A Coaching Legend on Training in the Heat

One of the first running books I acquired was a cast-off from one of my present athletes. He purchased it to see what great advice & counsel he could glean from its pages, but was immediately scared off by a couple of the formulas printed at the front end of the text. I gladly lightened his load, sat down for a brief read one fine weekend, & subsequently informed him of his folly.

It doesn't take a degree in physiology or a USATF Level III coach certification to understand or appreciate Dr. Jack Daniels seminal work, Daniels' Running Formula (Human Kinetics). In fact, if a runner did not want to invest in Timothy Noakes' Lore of Running I would recommend Daniels' work as an 80-percent (plus!) solution to the (as I wrote previously) one running book only question.

In fact, Daniels is (probably) one of the few former Olympian & Olympic medal-winning athletes who have gone on to coach (24) NCAA national individual champions, (7) NCAA national team championships, (110) collegiate All-Americans, and (4) Olympic marathon medalists. In my humble opinion, those are bona fides.

So, I'm shamelessly borrowing some his advice to Leukemia & Lymphoma Society Team In Training participants on running in the heat.

Respect the Heat - Of all the adversities that distance athletes face, heat is one of the worst. Although not necessarily so, excess heat often leads to dehydration, another major enemy of endurance athletes. It is possible to be adversely affected by the heat without becoming dehydrated, you can also become dehydrated without getting overheated. These two conditions affect the body independently.

Overheating - An overheated body is the result of inadequate cooling. Adequate body cooling depends on evaporation of water from the skin. The fluid must evaporate from the body's surface. So, when the body heats up, it starts to sweat and also starts to send more blood to the skin where it is cooled by coming in contact with the relatively cooler skin. The cooler blood then circulates, picking up heat from exercising muscles, which allows them to continue contracting more efficiently. When cooling cannot keep up with heat buildup, core temperature rises, and body functions start to suffer. When the temperature rises more than just a degree or two, function is adversely affected. When blood flow increases to the skin for cooling, less blood is being directed to the muscles. With less blood going to the muscles, less oxygen gets to the muscles, which affects performance. The body is more interested in self-preservation than in ideal race performance, so it usually chooses to maintain a desirable temperature before it allows you to keep a particular pace which would interfere with cooling. It's either go at a pace slower than you want, or overheat.

Give in to your body under these circumstances - it knows best. Slow down in the heat, if you must be in the heat.

Minimize the Effects of Hot Weather - You can acclimatize somewhat to hot weather, and exercising in the heat will speed up that process. However, it is not advisable to purposely exercise in the hottest part of the day. Rather, seek out the cooler times of hot days - early morning and evening. Early mornings are the coolest part of the day, but are often more humid. Evenings are often less humid, but considerably warmer. It is really a matter of personal choice - higher humidity and lower temperature or higher temperature and lower humidity. Either is certainly better than exercising when the sun is up. Wear light, loose-fitting clothing. Experiment with different types of garments, caps, socks, etc.

Dehydration - Dehydration is most often associated with the heat, but occurs even in cool weather. It is simply the process of losing fluid from the body. Again, the body knows what is best for it; when fluid levels get below a certain desired amount the body slows down in hopes of lowering the stress. If fluid levels get low enough, the body will just about stop functioning and you will pass out. Dehydration is a terrible way to go and must be avoided at all costs. Among healthy individuals, exercise is the most usual cause of becoming dehydrated, as a result of loss of fluid (via sweat) as you work to maintain desired temperature. Different people react differently to the same set of conditions. A loss of about 5 percent will negatively affect performance; more than 7 percent or 8 percent will not be tolerated.

Minimize the Effects of Fluid Loss - First, learn to drink during long runs or walks. Drink a lot with higher ambient temperatures. Your body can absorb about 1,000ml of fluid per hour, so learn to be able to take in that much, if necessary - just over a cup every 15 minutes. Drinking more than about 1,000ml per hour may not be beneficial, if not more than that can be absorbed anyway. If you lose 240ml per km (10 liters) and drink 4 liters in a 4-hour marathon, the net loss is 6 liters (13.2 pounds - 8 percent of a 165-pound runner's body weight - not good).

Some people will have real trouble completing a marathon, others very well may not. But, if it is hot enough, almost everyone will have trouble, and under some conditions, a run must be given up or the approach altered (walk/jog or just walk, which will lengthen the time taken to complete the distance, but which allows for greater fluid intake).

More To Sweat Than Water - As you sweat, you lose water and electrolytes, which is the reason specialized sport drinks have become popular - they provide you with water, electrolytes and energy. Unfortunately, many distance athletes become serious about what they consume only during races, but the body can gradually become lacking in electrolytes if fluid intake during daily training sessions is water only. Get in the habit of consuming a reputable sport drink during practice sessions. This will get you used to that particular drink and will also keep your body supplied with needed nutrients. The trouble some endurance athletes have in competitions is brought on by inadequate attention to what they do during practice, and they go into a competitive effort already partially depleted in some important nutrients.

How To Calculate Your Reaction To Warm Weather - Follow these steps to prepare your own guide to determine how much you need to drink to avoid dehydration during a marathon:

1. Record your nude body weight prior to and following runs or walks of 40 to 60 minutes at the intensity you expect to perform.

2. Record the temperature and humidity conditions for each of these test efforts.

3. If you drink, record exactly how much you drink.

4. Generate a table that presents the rate at which your body loses fluid under different temperature conditions, and what the loss would be over the course of a full marathon.

5. Take the steps necessary to counteract the predicted loss, to stay under a 5-percent loss.

The table below indicates how much slower you might expect to complete a marathon under different temperature conditions (compared to a nice day of about 55 degrees and moderate humidity). Under the indicated temperatures and with abnormally high humidity, these adjustments may underestimate the effect. Walkers will face similar reductions in time, but they have more time to ingest and absorb fluids so the problem should not be as great.

TEMP (F*) - RACE DURATION IN MINUTES
55 - - - - - - -2h10m (130’) - 2h30m (150’) - 3h (180’) - 4h (240’) - 5h (300’)
70 - - - - - - -2m - - - - - - - - 2.5m - - - - - - -3m - - - - -4m - - - - - 5m
81 - - - - - - -4m - - - - - - - - 4.5m - - - - - - -5.5m - - - -7.5m - - - - 9.5m
90 - - - - - - -6m - - - - - - - - 7m - - - - - - - - 8.5m - - - -11.5m - - - 14.5m
100 - - - - - -8m - - - - - - - - 10m - - - - - - - 12.5m - - - 17.5m - - - 22.5m