Every single year since I moved to Mississippi more than a decade and a half ago, I think that I'm ready for summer running. And every single year June, when the hot weather starts, is a disillusioning wakeup call.
I learned years ago to beware of triple witching hour: that period of the morning between 8 and 9:30 AM when heat, humidity, and radiant sun combine to broil your a** in a bad way. So I avoid that by rising at 5 and getting on the roads by 6.
I learned years ago to weigh myself before and after runs and assess water loss that way, then place water bottles along my various routes and pause at least a couple of times to rehydrate. But even rehydrating generously, it's still easy to end up three pounds down by the end--and I've learned that you absolutely feel that as increased HR and effort for a given pace. In the summer I sometimes switch to loop runs--running 5 mile-and-a-half loops in a park--so that I can stop every loop and gulp some water from a big bottle placed in a strategic location.
I learned a couple of years ago that the summer slowdown-effect in warm, muggy weather isn't just caused by dehydration and overheating (i.e., the body having to work harder to push out sweat and keep cool, like a small car laboring to keep the A/C pumping), but by the fact that water vapor in the humid air proportionally decreases the amount of oxygen you're getting with every breath. In effect, running at low altitudes in warm, muggy weather is a kind of altitude training--which is why, when fall comes and the humidity fades away, or when you happen to score an unseasonably cool, dry summer day, you feel much stronger.
I've learned all that. I think of myself as a competent summer runner. But as I age--60 this spring--I'm finding the whole thing harder to take. This morning was a good example: I missed my long run yesterday, so I decided to run an easy 10 this morning. (I'll run 8 on Wed/Fri and 12 or so on Sunday, with 3-mile jogs on the other days). My easy pace has declined over the years, but summer just makes it worse. I started slow and stayed slow. For the first time in maybe forever, every mile was 10:00 or slower. I averaged 10:20 at an average HR of 140, which is 75% of max for me. That's not running. That's barely jogging. It was no fun. 73 degrees and 90% humidity when I started, low 80s when I finished. Dew point around 70. That's not as bad as it sometimes gets.
Ten years ago I was easily running 15 milers on summer weekends, and they weren't slow.
Please share tales of summer misery--and triumph, of course. Tips and tricks for surviving the hot stuff. Better yet, share tales of running at genuinely bad dewpoints. Florida, Louisiana, lemme hear your tales of woe.