You've grabbed a hooded jacket, and you're ready for a brisk walk in the great outdoors. But is that enough to keep you safe in cooler temperatures? An outdoor exercise routine at this time of year brings unique risks and benefits. You need a little planning and preparation to keep exercising outside in the weeks or months to come.
KNOW THE RISKS
Being exposed to long periods of cold weather poses numerous health risks.
Heart strain. Temperatures at or below 59° cause blood vessels to narrow, making it harder for the heart to pump blood throughout the body. "When your heart is asked to work harder, it requires more oxygen and greater blood flow. If your arteries can't meet that demand because it's cold outside, or because the arteries of your heart are narrowed by atherosclerosis, or both, it could put a strain on your heart or cause a heart attack," explains Dr. Beth Frates, director of wellness programming for the Stroke Research and Recovery Institute at Harvard-affiliated Spaulding Rehabilitation Hospital.
Muscle injury. Narrowing of blood vessels caused by cold weather could keep your muscles from getting the oxygen they need to work properly and stay warm and flexible. That could lead to muscle strain or injury.
Hypothermia. This condition occurs when the body loses heat faster than it can produce it, causing a dangerously low body temperature that can trigger a heart attack, kidney or liver damage, or worse. "Older adults lose body heat faster than when they were younger, and they may not be aware of it," Dr. Frates says.
Frostnip or frostbite. Exposure to severe cold leads to the freezing and injury of body tissue. Frostnip (when skin is red, swollen, and a little numb) hurts, but your body recovers when you warm up. Frostbite causes lasting damage.
Falls. If the ground is icy and slick from freezing temperatures, there's an increased risk for falling and suffering an injury like a hip fracture.
COLD WEATHER BENEFITS
Despite the risks, exercising in cold temperatures does offer benefits that you don't get in warmer weather. For example, exercising in the sunlight can help people who have seasonal affective disorder, a type of depression triggered by decreased exposure to daylight.
And some evidence suggests that exposure to cold weather may help activate brown fat cells, which are known to burn calories.
USE THESE STRATEGIES
If you have any kind of cardiovascular, lung, or balance issues, check with your doctor before exercising outdoors in the cold, and do it safely.
Watch the weather. "If it's extremely cold, rainy, snowy, or icy, exercise indoors," Dr. Frates advises. A good rule of thumb: skip your outdoor workouts when outside temperatures drop to 32° F (0°C) or below.
Choose the right time of day. Try to exercise during the warmest part of the day, around lunchtime, when the sun is at its peak. (Of course, this is something you should avoid during the summer.)
Protect skin, lips, and eyes. Even though it's cold outside, the sun still shines its powerful ultraviolet (UV) rays on us. Use a broad-spectrum sunscreen (one that protects you from both UVA and UVB rays), with a sun protection factor (SPF) of at least 30. Use lip balm with sunscreen as well, to protect your lips from the sun, wind, and cold. Remember to wear sunglasses.
Bundle up. Dr. Frates recommends dressing in layers so you can be comfortable without getting overheated. "Once you get going and moving your muscles, you'll get hotter. You may want to take off a layer and wrap it around your waist or put it in a small backpack." Avoid cotton, and wear athletic clothing that wicks away moisture while keeping you warm. Don't forget a hat, gloves, and heavy socks; we lose a lot of heat through our head, arms and hands, and legs and feet.
Do the warm-up. No matter what the weather, a warm-up is crucial to help your body adjust to increased demands on the heart and to get blood and oxygen to the muscles. "A fit young person can start with a sprint, but an older person is risking muscle injury and heart strain by doing that," Dr. Frates says. "Start exercising gradually: walk slowly or march in place for five minutes. Work out for 20 minutes, and then slow down for five minutes to cool down."
Stay hydrated. "You need to stay hydrated, even when it's cold outside, because you'll still sweat and lose fluid," Dr. Frates says. Drink water before, during, and after your workout.
ONE FINAL STRATEGY
Don't ignore your body's warning signs. Take it seriously if you're shivering, have chest pain, are out of breath, or feel extremely fatigued, and call for help immediately.