As midsummer heat and high humidity persist and dehydration cases rise, experts warn that drinking large amounts of water without moderation can actually harm health. Gulping down a large quantity of water at once because of thirst can disrupt the body's electrolyte balance, leading to headaches, nausea, and in severe cases, brain swelling.
According to statistics from the Health Insurance Review and Assessment Service on Monday, dehydration cases totaled 19,937 last July. That marks a 31.3% increase compared with the previous month, when there were 15,189 cases.
The number of dehydration patients remained at a similar level in August last year, at 19,829.
Kyung Hee University Medical Center explained that dehydration should be viewed not simply as a lack of water in the body, but as a state in which the electrolyte balance has collapsed along with fluid loss. By the time a person feels thirsty, dehydration may already have progressed to some degree.
Continued fluid deficiency can cause fatigue and headaches, and may lead to reduced concentration, low blood pressure, and diminished consciousness. However, drinking excessive amounts of water to prevent dehydration is also not advisable.
"When the body lacks fluids, the risk of dehydration increases, but excessive fluid intake can cause an electrolyte imbalance," said Park Jung-ha, a professor of family medicine at Kyung Hee University Hospital. "Adequate fluid intake is important to prevent dehydration, but drinking a lot is not always beneficial to health."
Replenishing water little by little and frequently is better than drinking a large amount at once. "When you drink a large amount of water at once, the water taken in beyond what the body needs is quickly excreted as urine, so it may not be effective in maintaining an optimal hydration state," Park said. "In particular, drinking too much water after sweating heavily can lead to hyponatremia (water intoxication), in which the sodium concentration in the blood drops abnormally low, as well as headaches, nausea, and brain swelling, so caution is needed."
If you have sweated heavily, you also need to replenish the electrolytes lost along with the fluids. Ion beverages can help, but drinking too much of products high in sugar content should be avoided. High sugar can increase the movement of water in the intestines, causing diarrhea or worsening existing symptoms.
Beverages containing caffeine or alcohol are also not suitable for replenishing fluids. They promote diuresis, which can actually increase the body's water loss.
"Summer health management is not simply about drinking a lot of water, but about replenishing appropriate fluids and electrolytes according to one's individual health condition and activity level," Park said. "You should take in fluids little by little and frequently before feeling thirsty."
