As with many activities, your exercise or fitness routine has a ''dress code'' of sorts. That is, there are things you can wear - or avoid wearing - that will make you more comfortable. For a start, all exercise clothing should be loose-fitting to permit freedom of movement. The President's Council on Physical Fitness and Sports advises never wearing rubberized or plastic clothing, since they interfere with the evaporation of perspiration and can cause body temperature to rise to dangerous levels.

As a general rule, you should wear clothes lighter than the temperature might indicate. Exercise generates a lot of body heat. In the summer, wear light-colored clothing to reflect the sun's rays. In the colder months, dark clothes will keep you warmer. When it's very cold, it's better to wear several layers of light-weight clothing than one or two heavy layers. The extra layers help trap heat, and it's easy to shed one if you get too warm. Also in winter, it's important to wear a hat such as a wool ski cap since you lose 40% of body heat through your neck and head. Don't forget gloves or mittens to protect your hands. And if your feet get cold, buy a slightly larger pair of shoes to accommodate extra thick socks.