Monday, June 02, 2008

Heart rate and heat

This is a nice 4-mile jog around the neighborhood on a 78*F day. The blue part is pace, the red line is heart rate. Notice how the heart rate keeps climbing steadily up and up and up, moving up from 150s to nearly 170?

That's really BAD news on a hot day. Because on very hot humid days, my body starts accumulating heat and even at a nice steady modest jogging pace, the heart rate continues to climb up beyond what I can maintain. So I bonk and have to walk.

These are my past times to beat on Sunday - race day - at Eagleman. If I improve or hit close on all of them I have a chance of finally going sub-7 hours.

Swim (2007) 48:50
Bike (2007) 3:24:55
Run (2006) 2:42:02

However, the Race Gods may have other plans. Intellicast is calling for a high of 87 degrees and partly cloudy, the same as does Which, combined with ultra-high humidity (surrounded by open water on three sides and an ocean not too far away in the fourth direction), baking sun, radiant asphalt, and no shade -- spells a melt-down for many people (such as myself) on the run course.

Accuweather, however, is calling for 84 degrees and mostly cloudy. I sure hope they're right. *fingers crossed*

In any event, you can be sure I'll be keeping a close eye on my heart rate meter any time I race in hot, humid, tough conditions. I have no intention to push myself into heat stroke if I can help it - not even for a sub-7. I'm doing this for fun and health, and have no desire to wind up in an ambulance (the antithesis of health!).

Update: Uh oh, now the forecasts are a couple of degrees higher. MUST. STOP. LOOKING.


Lesser is More said...

You'd think if you hit refresh enough on the weather channel website, the temperature would go down...but no. Stuck at 87...for now.

The Wrench said...

My god have mercy on our souls. And I have a mop of black hair too........Thank god its been in the 80s and 90s down here all week.

GeekGirl said...

When I was listening to Galloway talk before the Ogden marathon, I think he said that for every ten degrees in ambient air temp above 60, your pace falls off by about 30 seconds. I don't know if that's true or not, but the heat will definitely slow you down. As you probably know, your heart uses your blood to try to cool you, so it's going to beat harder when its warm, leaving less energy for running, etc.
(But then, you probably knew that.) That's your science moment for the week. :-)

Nancy Toby said...

And Galloway is a walking skeleton.

I'll say for me (scientifically speaking) it falls off a ****load when I walk.

I'm even slower than that with heat stroke, though....