The authors of the study say elderly with heart problems should avoid fog and low cloud in the winter as a preventive measure.

The study, led by researchers at Universite Laval and Universite de Sherbrooke in Quebec, Canada, reveals the impact of changes in temperature and air pressure on heart patients.

“So with the extreme differences in temperature due to climate change, we wanted to show how the weather is becoming a more relevant factor,” Gosselin added.

The study showed that exposure to cold or high-pressure weather could trigger events leading to hospitalisation or death in heart patients.

The team assessed 1,12,793 people aged 65 years and older that had been diagnosed with heart failure in Quebec between 2001 and 2011. The participants were followed for an average of 635 days.

During this time, they measured the mean temperature, relative humidity, atmospheric pressure and air pollutants in the surrounding environment and studied the data to see if there was an association.

The results showed a higher risk of hospitalisation or death in the winter period of the year (October to April) compared to the summer period (May to September).

In other words, a drop of 10°C in the average temperature over seven days, which is common in several countries because of seasonal variations, is associated with an increased risk in being hospitalised or dying of heart failure of about 7% in people aged over 65 diagnosed with the disease.

During the follow-up period, 21,157 heart failure events occurred, representing 18.7% of the people studied. In total, 18,309 people were hospitalised and 4,297 died.

Researchers concluded that heart patients should avoid exposure to fog and low cloud weather in winter as they often accompany high pressure systems.