By Coach Janet Hamilton, MA, RCEP, CSCS
Drink it in!
It’s toasty outside and the humidity is climbing. How does that affect your training?
It’s a well-established fact that performance in hot environments isn’t as good as it is in cool environments. Wonder why? It’s got a lot to do with something called homeostasis – or your body’s desire to keep things within a narrow operating range. When your core temperature climbs, your body responds by trying to ventilate that heat – and it does so most effectively through the evaporation of sweat and the redistribution of blood toward the skin to be cooled by that sweat evaporating. Trouble is – you have a limited amount of blood, and when it gets redirected to the skin for cooling, it’s not getting sent to the exercising muscles.
What this means is that muscles get a little less oxygen than they’d like and they have to rely on mechanisms of energy production that don’t require as much oxygen.
In order to satisfy the two opposing demands for the blood (fuel the muscles and cool the core) the heartrate increases. So if you're one of many athletes who use heart rate monitors to help determine proper training zones you may find that your pace and heart rate don't match up the same in warm temperatures as they do in cool ones.
Now the really cool part... your body recognizes that it doesn't really have enough blood to do BOTH things well (cool the core and fuel the muscles) so it adapts by building more blood! What? You mean I can make MORE blood? Yup... and you can use that little adaptation mechanism to your advantage!
This physiological adaptation takes time though, so be a little patient with yourself as you transition from cooler spring temperatures to the heat of summer. Ease your pace a bit and make certain that you're maintaining a well hydrated state during and between training sessions.
How will you know if you're well hydrated? You've got choices here:
- look at the color of your urine (if it's dark and you don't urinate often you're probably under hydrated, if it's clear and you "go" all the time you're probably over hydrated) or
- do a sweat test. For a sweat test, you'll simply weigh yourself nude, and then go out for a run in the heat. As soon as you finish your run and cool down walk (you do a cool down walk don't you?) go in and strip off your wet running clothes, dry all the sweat off your body and weigh again. The amount of weight you lost is how much sweat you lost during that run. Lost a pound in that hour-long run? You should probably try to consume somewhere between 12 and 16 ounces of fluid per hour when training in similar conditions. Most people can perform well even when slightly dehydrated, so there's no need to be obsessive and try to match it ounce-for-ounce, but you'd be smart to avoid getting dehydrated by more than 2% of your body weight.
Now for the fun part. You've endured the summer months, training in the sweltering heat and humidity and your body has increased its total volume of blood. Now -- when the cool fall temperature comes back (I promise ... it will come back eventually), your body will have more blood, but now there's no opposing demand for it and all that blood can now be used to fuel the exercising muscles! Yippee! One of my favorite tricks for shooting for PR in a race is to train through the summer, and then schedule the target race for the early part of fall, before you’ve lost all your heat adaptation! So – summer time running – the “pain” is definitely worth the gain!
Visualize your success -- and get there by training SMART
Coach Janet Hamilton, MA, RCEP, CSCS
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Barefoot Running, Is it Right for Me?
Nutrition for Taper
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Returning to running after an injury
Soothe the victim, go after the perpetrator
Stages of grief / denial in an injury
Mental Focus for Optimum Performance