The emphasis on core temperature comes from Allen Lim, Lance's new advisor. Lim previously served as nutritionist and special consultant with Garmin, and before that he had been an advisor to Floyd Landis. Lim is known for a lot of things, but foremost has been his emphasis on core temperature, from the cooling vests Garmin riders wore while warming up for time trials to his explanation for Floyd Landis using over 70 water battles during his epic stage seventeen solo break win in 2006. Stated Lim:
For Floyd, all of that direct access to bottles from the team's follow vehicle kept him in a virtual microclimate of 70 degrees F. This is such an extraordinary advantage that it's hard to conceive of any drug that could give him such a boost. It was water, plain and simple, not testosterone that was responsible for his incredible ride.
Whether you buy Lim's explanation or not, the effect of heat on performance is clearly negative. In a post from last year reviewing the Aspen Cooling Collar, I mentioned a study that found that raising the temperature from 70 to 90 leads to a 5% reduction in power in 20 minute TTs.
I'm not only curious about how heat harms performance, I'm curious about why Lim is concerned about core temperature during training efforts. Lance isn't pooping thermometers while racing; he's doing it while training. My guess is that Lim is tracking the effect of training on Lance's core temperature. That is, core temperature is another variable, along side heart rate and power, that indicates fitness and improvement.
I've often wondered how training in cold weather has a different effect on the body than warm weather. One notable effect is on breathing; nearly all cold-weather endurance athletes develop asthma. But my question has to do with specificity--does training in the heat prepare you for the heat? And if it does, how does it do it? This has relevance for those of us who ride indoors, which has the advantage of mimicking summer heat, but the pedalling action is not as beneficial as the real thing.
Several studies show that living in the heat allows the body to maintain a lower core temperature at rest and during exercise. When I examined the concept of mechanical and biological efficiency, I didn't mention the role of core temperature in efficiency; certainly, a body that is able to get rid of excess heat during hard efforts is more efficient than one which hoards heat.
All this talk of heat in the middle of January is absurd, I know. It's this little stuff, though, this anal attentive attentiveness, so to speak, that won Lance his seven Tours. Who knows? Look at what Lim's approach did for Garmin and Wiggidy Wack Wiggins.
Now he wears silk scarves.
Some day twenty years from now we may say to our grandchildren, "...and that's how Lance won his eighth Tour, by pooping out thermometers when everyone else was just looking at their SRMs."