In recent times, there have been frequent thunderstorms and high temperatures and humidity. It is also important to take care of heart health. Medical research has shown that when the ambient temperature exceeds 32 ℃ and the humidity exceeds 60%, the cardiovascular system begins to experience additional pressure. Because in high temperature and high humidity environments, the human body will activate a complex heat dissipation mechanism, and the core participant of this mechanism is the cardiovascular system.
When the ambient temperature approaches or exceeds the skin temperature (about 33-35 ℃), evaporative heat dissipation becomes the only effective cooling method. At this point, the body will increase blood flow by dilating skin blood vessels - skin blood flow can surge from about 500ml/min at room temperature to 7000-8000ml/min at high temperatures, equivalent to completing a "skin circulation" of blood throughout the body in just a few minutes. This redistribution of blood presents a dual challenge: on the one hand, the heart must increase its output by 40-60% to maintain this high flow state; On the other hand, the blood supply to internal organs (including the heart itself) is relatively reduced. For healthy individuals, this may only manifest as mild discomfort, but for patients with cardiovascular disease or the elderly, the consequences of this change can be more severe.
In addition, in high temperature environments, the human body can lose 500-1000ml of fluid per hour through sweating. When the water loss reaches 1% -2% of body weight, the blood begins to concentrate, viscosity increases, and the heart needs greater force to promote blood circulation. Meanwhile, the loss of electrolytes (especially sodium and potassium) can interfere with the electrical signal transmission of myocardial cells, increasing the risk of arrhythmia. The American Heart Association points out that without timely hydration, exposure to high temperatures for 2 hours can increase blood viscosity by 8% -12%.
