pm) 4 miles, 27:55 at HR average 147. I did a little experiment today and decided to try some Benji Durden methodology. It was 90 degrees and I wore thermal tights under running pants, a long sleeve shirt under a winter running jacket. And a winter hat. "Why?" you may ask? Benji told me that he felt that the extreme heat simulated high altitude and that a 4 mile run, for instance, was more like 6 in terms of aerobic benefit. Come to find out after doing quite a bit of reading.. he was on to something.. and this was back in the 70's, long before you saw the Kenyans and the Japanese donning sweat suits on hot days.
One theory suggests that increased blood flow to the skin in an effort to try and cool your body depletes your working muscles of oxygen, hence the high altitude simulation effect. I know that when I spend a particularly long time in the sauna I will see HR's up in the 150's while being fully hydrated.
Another possible benefit to the increased heat and subsequent oxygen debt is that it tricks your body in to thinking it needs more blood (this is what I read) and starts to increase blood volume.
And yet another possible benefit- your body may actually learn to preserve it's electrolyte stores and will be more reluctant to sweat them out. If your body senses that it may be in danger it will hold on to those electrolytes. This process happens over a long period of time. This is also why an athlete needs to acclimatize to heat for a hot race.
All this may be crap from a physiologists point of view.. but when I see the best runners in the world doing it, I may not let the facts get in the way of the truth.
For those of you who don't know who Benji Durden is, he's the guy with the beard...
I met Benji while on a run with Alan a few years back.. and sure enough, it was 90 degrees out and he was bundled up. Benji is one of those guys that I always held in high regard. The guy was tough- he ran 2:09:57 and placed 3rd at Boston in 1983. This was a decade where the fields were loaded with fast runners and a 3rd at Boston was something. Often times when you meet your 'idols' you are disappointed. Not so with Benji- in fact it went the other way. After getting a chance to run with him and talk to him I was even more impressed.
7 comments:
Great post. Personal experience, science, some history and a picture for the full effect. I guess avg. HR gets kinda thrown-out when one's all bundled-up.
Matt- I do think HR is thrown out and it's possibly due to the 'artificial' increase in effort. By shunting blood to the skin there isn't enough blood to supply oxygen to the muscles, mimicking high altitude or higher intensity/ volume.. this is speculation of course. I've read a bit about thermoregulation response but there is more research on reptiles than humans. The research on saunas is good though and this is a similar science but you throw exercise in to the mix which does change the bodies response.
I remember feeling the same when I had the opportunity to run and talk with Bill Rogers back in 1982. Those were an amazing group of athletes.
Good stuff Tim, I like reading your insight on training.
Well this one made me break out the textbook. It turns out that very similar to the way aldosterone affects reabsorption of sodium in the renal tubal it also does the same thing within the sweat gland itself. This addaptation happens rather quickly when a person is newly exposed to hotter temps. So we can change sodium loss to some degree but not completly. And as I'm sure you know water follows salt. Now the problem with this could be heat exhaustion or worse heat stroke. As you continue to push your body in the heat your core temp will steadily increase.For reasons not fully understood but possible due to tissue damage from sustained exercise this causes a release of interleukin-1,there are other factors as well but IL-1 is the main endogenous pyrogen. One of IL-1 functions in increased vasoconstiction of skin arterioles. In other words we can only take so much, that will be different for each of us. And then as was once written "boom boom out go the lights".
Nice Brfoot! I did take my temperature immediately following the run yesterday and it was 100.3, far from being in danger. I do think that one should be cautious with this.
I would have guessed that the body would respond with dilation rather than constriction in order to lower body temperature.
I wonder.. could you assume that the release of endogenous pyrogens through this type of training help to stave off sickness and infection! I know that the release is stimulated by the bodies response to damage, but is there crossover to say- a runny nose?
The endogenous pyrogen would actually be a negative side effect of the excercise and the part of of the equation that could get you into trouble. The IL-1 does not know you are exercising it thinks that something is hurting the body therefore it is trying to heat things up to kill off the offender. But yes I do think that if done carefully and at the very early signs of cold etc it can aid in preventing it from becoming a full blown infection.
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