A new study underscores the crucial role of hydration in managing stress, revealing that insufficient water intake can significantly elevate stress hormone levels.
Researchers at Liverpool John Moores University (LJMU) found that individuals consuming less than 1.5 liters—or roughly seven cups—of water per day exhibited cortisol responses to stress that were 50% higher than those who met recommended hydration levels. The findings were published in the Journal of Applied Physiology.
The study monitored 62 healthy adults, selecting 32 participants based on habitual fluid intake. Participants drinking under 1.5 liters per day were classified as the “low-fluid” group, while those meeting daily recommendations—two liters for women and 2.5 liters for men—comprised the “high-fluid” group.
Over seven days, researchers assessed stress responses using the Trier Social Stress Test (TSST) and tracked hydration markers through blood and urine tests.
Results showed that inadequate hydration increased stress-related health risks for both men and women. Professor Neil Walsh, lead author and head of LJMU’s School of Sport and Exercise Sciences, emphasized that keeping water nearby during stressful periods could benefit long-term health.
“Cortisol is the body’s primary stress hormone, and exaggerated cortisol reactivity is linked to higher risks of heart disease, diabetes, and depression,” Walsh said.
Study team member Dr. Daniel Kashi noted that while both groups reported similar levels of anxiety and heart rate increases during the stress test, only the low-fluid group experienced a significant rise in saliva cortisol. “Even though they did not feel thirstier, their darker, more concentrated urine indicated poor hydration,” Kashi explained.
Long-term dehydration, the study suggests, may contribute to serious health issues such as kidney damage, heart disease, diabetes, anxiety, and depression. Dehydration also triggers the release of vasopressin, a hormone that pressures the kidneys and influences the brain’s stress response, leading to increased cortisol.
Researchers recommend simple hydration checks, such as monitoring urine color, with light yellow generally indicating adequate hydration.
While the study reinforces the importance of meeting daily water intake recommendations, the researchers note that additional long-term studies are necessary to further understand hydration’s role in stress and overall hormone health.
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