Cooling Down During the Hot Months and Your Blood Pressure: What to Do.

When summer temperatures soar, your body works hard to stay cool and your blood pressure can change as a result. While heat can sometimes lower blood pressure through vasodilation (widening of blood vessels), extreme temperatures and dehydration can cause sudden drops or dangerous spikes.

For people with hypertension or heart disease, understanding how to manage blood pressure during the hot months is essential.

Why Heat Affects Blood Pressure

Hot weather causes blood vessels to widen to help release heat. This can lower blood pressure temporarily, but for people on diuretics, beta-blockers, or ACE inhibitors, it can also lead to:

Dizziness or fainting
Irregular heart rhythms
Heat exhaustion or heat stroke

On the other hand, excessive heat stress can increase heart rate and put pressure on the cardiovascular system, especially if you become dehydrated.

Stay Hydrated — The First Line of Defense

Drink water consistently throughout the day (don’t wait until you’re thirsty).
Steer clear of excessive alcohol and coffee as they can increase fluid loss.
Add electrolyte-rich drinks if you’re sweating heavily.

Expert Tip: Keep a reusable water bottle nearby and sip regularly, sudden large intakes of water are less effective than steady hydration.

Keep Your Environment Cool

Use fans or air conditioning during the hottest hours (11 a.m. – 4 p.m.).
Keep curtains closed to block sunlight.
Sleep with light, breathable bedding.
Take cool showers to bring down body temperature.

Adjust Physical Activity

When it’s cooler outside, work out early in the morning or late at night.
Avoid strenuous activities during midday heat.
Wear lightweight, loose-fitting clothing.

Monitor Your Blood Pressure More Often

Check your blood pressure at several times during the hot months. If you notice:

Readings much lower than normal with dizziness — contact your doctor.
Unusual spikes despite medication — also check with a healthcare professional.

What the Research Says

The European Society of Cardiology notes that heat-related drops in blood pressure are more common in older adults and people on certain heart medications.
Dehydration is a leading cause of heat-related hospital admissions in hypertensive patients.