Wednesday, June 28, 2017

Running in the Sun for Beginners

The sun is shining, the birds are chirping, and the world is conspiring to give you zero excuses to lace up and go for a run. It's really *really* hard to resist after being cooped up inside all day. A few precautions though can make that outdoor run much more enjoyable, not to mention safe.

There are actually three factors to consider: light, heat / temperature, and humidity. Light is the easiest to deal with. Basically, protect your eyes and protect your skin. For your eyes, I like wearing these Tifosi shades I found online. They're lightweight, durable, and come with their own case and cleaning cloth.

Next, protect your skin with sunscreen that covers with both UV-A and UV-B light with an SPF of at least 30. Remember to reapply hourly if you are doing a long-run, as you will sweat away your protection. Keeping a travel size sunscreen on you is not a bad idea.

Lastly, you want to wear clothing that covers your skin well while letting it still breathe and be ventilated. This means a cap or visor with clothes that wick away moisture. I prefer the Nike DriFit line of clothing but any of the wicking technology from the major brands will do. A cap like the Nike Aerobill works well, especially for runners.

While you want to look hot in your clothing, you don't want to *feel* hot. That feeling of overheating mixed with dehydration is awful. Why does this happen? According to Runner's World, the slowdowns due to heat can be significant:
It's generally recognized that for every 10-degree increase in air temperature above 55 degrees, there's a 1.5 percent to 3 percent increase in average finishing time for a marathon. (Translation: An extra 3 to 6 minutes for a 3:30 marathon with every 10-degree increase.) This slow-down occurs because heat impacts runners at a physiological level through various means, including dehydration, increased heart rate and reduced blood flow (and subsequently oxygen) to the muscles used for running.
Sweating helps you remove that heat from your body, as water has a high heat-capacity. That means each drop of water can carry away a large amount of heat relative to its volume. Unfortunately, as you keep running, the beneficial effects of sweating are offset by the dehydration that occurs. The lost circulating volume in your blood combined with the blood shunted to your skin to dump heat both reduce the blood available to your muscles to, you know, run! It's a vicious cycle that causes you to feel significantly slower.

And that's okay!

Learning how to listen to your body and adjust accordingly is the key to being a happy and healthy runner. In hot conditions, adjust your expectations and try to run to the same effort you trained for, rather than the same time. But what about humidity?

Humidity is defined as the percentage of water vapor in the air. It is related to the dew point, which is the temperature at which water condenses. As the Runner's World article notes, the closer the dew point is to the atmospheric temperature, the more difficult it is for your sweat to evaporate. This is also related to why a breeze feels good on a warm day: the breeze brings in new air that can be saturated with water vapor from sweat to carry off more heat. If the air around you is stagnant, there is nowhere for your body to dump that heat off.

All this science is awesome, but what should you actually do practically while running on a hot day, especially during a race?
  • Make sure your skin is protected from the sun 
  • During the race, try to run in shaded areas as much as possible
  • Re-hydrate more frequently than usual
  • Either drink or ingest electrolytes (ie Gatorade) especially later in the race 
  • SLOW DOWN - run to a particular effort / comfort level rather than a particular pace
As a rule of thumb, you can run up to a marathon in 50 degree weather, a half in 60 degree weather, a 10k to 15k in 70 degrees, and a 5k at most in 80 degree temperatures. Above 80 degrees? Consider that a rest day B-)


Disclaimer:  The information provided here is for general information purposes only. You should consult with your primary health care physician before beginning any nutrition or exercise program

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