A new study led by researchers from the Université Laval and Université de Sherbrooke in Quebec, Canada are concluding that negative shifts in temperature increase the likelihood of heart failure and death, especially among the elderly or those with a compromised immune system.
“We know that doctors rarely take the weather forecast into account when treating or making recommendations to heart failure patients,” said Professor Pierre Gosselin who was the lead author of the study. “Our study shows that exposure to cold or high-pressure weather could trigger events leading to hospitalization or death in heart failure patients.”
Gosselin and his team followed roughly 100,000 elderly people in Quebec, aged 65 and older, who had been diagnosed with heart failure between 2001 and 2011. These cardiovascular diagnoses was taken from the Quebec Integrated Chronic Disease Surveillance System (QICDSS) database using the International Classification of Diseases (ICD).
Participants were observed for an average of 635 days (or a year and eight months). During this period, researchers took note of the mean temperature, relative humidity, air pollutants in the environment, and atmospheric pressure. These contributing factors were then calculated against the risk of hospitalization or death in the winter period of the year (typically October to April) compared to the summer period (May to September).
The results were shocking. The team found that for every degree Celsius drop in mean temperature, participants had a 0.7 percent increase of heart failure or death. Said another way, a 10-degree Celsius drop in average temperature (which is normal in most temperate countries) would increase the risk of elderly patients dying of heart failure by seven percent.
Prof. Gosselin said that patients 65 years old and older with a history of a heart condition should be made aware of the impact weather could have on their overall health. (Related: Two Important Ways to Lower Risk of Heart Failure.)
“[Patients] should avoid exposure to fog and low cloud weather in winter as they often accompany high pressure systems,” he concluded.
This is not the first time that low temperatures have been linked to an increased risk of heart failure. Medical experts at Harvard Health have already noted that cold weather may raise the likelihood of cardiovascular problems. These health professionals noted that lower temperatures decrease the amount of oxygen-rich blood being provided to the heart. The heart, thus, has to work harder to ensure proper function. Those who are of a certain age, are sickly, or obese are most at risk of overexerting their bodies just to survive in colder weather.
Those with compromised immune systems can also suffer from heart failure due to seasonal flu. Influenza can cause fever, forcing the heart to beat faster and raising its demand for oxygen. The flu likewise triggers dehydration which reduces blood pressure, cutting the heart’s supply of oxygen.
A 2013 review entitled, “Winter Cardiovascular Diseases Phenomenon” concluded that of the 30 percent of all global deaths being caused by a cardiovascular disease, a disturbing percentage appears to be seasonal, with winter being the most dangerous for elderly people.