Written by Matt Mandel
Performance360 member and content contributor

It is summer time, and it is here to stay. It’s hot, were breathing harder, sweating all over the place and if you’re like me, it kind of hit with a ton of bricks. Morning classes might not experience it as much but if you’re at the midday and later afternoon classes it’s probably rocking your world unless of course you’re just a bad ass. Running down the alley way gets a little foggy and our bodies are asking what the hell is going on. Maybe even your “numbers” are not exactly where they were a few months back and you just feel like your sucking wind.

Unfortunately it’s not going to cool down for a while so let’s embrace it, work through it and accept the benefits that come with exercising in the heat because there are a lot of them.

(Oh, and if your preparing for any competition in the heat then you might want to read on.)

Quite a few things are actually happening physiologically when we are punishing ourselves out in the heat and it might not be such a bad thing. For starters, we start sweating profusely and if your pale and white like me you’ll look like a lobster not only during the workout but for hours after and you just can’t stop sweating. This is just our body’s way of sending more blood to our skin. Nothing to be concerned about but just our body’s way of trying to cool us down and thermoregulate.

Our bodies do not like it if we become too hot. If so, we usually seek refuge, like shade, an air conditioner or a cold shower. So nothing that should come of surprise to you, it’s hot, we sweat and turn red…..and we try and cool ourselves down…so what.


There are some things we can do to mitigate the heat stress we are placing on our bodies one of which is by staying hydrated. Not just the day of working out but the day before and the day before that so going out on an all-night binger and hitting it hard the next day might leave you flat on your back….ok that’s established. So when the total water and plasma volume of our bodies is reduced (state of dehydration), we are increasing the cardiovascular strain on our hearts and actually impairing our aerobic performance when exercising in the heat.

You will be unable to sustain blood pressure thus reducing skeletal muscle blood flow during exercise. In other words, you will be sucking wind and again your performance will suffer. So drink plenty of fluids….your body will thank you.

So as we continue to attend class during those peak temperature hours of the day, we are repeatedly exposing ourselves to heat stress, we start to acclimate, and if we do it for consecutive days, even as little as 3-4 days consecutively, some pretty cool things can happen. We see increases in submaximal exercise performance such as those longer type (30 minute) workouts as well as increases in maximal aerobic capacity (ie. 1 mile time, etc.). Our heart rates are actually able to decrease allowing for greater aerobic capacity resulting in better performance in or outside the gym.

If you’re hiking and doing some more endurance type workouts over summer like a 5k, 10k, half/full marathons, tough mudder, Spartan race, etc. this might be something to think about.

How to Burn Fat and Build Muscle

As we begin to acclimate to the heat, our sweat glands are actually able to conserve sodium better which allows us to conserve more fluid thus increasing our sweating efficiency. Essentially as we acclimate to the heat our body temperature decreases at which we be begin to sweat. There are several studies that suggest that heat acclimation increases total body water by 2-3 liters or 5-7%. So don’t be too concerned about what the scale says because it’s probably just a little “water weight”. It has nothing to do with % of body fat.

If you have found in recent weeks that your weight has actually increased a little, it’s going to be ok. This extra water on board is going to help. On those hot days if you have been working out in the heat you will be better off maintaining hydration through your workout and minimize the deficit after the workout. When you feel like you need water during the workout this may decrease as well as you become more “heat acclimated”.

If you haven’t been working out in the heat (normally early morning times) and think you just need to drink a bunch of water before you hit the 4:00 class and you’ll be fine, think again.

It might take a week or two of working out at that time to fully acclimate.


But wait it gets better, now that we have more water on board, our plasma volume expands as I mentioned. Why does this matter and what does it mean to me? Because our plasma volume expands during this heat acclimation phase our heart doesn’t actually have to work as hard during exercise because the increase in fluid/plasma volume will increase the blood pressure in our arteries allowing for an increase in oxygen delivery to our skeletal muscles allowing us to go faster and longer…the stuff that really matters.

Ultimately you’ll be able to increase blood flow and oxygen to those prime moving muscles and be able to cover more ground and all around optimize your performance. If you want to improve your performance in the heat, the stress we place on our bodies on those hot days like this past week will most definitely help. It may suck for a little bit and by all means if you feel like you’re going to pass out that’s probably your body saying, “STOP”.

It’s not the sexiest stuff we like to talk about like our huge deadlift numbers or our mile times but there is conclusive evidence that suggests there are several benefits from getting our sweat on and working out when it’s hot.

So, take home message. Repeated heat exposure induces adaptations that decrease strain on your heart and increase exercise performance and will actually reduce the risk of you suffering a heat related illness.

See you all in class at 4 tomorrow.

Matt Mandel is a member at Performance360 and content contributor. He holds a Masters of Science in Exercise Science, is a Certified Personal Trainer and former federal, state and county firefighter.

Cardiovascular adaptations supporting human exercise-heat acclimation.
Périard, Julien D. et al. Autonomic Neuroscience: Basic and Clinical, Volume 196 , 52 – 62.

Adaptations and mechanisms of human heat acclimation: Applications for competitive athletes and sports.J. D. Périard, S. Racinais, M. N. Sawka. Scand J Med Sci Sports. 2015 June; 25 (Suppl 1): 20–38. doi: 10.1111/sms.12408.

Consensus Recommendations on Training and Competing in the Heat Sports Medicine, 2015, Page 1. Sébastien Racinais, Juan-Manuel Alonso, Aaron J. Coutts, Andreas D. Flouris, Olivier Girard, José González-Alonso, Christophe Hausswirth, Ollie Jay, Jason K. W. Lee, Nigel Mitchell, George P. Nassis, Lars Nybo, Babette M. Pluim, Bart Roelands, Michael N. Sawka, Jonathan
Wingo, Julien D. Périard.

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