Cold Weather Alert: Higher Risk of Stroke, Especially for People with Heart Disease, Hypertension, Diabetes, and High Cholesterol

25 October 2025 – Thailand – Health authorities are warning the public to be cautious of stroke (cerebrovascular disease) during the cold season, as the risk of acute stroke tends to rise significantly when temperatures drop.

Cold Weather Can Trigger Blood Vessel Constriction and Thicker Blood

Cold weather may feel pleasant for many, but it can pose serious health risks — particularly for those with heart conditions, high blood pressure, diabetes, or high cholesterol. Low temperatures cause blood vessels to constrict, leading to increased blood pressure, while blood viscosity also rises due to lower fluid intake. These changes heighten the risk of blood clots or ruptured vessels in the brain, which can result in stroke.

Experts explain that several physiological and behavioral factors contribute to this increased risk, including:

• Vasoconstriction: Narrowing of blood vessels that raises blood pressure

• Thicker blood: Resulting from dehydration or low water intake

• Reduced oxygen flow to the brain

• Increased heart rate caused by nervous system stimulation

• Lifestyle changes during winter, such as drinking less water, exercising less, or eating higher-fat foods

How to Prevent Stroke During the Cold Season

Simple preventive measures can help reduce the risk of stroke:

• Keep the body warm and maintain body temperature

• Stay hydrated and drink enough water each day

• Monitor blood pressure regularly

• Do light physical exercise on a regular basis

• Eat a balanced diet and avoid fatty foods

Recognize Early Warning Signs with “BE FAST”

People are urged to remember the BE FAST method to recognize stroke symptoms early:

• B – Balance: Dizziness or loss of balance

• E – Eyes: Sudden blurred or double vision

• F – Face: Facial drooping or uneven smile

• A – Arm: Weakness or numbness in one arm or leg

• S – Speech: Slurred or unclear speech

• T – Time: Act quickly and seek medical help immediately

Cold weather can be refreshing but also risky — especially for people with underlying health conditions. Staying warm, drinking enough water, and being alert to warning signs can help prevent life-threatening complications from stroke.