Cold weather doesn't have to put a freeze on your outdoor exercise program. If you're careful, you can still work out when the weather turns chilly.

Clothing is critical. Although a double-thick cotton sweatshirt may seem like a good choice, it doesn't insulate nearly as well as synthetic fabrics like lightweight polyester, polypropylene, or moisture-wicking materials.

Don't overdress. You can overheat even in below-freezing temperatures. If you dress too warmly, you'll sweat a lot. Then, when cold winds hit, perspiration will rapidly evaporate, chilling you. You want to limit perspiration and keep it away from both your skin and the outside air.

Wear a synthetic material against your skin. This will let the sweat pass through the fabric away from your body. The second layer should be wool, polyester, or fleece for primary insulation. The third layer should be chosen for its ability to keep out the cold air, wind, and rain. This layer should be something lightweight and synthetic.

Layering also helps regulate your temperature. If you get too warm, you can strip off a layer.

You can lose a tremendous amount of heat through your uncovered head, so wear a hat, cap, or hood.

Your feet get cold first. Wear warm, waterproof boots or shoes. Insulate them with warm socks and keep them dry.

Because of the large surface area to volume, your hands are also more susceptible to cold. Gloves or mittens should be worn before the hands become cold. Choose mittens over gloves, because the fingers can warm each other and the mitten decreases the exposed surface area.

If you can see your breath, you're seeing moisture leave your body. So drink plenty of fluids, particularly if the air is cold and dry. Drink water before you go out, and bring some with you. Don't drink alcohol. Alcohol makes you lose heat.

Cold is a stress on the body, and so is exercise. Together they may be too much for someone not in the best of health. Talk to your doctor before you start a winter exercise program.

Older adults and people who take certain medicines or who have diabetes are at greater risk of their body temperature dropping in cold weather.

Here are other things to consider:

• Warming up before exercising is always important but even more so when it gets cold.
• If you drive to where you are exercising, make sure your car is equipped with emergency supplies, such as blankets and a portable charger.
• If the weather is particularly cold, it's probably too cold for you to exercise outdoors. If you do have to go out in extreme cold, cover all exposed skin to prevent frostbite. Know the symptoms of hypothermia (dangerously low body temperature), such as pale skin, shivering, exhaustion, confusion, slurred speech, fumbling hands, and memory loss.
• Cold air doesn't damage the lungs. Even very cold air is warmed to body temperature by the time it gets to the lungs. This cold air may, however, cause irritation of the airways for those who have asthma or COPD. These symptoms are described as shortness of breath or having a tight or burning feeling in the chest. Wearing a protective layer or scarf over your nose or mouth helps warm and humidify the air you breathe to lessen the chances of irritation of the airways.
• Check weather reports and pick the warmest time of the day to be outside. Take a break when you find a warm spot to rest for a minute.