How safe and effective are hot fitness classes?

Hi! How’s the morning going? Hope you’re having a great one so far! 

I’ve received quite a few requests for a monthly workout calendar for November. We’re going to have something a little different this month leading up to the holiday: Give PLANKS. 🙂 I’ll send the pre-turkey-day plan out tomorrow. If you’d like to receive it (along with the 30-day meal and fitness cheat sheet I put together), just enter your email below!

So, today I thought we could talk about hot fitness classes.

How safe and effective

They’ve been popular for a quite a while (especially with the presence of hot and Bikram yoga classes), and have lately expanded to various formats including heated spin, barre, and strength/bootcamp-style classes. I did some research on the effectiveness of hot classes -especially since there has been a bit of controversy- and had a hard time tracking down peer-reviewed studies. The one I did find, which examined the physiological effects of Bikram yoga, solely concluded that it is indeed a light to moderate strength workout.

Yoga journal

Some of the things I’ve noticed from my experience with hot classes:

-I feel more flexible. For hot barre especially, I feel so much more flexible during the stretches, and during hot yoga, I’ve been able to accomplish variations of a pose that I hadn’t previously attempted. When the room is heated, there’s also less need for an extended warmup because the muscles are already relaxed. 

-I don’t burn as many calories as I think I do. According to this article, because your body is consistently working to cool down, you’re redirecting energy that could be used for your workout. I’ve noticed this in my own experience, too. When I wore my heart rate monitor to Bikram yoga, my heart felt like it was POUNDING after each posture, and I looked down to see that my heart rate was in a low range (like I was leisurely walking around the neighborhood). The heated environment increases your perceived exertion, which makes you think that you worked harder and/or burned more calories than in reality. 

Yoga mats

-If I’m not working as hard, then why do it? I AM A SWEAT JUNKIE. I love, love, love leaving the gym in a pool of sweat. Of course, not every workout should end like that -you should alternate workout intensities to prevent plateaus and overtraining- but at least a few times a week, I like to look like I showered with my clothes on (usually after OTF, teaching spin or Zumba). I love the way a great sweat feels (so gross I know), and sometimes a hot yoga class is everything I need. It feels very cleansing and therapeutic to me.


(After a sweaty flow with my favorite Session Yoga girls)

-Speaking of cleansing, what’s all this about detoxification benefits with heated classes?? One of the commonly touted benefits of heated classes is that they aid the body in detoxification. There are two very opinionated schools of thought on the “detoxification” claim, so I’m not really sure of its validity. After a hot class or super sweaty workout, I do notice improved complexion.

Some tips for heated fitness classes:

-Check out the temperature and humidity of the studio before you go. Studios vary: some are mild in temperature while others are straight-up steamy ovens. For beginners, I suggest lower temperatures that feel warming (around 90 degrees or less) without being too hot. 

-If it’s your first time, be sure to let the instructor know. Drink lots of water the day before, the day of class, during and after class. Don’t be afraid to rest as needed, or to leave the room/studio if you get too hot. (If you’re taking power yoga, here’s a Focus On post so you know what to expect + one for Bikram.) Wear light, breathable clothes and bring a towel + water bottle.

Yoga stuff

-I don’t recommend heated intense cardio classes. For strength and yoga, I think it’s a great option to change up a workout, but wouldn’t personally recommend taking an intense cardio class (like spin or bootcamp) with the added energy expenditure of constantly trying to cool down the body. 

Some articles I found while looking around:

Are hot workouts safe? 

Experts say hot yoga is safe, but does it really have added benefits?

Hot yoga: the dangers and myths you need to know

Are hot exercise classes more effective?

What do you think about heated fitness classes? Where are my fellow sweat junkies?? 🙂 Any awesome new classes you’ve tried lately?



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  1. clare @ fitting it all in on November 5, 2014 at 4:19 am

    Oh, great topic!! I used to be a Bikram junkie, but now love “warm” vinyasa classes so much more! I didn’t like that in Bikram I was focusing SO MUCH on how hot I was and trying to breath, sacrificing my yoga work in the process! I feel like I can do SO Much better in just warm classes and still get a great sweat.

  2. Michelle C on November 5, 2014 at 4:27 am

    Oh man. I love, love, love both Bikram and spin but the idea of heated spin makes me a little woozy. Sometimes in a totally normal bikram class I’ll have to sit out a handful of poses (camel what?) So I really can’t imagine a high energy heated cardio class!

    • Fitnessista on November 5, 2014 at 8:32 am

      right?! i think it sounds terrible haha

  3. Tina on November 5, 2014 at 4:38 am

    Great post! I am also a sweat junkie. I’ve tried Bikram a handful of times and really loved it, but couldn’t justify the price for a membership. I agree with you that heated classes are better suited for certain types of exercises. And hydration is key! I remember leaving Bikram and wanted to jump in a pool of water.

  4. Linda @ TheFitty on November 5, 2014 at 4:47 am

    Humidity and heat are a combination of death for me. I absolutely detest summer and will never try hot yoga! I prefer to workout in the cold, wherr I feel more adrenaline.

  5. Tina Muir on November 5, 2014 at 5:05 am

    I have wondered about this too! I also read about how you do not burn as many calories as you think, which is interesting, but I definitely agree with you about the flexibility issue. Running 80 miles a week, I tend to get VERY tight, especially in my hips, and I notice a huge difference when I go to yoga, especially hot yoga in how much more relaxed they feel after. Thanks for the tips 🙂

  6. Dietitian Jess on November 5, 2014 at 5:09 am

    Awesome article, tweeted to share to others! This is definitely something I think alot of people think about but not a lot of research available like you said, thanks for sharing 🙂

  7. Brynn on November 5, 2014 at 5:18 am

    I like when a class is warm, but not hot. When the room is too hot I feel as though my performance decreases.

  8. Amanda @ Slimplify Life on November 5, 2014 at 5:19 am

    I’m the worst and I know I need to change but my favorite workouts are the ones where I leave pouring sweat. This is where my love for running comes from….even though I know some non-sweating ones are just as effective.

  9. RachelG on November 5, 2014 at 5:26 am

    I used to volunteer at my old yoga studio and for a few weeks worked the hot yoga night (couldn’t call it Bikram but it pretty much was). I know this is absolutely not true for everyone but a LOT of hot yoga/Bikram people I know are super Type A…even the teachers. This doesn’t mean they are bad people at all but I think the connection makes sense because these are the people who want to push to their max and then some, and they want to see results right away (aka a pool of sweat at your feet).

    There was a nurse/yoga student at that studio who was very much opposed to hot yoga. She said that when your body is warm like that you *think* you can push it harder than you can and this can cause injury. I think everyone should do what’s right for them but know when to back off.

    Personally I’d rather be in a yoga room that’s around 75-80 degrees and build up the heat and sweat through my practice rather than have it pushed on top of me.

  10. haley @Cupcakes and on November 5, 2014 at 5:38 am

    I tried out a hot yoga class and quickly learned it was not for me! I tried so hard to stay in the room, but felt dizzy and light headed for the entire 1 hr. and 30 min. class. I ended up just laying flat on my back on the mat and working on my breathing. I think I would definitely prefer a “warm” class instead of a hot one.

    • Fitnessista on November 5, 2014 at 8:31 am

      i prefer the warm classes, too. they help you get a good sweat going and relax the muscles, but you aren’t struggling to BREATHE

  11. Julie on November 5, 2014 at 5:49 am

    It seems like you know actual places to get evidence based sources judging by your first link to the NIH website, but then you cite sources such as huffington post and great list? I don’t understand this post, it’s just a compilation of generalized statements about working out in extreme heat.

    The reason it has me concerned is because after working as an exercise physiologist, I’ve seen slightly out of shape people, (as well as conditioned athletes – but usually this has been in an event, not just recreational fitness), try and fail at these classes, especially those with undiagnosed heart disease or electrolyte imbalances caused by the exercise. There is no disclaimer in your post and it seems like you are trying to come at it from an expert angle.

    Exercising in extreme heat can actually weaken the blood-brain barrier and decrease performance. The increase in heart rate is only temporary and combined with dehydration can cause even the most conditioned athletes to counter act any benefit of the exercise. This “high” from sweating you are talking about is actually dizziness from your body shunting blood to your major organs, because it thinks you are in crisis mode. Don’t even think about it if you are pregnant, either.

    There is no reason the average reader here should seek to exercise in extreme heat.

    • Fitnessista on November 5, 2014 at 8:28 am

      really glad to hear an exercise physiologist chime in. i wrote this late last night, so wasn’t able to reach my ex phys friends for their input. i do know where to get quality sources, but found that little research has been done about this topic. so instead, i thought it would be fun to talk about my experience (as this hasn’t been discussed in my training certs or any workshops i’ve attended) and turn it into a discussion topic. no where in this post do i state to be an expert on this, and i constantly encourage readers to seek medical advice before trying any new workout and to honor their bodies. at the same time, this is a blog, which facilitates discussion, which was the exact purpose of this post. i like reading about what others think about heated workouts and if they’ve enjoyed them or seen benefits in their own practice or workouts.
      i totally agree with many of your points, and would like to hear more about heated classes while pregnant. i know of a women who took bikram until the day she delivered, but personally, i didn’t want anything to do with hot classes while i was pregnant. it made me wonder if the body adapts to the heat over time as it does with other stressors and it doesn’t have the same impact after a while? like i said, i personally wouldn’t do it, but i thought it was interesting that many women who have taken hot yoga classes previously continue to do so without complications during pregnancy. thank you again for chiming in.

    • Julie on November 5, 2014 at 6:21 pm

      I’m not trying to start a debate or anything (I don’t really like hot yoga – too hard to breathe in my opinion), but if these classes are so harmful, why are they offered everywhere? Just a trend thing? I’m honestly just wondering. They seem to be offered at every gym now, so it doesn’t make sense, unless it’s just a lack of research thing…but that seems kind of odd, too. ??

    • mary on November 6, 2014 at 5:46 am

      This is a blog, not a masters thesis or a site making recommendations. There’s nothing wrong with this topic or those links (or doing yoga in heat, for that matter).

    • Alex on November 9, 2014 at 11:18 am

      I started practicing Bikram yoga 4 years ago and kept on practicing throughout my first pregnancy. During the first trimester it really helped me with nausea, I started the modifications during the second trimester and kept going 3 to 4 times a week until the night before I went into labour. I had a fast and natural delivery, I recovered very quickly, no perineum issues, my abs came back together in no time and I was back in the hot room 5 weeks after my daughter was born.
      I’m not saying that this kind of exercise suits everyone, but your statement “Don’t even think about it if you are pregnant, either.” really pisses me off.
      I believe exercise during pregnancy is very healthy, as long as the woman listens to her body and gets guidance from professionals. I wouldn’t recommend anyone to start a Bikram yoga practice after they found out they are pregnant but if you have been doing it for long enough and you are still enjoying it then there is no reason to stop.
      I’m pregnant with my second baby and I absolutely intend in going to the hot room several times a week. If anything, your ignorant and self-righteous comment just motivated me even more!

  12. Kelly @ Kelly Runs For Food on November 5, 2014 at 5:50 am

    Great topic. I’m a total sweat junkie too. I love hot flow classes because the added intensity makes me focus more on the moves. I tend to zone out in classes that are too low-key, but the heated room helps keep me in the zone with what I’m doing. I also love how much more flexible I get!

  13. Britt@MyOwnBalance on November 5, 2014 at 5:56 am

    I love hot yoga! I’ve never tried hot barre. I’ve
    been to some spin studios where it feels like it
    is hot but it is just a regular class with a ton of
    people sweating! I try to sit near the fans! I’ve given up hot classes during pregnancy though!

  14. kristin @ W [H] A T C H on November 5, 2014 at 6:07 am

    i’ve never been convinced of the scientific benefits of hot classes, but i just love the way i feel after a hot yoga class. there’s something about sweating so much and actually feeling clean at the end of the class that i absolutely love.

  15. Kris on November 5, 2014 at 6:22 am

    I cannot even imagine taking a “hot” spin or cardio class! I’m already dripping with sweat, I don’t need the room to be hot. I take a cardio & strength class twice a week and would probably collapse if it was a “hot” class as I’m already dripping in sweat 15 minutes into it.
    In all honesty, I don’t think it would even be safe.

    • Fitnessista on November 5, 2014 at 8:30 am

      i don’t think it’s safe, either. also, you sweat PLENTY during a regular spin or cardio class

  16. Kirsten on November 5, 2014 at 6:58 am

    I love hot yoga. I try to do it once a week. Our studio offers 60 or 75 minute classes. I have learned that the 60 minute class suites me better. Some people might think, what does 15 minutes matter? Well, in a room that is heated to 105 degrees 15 minutes is HUGE!

    I am currently training to run a half marathon in December. I do my long run on a Saturday morning then go to hot yoga at lunch time. Since doing this, I have had no soreness the next day. I think the warm stretch really helps my recovery.

    Hot yoga is not something that you can take lightly. I have been in a few classes and have seen people pass out, or five minutes into the class they are are laying down and done! A guy ran to class and then attempted the workout only to be humbled and spent the class in corpse pose!

  17. Cassie Vaughn on November 5, 2014 at 7:05 am

    I am not a sweat junkie, so I’ll be leaving the heated rooms to others.

  18. catherine c. on November 5, 2014 at 7:07 am

    From previous experiences not fitness related, too much heat and humidity have caused me to feel sick. For that reason, I have avoided hot yoga like the plague haha! I would try a “warmish” class however. I also liked the opinion of one of the above commenters about having a warm yoga class and then push yourself to that sweaty limit. Not be super sweaty because it’s so hot!

  19. Catherine on November 5, 2014 at 7:08 am

    Great topic! I have taken a hot yoga class. I was so nervous about it because I have a medical condition related to my blood pressure-my BP drops rapidly with sudden changes in temperature, position, etc. Yeah I know-why did I take hot yoga right?! I wanted to try it so I did it in summer as I figured then it wouldn’t be a sudden temperature change-it would just be really hot inside and outside! I got there a few minutes early to get acclimated to the temperature, which I think really helped. I survived the class and was a big sweaty mess! So much so that the next time I took the class, I brought a beach towel to put in my car so I could drive home (they did not have showers or a locker room-so I couldn’t change) without feeling like I was getting my car soaked. The beach towel was fitting, too, as I looked like I had went swimming :).

    There is a “celebrity trainer” who advocates doing cardio in a heated room to burn more calories or get results more quickly or something-but I would think that is dangerous. Besides, anything you lose by such means is just water weight anyway, right, so what’s the point?

  20. Lauren @ The Bikini Experiment on November 5, 2014 at 7:19 am

    I like hot yoga a lot and agree with a lot of these points. I feel like I have worked harder than I really have but it does aid in my flexibility and mobility which is a great feeling.

  21. Megan @ Skinny Fitalicious on November 5, 2014 at 7:24 am

    I actually like Bikram yoga for the perception it gives me of a cardio session and I’m not a yoga person at all. Unfortunately I couldn’t continue doing it. Couldn’t get over the stinky smell.

  22. Carrie (This Fit Chick) on November 5, 2014 at 7:29 am

    Ive actually never done a hot yoga class, but I agree with your points! Sometimes I just want a real good sweat, so thats why I would take it!

  23. Erin @ Her Heartland Soul on November 5, 2014 at 7:37 am

    I’m not sure these classes would be my thing but I definitely want to try them!

  24. Erika S. on November 5, 2014 at 7:41 am

    I’m not the most flexible person but I do like the feeling that hot/warm yoga gives my muscles. I’m trying a new to me place called Core Power Yoga. They have a sculpt class in a heated room…which is a blend of yoga w/weights. I like it but also realize that the room gets warmer if there are more students.

    I like the detox theory and go to korean spas a lot…and like you, love looking like I showered w/clothes on.

    So to me…it’s all about preference and variety.

  25. Christa @ Living Unbalanced on November 5, 2014 at 7:51 am

    I am with you on the sweat love. I LOVE a good sweat and there really isn’t a better feeling than walking out of the studio into cooler air after a hot yoga class. I’ve read that these classes are really just dehydrating your body…so I’m still trying to read up on the risks vs benefits of it.

  26. Lizzie @ The Magic Tree on November 5, 2014 at 8:07 am

    Thanks for posting about this. I have always wondered if there were any benefits from the heat except increased flexibility. There is a heated barre class that I attend regularly – the room is supposed to be set at 95, but I always check the gage and sometimes it’s in the 100s and you can FEEL it. If prefer a class in the 90-degree range but if there is any humidity, I will often get light headed or sick to my stomach (I’ve always hated being hot, so maybe that’s just my body’s response). I’ve only taken hot yoga once when I was a teen. I remember being so traumatized because I’d never even taken a yoga class and was so overwhelmed. I would love to try it now since I’m more familiar with yoga. As always, thanks for the great insight!

  27. Sandra F. on November 5, 2014 at 8:10 am

    Great post! I love a good sweat too! I have taken hot yoga and had to step out some times because it was too hot. I like it, but can only handle it once a week, because I get tired from it. I felt like I needed a nap afterward and the rest of the day I was drained. For this reason, I could not do a hot spin or bootcamp. Those classes are hard in itself, never mind adding HEAT. I’d die lol

  28. Tracy @ sprinklesandsquats on November 5, 2014 at 8:22 am

    I am 100% a sweat junkie… though, it really doesn’t take much to make me break a sweat hahah – I unfortunately (fortunately?) sweat wayyyy more than the average woman. I do love a great hot yoga class, though I agree, hot cardio or any other high intensity class just sounds like a recipe for disaster!

  29. Ashley @ A Lady Goes West on November 5, 2014 at 9:03 am

    Yes, I’m a sweat junkie too, and I love to get completely drenched during my workout. I would agree with all your points about feeling more flexible, and I DO feel cleansed after walking out of a heated room. I know that it is not for everyone, but I like that heated classes are offered a lot more now, because it’s just another way to get active and feel good (in moderation of course). Thanks for doing the research!

  30. Cara's Healthy Cravings on November 5, 2014 at 9:32 am

    I am not a fan of heated classes. I don’t like the stuffiness and the feeling that I can’t really breathe. I also don’t like saunas or steam rooms, so I guess that has something to do with it.

  31. Jennifer @ Show Me the Yummy on November 5, 2014 at 10:30 am

    Thank you so much for this information! It’s such a huge “fad” right now, and there are so many opinions on it.

  32. Christina @ The Beautiful Balance on November 5, 2014 at 10:38 am

    I used to live for super hot yoga but now definitely lean more towards no heat (room temperature) to low heat. I had the same experience with wearing a heart rate monitor and I was shocked.

  33. Tracy on November 5, 2014 at 10:55 am

    I love hot yoga for the increased flexibility and ability to go deeper into poses but I really prefer around 85-90* not higher. It starts to get difficult to concentrate on good form when all I’m thinking about is the heat and the sweat dripping in my eyes!

    My favorite class would be called “really really warm vinyasa flow”! Haha

  34. Amy S on November 5, 2014 at 12:03 pm

    I have never taken a hot yoga class before, but I would like to give it a try at some point. I enjoyed your post – it’s an interesting topic.

    Oh and can’t wait to see what GIVE PLANKS! is all about! What a cute name. Looking forward to getting it in my e-mail 🙂

  35. mary on November 5, 2014 at 12:11 pm

    I used to be a Bikram junkie but it caused an injury in my back that I still have to take pain pills for most days, and I haven’t practiced in 15 months. So I don’t recommend that class. But I love the heat.

  36. Megan on November 5, 2014 at 12:30 pm

    I am a Yoga teacher and I love hot yoga! But here is my issue~ right now it is very trendy and because of this many classes are instructed by people who should not be instructing. People who are not certified yoga teachers or who just don’t have much experience – and that is big problem. For example, in one class I took the teacher asked the class to perform headstand and forearm stand with little to no instruction. This was not an “experienced” class, from my judgement, and I was very worried that someone would get hurt. I have also experienced classes where instructors have students walking around/doing movements on slippery floors. Finally I have experienced classes where no one could do any of the movements besides the instructor – ummmmm??
    My advice is to do some research, or go by word of mouth and find a certified instructor. I think the biggest benefit or these classes for me is that the heat forces me to stay focused and really think about my movements – and this can only be facilitated by a really good teacher.

  37. Nikki on November 5, 2014 at 1:06 pm

    Looking forward to the plank/pre-turkey day plan tomorrow!

    Also, thank you for sharing your research about the ‘hot’ trend. I had wondered if it was all hype or if there were some benefits. I HATE being hot when I workout (guess that’s why I enjoy running outside in MN in the winter, lol), so based on this review, I know this is not for me. Thanks again!

  38. Julie on November 5, 2014 at 1:14 pm

    I can’t stand hot (or even warm) rooms while exercising. I’m perfectly happy to break a good sweat because I’ve exerted myself, but would rather not just be overheated. Yuck!

  39. Michelle @ Vitamin Sunshine on November 5, 2014 at 2:59 pm

    Here in Asia, they believe air conditioning is bad for during a workout. And because this is the tropics, just about all my yoga classes are “heated.” I do go to a hot class on Fridays though, and laugh, because half the girls try to get the instructor to not fully heat the room. I find it relaxing, and love the sweat. I think I focus better in those classes than the others. I wouldn’t go to a heated class every day though!

  40. April on November 5, 2014 at 5:09 pm

    Great post! I am a total sweat junkie and LOVE Bikram! The bummer is my acupuncturist cringes when i told her i use to do Bikram, she said it gets rid of the ‘chi’ in our bodies. I wouldn’t care so much, but I am trying to get preggers again so she said ‘no’ to the heated classes:( I do want my acupuncturist to give me more detail as to why it is bad to not have ‘chi’ so i have a better understanding….maybe your acu can shed some light on it?

    • Fitnessista on November 5, 2014 at 9:55 pm

      that’s very interesting! i’ll ask him what he thinks about it

  41. Livi @ Eat, Pray, Work It Out on November 6, 2014 at 5:46 am

    I used to do Hot Yoga all the time! I have to try again and see how it goes!

  42. Brittany @ Fun on a Budget Blog on November 6, 2014 at 5:24 pm

    My name is Brittany, and I’m a sweat junky…regardless of whether or not it enhances my workout. I love the feeling of being in that hot, humid yoga room.

  43. Amanda @ Diary of a Semi-Health Nut on November 6, 2014 at 8:41 pm

    Great topic and something I’ve wondered about since I took a hot yoga sculpt class a few months back!! The instructor is a friend and not to discredit her at all.. but it was awful. All I was thinking about was how HOT it was and how much pain I was in!! What are your thoughts on yoga sculpt? To me it was a bit like a bootcamp with yoga mixed in so I’m just curious on what your read is on these types of classes.

    That all being said, I do enjoy warm yoga classes. I totally feel like it improves flexibility and if you aren’t moving super fast it’s a comfortable temperature.

    My overall thoughts are…why get THAT sweaty? If the exertion is overly perceived I’d much rather sweat a bit in a cool room than feel like I’m dying to just look like I got a good workout! If I wanted to look all sweaty and feel gross at the end of my workout I’d just run in all cotton clothing!! 🙂

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