High blood pressure and hot weather: the risks

High blood pressure and hot weather: what happens to our body in summer

When summer arrives, many people think that heat automatically lowers blood pressure. In part this is true: high temperatures cause the blood vessels to dilate, which tends to lower blood pressure readings. However, for people with arterial hypertension, the reality is much more complex.

Sultry weather, dehydration, excessive sweating and changes in fluid and electrolyte balance can make blood pressure harder to control and increase the risk of cardiovascular complications, especially in older adults and in patients with kidney disease, diabetes or heart failure.

Understanding how heat affects blood pressure and knowing how to manage your therapy correctly during the summer lets you face the season more safely, protecting your heart, brain and kidneys.

Why heat changes blood pressure

To dissipate body heat, the body puts several physiological mechanisms into action.

The main one is vasodilation, that is, the widening of the blood vessels near the surface of the skin, which helps release heat through the skin. This can cause a drop in blood pressure, which is why many people feel weak, tired or dizzy on the hottest days.

At the same time, sweating increases, with a loss of water and electrolytes. If these fluids are not adequately replaced, dehydration can set in, changing the volume of circulating blood and forcing the heart and kidneys to work harder.

In people with hypertension, these changes can make blood pressure readings more unstable and affect the response to antihypertensive medications.

High blood pressure and sultry weather: why cardiovascular risk increases

Summer is a delicate time for people with high blood pressure.

High temperatures, especially when combined with high humidity, increase the stress on the cardiovascular system. The heart has to work harder to keep blood circulating properly and to supply oxygen to the organs.

If dehydration, intense physical activity during the hottest hours or prolonged sun exposure are added to this, the risk of cardiovascular events rises, especially in the most vulnerable people.

The people most at risk are:

• older adults;
• patients with arterial hypertension;
• people with diabetes;
• people with chronic kidney failure;
• people with heart failure;
• those taking diuretics.

High blood pressure and the kidneys: a link not to be underestimated

Hypertension does not affect only the heart.

The kidneys are among the organs most affected by high blood pressure. Over time, inadequately controlled blood pressure can progressively damage the small blood vessels of the kidneys, reducing their ability to filter the blood.

In turn, kidneys that work less effectively can contribute to a further rise in blood pressure, creating a vicious circle that speeds up the progression of chronic kidney disease.

To learn more about this important relationship, you can also read our in-depth article on High blood pressure and the kidneys: the risks of hypertension, available on the NefroCenter blog.

High blood pressure and the kidneys: the risks of hypertension

Blood pressure medications in summer: should you stop taking them?

One of the most frequent questions concerns antihypertensive therapy during the summer months.

The answer is simple: never stop your medications on your own.

Heat can temporarily change blood pressure readings, but this does not mean that therapy should be interrupted.

In some cases your doctor may consider adjusting the dosage, especially for patients who take diuretics or who have recurring episodes of excessively low blood pressure. These decisions, however, must be made only after a clinical evaluation.

Stopping medications without medical advice exposes you to the risk of sudden spikes in blood pressure and increases the likelihood of cardiovascular complications.

Diuretics and heat: extra care is needed

Diuretics are one of the most widely used classes of drugs in the treatment of hypertension.

These medications promote the elimination of water and sodium through the urine, helping to lower blood pressure.

In summer, however, the effect of diuretics can add to the fluid loss caused by sweating, increasing the risk of:

• dehydration;
• drops in blood pressure;
• electrolyte imbalances;
• worsening of kidney function.

For this reason, people who take diuretics should monitor their blood pressure closely and follow their doctor’s instructions carefully.

Blood pressure swings in summer

In summer it is not uncommon to see significant fluctuations in blood pressure over the course of the day.

Factors that can contribute to these swings include:

• intense heat;
• dehydration;
• large meals;
• physical activity in the sun;
• excessive alcohol consumption;
• staying in very hot environments.

Checking blood pressure periodically, especially in patients with hypertension, makes it possible to spot any significant changes and report them to your primary care doctor.

High blood pressure and hot weather: what to do when temperatures are high

To face the summer months safely, it is helpful to take a few simple precautions.

It is advisable to:

• drink water regularly throughout the day;
• avoid sun exposure during the hottest hours;
• prefer cool, well-ventilated places;
• limit alcoholic drinks;
• follow a diet rich in fruit and vegetables, unless your doctor advises otherwise;
• measure your blood pressure periodically;
• take your prescribed therapy regularly.

People with kidney failure or on dialysis must follow only their specialist’s instructions regarding the amount of fluids allowed.

When you need to contact your doctor

It is important to contact your doctor if, during the summer, you experience:

• persistently high blood pressure;
• repeated episodes of very low blood pressure;
• frequent dizziness;
• fainting;
• chest pain;
• difficulty breathing;
• sudden swelling in the limbs;
• a marked decrease in the amount of urine.

These symptoms may call for a reassessment of therapy or further tests.

Advice from the NefroCenter specialists

Summer should not be faced with worry, but with greater awareness.

People with arterial hypertension should monitor their blood pressure regularly, stay properly hydrated and never change their prescribed therapy on their own.

High blood pressure is one of the main risk factors for heart attack, stroke and chronic kidney disease. For this reason, keeping it under control throughout the year, even in the hottest months, means protecting the heart, brain and kidneys at the same time.

At the NefroCenter Group, cardiologists, nephrologists and internists work together to offer integrated management of hypertension, with personalized pathways aimed especially at patients with cardiovascular risk factors or kidney disease.

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