Insufficient Hydration Linked to Elevated Stress and Health Risks
Not drinking enough water might be raising stress levels and heightening the risk of serious health issues, according to recent warnings from scientists.
A study conducted by researchers at Liverpool John Moores University discovered that individuals who did not meet daily hydration goals exhibited significantly elevated levels of the stress hormone cortisol in high-pressure situations.
Regularly high cortisol is associated with various health concerns, such as hypertension, heart disease, type 2 diabetes, obesity, as well as both depression and anxiety.
Additionally, chronic stress can weaken the immune system, making people more susceptible to illness.
This study involved 32 volunteers, with one group restricted to 1.5 liters of water a day, while the other adhered to recommended hydration levels.
Researchers monitored hydration through urine and blood samples before participants faced a controlled stress test, designed to replicate an anxiety-inducing real-life scenario.
During the test, each participant had ten minutes to prepare for an unexpected job interview where three individuals in white coats awaited them, all set up with a fake camera.
Following the interview, participants quickly engaged in a mental arithmetic challenge, subtracting numbers at speed.
Saliva samples taken before and after indicated that cortisol levels surged significantly more in those who had not adequately hydrated, suggesting that even mild dehydration could amplify the body’s stress response and potentially lead to health issues over time.
Professor Neil Walsh from the LJMU School of Sport and Exercise Sciences described the testing environment as ‘really flustering.’
Commenting on the results, he noted, “We know that individuals with low fluid intake, those who don’t meet hydration recommendations, tend to be poorly hydrated. But we were uncertain about how stress would affect them under controlled conditions.”
Interestingly, he pointed out that physical signs of stress—like increased heart rate, sweaty hands, and dry mouth—were similar for both groups.
“Both sets of participants reported comparable levels of anxiety and heart rate increases during the stress test,” he explained. “However, those who were poorly hydrated had significantly greater cortisol responses.”
Moreover, this lower fluid intake group did not report feeling thirstier than their better-hydrated counterparts, according to Professor Walsh.
He elaborated: “Cortisol acts as the body’s main stress hormone, with exaggerated levels tied to a higher risk of heart disease, diabetes, and depression. If you’re aware of an upcoming deadline or a public speaking engagement, keeping a water bottle nearby could become a beneficial habit for long-term health.”
However, Professor Walsh emphasized the need for further research to clarify these findings, recently published in the Journal of Applied Physiology. This should include examining whether increasing water intake in those who drink less can reduce reactions to everyday stressors such as traffic jams or work presentations.
“We hope that following hydration guidelines could be one of many strategies to help manage cortisol response on a daily basis,” he added.
In the UK, health authorities recommend that adults drink six to eight cups of fluid daily, roughly translating to 1.5 to two liters. However, more may be necessary in hot weather, during vigorous activity, while recovering from illness, or for those who are pregnant or breastfeeding.
Earlier this year, analysis by the British Heart Foundation found an increase in heart disease-related deaths among working-age adults, highlighting urgency in addressing such health concerns.
Between 2019 and 2023, cardiovascular deaths in this demographic in the UK rose by 18%, from 18,693 to 21,975, averaging around 420 per week.
