The heat wave that hits much of the country this week will raise temperatures 5ºC above average, according to Inmet (National Institute of Meteorology), and demand special attention with health.
At temperatures close to 40ºC, as expected in Manaus, Palmas and Cuiabá, there is greater demand on the thermoregulation mechanism. Changes in the body to deal with heat generate not only uncomfortable effects, but also serious risks.
“The first consequences are usually dizziness, loss of appetite and increased sweat production”, says researcher Fabricio Azevedo Voltarelli, professor at UFMT (Federal University of Mato Grosso).
This is because the thermoreceptors present in the skin perceive the temperature of the environment and send signals to the brain. In response, there is dilation of the vessels and a redirection of blood flow from the most internal parts to the periphery, to facilitate the dissipation of heat to the external environment, and the elimination of sweat in an attempt to regulate the body temperature.
Excessive sweating can lead to skin irritation and also cramps, as the body loses many mineral salts.
Changes in circulation can cause swollen ankles and feet, headache, reduced blood pressure and consequent increase in heart rate.
“The heart tries to compensate for the drop in pressure by raising the heart rate. If there is an underlying heart disease, it can decompensate and put the patient at risk”, says Abrão Cury, a cardiologist at Hcor.
Other patients who should be aware are hypertensive patients. Because of the heat, the effect of blood pressure control medications can be enhanced, leading to low blood pressure.
“It is common to see hypertensive patients who, in the heat, feel dizzy, weak and even fall”, says Antonio Carlos Lopes, president of SBCM (Brazilian Society of Medical Clinic). “These patients should talk to their doctor so that, if necessary, the dose of the medication can be adjusted.”
How to reduce the effects
The main advice is to keep the body hydrated. In addition to drinking water, specialists suggest drinking coconut water and isotonic drinks to replace mineral salts.
“It is better to avoid the consumption of alcoholic beverages as much as possible”, advises Cury. “Although the drink is seen by some as something refreshing, it is a problem because alcohol inhibits the production of the hormone that controls the secretion of urine. The person thinks he is drinking liquid, but ends up losing more water.”
Another way to take care of hydration is by consuming fruits, vegetables and legumes, foods that contain more water in their composition. Still in relation to food, it is necessary to be more careful with the origin and conservation, since the heat makes it spoil faster.
Lopes highlights the importance of keeping the environment well ventilated, giving preference to windows and air circulators. He also recommends the use of light, loose-fitting clothing with light fabrics for thermal comfort.
Avoiding direct exposure to the sun and redoubling hydration in places with air conditioning are other recommendations from experts. According to Voltarelli, the artificial climatization of the environment can deceive the body. The body does not realize how dry the environment is and the person ends up not drinking water.