There’s something uniquely unforgiving about winter. While it brings misty mornings and the romantic appeal of soft blankets, it also carries an invisible weight. It turns out, cold weather is a physiological minefield, especially for those at risk of strokes or seizures.
Strokes are often sudden and devastating, caused by either a burst blood vessel or a blockage that cuts off blood flow to the brain. This results in damaged brain tissues and impaired neurological functions. While high blood pressure, smoking, and obesity are well-known risk factors, the cold itself plays a surprisingly significant role.
According to research presented at the American Heart Association International Conference, every five-degree drop in temperature raises the chance of hospitalization for stroke by 6%. It is not just an abstract danger. Dr. Lomesh Bhirud, Neurologist and Neuro-Interventionalist at Ruby Hall Clinic says, “The cold affects the way our bodies work. Cold weather can increase the risk of stroke and seizures due to several physiological and environmental factors.”
The Body’s Response To Cold
In cold temperatures, the body has one primal goal: to keep you warm. It does this by triggering vasoconstriction, the narrowing of blood vessels to conserve heat. Says Dr. Shruti Satish Vadke, Consultant Neurologist at Manipal Hospital Baner in Pune, “When temperatures plummet, your body’s priority is warmth. Enter vasoconstriction, a process where blood vessels narrow to reduce heat loss. This helps maintain your core temperature, but there’s a catch: narrowing blood vessels creates resistance to blood flow, which raises blood pressure.”
“This vasoconstriction increases blood pressure and strains the cardiovascular system, potentially leading to strokes,” adds Dr. Bhirud. Think of it like traffic on a freeway during rush hour. Narrowing the lanes (blood vessels) only makes the pressure (blood flow) rise.
High blood pressure is a known culprit behind strokes. When blood vessels constrict, it’s easier for clots or blockages to form, cutting off blood supply to the brain. That’s when trouble begins. A clot lodged in the wrong place can cause ischemic strokes, the most common kind. But the cold doesn’t stop there.
Says Dr. Showkat Nazir Wani, Department of Neurology at Sharda Care – Healthcity, "Respiratory tract infections surge during the winter period and inflammation from infections can damage blood vessels, making it more likely for clots to form."
Thicker Blood, Bigger Problems
Studies have shown that cold weather causes blood to become more viscous(essentially thicker and stickier). “Thick and sticky blood flows slower and may form clots that block blood supply to the brain,” says Dr. Vadke.
“Cold weather may cause blood to become more viscous, raising the risk of clot formation,” Dr. Bhirud says. These clots can travel through the bloodstream, clogging critical arteries and stopping oxygen from reaching the brain. The result: another pathway to a stroke.
If you imagine the brain as a command centre, a lack of blood flow is like pulling the plug on electricity; it disrupts everything. For those already vulnerable to stroke risk factors, such as high blood pressure, diabetes or smoking, winter increases their susceptibility.
Dr. Wani adds, "Cold and flu can also exacerbate other health conditions such as high blood pressure and heart disease, further adding to stroke risk. Febrile illness may provoke seizure episodes, particularly in children."
Seizures And The Cold
Seizures too have a complex relationship with cold weather. Dr. Bhirud notes, “Prolonged exposure to extreme cold can result in hypothermia, which disrupts the body’s normal functions, including brain activity regulation. This may trigger seizures, particularly in vulnerable persons.”
Hypothermia occurs when the body loses heat faster than it can produce it. Ever sensitive to change, the brain reacts poorly to these disruptions. Seizure triggers can include drops in body temperature, stress and even dehydration (factors far more likely during harsh winters).