When the weather gets hot, it's important to drink more water. However, if you sweat for a long time while drinking large amounts of water, you may experience symptoms of "water intoxication" such as weakness, headaches, vomiting, and dizziness. Yesterday, Zhou Rongbin, director of the emergency department at the General Hospital of the Beijing Military Command, told reporters that after heavy sweating, it's advisable to replenish with salt water, with 1 gram of salt per 500 milliliters of water being generally appropriate.
Last Saturday, when the temperature was slightly lower, Xiao Li, who had been "roasted" by the high temperatures for a week, went hiking with some friends. As soon as he started up the mountain, Xiao Li, who sweats easily, was drenched in sweat. Along the way, Xiao Li just kept gulping down water, sweating continuously, and drinking more... Around noon, Xiao Li suddenly felt weak and had a headache, then started to feel nauseous and vomit. His companions hurriedly rushed the disoriented him to the hospital. After examination, doctors concluded that Xiao Li had suffered from water intoxication from drinking too much water.
Zhou Rongbin explained that water intoxication caused by excessive drinking is related to the loss of salt in the body. Water is a vital substance in the human body, accounting for about 65%-70% of body weight. Water can freely pass through human cell membranes, maintaining the balance of water and electrolytes in the body and allowing normal metabolic activities to proceed. When a person sweats, they lose not only water but also a significant amount of salt. One liter of sweat contains nearly 3 grams of salt.
If you only drink water after sweating, the water absorbed by the gastrointestinal tract is then excreted through sweat, causing further loss of salt. This continuous cycle of drinking and sweating depletes the salt content in the blood. With low salt levels in the blood, its ability to absorb water decreases, and water enters the cells through the cell membrane, leading to hypotonic dehydration and cell swelling. This results in symptoms of "water intoxication" such as dizziness and blurred vision.
Drinking large amounts of water dilutes the blood, affecting the oxygen exchange of cells throughout the body. Once brain cells become deprived of oxygen, a person can become lethargic. Brain tissue is enclosed within the rigid skull; once brain cells swell, intracranial pressure increases, leading to a series of neurological symptoms such as headaches, vomiting, drowsiness, and slowed breathing and heartbeat. In severe cases, it can lead to coma, seizures, and even be life-threatening.