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Wednesday, September 11, 2013

Tail wind overheating, Cool Water

9/10/2013 25m 229#
Because of scheduling issues I started at the Bastille at 1pm on a very hot and humid day.

I crossed over to the South Side trail in search of shade. As I continued the heat was just killing me, I was overheating tremendously and was really going through water. So how do you travel through the desert? From water hole to oasis, so I stopped at UPMC's sports medicine facility by the trail on the South Side.

Holy Better Mousetrap, Batman! They've got a better scuttlebutt water fountain, just for bidons. I was really feeling the heat so I lingered in the air conditioning, and set out with fresh bottles of cool water.

I can't overstate the importance of water on the trail (and there isn't a lot of it). I was reminded as I was riding of these lines from Gunga Din:

When it comes to slaughter
You will do you work for water
And you'll lick the boots
of him that's got it

My father had this record:

Turning onto the Waterfront Trail I saw that the folks at Mitchells Seafood Restaurant had two coolers of cold water and paper cups out for the trail users. Absolutely wonderful.

At the Homestead Waterfront I deviated into the McDonalds (ice machine, water dispenser, air conditioning) to renew the water bottles and cool off for a bit. Although I had originally planned to ride to the Riverton Bridge across the Mon to McKeesport, this was just way too hot so I reversed and rode northwest to the city.

Remarkably, when I turned onto the route I realized I was turning into a decent headwind - and it felt much better. In fact, the whole second leg I was cooler, rode faster, and felt better while riding into a headwind and doing more work.

I have heard of this phenomenon but not experienced it before. When your groundspeed roughly equals the tailwind airspeed, the relative wind is near-zero and you lose the benefit of evaporative cooling from sweat. From this physiology site:

Head winds and tail winds

A head wind also greatly increases convection [heat loss] by removing heated air right near the skin and replacing it with air at the ambient temperature. Likewise, a tail wind at or near the same speed as the runner’s pace leaves air trapped near the skin and substantially decreases convection. Sweat evaporation is higher at lower air humidity and when running into a headwind, and lower in humid conditions or when downwind.

In these conditions (Hot/humid/tailwind approximating forward speed), it would seem like you were riding inside a sauna which is pretty much what I experienced. I loved riding home into the headwind. Never thought I'd say that.

And then finally, with two miles to go, I saw two young ladies and Yale Cohen riding together and I thought, Hey it's Yale Cohen! It's good to be back in the Burgh.

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