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How to Train for Running in the Heat

By April 24, 2019May 20th, 2023One Comment
man dressed in layers of warm clothes, looking sweaty after heat training for running

There are many physiological benefits to heat training, not just for running in the heat. You train your body to cool itself down, reduce your core body temperature. You develop your sweat glands and don’t have to drink as much. Other benefits include improving your VO2 Max and blood plasma volume, so you get more blood to the muscles. 2:21 Marathoner Jason Cherriman (Strava) from Running Obsessive shares insights on why and how he uses heat training for running.

Heat training for running

I have a treadmill in my garage. We have had some nice weather here over the last few days, it has been gettin 23 degrees Celsius (73 Fahrenheit) outside. It’s a bit cooler in the garage. 

The idea is to put on loads of layers of clothes. So I will have a base layer, another termal layer, then a coat, wooly hat, 2 pairs of gloves, termal tights and some tracksuit bottoms. So I am wearing lots of clothes.

Some people might think I’m stupid or a bit crazy doing that, but there are several sound physiological benefits to heat acclimation. It’s not just for preparing yourself for running in the heat. 

It’s massively unpleasant when you are doing it.  What you will notice is that your heart rate is higher for a given pace, but what your body is trying to do is cool itself down. 

Benefits of heat acclimation training

  • it will reduce your core body temperature, which will help with cooling. 
  • It will increase your sweat rate, what that means is that when you are running at higher intensities like Marathon pace, your body has the ability to cool itself more easily. 
  • You will get more developed sweat glands, what that means is you will retain more electrolytes. Your balance is less likely to be out of kilter. You don’t have to drink as much as non-adapted runners would, especially within a marathon. 
  • It has demonstrated to improve your VO2 Max
  • It improves your blood plasma volume, so there is more blood to go around, which can only be good to get oxygen to the muscles 

There are a huge amount of benefits to doing it and it’s a cheap mans way to getting adaptations from 4 weeks of altitude 😀 

How to heat train for running?

You only have to do it for a couple of weeks, for those who do adapt to heat, you will have all the adaptations within a 2 – 3 weeks period. The good thing is, you don’t have to do it all the time. You don’t have to walk out to the garage every morning with your neighbors thinking you are a bit of a weirdo. You only have to do that for a few weeks in every marathon build up to be fully acclimatized.

I started them 5 weeks before my race (London Marathon on April 28, 2019), because I was nervous of doing them again, they are really not pleasant. Especially the first couple, they are absolutely horrific, but you get used to them. 

The aim is to gradually introduce them. What I did find, after one of the sessions, I felt terrible the next day. I realized I hadn’t properly hydrated after that session. I would like to get in 5 to 6 heat acclimation runs over a 2 – 3 weeks window before a marathon, to make sure I have got those adaptations.  

Some folks will spend time in saunas, steam rooms and stuff like that. I can see the benefit of that, unfortunately we don’t have one at home. I will stick with the garage for now. 

Full 80 minute episode of The Extramilest Show with Jason Cherriman, launches Friday April 26.

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More about Floris Gierman & Extramilest:



One Comment

  • Christof Schwiening says:

    I would add a couple of comments. Whilst Jason is right that many of the heat adaptation processes only take a few weeks to occur, there are some critical ones that take longer. My view is that ‘training-warm’ is probably something that athletes should do in general training all year round. First, the plasma volume expansion that occurs through training is greater when the training is done hot – probably because albumin is drawn in from the extracellular space in the skin as well as muscles. Long term plasma volume expansion is probably what drives a lot of the ventricular volume expansion that occurs during endurance training – i.e. increase venous return. Second, stressing osmo and volume regulation probably adds to the stress that causes adrenal gland hypertrophy (see Sports Adrenal Medulla) and it is likely that growing a large adrenal gland will take many months. Third, large amounts of fluid loss stress the volume regulatory elements of the circulation in general (not just the adrenal) but also – and this is speculation – the robustness of the neuromuscular junctions of the smooth muscle in the non-exercise portions of the circulatory system. During haemorrhage it is known that these junctions fail and that administration of catecholamines is effective at supporting blood pressure. During a marathon there is a lot of the circulatory system that is ‘switched-off’ by vasoconstriction and a failure of those ‘taps’ will cause a problem. Set against this is the ‘intensity’ of the heat adaptation stress. Jason is doing the equivalent of a ‘sprint’ effort heat adaptation with a few massive stimuli. My approach would be a big more mild with a lesser stress on every run. If heat becomes the limiting factor towards the end of your runs, then you are probably not far off the right level of insulation. Of course layering adds a stress – the layers add weight and the raised heart rate makes the training stress greater for a lower level of muscle damage. If you normally layer-up then racing suddenly becomes wonderful as the excess weight of the clothes are left behind and heat isn’t a problem. Indeed, excess sweating will make you a lighter runner in the later stages of the run – and lighter means a lower energy requirement, or a faster pace for the same effort.

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