am) 13 miles steady and relaxed. HR came up easily and I never really felt like I was running.. more jogging.
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.