Heatwaves Pose Growing Threat to Human Immune System, Bulgarian Professor Warns
Jerusalem, 6 August, 2026 (TPS-IL) -- Vratsa, Northwestern Bulgaria (BTA) – Climate change and increasingly frequent, prolonged heatwaves pose a growing threat to human health worldwide and in Bulgaria, Associate Professor Petya Dimitrova said in an interview with BTA on Wednesday.
Dimitrova is an immunologist at the Laboratory of Experimental Immunotherapy at the Bulgarian Academy of Sciences’ Stephan Angeloff Institute of Microbiology. She said that extreme weather events, particularly heatwaves and droughts, are becoming more common and periods of high temperatures are growing longer.
Although the human body has mechanisms for thermoregulation and adaptation, prolonged heat and abrupt temperature changes place it under severe physiological stress and adversely affect both thermoregulation and the immune system, Dimitrova explained. These mechanisms are vital to the normal function of all organs and systems, including the cardiovascular, respiratory and immune systems, she added.
Extreme heat also disrupts the body’s circadian rhythm, potentially triggering inflammation and, in some people, chronic inflammation, Dimitrova said. This helps explain why the health of people with chronic conditions such as cardiovascular disease, diabetes or obesity often worsens during the summer months. Among patients with cardiovascular disease, there is a direct correlation between high temperatures and mortality, she added. Dimitrova said the incidence of infectious diseases does not decline in summer despite sunny weather and generally strong immune function, because high temperatures and temperature fluctuations adversely affect innate immunity.
Dimitrova urged people, particularly those with chronic conditions, to take care during hot periods, rest regularly, drink enough fluids, engage in moderate physical activity and take responsibility for their health. Regular sleeping, waking and mealtimes are important for everyone, regardless of the weather, she added.
