The answer from experts: No.
(The answer from my friends Alicia and Karen: Chris, are you out of your mind????)
But back to the experts. John W. Castellani, an exercise physiologist at the Army Research Institute of Environmental Medicine, says heat causes more injury to athletes than the cold ("Too Cold to Exercise? Try Another Excuse," New York Times, January 17, 2008).
The key I have found, and experts agree, is dressing for success. Wear the right clothes: warm and dry makes a difference. Layer to prevent overheating with layers that can be adjusted as the athlete warms up, wear a hat, consider gloves and wear lip balm.
(Hint: cotton t-shirt under a cotton sweatshirt covered with a windbreaker won't help, no matter how many t-shirts you wear. Trust me on this one; some of us make mistakes so others don't have to. Sweat means wet clothes, and wet means cold. Remember that sweat is designed to cool down your body.)
Layers should include clothing that wicks away moisture. Check athletic stores and catalogs for suggestions.
Never underestimate the power of the hat. The body's heat quickly escapes from your head, the part of your body that always has plenty of blood supplying your brain. Even on cool (not cold) days, I wear a headband that keeps my ears warm.
I don't wear gloves, but my shirts all have really long sleeves. Wait, I take that back: I wore gloves in Central Park when the temperature didn't quite reach the 20s.
When you step outside, you should be cool — not toasty warm, or you'll overheat.
If you're worried that you'll freeze your lungs by breathing frigid air, don't. Your body warms up your breath before it reaches your lungs. Dry air, however, is a problem, no matter the temperature; athletes with respiratory problems should visit their physicians for guidance.
Freezing air can be dangerous for extremities, such as ears and fingers. Beware frostbite and protect yourself with gloves, hats and, if it's bad enough, balaclava. However, watch for overheating (as noted above).
Finally, experts say to keep moving. Hypothermia occurs when the body's core temperatures drops below 96ºF, and exercise generates heat. Water, or sweat, takes heat away from the body, so don't overdress and don't wear clothing that stays wet from sweat.
So, don't stay inside out of fear. Take to the road, the field, the diamond, the track — and be safe and smart.
See you outside!