Originally Posted by
Road Fan
How variable are the symptoms? Does everyone get the same symptoms, or do some of us only get a few? I'm nearly 59.
Yesterday I was out on a 35 mile ride in central Michigan, and toward the end the temp had to be near 100 if not above. The ride was challenging, but toward the end I saw my HR between 150 and 160, with no sensation of being near the edge or any unusual symptoms other than that reading. I had drunk three large bottles of water, ate a gel mid-ride, and tried to moderate my effort when I noticed the high HR. 2 miles before the ride end I dialed it back to about 8 mph/low cadence to initiate a cool-down before getting into the heat-soaked car, and HR decline was very slow.
5 years ago my LT measured at around 162 (maxhr in the same test was around 195), but I really don't know what it is today. On many cooler days I feel quite stressed when I see 160 on the HRM.
Was that heat exhaustion? The only one of the standard symptoms was the high HR.
Unusually high HR for the effort is almost always dehydration. If you keep pushing it in the heat with a HR like that, you'll get heat stroke, meaning a high internal body temperature, which is a medical emergency. Your body water is all you have to keep you cool. You run low on that, and it's not good. It's impossible to drink enough to keep up with water loss when exercising in the heat, so you're time limited. The trick is to practice drinking larger quantities of water/hr., and to have a plan B if it all goes wrong. The easy fix is to sit in the shade or some A/C place and drink water with electrolytes until your HR comes back somewhere near normal. I've seen mine at 135 just sitting. My experience is that I can ride at a sitting HR of about 105, just not hard. My normal resting HR is about 50, standing about 65. It doesn't take as long as you might think. 20 minutes will often do it. But that depends on having both shade and water.