Questions about heat acclimatization and athletics

We're in the final laps of the southern summer, which means that I've had several months to think about the heat and how the body adapts to it. It's clear that the body does indeed adapt to performing in hot conditions, and I know what a few of those adaptations are, but there is a lot that I don't know about heat and athletic performance. I'm not sure if anyone knows.

How do you adapt to heat?
Obviously you're going to adapt to running in the heat if you get out and run in the heat. But is there anything else you can do? World-class runner Benji Durden had a reputation of getting out in the heat of the day and running in double sweatsuits. I can't say that I ever saw him actually doing this, but it's one of those great stories that the truth is never going to kill. Would such training increase the degree of heat adaptation, or cut down on the time required to adapt to heat? Durden was also rumored to sleep in a warm-up suit. This brings up the question of whether spending more time in the heat either hastens or increases heat adaptation. Should you avoid air conditioning? Wear flannel shirts? Drive around with the heater on?

Does a greater volume of training help?
If you run a lot of miles, it seems like it would increase metabolic efficiency (cutting down on the waste heat your body produces). At the very least, though, it should lower your body mass, decreasing the amount of energy your body needs to run and giving your body a more favorable surface-area-to-mass ratio for radiating heat (beach balls have a poor shape for heat radiation, so the less you look like one, the better). Are there other heat adaptation mechanisms that would be triggered by high mileage?

Does training in heat only get you ready to race in heat?
Assuming that the best way to prepare to race in heat is to train in heat, is there a more general benefit to training in the heat? This is an attractive idea if you're sweltering on the coast without the means to relocate to an altitude training camp. Altitude training seems to have some general benefits, so why not heat training? I've asked around, though, and haven't come up with any answers. I once spoke with Chuck Amato, an assistant football coach at Florida State University, when his players were in the middle of two-a-day August workouts, and asked him about the possible benefits of heat training. He shrugged. "We have to do the workouts, and it's hot." Maybe the University of Minnesota football squad is missing out on an advantage that the Florida schools have in the pre-season, but there doesn't seem to be any research that indicates so.

Does ability to adapt to heat decline with age?
This is something you start to think about as the miles and the years behind you add up. You'll find many older runners who say that they don't handle the heat as well as they did in their rosy youth, but is that true, or are their recollections blurred by the foggy lens of memory? Assuming that it is true, though, there are other age-related variable to consider--lighter training loads, slower pace (the same number of miles has you out in the heat longer), and, um, increased body mass. If there is a separate age-dependent factor in heat adaptation, it would be interesting to know what it is.

Those are some of the questions I think about when I'm sweating. If they haven't been answered yet, then they're going to need someone with an exercise physiology lab (and maybe some grant money) to settle. Budding scientists are welcome to any of these puzzles; send me a link to your dissertation when you've got a solution.

Links:

• An article I should have read first:
  http://www.sportsci.org/encyc/heataccl/heataccl.html