The Heat is On

Running (and racing) in high temperatures means more than hydrating properly. Here's a summertime survival guide.

July 14, 2011

Water Gauge
How much you sweat tells you how much to drink

Proper hydration requires replacing fluids—on the run—that you lose through sweat. Figure out your sweat rate so you know just how many liquid ounces you need.

1] Weigh yourself naked (with an empty bladder) before your run.

2] Run at or close to your race pace for one hour and keep track of how much you drink (in fluid ounces) during that time.

3] Weigh yourself naked after your run.

4] Subtract your postrun weight from your prerun weight.

5] Convert the difference into ounces (multiply by 16).

6] Add to that number the amount of fluid ounces you consumed. For example, if you lost one pound (16 ounces) and drank 16 ounces of fluid, your total fluid loss equals 32 ounces.

7] Divide your hourly fluid loss by four to determine how much to drink every 15 minutes. In the example above, you would need to drink eight ounces every quarter-hour.

Super Cool
New technology helps runners survive the dog days of summer

After being submerged and placed in the freezer for two hours, the Arctic Heat Cooling Vest can stay cold for up to two hours. $220

Coldblack running shirt blocks up to 80 percent of heat absorption from sun. Find it on Trail Blazer Tee Coldblack. $50

IceFil's fabrication absorbs and disperses heat—not just sweat. Find it in Zoot Sports Ultra IceFil Cap. $30

Don't Cook Yourself
How to recognize when you're overdoing it

The best thing about heat illness is that it's preventable. "You simply have to pay attention to how your body feels," says Douglas Casa, Ph.D., A.T.C. "If things feel strange, back off." Here's what happens if you push it too far—and how to bring yourself back.

HEAT CRAMPS: Painful muscle contractions that occur during or after intense exercise
The Cause: Muscle fatigue, water and sodium loss
The Symptoms: Dehydration, cramps, fatigue
The Treatment: Massage, rehydrate

HEAT EXHAUSTION: Inability to continue exercise due to overwhelmed cardiovascular system, depleted energy
The Cause: Exercising in hot or humid environments, dehydration
The Symptoms: Include fatigue, irritability, nausea
The Treatment: Move to shade, elevate legs, apply ice bags, rehydrate

HEAT SYNCOPE: Fainting episode that occurs in high temps, typically during initial days of heat exposure
The Cause: Coming to a standstill immediately after activity, or standing suddenly or for long periods causes blood to pool in legs
The Symptoms: Dizziness, tunnel vision, pale skin, weakness, decreased pulse rate
The Treatment: Move to shaded area, elevate legs, rehydrate

EXERTIONAL HEATSTROKE: Potentially fatal condition characterized by a core temp of 105&deg F
The Cause: Includes vigorous exercise in a hot environment for more than one hour, poor fitness
The Symptoms: Include hyperventilation, disorientation, dizziness, vomiting
The Treatment: Full immersion for 30 minutes in cold (35 to 59&deg F) water