|Me After a Really Hot Ride Feeling Awful|
Fact: On hot days you'll be slower.
Dissipating Heat Takes Energy
Your body first tries to cool itself - it moves blood to the skin, sweats, and all of that takes energy. This is "cardiovascular strain" - shows up as cardiac drift (higher heart rate in heat).
There's a point where you can't keep up and your core temperature starts increasing. Once it gets high enough, your body will intentionally slow you down to produce less heat so as not to risk overheating.
So that shitty fatigue you feel is mostly your body trying to protect you. Thank it.
What can you do?
- There are ways to trick your body/mind into thinking you're cooler than you are. This is probably a bad idea... it's doing everything it can to keep you safe, don't trick it into not doing that. Unless you hate your organs functioning.
- Evaporation of water dissipates more heat than drinking it! Dumping water on your head can work - if it's dry. If it's humid (ie. around my place, gahhh) then it's useless (or worse) It won't evaporate well, it'll just drip off and not cool you much at all.
- Some cyclists use women's nylons full of ice, stuff it down their jersey, and let it melt and keep them cool. Ice vests, too! Wild. Some people use pre-cooling too - drink a slushie, swallow ice cubes.
- Dehydration is actually not as big of a deal as people think... it's more important to lower your core (cold drinks or ice slushies!) rather than just consume luke-warm water.
- Clothing ... light colours are maybe not even better - hard to say.
Base layers when it's hot - this is something people do. For moderate heat this might be ok - we can spread out the sweat better. But if we're going to be soaking, it's not helping.
What can I do?
I'm going to make more of an effort to have cold / frozen beverages in the heat, but it's tough.
I have a 50km trail run coming up this week - and the high is about +19C - not crazy hot, but uncomfortable for running. I'm thinking of taking an ice bottle with me (it's 2 loops, so maybe I'll put it somewhere and pick it up on the 2nd lap?? If that's allowed - I'll check first).