Sunday, July 6, 2014

Effects of Heat

Today, I took a four mile walk along a blacktop in on 98 degree sunny day. It was around local noon, so that made the conditions a little toasty.

Nothing serious happened, as it was only four miles, but I wanted to record for myself what did happen.

First of all, I wasn't a bit thirsty. I stopped after about 3.5 miles for a 32 ounce drink, and then walked home.

After I got home, I found myself  craving water. Over the next few hours I drank over a gallon of water. If I had to stay outside in the heat, it's possible some problems might have developed.

My urine was clear, so theoretically, I wasn't dehydrated. However, I did feel like I wanted to stay inside where it was cool instead of going outside.

What surprised me was the delayed nature of the minor symptoms. When I stopped walking, I felt good enough to go another four miles. It wasn't until after I stopped that other minor symptoms started developing. I started craving water. I was a little more tired than normal. I lost some of my appetite.

I found this information on air temperature and pavement temperature.

Extreme Maximum (C)
Ta 6.0 0.3 11.1 27.9 34.9 34.5 34.7 37.5 29.9 29.9 21.7 14.7 37.5
Ts 10.7 19.1 33.6 49.8 59.8 63.7 63.2 64.6 51.9 39.9 27.3 13.0 64.6
Tp 5.2 9.6 23.2 39.0 47.4 52.9 52.8 54.2 42.8 31.4 21.7 9.7 54.2

The outside air temperature was 98 F, or 36 C. According to this table, the surface temperature would have been about 63 C, or 145 F. This is a rough estimate, but I think I can safely say it was hot. My feet didn't feel it as my combat boots are made for desert conditions.The air temperature I felt was somewhere between 98 and 145 degrees. I learned roads give off radiant heat, so the temperature may not be a complete measure of the heat absorbed.

Another mild symptom was a little tiredness in the eyes. I was wearing sunglasses. I suspect a person who walked all day could develop something like snow blindness.

The important lessons in this post are NOT about surviving the desert heat. It is, for the person thinking of real-hiking this route, to get as much experience in expected conditions a s possible. Today, I learned it would be difficult to cross the Nevada desert unsupported, except in the cooler temperatures of spring and fall. Even then, the real-hiker should attempt a similar trip in safer conditions. Although I live in the desert, I am not familiar with desert survival except in an air conditioned car or within easy walking distance of safety.

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