Cold Weather Exercise

Heart attacks and strokes are associated with high blood pressure and increased clotting, and systolic blood pressure increases up to 1.7 mm Hg in the winter months compared to the summer months (Am Heart Assoc Hypertension Scientific Sessions, Abstract 493. Sept 9, 2023). Cold weather is associated with an increased incidence of heart attacks (Arch Intern Med, 2004;164(8):863-870). If you have heart or lung disease, you are far more likely to die in cold weather than in the heat (Lancet, May 10, 1997;349(9062):1341-6).

How Cold Weather Can Cause Heart Attacks
• Cold temperatures cause your body to produce large amounts of adrenalin which constricts your arteries to raise your blood pressure and to make your heart beat faster. If you have damaged arteries or heart muscle, your heart can start to beat irregularly and you can die.
• Cold thickens your blood and makes it more likely to clot. A clot can shut off blood flow to the heart to cause a heart attack (BMJ, 1984; 289: 1405–1408).
• Cold causes the liver to make more fibrinogen that increases clotting (Lancet, 1994; 343: 435–439).
• Cold raises blood cholesterol levels (Am J Med, 1986; 81: 795–800).
• A drop in body temperature weakens your heart muscle, and people with weak or damaged hearts can go into heart failure and die. Winter also deprives many people of sunlight and vitamin D which weakens the heart muscle.

Cold Weather Can Damage Your Lungs
Almost 20 percent of North Americans have exercise-induced asthma, which usually is caused by breathing dry cold air, not by exercise. When these people breathe dry cold air, the muscles around the tubes that carry air in and out of the lungs can constrict to make them short of breath. Exercise-induced asthma can occur in people who do not have asthma otherwise. It affects almost 50 percent of elite cross-country skiers, ice skaters and hockey players. Exercise-induced asthma is far more common in winter athletes than in those who compete in the summer. Dry cold air also increases risk for common winter infections such as colds or influenza, which cause inflammation that can damage arteries to increase risk for heart attacks.

Tips for Outdoor Exercise in Cold Weather

• If you have heart disease, your doctor probably will recommend that you should not exercise outdoors in temperatures below 50 degrees Fahrenheit. 

• Exercising in cold weather can cause chest pain in some people who have no problems when they exercise in warm weather. When cold wind blows on your face, your heart rate slows down. This decreases the blood flow to the heart and can cause pain in people with blocked coronary arteries. While freezing your face slows your heart, freezing your fingers makes your heart beat faster. Cold hands will not cause chest pain, but a cold face can. 

• Air is an excellent insulator, and layering clothes traps air. Wear a silk or loosely-woven polyester inner layer that wicks sweat away from your body. Loosely woven wool or synthetic-fiber sweaters or vests are a good middle layer because they trap insulating air and wick moisture to the outside. The outer layer material should be tightly woven so it blocks the wind; a waterproof rain jacket can perform this function. Nylon and Gore-Tex are outstanding because they can be extraordinarily light and still block the wind. Winter jackets do not need to be heavy, they just need to provide insulation and a barrier from wind and rain. 

• You feel cold most in your fingers, ears and toes, so be sure to cover these areas. During World War II, gunners on bombers complained bitterly about frozen hands, ears and toes. Special insulation was added to their gloves, hats and boots, and they stopped complaining, but they suffered frostbite on their necks and chests. They had unzipped their jackets because they didn’t feel cold.

• To help keep your hands warm on cold days, wear mittens that do not let wind or water in. The single compartment of mittens retains heat better than gloves that have separate compartments for each finger. If your hands still feel cold, swing your arms around rapidly from your shoulders with your elbows straight. This motion imitates a centrifuge that will drive blood toward your fingers and open up the blood vessels in your hands. You can buy single-use hand heating packets such as “HotHands,” online or in sporting goods stores, and rechargeable warmers are also available.

Frostbite
Raynaud's Phenomenon
Hypothermia

My Recommendations
If you suffer from heart or lung disease, you should be very careful about exercising in cold weather. Breathing dry cold air constricts arteries and increases clotting to increase heart attack risk, and constricts bronchial tubes to reduce oxygen intake through the lungs. When the temperature drops, people with known heart disease or lung disease are safer exercising indoors where they can breathe warmer air.

This article is reprinted from content courtesy of DrMirkin.com