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Winter is a dangerous time for cardiac patients
Last reviewed: 01.07.2025
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People with heart disease cannot compensate for their body's increased need for oxygen when they breathe cold air, meaning that shoveling snow and other activities in the cold can be dangerous for some.
This is the opinion of scientists from the College of Medicine at the University of Pennsylvania (USA), who conducted a study and figured out why cold air often provokes coronary attacks.
Inhaling cold air during isometric exercises (such as shoveling snow or walking with a briefcase or laptop in your bag) can cause uneven distribution of oxygen through the heart. A healthy body corrects this problem and redistributes the blood flow so that the heart continues to function normally. However, in people with heart problems, the body cannot cope with this task. At low temperatures, the load on the heart increases significantly, which is why the peak of deaths from cardiac arrest occurs in winter.
In the study, the researchers examined healthy young people in their 20s and a group of healthy patients over 60. Each participant had their lung and heart function checked.
To assess how the heart functions during exercise, the researchers asked subjects to perform isometric (static) hand grips, which increase blood pressure. The subjects gripped an object and held it for two minutes, providing a consistent load on the heart. The data showed that there was a mismatch between oxygen supply and demand in the left ventricle, which receives oxygenated blood, although the heart was still functioning normally.
The work, according to its authors, demonstrates that a healthy organism adequately redistributes blood in the endocardium (the inner lining of the heart cavity) during the combined stimulating effect of inhaled cold air and isometric exercise.