[#3] Is Working Out While Pregnant Safe?

In today’s episode, I answer the question “Is working out while pregnant safe?” by unpacking the three most common myths active women hear about working out while pregnant, where those ideas came from, and what the research and current medical guidelines actually say.

Main topics covered:

• Myth 1: Don’t let your heart rate go above 150 bpm
• Myth 2: Exercise can cause miscarriage
• Myth 3: Don’t lift more than 20 pounds
• How I exercised during my pregnancy

This podcast is for general education only and is not medical advice. If you have specific concerns, speak with your OB provider. 

References

1. Physical activity and exercise during pregnancy and the postpartum period. ACOG Committee Opinion No. 804. American College of Obstetricians and Gynecologists. Obstet Gynecol 2020;135:e178–88.
2. Salvesen, K. Å., Hem, E., & Sundgot-Borgen, J. (2012). Fetal wellbeing may be compromised during strenuous exercise among pregnant elite athletes. British journal of sports medicine, 46(4), 279–283. https://doi.org/10.1136/bjsm.2010.080259
3. Wowdzia, J. B., Hazell, T. J., Berg, E. R. V., Labrecque, L., Brassard, P., & Davenport, M. H. (2023). Maternal and Fetal Cardiovascular Responses to Acute High-Intensity Interval and Moderate-Intensity Continuous Training Exercise During Pregnancy: A Randomized Crossover Trial. Sports medicine (Auckland, N.Z.), 53(9), 1819–1833. https://doi.org/10.1007/s40279-023-01858-5
4. Barakat, R., Zhang, D., Silva-José, C., Sánchez-Polán, M., Franco, E., & Mottola, M. F. (2023). The Influence of Physical Activity during Pregnancy on Miscarriage-Systematic Review and Meta-Analysis. Journal of clinical medicine, 12(16), 5393. https://doi.org/10.3390/jcm12165393
5. Meah, V. L., Davies, G. A., & Davenport, M. H. (2020). Why can't I exercise during pregnancy? Time to revisit medical 'absolute' and 'relative' contraindications: systematic review of evidence of harm and a call to action. British journal of sports medicine, 54(23), 1395–1404. https://doi.org/10.1136/bjsports-2020-102042
6. Prevett, C., Kimber, M. L., Forner, L., de Vivo, M., & Davenport, M. H. (2023). Impact of heavy resistance training on pregnancy and postpartum health outcomes. International urogynecology journal, 34(2), 405–411. https://doi.org/10.1007/s00192-022-05393-1

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Transcript

SPEAKER_00 0:07

Hello and welcome to Candid Conversations with Dr. Kelsey. I'm your host, Dr. Kelsey, and this is the space where I share my honest thoughts, real experiences, and the no BS conversations I wish more people were having about movement, training, injury recovery, and life as an active human. The goal of this podcast is to help you better understand your body, think more critically about rehab and fitness, and feel more confident making decisions so you can stay active long term. Before we start, a quick reminder. I am a physical therapist, but I am not your physical therapist. Nothing here is medical advice. So if you're dealing with something specific, please reach out to your PT or schedule a session to work with me. Alright, now let's get into today's conversation. If you lift, run, or train consistently, you probably heard mixed messaging the second you announced that you were pregnant. Keep doing what you're doing, but don't let your heart rate get too high. Listen to your body, but don't lift more than 20 pounds. Everyone under mom suddenly has advice about what you should and shouldn't do with your own body, and that was definitely my experience when I was pregnant. And I understand that it's usually coming from a good place, and that people, especially family members, are just trying to be protective. But a lot of that advice is large is largely based on traditions or things people have simply always been told about pregnancy, which is why some misercise advice during pregnancy can sometimes seem contradictory. For a long time, we didn't have actual evidence on what was and wasn't safe, so most people erred on the side of caution. But we've had a lot of research come out in the last few years, finally providing us with actual evidence on the effects of exercise during pregnancy. Exercise and pregnancy is one of the areas I specialize in, so a lot of the constant badgering was mostly just annoying to hear when I was pregnant, because I already knew what I actually should and shouldn't be doing. But even then, it would sometimes get pretty distressing at times because it would make me feel like my choices about my own body weren't being respected by my family members and like people didn't trust me to make thoughtful decisions about my own health and the health of my baby. So I can only imagine how a person who is pregnant and has no idea what actually is and isn't safe during pregnancy would feel. So in today's episode, I want to unpack the three most common myths active women hear about working out while pregnant, where those ideas came from, and what their research and current medical guidelines actually say. But firstly, is working out while pregnant safe? For most healthy pregnancies, the answer is yes. According to the American College of Obstetricians and Gynecologists, or ACOG, in the absence of medical or obstetric complications, physical activity during pregnancy is safe and beneficial. Now let's start with myth number one, which is don't let your heart rate go above 150 beats per minute. If you've been told to keep your heart rate under that random beats per minute, 150 beats per minute, while exercising during pregnancy, that advice likely came from a single study done in 2012. In that study, six pregnant elite endurance athletes exercised up to about 90% of their maximum heart rate, and then researchers observed temporary decreases in uterine blood flow and temporary fetal heart rate changes at those very high intensities. But here's the problem. So again, the all the things they observed were temporary. And yeah, all the changes observed are temporary. So all of these things alone are not strong enough evidence to justify this arbitrary 150 beats per minute heart rate cap for every single pregnant person. It's additionally become outdated anyway, based on new evidence. So more recently in 2023, another another study was done that looked at pregnant uh participants performing vigorous exercise while monitoring their fetal heart rate and uh the blood flow in real time. All the pregnancies were healthy and they did not find it clinically meaningful, harmful effects when intensity was appropriately managed. So, in other words, high intensity exercise during pregnancy did not automatically compromise fetal well-being. And this new study, or relatively new study, aligns with ACOG's current guidance, which no longer recommends strict heart rate limits and instead emphasizes perceived exertion and individualization. And I'll go uh I go over this um when I talk a little a bit more about my own experiences later in this episode. So that brings me to myth number two, which is that exercise can cause miscarriage. So this is obviously one of the most fear-inducing myths around exercise during pregnancy. And I know the topic of miscarriage is such a sensitive topic, and it's you know, pregnancy is is such a vulnerable time in a person's life, and uh our tendency as women in general is to blame ourselves when any when anything goes wrong. Um, and miscarriage is no exception, but a recent study found that women who exercise during pregnancy had no increased risk of miscarriage compared to those who did not exercise. And you know, I also want to remind people that early miscarriages, so miscarriages in the first trimester, are largely related to chromosomal abnormalities. So it's it has nothing to do with what the woman is doing or if they're continuing to lift weights or exercise, you know, while they're pregnant, and it's just something that happens and we don't have we don't really have any control over it. So, you know, I it's easier said than done to just say like don't blame yourself if you've ever experienced a miscarriage, an early miscarriage. But hopefully this new paper kind of helps give you some solace if one of the things that you were wondering is whether continuing to exercise during the first trimester contributed to the miscarriage. So, again, for healthy pregnancies without contraindications, exercise does not increase miscarriage risk. However, there are certain conditions where moderate to vigorous exercise should be restricted or modified, and these can be thought of as red and yellow flags, um, where a red flag would be an absolute contraindication, like probably stick to low intensity um things, and yellow flags are just kind of taking it day by day, monitoring your symptoms, um and coordinating with your OB. Um, and for the red flags, these are things that you're gonna know ahead of time. So there are things that you're gonna be diagnosed with that your OB is going to be screening for, and you're going to be given restrictions on moderate to vigorous exercise by your OB for these. So the first one is severe respiratory or cardiovascular disorders with exercise intolerance. So if you're not able to tolerate exercise at all because of like a respiratory or cardiovascular disorder, obviously a red flag, absolute contraindication. Next are uncontrolled or severe arrhythmias, um and placental abruption, vasoprevia, uncontrolled type 1 diabetes, so emphasis on the uncontrolled part, intrauterine growth restriction, and so that's if you're diagnosed with intrauterine growth restriction, um then you will be placed on restrictions for exercise. And this is not if you've been exercising throughout your whole pregnancy, and now in your third trimester, you know, you're close to giving birth, like end of your third trimester, and then you're diagnosed with intrauterine growth restriction. Like um, so this isn't saying that exercise causes it, it's if you are diagnosed with it, don't exercise after the diagnosis. Um that's something that I've been asked on uh social media. Um, but obviously verify with your OB. Um, this is just my interpretation as a physical therapist, but I am not I am by no means an expert. So that's my interpretation of the paper. Uh next medical condition is active preterm labor. Um so if you're if you're going into labor um and and it's before the end of the before you're fully termed, obviously don't continue to exercise. Severe pre-eclampsia and cervical insufficiency. So all of these conditions are um I guess it's not red flags, but like a red light, like stop, like don't exercise if you have these conditions. So the next conditions are more um yellow lights. So in certain instances you can continue exercising, but if you but if obviously if you don't feel good, then definitely stop exercising. So yellow light versus yellow flag. Um so these relative contraindications are mild cardiovascular or respiratory disorders. So if you have some sort of like mild cardiovascular or respiratory disorder, but you feel like you're still able to exercise, like it's not really affecting you too much, um, like you still feel up for it, like it's not something you need to stop right away. Uh, mild pre-eclampsia. Um, so again, this is where you're going to be coordinating with your OB. Next is well-controlled type 1 diabetes. Obviously, keep an eye on your numbers, but if it's well controlled, then it's not as big of a concern in terms of exercise. Um, preter, premature rupture of membranes, um placenta previa after 28 weeks, untreated thyroid disease, multiple nutrient deficiencies, and or chronic un undernutrition, symptomatics or severe eating disorders, and heavy smoking in the presence of comorbidities. So obviously, all of these are, you know, if if you're being monitored and you're being treated by a care team, by your OB, by, you know, like other doctors, nutritionists, uh, not nutritionists, uh dietitians, then exercise um can be on the table, but it's something that you're gonna have to discuss with your care team on whether the benefits are gonna outweigh the risks that you have. Because if you have these conditions, there are still gonna be some risks. Um, but I also want to have you keep in mind that someone's moderate to vigorous like intensity is gonna look different than another person's. So um, so yeah, so so these yellow light conditions are gonna be something to keep in mind and something that you're gonna be continuing to monitor. But if you don't really have any conditions, if again, if you're um you have a pretty routine pregnancy, then there's really no increased risk of miscarriage if you exercise. So next is uh myth number three, which is you shouldn't lift more than 20 pounds. So there is no study that ever uh like predicated this um this random weight cap. It was just something that someone made up one day, basic pretty much. Um not one day, but it was just something that's like, oh well, maybe you shouldn't lift more than 20 pounds. But the problem is that it's well, firstly, it ignores your training history. So, like for some people, 20 pounds is yeah, kind of heavy, but for me, like 20 pounds is nothing, or even for like an a professional Olympic weightlifter, for example, like 20 pounds is absolutely nothing. So, yeah, the idea that lifting weights while pregnant should be kept at 20 pounds is kind of laughable. Um, firstly, it ignores your training history and your low tolerance, and it also doesn't take into account real life. I mean, if it was true that like if you lifted more than 20 pounds while you were pregnant, if it was true that that was gonna cause something to go wrong with your pregnancy, then no pregnant mom would be able to pick up their toddler. Um, like that, it just does not make sense at all. And also, a relatively recent study examined heavy resistance training during pregnancy and found no increased risk of adverse fetal outcomes or miscarriage. Um, it also found lower rates of certain pregnancy complications among trained individuals. I think a lot of it is because one of the biggest risk factors or one of the biggest complications during pregnancy is developing gestational diabetes. And the thing that's gonna decrease your risk of developing gestational diabetes the most is exercise. But yeah, so no surprise there that continuing to exercise did not increase um uh the risk of adverse fetal outcomes. Um, but again, I do want to bring up, like I mentioned earlier, that load is relative. Like someone, so whatever seems heavy to someone who's been lifting for a while is not gonna be the same as someone who's never done weight trading before. Like there are certain things that my mom or my mother-in-law consider heavy, and then like I pick it up and I'm like, this is nothing. So instead of limiting everyone to like some arbitrary weight limit, a more practical approach is to monitor how movements feel firstly, watch for symptoms, and then monitor for like how things feel, so not just movements, but um, and if somebody's having any symptoms, that's gonna signal the need to modify. So the yellow flags, so things that you're gonna be looking for to signal that maybe it's time to reduce load or maybe change um the exercise, like modify the exercise, for example, if you do barbell lifts, uh barbell Olympic lifts, maybe changing to dumbbells because it's your your belly's getting in the way, for example. So some of the yellow flags are pelvic heaviness or pressure, persistent pain during or after lifting, um, and that's gonna be anywhere, not just in the pelvis. So even like leg pain or whatever, um, loss of control or stability during the movement. So obviously, if you feel like you're you don't have good body control, then you know it's time to um it's time to pull back a little bit, and excessive fatigue that doesn't resolve. And um I can speak to that part um in a little bit when I talk about my own experiences during my pregnancy. So just like with the heart rate um restriction, that random like the 150 beats per minute, the goal here isn't to follow some arbitrary number, it's to adjust your intensity based on how your body responds and how it's feeling. So now I'm gonna talk about what this looked like during my own pregnancy. So how I applied this in my own pregnancy. Um so for strength training, um, I was surprisingly, like I surprised myself, I was surprisingly able to continue lifting weights um uh for most of my pregnancy. I think it wasn't until the very end where things started feeling way heavier, and so I um pulled back a lot. Um, but instead of using percentages or specific weight targets, um I just trained by feel. So, and then that's how it surprised myself. Like I think um I deadlifted like 180 um at some point. I think when I was in my second trimester, and I'm like, oh, this is also heavy when I'm not pregnant. So um, so yeah, that was surprising. Like I thought things would feel heavier. Um, but yeah, definitely by the end, I was just very uncomfortable, and so I did scale the weights back a lot. Um, I also paid attention to things like RPE, which is rate of perceived exertion, um, how stable I felt, and whether anything created unusual pressure or discomfort in my core and pelvic floor. And so that's kind of really when I started to scale the weights. Um, most of it was like the pressure in my pelvic floor. Um, same thing for my core. I I know a lot of people on social media asked me about like coning and doming because they would otherwise feel fine doing certain like toes to bar, for example, um, certain core exercises, but then they would they would get distressed with like the combing, sorry, coning and doming. Um my professional opinion, I know it's not the same as most other um pelvic floor PTs, but my professional opinion is just the presence of the conning and doming is not necessarily like um does not is not like the hard line that you need to stop doing core exercises. Um because the reason the reason why I like because you need your core, you need to continue exercising your core so that you don't lose too much of that um muscle strength after you give birth. Because especially, for example, I had a c-section, so like core stuff was definitely like not great right after I gave birth, um, or had my c-section. So like being able to exercise your core your core, strengthen your core, or maintain that strength for as long as you can is key and to me to in my professional opinion. However, conning and doming and discomfort, like for me, that's the that's the when you need to start uh modifying things. And and that's kind of what I did for my with myself. Like I I did start noticing some like conning and stuff, but it wasn't until like I just it just felt so uncomfortable and also had a lot of pressure, that's when I stopped doing a lot of the core stuff like um like toast bar, like hanging things from the bar, um like toaster bar and and pull-ups. Um, I think I did setups for a little bit longer, but eventually, yeah, that was also like my belly was way too big at that point. Um, I do uh so and then when it comes to um the cardio, so the excessive fatigue that doesn't resolve. So that happened really early in my pregnancy. Like even I think it was like even the week after I found out that I was pregnant. Um, like I just got so winded after running a mile. Um, and I think that's largely because I have beta talassemia minor, which means that my red blood cells are smaller and have less hemoglobin, so they carry oxygen less efficiently. Um, and so normally when I'm not pregnant, like right now I'm not pregnant, so my body has adapted to that. Um, and so I don't really notice symptoms day to day. Um, but when I was pregnant, obviously the pregnancy added extra demand to my cardiovascular system. And so, like once I realized that that I would just get winded so much earlier than expected, then I'm like, okay, I gotta, you know, I I guess I'm not gonna run throughout my pregnancy. Um, I like I would do 400 meters at a time, that was fine, but anything longer than that, like I would I knew I would have to scale back um or like do machines or something. And um anything, any workouts with the Echo Bike would also be terrible. So I knew I would have to super scale back the like the distance or the calories or whatever on the Echo Bike um because like I couldn't really go as hard on the Echo Bike. I would just have to like take it re uh like really easy, otherwise I would get two winded. Um, so that was my uh experience with my pregnancy and kind of how I modified things and I also want to remind you that each pregnancy is going to be highly individual. So another woman at my gym was also pregnant around the same time as me. Like I think she gave birth a couple weeks after I did. And she was able to continue exercising almost until the day she delivered, basically. Like she was doing like absolutely everything. Um, I mean, obviously, like towards the end, I think she had to modify things mainly because her belly was in the way, but like she was doing she continued doing box jumps for longer than I did. Um, she was able to do cardio for longer than I did. But I just felt but it's mostly because she felt fine, like the exercise didn't bother her versus like I like some of those stuff, like I did box jumps for as long as I could, but eventually I I would had too much pressure in my pelvic floor. Um, and again, I would get way too winded with certain cardio things. So, you know, all of these training decisions are gonna come down to what if you're having any symptoms and how you're feeling, um, and your own personal risk tolerance. So, again, with the box jumps, like some people might feel a little too scared to jump while they're pregnant, and that's totally fine. Um, obviously, I continued to jump for a while, and I think the other woman jumped for like even into her third trimester. So, so as long as you're not having any of those um yellow flag symptoms, then continuing to exercise um is perfectly fine for the most part. And so I've already kind of alluded to this, but if you're wondering what you should be paying attention to when exercising during pregnancy, there's no hard and fast rule. Like, unfortunately, if you're one of those, like, you know, one of those people who needs like a hard and fast rule, unfortunately there isn't one, unless you want there to be, but like it's all going to be based on how you feel and what that means, because I know that I know that phrase listen to your body like drives people crazy. It kind of drove me crazy a little bit, but but what it means is basically go by feel instead of like absolute percentages, either for weight or like heart rate ranges or something if you're doing cardio. Like if the intent so figure out the intent of the workout, if it's to be use a moderate weight, or if it's to um go at like a moderate intensity or something, then do what feels like it's moderate. Um, if you've been training for a while, then you'll know what that feels like. Um if you just started training, you might not be able to judge what's you know moderate or heavy or light or anything, but um you'll eventually learn what moderate feels like. So like moderate is just a little bit harder than like super easy. Um the next thing to look at is if you're having any symptoms. So definitely pay attention to if you're experiencing any symptoms while exercising. So um I mentioned the yellow flags earlier. Um, and so if you have those yellow flags, definitely it's time to modify. And if you want, you can consider consulting your OB. But red flags for for red flags, definitely stop exercising and consult with your OB. Um, and that's if you have vaginal bleeding, persistent dizziness, severe abdominal pain, excess vaginal fluid leakage, chest pain, or regular painful contractions. So all of those are signs that even if it's like the middle of your workout, definitely like stop the workout, see how you feel, um, and then call your OB as soon as you can. Um next thing to keep in mind is your individual physiology. So this is another reminder to not compare yourself to other people while you are pregnant, especially to other people pregnant as at the same time as you, um, even if it seems like you have the same fitness level. So as an example, I mean my personal example is not a great example because the other women also had a higher fitness level than me, but but you know, like I I didn't even try to pretend to compare myself to her because well, one, she I knew she was more fit than I was, but but two, like I know I the um blood condition I have is I think it's rare, I don't know. Um, because whenever I mention it, people don't know what I'm talking about. So um, but again, it's you know, I just want to remind you that everyone is gonna respond to pregnancy differently. So even if you want if you're like um one of my clients was um she's like a high she was she is a high lever level CrossFit athlete, and I think around the same time, uh oh my gosh, I forgot her name already, but um a a CrossFit Games athlete had like qualified for quarterfinals just like a few days after giving birth. Um she had completed like an open workout and like if you find someone like kind of at the same or similar fitness level as as you like it's really easy to try to compare, but but then luckily my client had like a really healthy outlook and she wasn't like I mean she well we both were like wow, how does she do that? But she didn't beat herself up about you know like not bouncing back, quote unquote, so to speak, right away. So definitely don't compare yourself to other people because you don't know what's going on with them, like you don't know if they feel great and you just feel terrible and yeah, so on and so forth. Lastly, is gonna be risk tolerance. So I touched on this a little bit with the box jumps. Um some people are gonna feel comfortable continuing with higher skill and higher impact movements, so like box drumps or toast bar or like um kipping pull-ups, others are gonna prefer to scale earlier. So even if I say, so going back to like the toasubar, for example, even if I tell someone like, oh, just because you're conning or doming right now doesn't mean you necessarily need to stop, they might choose to stop anyway, and that's fine, like that's their personal decision. Um and the same is true for like other things like cycling or even snowboarding. Like I've seen women continue to do all other sports like that. Um, but I mean again, they know their body their best, they know when they feel in control and when they feel out of control. So everyone's risk tolerance is gonna be a little bit different, and so that's what they're gonna use to determine if they want to continue doing something versus like pulling back or stopping. And so, in conclusion, is working out with pregnant safe? Well, obviously, yes. Um, if you have a healthy and uncomplicated pregnancy, there's not really a reason to stop exercising, um, unless you don't want to exercise. Um, I still encourage people to at least do some sort of physical activity, but if someone wants to pull back and they don't want to exercise as intensely as they were before, that's totally their um their decision. But there are definitely benefits to exercising. So just because you aren't uh exercising at the same level, at the same higher intensity, higher level as you were before, doesn't mean you should stop completely. Like you should still like at the bare minimum, like go on walks, you know, do do something, but you don't necessarily need to exercise at the same level as you were pre-pregnancy. So again, ask yourself does this feel okay to me right now? And if it does, you can continue doing it. If it doesn't, then pull back, modify. And my last reminder, the last um my parting statements that I want to leave you with is being pregnant doesn't mean that you need to start avoiding certain movements. It's just the pregnancy is an just another thing to take into consideration while you're training so that you can adapt as your body changes. So if you want to continue training while you're pregnant, the pregnancy kind of just adds another variable, much like having, you know, a bad sleep day or like not eating super well or being more stressed than like then that week than the week before. All of those things are factors that play into your training. The pregnancy is just another factor when it comes to your training. So that's it for today. If you like this episode, I'd really appreciate if you uh I'd really appreciate it if you can leave a rating or a review so that more people can find my podcast. Thank you so much for listening, and I'll see you in the next conversation.