Heat and Humidity >> More Red Zone

I took my daughters to see The Miami Open, a pro tennis tournament with all the big names. Between outings of watching the pros, I found some time to go out and hit a few tennis balls with a local pro.

I strapped on the Polar monitor to track the intensity of a brief tennis outing in 85 degree humid weather. The weather was so hot and humid that some of the pros were having trouble with dehydration and fatigue. But – I like working out in hot weather because it’s easier to work up a good sweat.

After a 15-minute warm up of soft hitting, I asked the pro (Jimmy) to move the ball around the court, so I could get a good run. He adeptly hit drop shots, lobs and balls to the deep corners – and like a good golden retriever, I did my best to chase down most of them. 20 minutes into the session I needed a break for water and noticed that my shirt was already soaked. We upped the tempo, and my water breaks had to come every 5 minutes. After just 45 minutes I waved the white flag and sat down for a long drink turning over the court to one of my daughters.

The workout? 18 minutes at 90%+ of HR max (red zone) – and 12 minutes at 80+% of HR max (orange zone). The session was a cleansing sweat with all toxins and stress washed out of the body. After a cool swim I felt great – and I felt very good the next day with limited soreness (probably due to the shortness of the session).

Why the high heart rate? To cool down the body increases blood flow to the skin which decreases blood available for the muscles. The body also cools itself with sweat which evaporates in dry heat – but not in humid weather. The sweat on the skin drives up the body temperature which in turn raises the heart rate again.

Therefore, please be careful when exercising in hot, humid weather. Drink water frequently – and STOP exercising if you feel dizzy. We will continue to keep the temperature at Cardio High in the 60s – and we will not be pumping in hot humid air. So clients will have to work a little harder to generate those high heart rates.

– Mark G.