A guide to heat accli­ma­tion

Com­pet­ing in an extremely hot envir­on­ment is not only phys­ic­ally gruel­ing but over­heat­ing is a ser­i­ous risk which needs to be planned for. Hot cli­mates can lead to mild per­form­ance impact­ing prob­lems like heat cramp or exhaus­tion but also more severe con­di­tions such as heat stroke, when the bod­ies mech­an­ism to con­trol its own tem­per­at­ure lit­er­ally shuts down. By being adap­ted to the heat, your body can cope bet­ter with the stress and you can guar­an­tee a more enjoy­able race exper­i­ence.

Heat accli­ma­tion should be a key con­sid­er­a­tion for ath­letes look­ing to suc­ceed in any event with heat, such as Ultra X Jordan or Ultra X Sri Lanka.

How can we adapt?

The good news is that we can adapt to man­aging at high­er tem­per­at­ures pretty quickly, so run­ners don’t have to think about it until they start taper­ing for an event.

Here are a few options:

Heat Cham­ber If you don’t mind splash­ing a little, heat cham­bers are the gold stand­ard for heat train­ing as you can con­trol all vari­ables (temp, kit, pace etc) and there­fore sim­u­late the race envir­on­ment. To optim­ize the adapt­a­tion, it is recom­men­ded to do heat accli­ma­tion every day for a min­im­um of five days but up to 10–14 days before you line up on the start line. These ses­sions should last between 60 and 90 minutes.

Lay­ers To sim­u­late heat run with a few extra lay­ers of cloth­ing. Aim for about five to ten ses­sions over a peri­od of two weeks pre­ced­ing a race. This is a very basic DIY approach that may work if out­door tem­per­at­ures are high enough. When start­ing out, you should reduce your intens­ity slightly for the first few ses­sions to avoid any neg­at­ive heat-related effects.

Saunas and Baths Using an arti­fi­cial source of heat such as a sauna or bath can also aid adapt­a­tion. It is recom­men­ded to train for up to an hour pri­or doing so. This is so that your core body tem­per­at­ure is already increased, which will allow for great­er heat adapt­a­tion. You should start this approach three weeks out from your event for 15 minutes a ses­sion, three times a week. Closer to the event, you can increase the dur­a­tion to 30 minutes, four times a week. Whilst there may also be bene­fits from solely using the sauna or bath without exer­cise, exer­cising at 60% of your VO2 max in the heat pro­duces the quick­est res­ults.

Hot Yoga and oth­er meth­ods Any exer­cise in a hot envir­on­ment that raises your core tem­per­at­ure to suf­fi­cient levels for a long enough time induces adapt­a­tions. To max­im­ize the bene­fits try to do ses­sions of 60 mins and raise your heart rate whilst doing so. At the end of the day you want to ensure that you are doing some­thing which fits in with your life and if hot yoga is some­thing that appeals more than sit­ting in a sauna every day then go for it!

An Ultrarunners guide to Heat Acclimation Ultra X

Why it’s worth it

Sweat Rate By spend­ing a little time adapt­ing pre-race your sweat rate increases and you begin to sweat faster. This means that more sweat can evap­or­ate and you can cool down bet­ter. In addi­tion, the body adapts to lose less sodi­um which helps to main­tain the cor­rect salt bal­ances (mean­ing you are less prone to heat stress dur­ing the race).

Phys­ic­al Adapt­a­tion Your per­ceived rate of exer­tion at high tem­per­at­ure decreases as your body gets used to work­ing in the heat. If done cor­rectly there will be a reduc­tion in the core tem­per­at­ure com­pared to the same effort before accli­ma­tion. Since the body is now los­ing more flu­id through sweat (see above), the blood volume increases so that blood pres­sure can be more eas­ily main­tained and the heart rate will be lower.

Per­ceived Exer­tion Aside from becom­ing bet­ter equipped to func­tion when the sun comes out, there are noted per­form­ance bene­fits of heat accli­ma­tion that go bey­ond being ready to sur­vive in the extremes. Not only does heat accli­ma­tion bene­fit you when it comes to hot runs and races, but research shows that it aids per­form­ance in cool­er tem­per­at­ures as well. Essen­tially heat accli­ma­tion should make the hard efforts sev­er­al per­cent­age points easi­er and can boost run­ners VO2 max.


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