Heat training for a trail or ultramarathon race is one of many ways you can prepare yourself for a long day in the sun and help optimize your performance. If you are signed up for a summer or fall race, heat is an inevitable factor in your training. Your running options are to wake up well before the sun, load up on coffee, and hope you don’t start sleepwalking, or, wait until the sun goes down and get to bed late. Or, you can acclimatize to the heat through gradual and smart training and reap the amazing benefits that go with it. Heat acclimatization can be accomplished by anybody, its benefits are plentiful, and the differences can be felt in a relatively short time.
Heat training has been shown to increase your standard rate of sweat, which in turn helps you regulate your body temperature. Further still, the body naturally will increase its volume of blood plasma (An adaptation similar to how altitude training increases your red blood cells). A study in the 2012 European Journal of Applied Physics tested athletes before and after they trained for 90 minutes a day for five days in a state of moderate overheating. The study found that they increased blood plasma volume by 4.5%.
So, what does that mean in plain English? Blood plasma results in a greater cardiac output; you are more efficient at pumping blood. This also yields higher V02 max- the maximum amount of oxygen your body can process at your strongest physical exertion. Therefore, as your heat acclimatization improves, your perceived exertion drops across all paces. Things start to feel easier because they are.
Ways to Heat Train for Running
Heat training produces additional stresses on your body’s systems; like an intense workout program, it should not be piled on all at the same time. It is a delicate process, and too much of it all at once could also have very negative outcomes. Gradual exposure is key.
The Hot Bath Method
In our opinion, this is the easiest way to heat train and pretty relaxing too. Start off with spending some time in a warm to hot bath immediately after your run. These hot bath sessions should follow a normal-effort run that is done in temperatures that are typical to you. A good range of time to spend in the bath is 15-20 minutes, or as tolerable. Repeat this for 6-7 days before an event, leaving 3-4 days off from hot baths before the event.
The study found that athletes gained blood plama, started sweating sooner, had a lower rate of perceived exertion, a lower resting body temperature, and ran about 5% faster in a 5k time trial. Not too bad!
Weather Exposure Method
As you become more comfortable with the heat, start to run in the hotter part of the day. Do not do workouts at this point; keep your run at a pace that is comfortable to you, or even easier than normal. A 45-60 minute run at easy effort should be sufficient exposure. Run for a day at normal temperatures between the next mid-day run to allow your body to recover.
After a couple of weeks of running in the warm part of the day, start to gradually add clothing layers to your run. Start off with a long sleeve and work your way up to a beanie hat and puffy jacket over the following weeks. Heat training runs can start at 5 minutes, or in intervals/sets. Some ultramarathon athletes may be able to work up to 60 minutes or more. Heat training runs should be considered to have the bodily stress equivalent of a long run, regardless of the intensity. For safety, don’t attempt your speed workouts in heat gear unless you are well seasoned.
Always stop and de-layer immediately if you feel dizzy, confused, or sudden fatigue. Always allow your body to recover from heat workouts by sleeping in an air conditioned room. Heat training can fatigue the body in the same ways a long run does. Heat stroke and other dangers do exist, so use your best judgement to decide how to train safely.
Heat Training Tips
When race day comes and you are on your way to the finish line, your heat training can be fully utilized by pairing heat management strategies to it. Try some of the following ideas:
1. Stuff ice into whatever pockets you can. Running vests and belts work great for this. The ice against your body will be directly cooling your abdomen and critical organs. As water melts and drips, your body stays soaked and cooled.
2. Wear as much white as possible.
3. Wear removable arm sleeves and keep them drenched in water.
4. A desert hat can keep sun off your neck and shoulders.
5. Keep hydrated with plenty of electrolytes
As your body becomes more adapted to heat, you’ll notice yourself running faster or with less perceived effort, and well on your way to crushing your next race.