When temperatures and humidity increase, the human body must act as a natural cooling machine, and this has a significant impact on the circulatory system and especially blood pressure. For people with a history of heart disease or high blood pressure, this environmental change can have serious consequences if not recognized and properly controlled.
Mechanisms of Temperature and Humidity to Lower Blood Pressure
The human body maintains an average temperature of about 98.6 degrees F (37 degrees C). When faced with high temperatures from the environment, the body will activate several mechanisms to cool down and prevent overheating. One of the first reactions is vasodilation, the blood vessels near the skin’s surface expand to bring blood closer to the surface to dissipate heat.
However, when blood vessels dilate, blood pressure can temporarily drop. To compensate, the heart must beat faster and stronger, helping to circulate blood efficiently and maintain blood pressure at the level needed to nourish the body’s organs. This is a form of “overload” on the heart, especially evident in people with underlying cardiovascular conditions such as heart failure, high blood pressure or vascular disorders.
Along with vasodilation, sweating is a common way for the body to cool down. When sweat evaporates from the skin, it takes away heat and helps cool the body. However, losing too much sweat leads to dehydration and electrolyte loss, causing blood volume to decrease, which also causes blood pressure to drop.
Excessive dehydration can cause orthostatic hypotension, which is a sharp drop in blood pressure when you stand up after sitting or lying down, leading to dizziness, lightheadedness, and even fainting.
When the humidity in the air is high, the ability of sweat to evaporate is reduced. This makes it harder for the body to cool down, even if you sweat a lot. Because sweat cannot evaporate, body temperature remains high, forcing the heart and other systems to work harder to regulate body temperature.
Heat stress and high humidity combine to cause blood pressure to continue to drop, and if left unchecked, can lead to dangerous conditions such as heat exhaustion or, more seriously, heatstroke.
Strategies for controlling blood pressure in hot and humid weather
1. Stay hydrated
In hot and humid weather, the body loses water quickly through sweat. Dehydration not only makes you feel tired, but also directly affects blood pressure (can cause hypotension), dizziness or even loss of consciousness in older adults.
To keep blood pressure stable, you should maintain the habit of drinking water regularly throughout the day, not waiting until you are thirsty to drink. Filtered water, coconut water or other drinks containing natural electrolytes are ideal choices on hot and humid days.
2. Avoid the harsh sunlight during peak hours
The time from 11am to 4pm is when the outdoor temperature is usually at its highest. At this time, going out not only makes the body more susceptible to dehydration but also puts pressure on the cardiovascular system due to the dilation of peripheral blood vessels. People with high blood pressure or the elderly may experience fatigue, dizziness or shortness of breath. Therefore, it is best to limit outdoor activities during this time frame as much as possible, unless absolutely necessary.
3. Prioritize cool and airy spaces
The living environment on hot days needs to be airy and cool enough. If possible, use a fan or air conditioner to reduce the indoor temperature. For the elderly, prolonged heat waves can cause blood pressure to fluctuate continuously and cause cardiovascular complications. Staying indoors in a cool place, avoiding hot winds will help the body maintain a stable temperature and reduce the burden on the circulatory system.
4. Choose the right clothes to help regulate body temperature
Clothing also plays an important role in controlling body temperature. On hot days, you should choose thin, light, light-colored clothes that absorb sweat well. Clothes that are too thick, dark, or tight on the body will cause heat to accumulate, forcing the heart to work harder to dissipate heat, thereby affecting blood pressure.
5. Monitor blood pressure regularly
Even if you have applied protective measures, daily blood pressure monitoring is still an important step that cannot be skipped. Especially for those who are being treated for high blood pressure, measuring blood pressure at home will help you detect early signs of abnormalities for timely treatment. You should measure at the same time every day, while resting, to get accurate results and monitor changing trends.
6. Increase the replenishment of electrolytes lost through sweat
When the body sweats a lot, not only water but also electrolytes such as sodium, potassium, and magnesium are lost. This can cause fatigue, cramps, and blood pressure disorders. Therefore, you need to pay attention to replenishing electrolytes through a diet rich in green vegetables, fresh fruits, natural juices, and potassium-rich foods such as bananas, sweet potatoes, and citrus fruits. In addition, if you exercise a lot or sweat excessively, you can consider electrolyte supplements that are not too high in sugar.
7. Rest properly after each exercise
Exercising outdoors in hot weather is still necessary but must be limited. After each activity or movement in the sun, you need to take time to rest in the shade or a cool place. Give your body time to recover, especially when there are signs of dizziness, rapid heartbeat or fatigue. Reasonable rest helps the cardiovascular system relax and blood pressure easily return to a stable level.
8. Pay attention to a light, easy-to-digest diet
On hot and humid days, the body often feels lethargic and digests more slowly. Eating too much, too much fat or too much salt will cause blood pressure to rise rapidly and make the heart work too hard. Instead, you should prioritize light, easy-to-digest meals, increase green vegetables, limit fried foods, red meat and salty foods. A diet rich in fiber and low in sodium will help control blood pressure more effectively.
9. Maintain a relaxed spirit, limit stress
The heat not only affects the body but also easily causes irritability and frustration, which can cause blood pressure to suddenly increase. Keeping a relaxed spirit, avoiding anger and excessive anxiety will help you control your blood pressure better during extreme weather days. Some simple relaxation methods such as listening to music, deep breathing, or light meditation are also very useful.
