*This interview has been edited and condensed for length and clarity.\n<\/p>\n
Q: Can drinking plain water actually give you more energy?\n<\/p>\n
Mercola: Yes, it can. When you’re even slightly dehydrated, your body\u2019s ability to produce energy drops. Research shows that fluid loss as low as 1% to 2% of your body weight slows down blood flow and reduces oxygen delivery to your brain and muscles. That means less energy, both physically and mentally.\n<\/p>\n
Dehydration<\/a> also interferes with how your brain uses dopamine and serotonin\u2014the chemical messengers<\/a> that help regulate mood, focus, and motivation<\/a>. So you may feel sluggish or irritable before you even realize you\u2019re thirsty.\n<\/p>\n Drinking water helps restore blood volume, supports neurotransmitter function, and improves oxygen delivery. The result is a real, measurable boost in energy levels, not just a placebo effect.<\/p>\n Can Drinking Water Help You Feel Better Overall? <\/p>\n Absolutely. Water doesn’t just affect energy; it impacts everything from stress levels to emotional balance.\n<\/p>\n When you’re dehydrated, your body releases vasopressin<\/a>, a hormone that signals the kidneys to conserve water. But vasopressin also helps trigger cortisol<\/a>, your main stress hormone. That means dehydration can raise your stress response, even if you’re not consciously anxious.\n<\/p>\n Drinking water helps lower these stress signals<\/a> and supports a calmer, more stable mood. In fact, research shows that people who drink less than 1.5 liters of water a day have significantly higher cortisol spikes<\/a> during stressful events compared to those who stay well-hydrated.\n<\/p>\n It also improves brain function by restoring blood flow and neurotransmitter balance. That can reduce headaches, clear mental fog<\/a>, and even ease symptoms like irritability and confusion.\n<\/p>\n Even if your energy doesn’t noticeably improve right away, your nervous system becomes less reactive, and that can make a big difference in how you feel overall.<\/p>\n Why Does Dehydration Affect Energy So Much? <\/p>\n Energy production depends on efficient circulation, oxygen delivery, and cellular function\u2014and dehydration disrupts all three.\n<\/p>\n When fluid levels drop, blood volume decreases, which slows circulation and limits how much oxygen and glucose reach the brain and muscles. This can lead to physical fatigue<\/a>, slower reaction time, and mental fog, even before you feel noticeably thirsty.\n<\/p>\n Dehydration also affects the nervous system and brain signaling. With less fluid available, nerve communication becomes less efficient, and the brain has to work harder to carry out routine tasks.\n<\/p>\n On a cellular level, water is required for metabolic reactions that produce energy. When cells don\u2019t have enough usable water, those processes become less efficient, making everyday activities feel more draining.\n<\/p>\n The takeaway: Even mild dehydration can shift the body into a lower-energy state, which is why drinking water can sometimes restore clarity and stamina rather than simply quenching thirst.<\/p>\n Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process<\/a> to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.<\/p>\n Dube A, Gouws C, Breukelman G. Effects of hypohydration and fluid balance in athletes’ cognitive performance: a systematic review<\/a>.\u00a0Afr Health Sci. 2022;22(1):367-376. doi:10.4314\/ahs.v22i1.45<\/p>\n Kashi DS, Hunter M, Edwards JP, et al. Habitual fluid intake and hydration status influence cortisol reactivity to acute psychosocial stress<\/a>.\u00a0J Appl Physiol (1985). 2025;139(3):698-708. doi:10.1152\/japplphysiol.00408.2025<\/p>\n Watso JC, Farquhar WB. Hydration Status and Cardiovascular Function<\/a>.\u00a0Nutrients. 2019;11(8):1866. Published 2019 Aug 11. doi:10.3390\/nu11081866<\/p>\n Liska D, Mah E, Brisbois T, Barrios PL, Baker LB, Spriet LL. Narrative review of hydration and selected health outcomes in the general population<\/a>. Nutrients. 2019;11(1):70. doi:10.3390\/nu11010070<\/p>\n Bia\u0142ecka-D\u0119bek A, Madej D, \u0141ojek E. Water intake, hydration status and cognitive functions in older adults – a pilot study<\/a>. Eur J Nutr. 2025;64(4):175. doi:10.1007\/s00394-025-03690-1<\/p>\n Armstrong LE, Johnson EC. Water intake, water balance, and the elusive daily water requirement<\/a>.\u00a0Nutrients. 2018;10(12):1928. doi:10.3390\/nu10121928<\/p>\n![\"Kathleen](\"https:\/\/www.newsbeep.com\/ie\/wp-content\/uploads\/2025\/11\/KFheadshot-9fe00fcb29c24a589a05cb7dea9ca150.jpeg\")
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