What happens to the body when you drink too little water?

A new study shows that people who don't drink enough water each day have a stronger biological response to stress, with significantly higher levels of cortisol—the hormone associated with stress—compared to those who drink enough water.

Studies show that cortisol levels are higher in people who drink less water. (Source: RTE)

Interestingly, this group didn't feel thirstier, but their bodies reacted more negatively to stress.

The study, conducted by experts at Liverpool John Moores University (UK), involved 32 adults, 16 of whom drank less than 1.5 liters of water per day, and 16 who met the recommended water intake.

Researchers monitored the hydration status of both groups over seven days using urine and blood samples, then invited them to participate in a laboratory stress test.

The test included a surprise job interview: Each person had 10 minutes to prepare, then had to enter a separate room equipped with fake cameras and answer questions in front of a "panel" of three people in white lab coats. Next, they were asked to perform mental arithmetic, subtracting numbers as quickly as possible.

According to Professor Neil Walsh of the School of Sport and Exercise Science at Liverpool John Moores University, this was a "truly perplexing" experience.

"We know that people who drink less water daily, below the recommended level, are often dehydrated. But what we don't know is whether, when placed in a controlled stressful situation, their stress hormone response is stronger," Professor Walsh said.

To measure cortisol levels, researchers collected saliva samples before and after the test. Cortisol, also known as the stress hormone, is produced by the adrenal glands when the body is stressed and plays a role in the immune response, metabolism, and blood pressure.

The results showed that the group that drank less water had higher cortisol levels.

Professor Shaw noted that external stress responses such as rapid heartbeat, sweaty hands, and dry mouth were similar in both groups. “Both felt equally anxious and had similarly increased heart rates during the test. However, the group that drank less water daily had a much stronger cortisol response.”

The research findings also reinforced advice from health authorities. Specifically, the European Food Safety Authority (EFSA) recommends that men drink 2.5 liters of water per day, while women should drink 2 liters. Meanwhile, the UK's Eatwell guidelines suggest that adults should drink 6-8 glasses of water per day, equivalent to 1.5-2 liters.

Experts emphasize that the need for water can increase during hot weather, strenuous physical activity, illness, or during pregnancy and breastfeeding.

According to the research team, keeping a bottle of water nearby during stressful times not only helps to improve mental well-being but also benefits long-term health.

Source: https://baoquocte.vn/dieu-gi-xay-ra-voi-co-the-khi-uong-it-nuoc-325356.html