Stressed? It Could Be a Sign You're Not Drinking Enough Water
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STORY AT-A-GLANCE
Researchers from Liverpool John Moores University found that drinking less than 1.5 liters of water daily raised stress hormones by 50%, suggesting that dehydration can add to your stress load
When you’re dehydrated, hormones like vasopressin quietly kick in, signaling stress and triggering cortisol
Signs of dehydration go beyond thirst. Fatigue, headaches, sugar cravings, and dry skin are your body’s early warning signs that it’s running low on water and energy
It’s also possible to drink too much water. Overhydrating dilutes minerals like sodium, causing fatigue, confusion, or nausea
Aside from drinking when you’re thirsty, you can stay hydrated by consuming water-rich foods like watermelon. Adding a pinch of salt and a splash of lemon or organic juice to plain water helps improve electrolyte absorption
Feeling burned out from the daily grind? If your routine feels like a blur of deadlines and distractions, you’re not alone. Stress builds quietly — until it spills over. And in the middle of all that hustle, it’s easy to forget something simple: drinking water. When was the last time you slowed down and took a sip?
These days, staying hydrated is widely promoted across social media. From #WaterTok videos to wellness reels, the message to “drink more water” is everywhere. Yet many people are still unaware that they’re chronically dehydrated1 — and it could be a contributing factor to the high levels of stress they are struggling with day after day.
Recent Study Highlights the Link Between Water Intake and Stress
A clinical study published in the Journal of Applied Physiology explored how daily water intake affects the body’s hormonal response to stress. Conducted by researchers from Liverpool John Moores University, the study tracked the hydration habits of 32 healthy adults to see the effects on their stress load.2
Hydration was isolated as the key stress variable — To determine whether water intake alone could influence stress responses, researchers controlled for sleep quality, psychological traits, and perceived stress. The participants were healthy, aged 18 to 35, non-smokers, and free from immune, cardiovascular, metabolic, or sleep disorders. Those who consumed excessive caffeine or alcohol were excluded.3
Participants were divided into LOW and HIGH fluid intake groups — Using national fluid intake data, researchers identified individuals with the lowest and highest daily water consumption. The LOW group drank less than 1.5 liters per day, while the HIGH group met recommended intakes (2 liters for women and 2.5 liters for men). Each group had 16 participants matched for age, gender, sleep quality, and anxiety levels.4
Hydration levels were tracked before a stress simulation — For seven days, participants recorded their fluid intake using smart bottles. On the eighth day, they underwent the Trier Social Stress Test (TSST), which simulates real-world stress through public speaking and mental arithmetic.
<label class="hide-text" contenteditable="false">Text within this block will maintain its original spacing when published</label>Hydration was assessed using urine concentration and color, as well as checking blood levels of copeptin (a hormone that helps regulate water balance and blood volume). The LOW group consistently showed darker urine, higher urine concentration, and elevated copeptin, which are clear signs of dehydration.5 6
Cortisol spikes were significantly higher in the low-fluid group — Saliva samples taken after the TSST also revealed that levels of cortisol, the stress hormone, were 50% higher in the LOW group. Both groups experienced similar increases in heart rate and anxiety, but only the LOW group showed a significant increase in cortisol.7 8
Thirst did not reflect actual hydration status — Despite similar thirst ratings and blood concentration levels, the LOW group had more concentrated urine and exaggerated cortisol responses. This shows that thirst is not always a reliable indicator of hydration.9
Poor hydration may increase long-term health risks — The study concluded that the exaggerated cortisol reactivity seen in the LOW group is associated with poor hydration and may contribute to long-term health problems. Chronic low fluid intake has also been linked to higher risks of metabolic, renal, and cardiovascular disease.10
The study’s weeklong design added real-world credibility — Unlike one-time observational studies, this research prospectively monitored participants for seven days while they maintained their usual drinking habits. This allowed researchers to observe how consistent hydration patterns influenced stress hormone responses, rather than relying on short-term or artificial changes.11
The findings of this study show how hydration may help protect long-term health and keep chronic diseases at bay. According to Prof. Neil Walsh, the study’s lead author:
“Cortisol is the body’s primary stress hormone, and exaggerated cortisol reactivity to stress is associated with an increased risk of heart disease, diabetes, and depression. If you know you have a looming deadline or a speech to make, keeping a water bottle close could be a good habit with potential benefits for your long-term health.”12
How Dehydration Quietly Activates Your Stress Response
Even if you don’t feel thirsty, your body may already be under stress. One of the first hormones to respond is vasopressin, a water-regulating signal made in the brain. It helps your body hold onto fluid, but it also triggers your body’s built-in stress response.
Vasopressin protects circulation when fluid is low — During dehydration, vasopressin signals your kidneys to conserve water and constricts blood vessels to raise blood pressure.
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