As the post-Diwali winter sets in across North India, doctors are sounding the alarm as cold weather doesn’t only bring fog and flu, it may also raise the risk of strokes. As per experts, every year after Diwali, there is a sudden spike in stroke cases and has become a seasonal trend.
Dr (Col) Joy Dev Mukherji, Vice Chairman and Head of Neurology at Max Super Speciality Hospital, Saket, New Delhi. “It’s a worrying seasonal trend that many people don’t connect with the weather, but cold temperatures play a big role in increasing stroke risk. Every year, especially post Diwali we see a sudden spike in stroke cases in the emergency ward,” he said.
Why does stroke risk rise in cold weather?
A stroke happens when the brain’s blood supply is cut off, either because of a blocked blood vessel (ischemic stroke) or a ruptured one (hemorrhagic stroke). Both carry high risks of disability or death.
According to a 2024 study published in The Lancet, which analysed data from over 522 cities in 25 countries, extreme cold days were associated with 9.1 excess deaths per 1,000 ischemic stroke deaths and 11.2 excess deaths per 1,000 hemorrhagic stroke deaths. In comparison, extreme heat caused 2.2 and 0.7 extra deaths respectively. The researchers found that cold weather poses a far higher danger for stroke mortality than heat.
A report from the Harvard T.H. Chan School of Public Health revealed that extreme temperatures, especially severe colds, can increase the likelihood of fatal strokes.
Another data published in PMC Archive 2024 showed that with every 1 degrees celsius drop below the average daily temperature, the incidence of ischemic stroke increased by 3.9 per cent especially in the Indian population.
What happens inside the body?
Dr Mukherji explains, “Cold weather causes your blood vessels to tighten, a process called vasoconstriction. This raises blood pressure, and at the same time, the blood becomes thicker and more likely to clot. These two effects together can easily trigger a stroke, especially in people with existing conditions like hypertension or diabetes.”
He adds that even an unusually cool summer day can be risky. “The risk isn’t just in winter. It’s relative. A sudden temperature drop, even in summer, can strain the cardiovascular system and raise stroke risk.”
Who is most at risk?
As per Dr Mukherji people with high blood pressure, diabetes, or heart problems are more likely to have a stroke during cold weather. The risk is also higher for older adults, especially those above 65, as their bodies find it harder to handle sudden drops in temperature.
“Those who live in poorly insulated homes or spend long hours outdoors in the cold are also more vulnerable,” he further added. Experts say people in low-income areas face higher risk because they often don’t have proper heating and may reach hospitals late, which can make their condition worse.
To stay safe this winter, Dr Mukherji advises to cover their head, neck, and hands before stepping outside. Staying active indoors helps keep blood flow in check, and avoiding sudden changes in temperature reduces stress on the heart and brain. He also shares that one must take extra care when it comes to monitoring blood pressure or diabetes and take medicines on time.
Most importantly, people should learn to recognise early signs of a stroke such as sudden weakness, slurred speech, or facial drooping and seek emergency medical help immediately. “Remember time is brain. The faster a patient reaches the hospital, the better the outcome,” he said.