Thursday, June 27, 2013

Hot Run

It was hot today.
Even in the shade.

But I went for a run anyway.
I ran slower than usual, which means I was REALLY slow.


According to an article in Runner's Magazine, the slow-down happens because heat impacts runners at a physiological level by various means - dehydration, increased heart rate and reduced blow flow, and thus less oxygen to the muscles used for running.

Can running in the heat help me adapt to running in the heat?

Yes, but it takes about a week or two of heat exposure for acclimatization to take place.
After a week or two of running in the heat, my perceived effort should decrease. I should have a higher blood plasma volume, an increased sweat rate, decrease in salt in sweat, reduced heart rate at a given pace and temperature and a quicker onset of sweating.

Then I did a little more research and came up with an article that said it isn't the heat or the humidity that makes it difficult to run...but the DEW POINT.
The Dew Point?
What the heck is that?

The dew point is the meteorological measure that best predicts how horrible my summer run is going to be.

Okay, so the dew point is the temperature when water condenses.

 Some television stations use the dew point system to tell about their weather.

So the closer the dew point is to the air temperature, the more saturated the air is and the less perspiration can evaporate and help the body cool itself, resulting in extra stress on the heart and lungs as the body attempts unsuccessfully to cool itself.

I found a chart that tells how running performance may be effected by the dew point:

50–54Very comfortablePR conditions
55–59ComfortableHard efforts likely not affected
60–64Uncomfortable for some peopleExpect race times to be slower than in optimal conditions
65–69Uncomfortable for most peopleEasy training runs might feel OK but difficult to race well or do hard efforts
70–74Very humid and uncomfortable
Expect pace to suffer greatly
75 or greaterExtremely oppressiveSkip it or dramatically alter goal

I did find a weather reading for Riverside for today that had the temperature and dew point. At noon the temperature was 98 and the dew point was 66.

Using the above chart, I can agree that it was uncomfortable.
Do I look uncomfortable? I thought I was smiling when I took the picture.
 I usually associate humidity with how hard my workout is going to be.

This chart shows the different combinations. I understand it better than the dew point.
My run took place today while it was 98 degrees and 35 percent humidity.
That put me right between the yellow and orange.
I like this chart better.

Heat index table
From now on, when I think of dew point, I am going to think of this -

This looks refreshing.
Tomorrow's forecast calls for temperatures ranging from 81 degrees with 49 percent humidity to 91 degrees and 33 percent humidity during my training swim and bike ride.
Caution and Extreme Caution.
I'll be in my air conditioned house drinking chocolate milk and reading a book before the weather gets to Danger.

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