[[File:2013 Badwater.jpg|right|thumb|500px|I've done quite a bit of [[Running in the Heat]], from North Carolina's brutal summers, to winning the [[2010 Keys 100]] or pacing Chris Moon at the [[2013 Pacing Badwater 135| Badwater 135]].]]
Heat acclimation training can improve performance in hot and cold conditions. It also helps protect against heat injury and is particularly important when training for spring races. However, heat adaptation training can be dangerous and care must be taken to avoid injury or death.
Training for a spring race requires extra caution as you will have been training through the winter and be unprepared for warm conditions. While a spring race may be cool, there is also a risk of conditions that are warm enough (above 40f) to impair performance (see [Impact of Heat on Marathon Performance] for more details). Heat acclimation training, sometimes called heat adaptation training, can prepare you for these warmer conditions. This type of training is also valuable if you are traveling to a warmer climate for a race, or if you are training in the cool part of the day for a race in the warmer times. In addition, heat acclimation can improve cold weather performance. One study<ref name="performance"/> showed that heat acclimation improved performance in the cold by 6% and by 8% in heat.
The following advice should be used as guidance for heat acclimation training. Please use caution and common sense.
* Like any new training routine, start off slowly and build up both duration and intensity over time.
Be aware of how you are feeling and avoid pushing hard.
* Build up to exercising at 50% [[VO2max]] or above<ref name="Armstrong-1991"/>. 50% of [[VO2max]] is about 70% of maximum [[Heart Rate]]<ref name="swain"/> or "very slow running"<ref name="brianmac"/>.
* Use gradually increasing periods from 30 to 100 minutes over 10 to 14 days<ref name="Shapiro"/>
* Maintain hydration levels, as dehydration may impair key adaptations, such as increased sweat rate<ref name="TraversNichols2020"/>.
* Once gained, heat adaptation can be maintained for at least a month by training in the heat every five days<ref name="PryorPryor2019"/>. Without continued heat exposure, it's estimated that 2.5% of adaptation is lost each day<ref name="DaanenRacinais2017"/>.
=Fellrnr Heat Suit=
This 'heat suit' will allow for heat training even in quite cool conditions.
<td class="mbox-image"> [[File:Ambox warning pn.svg|42px]]
This heat suit works by preventing the body cooling itself, so it increases the risk of heat stroke. If you overheat wearing this heat suit, you may not cool off after you collapse. Please be careful taking this approach
, and start off with very low intensity exercise. Build up the duration and intensity very gradually , and monitor for warning signs. Please be careful, as I've had some close calls using this technique and it is dangerous. See "Symptoms of Heat Stroke" above.
|[[File:HeatSuit4.JPG|none|thumb|x300px|A second waterproof or windproof layer that traps the body's heat in the insulation layer. In addition, wear hat, gloves and ideally a neck warmer or face mask.]]
This combination will prevent the
majority of heat escaping your body.
[[File:SteamShower.JPG|none|thumb|300px|My steam shower, with a nice mosaic and a bench to relax on.]]
=The Science of Heat Acclimation=
For those who want to know more details about heat acclimation, here is a summary of the scientific data.
==Changes with heat acclimation==
Heat acclimation will produce
a number of benefits
* Increased blood volume<ref name="NielsenHales1993"/>.
* Sweating occurs at lower temperatures<ref name="Noakes"/>.
* The ability to consume and absorb more fluids (anecdotal evidence only).
==Notes on Heat Acclimatization==
* Younger runners do better in the heat than older runners but training can negate this<ref name="Armstrong-1991"/>
* Acclimation is faster in fitter athletes<ref name="Armstrong-1991"/>
* On return to a cool climate, acclimation lasts for about a week, then decays<ref name="Armstrong-1991"/>
<ref name="Armstrong-1991"> LE. Armstrong, CM. Maresh, The induction and decay of heat acclimatisation in trained athletes., Sports Med, volume 12, issue 5, pages 302-12, Nov 1991, PMID [http://www.ncbi.nlm.nih.gov/pubmed/1763248 1763248]</ref>
<ref name="Shapiro"> Y. Shapiro, D. Moran, Y. Epstein, Acclimatization strategies--preparing for exercise in the heat., Int J Sports Med, volume 19 Suppl 2, pages S161-3, Jun 1998, doi [http://dx.doi.org/10.1055/s-2007-971986 10.1055/s-2007-971986], PMID [http://www.ncbi.nlm.nih.gov/pubmed/9694427 9694427]</ref>
<ref name="TraversNichols2020">Gavin Travers, David Nichols, Nathan Riding, José González-Alonso, Julien D. Périard, Heat Acclimation with Controlled Heart Rate, Medicine & Science in Sports & Exercise, 2020, pages 1, ISSN [http://www.worldcat.org/issn/0195-9131 0195-9131], doi [http://dx.doi.org/10.1249/MSS.0000000000002320 10.1249/MSS.0000000000002320]</ref>
<ref name="DaanenRacinais2017">Hein A. M. Daanen, Sebastien Racinais, Julien D. Périard, Heat Acclimation Decay and Re-Induction: A Systematic Review and Meta-Analysis, Sports Medicine, volume 48, issue 2, 2017, pages 409–430, ISSN [http://www.worldcat.org/issn/0112-1642 0112-1642], doi [http://dx.doi.org/10.1007/s40279-017-0808-x 10.1007/s40279-017-0808-x]</ref>