. When I work with women who are pregnant, none of that changes. The only variance is in the timing.

Of all the women that I’ve coached through pregnancy, few go exactly as planned. With that in mind, your training plan during pregnancy should be open, flexible and focussed on staying fit rather than building endurance or speed. Like the off-season after a target marathon, you should shift to a plan that allows you to more efficiently return to regular training post-baby.

These are the methods I employ with my pregnant athletes:

  • Focus on maintenance, rather than improvement. This allows the body to adapt to the incredible physiological adaptations and the workouts themselves. The more the athlete pushes, the more time it takes to recover and the harder it is on the body. Whether I’m coaching a pregnant athlete or not, the key to reaching goals and continuing to run strong is to train with an awareness of all the stresses on the body.
  • Train in minutes rather than kilometres. Runners love to track stats (I do!), but there is nothing more depressing than to see these stats get slower… and slower. Instead of focussing on running six or 10 kilometres, run by time. You’ll still get in your workouts, but you won’t feel the sense of loss in fitness.
  • Train by effort rather than pace. I believe this is important for all runners because it allows you to dial in on the optimal zone for the given run on the given day and fine tune your training. This is especially important for pregnant runners since it allows for the inevitable shift in pace rather than limiting you to running under a low heart rate number, which isn’t reliable or accurate.

The ACOG’s guidelines for highly fit women say workouts should stay within a moderate effort. Again, this is geared to those who are actively running and racing marathons. (If you’re new to exercise, discuss your program with your doctor.) A moderate effort run is below your lactate threshold and on the highest end of the aerobic zone. It’s an effort where you can talk but in 2-3 word responses, and you can hear your breath.

Based on recent research on pregnant elite (highly fit) athletes, exercising at an intensity above 90 per cent of their maximal heart rate may compromise fetal well being. A percentage of these highly fit pregnant athletes showed a fetal heart rate drop as well as a change in blood flow to the baby. That is a tipping point that isn’t worth crossing in my opinion because the gain isn’t worth the risk.

  • Leave your GPS at home. While we’re talking about it, some women find it’s easier to run without tracking of their pace. It frees you up to enjoy the run without focussing on the slower paces along the way. Pace doesn’t matter so why track it?
  • Stay strong. Include total-body strength exercises to maintain lean muscle tissue, core strength and posture.
  • Reduce the impact. Shift to or weave in lower impact activites like swimming, stationary cycling, or elliptical to provide a workout with less stress to the body and lowers the risk of injury. This is especially important later in the pregnancy when running can be painful or uncomfortable.
  • Avoid the heat and humidity (and the cold). Avoid exercise in hot, humid conditions since overheating and dehydration is dangerous to both mother and the fetus. Take your workouts inside to better control the environment. This is also important during cold, wintery days where the risk of falling is greater. The treadmill is a safe tool that allows higher quality workouts in extreme weather.
  • Find a new long run distance. Discuss with your doctor at what time length you should limit your endurance runs. Some of my runners can go up to 90 minutes through the second trimester, while others peak at 60 minutes. Any more than 90 minutes isn’t enough to make a difference in maintenance and can be too much on the body in terms of recovery and nutrition. Remember the goal is to maintain fitness and not improve it.
  • Run shorter, varied workouts during the week. Some may be easy effort for 45 minutes, while others could be 30 minutes but include moderate intensity intervals for 1-2 minutes. Mix it up and always go by how you’re feeling.
  • Change your mindset. Think in terms of maintaining movement rather than running. A competitive IronWoman I know has run through three pregnancies – all have been different. The first she was able to run all the way through. The second and third she ran through the first trimester, ran-walked the second, and walked the third. I might add she’s never raced a long event while pregnant and focusses on 30-60 minutes runs and cross-training while pregnant. The key for her was in staying healthy and fit through her pregnancies so she could resume training postpartum. (And she’s still a badass kicking butt and placing in her age group!)
  • Stay in the zone. Use running and walking as tools to modify your effort. When training by your listening to your body and effort levels, add walking when you need to and evolve your program. Typically, this can mean running early on, then run-walk intervals, then walk-run intervals (more walking less running) and if needed, walking.
  • Keep your recovery rate low. If you pushed hard in the off-season, eventually it would take a toll on your health and defeat the purpose the off-season – which is recovery and base-building – right? Avoid exercising to exhaustion. Although longer runs (90+ minutes) are done at an easy effort, they can be exhaustive due to the total amount of fatigue and stress to the body, and they can dehydrate you.
  • In the third trimester especially, focus on movement and self-care. It’s a little like tapering for a marathon in the later stages: Less is more.
  • Always be mindful of the signs to stop exercising.
    • Increased shortness of breath.
    • Headache, dizziness or feeling faint.
    • Chest pain, calf pain or swelling.

I don’t expect hugs and love from my critics, but I do hope that we can continue a smart conversation on how to help women continue to reach their performance goals while training wisely during pregnancy.


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