Swedish Study Links Extreme Temperatures to Heart Failure Risks

A large study conducted in Sweden, published in the Journal of the American College of Cardiology and presented at the 2026 European Society of Cardiology Congress, found that exposure to extreme cold and high temperatures significantly increases the risk of hospitalisation among heart failure patients. Researchers analyzed approximately 482,000 heart failure hospitalisations recorded in the Swedish National Patient Register from 2006 to 2021.

They defined cold spells as at least two consecutive days with temperatures at or below the fifth percentile between October and March, finding that these spells were linked to a higher risk of hospitalisation within two to six days, particularly between three and five days. Conversely, higher temperatures were associated with immediate risks within zero to three days.

Interestingly, no significant association was found between heat waves and heart failure hospitalisation. Dr. Wenli Ni, the lead author and postdoctoral research fellow at Harvard T.H.

Chan School of Public Health, emphasized the importance of understanding temperature effects on heart failure in Nordic populations. Dr. Tiantian Li from the Chinese Center for Disease Control and Prevention noted the necessity of integrating weather conditions into cardiovascular care.