Keeping cool

These nine warm-weather training tips might save your life

The return of warm weather may motivate you to expand your training programme and participate more frequently in week-end races, but it also increases your risk of heat cramps, heat exhaustion and even heat stroke while exercising. Many athletes believe that heat problems can’t occur unless they exercise for at least 30 minutes or so, but the truth is that heat difficulties can strike any athlete – from novice to elite – after just 12 to 15 minutes of strenuous exertion. Below, I’ve compiled a list of little-known, but extremely important tips which will help keep you cool – and in a vertical position – as temperatures and humidity climb:

1. Contrary to what we used to believe, you don’t have to train under hot conditions for an hour a day for eight days to become ‘acclimated’ to the heat (‘acclimated’ means your heart rate and core temperature remain under decent control during hot-weather exercise). In fact, you merely have to exercise at the moderately brisk pace of 85 per cent of max heart rate for about 30 minutes a day over a seven-day period to achieve nearly full acclimation. However, bear in mind that you’re only acclimated to the conditions under which you’ve trained. If you’ve been exercising in 75-degree, 20-per-cent-humidity conditions, that does not mean you’re ready to gambol along coolly on an 80-degree, 60-per-cent-humidity day

2. Since warm-ups ‘pre-heat’ your body (sometimes by up to 2 degrees Fahrenheit), you should always try to warm up in a shady area. That way, you won’t start your actual race or workout with already soaring body temperatures

3. If you swallow a packet of carbohydrate gel (such as Pocket Rocket, ReLode, Squeezy, or Gu) to replenish your body’s carbohydrate stores, make sure that you also simultaneously ingest about 10 to 11 ounces of plain water. Otherwise, those goopy carbohydrates will actually pull water into your gut, lowering the amount of water available to maintain blood volume and – in effect – dehydrating you

4. If you’re participating in a number of different events with breaks in between, stay in the shade between events. This will keep your body temperature down, and it will also prevent blood from accumulating in your skin, which is a natural response to sun exposure. If excess blood piles up in the skin, not enough is available to the muscles during exercise

Wear more clothes
5. It’s true that if you live in a cool climate but must compete in a hot place, you can improve your tolerance of heat by training while wearing excessive clothing. However, your inner garments should permit sweat to ‘wick’ away from your body quickly, so that you won’t plunge into heat exhaustion or heat stroke during your first few extra-clothes exertions. At least initially, you should also avoid prolonged bouts of exercise while you are too-heavily clad: start with just 10 minutes or so of such effort, gradually increasing the amount of time you spend ‘overdressed.’ Don’t attempt any of this without the advice and approval of your doctor

6. Don’t pin your staying-cool hopes on emptying cups of water on your head, sprinkling your body with a sponge, or running through water sprays which come from hoses or sprinklers. Even when this is done repeatedly, it doesn’t have much effect on body temperature. For example, scientists at the University of Wisconsin recently doused 10 fit runners with a fine water spray every 10 minutes during two-hour runs in the heat (85 degrees Fahrenheit), under both low-humidity and high-humidity conditions. Compared to the no-spray situation, spraying had no effect at all on core body temperature, heart rate, or the perceived difficulty of the runs

7. Sunblockers probably decrease your risk of skin cancer, but they can also heat you up, especially under non-humid conditions. Basically, applying sunscreen to your skin prior to exercise on a hot, dry day transforms your workout into a high-humidity training session. The sunscreen traps sweat on the skin surface, preventing its evaporation and hindering skin cooling, which eventually leads to higher-than-normal rises in body temperature. On the other hand, scientific evidence indicates that sunscreens can be used on sunny, humid days with little interference with body-temperature regulation. The humid air itself will prevent sweat evaporation and skin cooling; even a liberal application of sunscreen doesn’t seem to make that problem worse

8. Consumption of glycerol before exercising in the heat can preserve blood volume, improve your performance, and lower body temperature. The protocol for glycerol consumption is a bit rugged, though. Here’s what you have to do:
a) Two and a half hours before your exercise begins, drink about 5 millilitres (ml) per kilogram of body weight of a 20-per cent glycerol solution. Example: If you weigh 70 kilograms (154 pounds), you would drink 70 X 5 = 350 ml of your 20-per cent concoction. If you don’t usually think in ml, each 100 ml is about 3.39 ounces. Also, to make a 20-per cent glycerol drink, you must add 20 grams of glycerol to each 100 ml of water

b) Two hours before exercise, drink 5 ml of water per kilogram of body weight

c) An hour and 45 minutes before exercise, drink the same amount of water indicated in step b

d) An hour and 30 minutes before exercise, drink 1 ml per kilogram of your 20-per cent glycerol solution, along with 5 ml per kilogram of plain water

e) Finally, one hour before exercise, top everything off with 5 ml/kg of water

When you combine good glycerol intakes with hefty water consumption (as in the scheme above), the glycerol ‘holds’ the water in your bloodstream, allowing more blood to be sent to the skin for cooling as you exercise

9. Hot weather has a more dramatic impact on older athletes (those over the age of 40 or so), compared to younger individuals. That’s because the rise in body temperature that occurs during exercise is proportional to the intensity of the exercise, expressed as a percentage of VO2max. VO2max tends to decline fairly steadily beyond the age of 35 to 40, which means that – on average – any particular intensity will be a higher percentage of VO2max in an older person, compared to a young individual. Unfortunately, sweating – the key mechanism which keeps athletes cool – tends to decline with ageing, making matters worse (oldsters heat up more easily and cool off less easily, compared to younger athletes). As a result, in a crowd of people exercising at about the same pace in the heat, the older individuals will tend to get in trouble first. The point? Older athletes need to be especially scrupulous about the above precautionary measures. Since senior sports-active people also tend to lose more water via the urinary system, they also need to step up their water intakes: 12 ounces before a hot-weather workout or race lasting 20 minutes or more and six to eight ounces every 15 minutes or so during the effort.
Jim Bledsoe

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