Cold weather shouldn't present any serious problems if you protect yourself and are in reasonably good health. If you have heart problems, however, ask your doctor if it is okay for you to brave cold weather -- even if he or she has already given your walking program the go-ahead.
The reason for this precaution is that the body's reactions to low temperatures put stress on the cardiovascular system. These reactions include constriction of blood vessels in the skin, shallow breathing through the mouth, and slight thickening of the blood, all of which can lead indirectly to angina (chest pain) in people with heart disease.
Cold lowers the heart's supply of blood, while exertion raises the demand for it. This imbalance between supply and demand can also cause attacks of chest pain. If you have heart trouble, your doctor can give you advice on how to minimize adverse effects of cold on your heart and when to do your walking indoors.
Even in people who don't have heart disease, cold exposure can raise blood pressure. To conserve heat, the muscles contract to obstruct the flow of blood to the arms and legs. This reroutes extra blood to the vital organs and boosts the blood pressure.
People who have high blood pressure, therefore, need to take extra care in dressing warmly for cold-weather walks.
Asthma is another condition that can worsen in the winter. Inhaling cold, dry winter air can trigger bronchospasms -- contractions of the air passages in the lungs.
To avoid this, many doctors advise their asthmatic patients to take their anti-asthma medications just before they exert themselves. If you have asthma, see your doctor before you walk in cold weather.
Also at special risk in the cold are people with Raynaud's disease, which often accompanies connective tissue diseases such as scleroderma and lupus. Cold causes spasms in their blood vessels, which cut off the circulation to their fingers and toes and turn their skin a "chalky" color. These people are advised to exercise indoors during cold weather.
Learn about weather hazards to avoid when walking in our final section.
To learn more about walking, see: