Roll your eyes, then drink some water!
Let’s be honest: most people roll their eyes or even groan when they hear “15 cups of fluid a day.” It sounds like a small swimming pool. But here’s the thing: dehydration is no joke. Studies show that up to 17–28% of older adults are chronically dehydrated, and many end up in the ER with dehydration as a primary or secondary diagnosis. For adults over 65, it’s one of the leading preventable reasons for hospital visits.
And it’s not just the elderly, mild dehydration—losing just 1–2% of your body’s water— despite your age can impair focus, mood, and physical performance. That means if you feel thirsty, you’re already playing catch-up.
So while the recommendation might make you roll your eyes, chances are a lot of us are walking around a little under-hydrated. And if a few extra cups of healthy fluids can keep you out of the ER, improve your focus, and keep your skin looking fresh, it’s a small price to pay.
So, How Much Water Do You Really Need Each Day?
We’ve all heard the advice: “Drink eight glasses of water a day.” But hydration needs are actually more personalized—and usually a bit higher—than that old rule of thumb. Two trusted health institutions, Mayo Clinic and Harvard Health, provide clear guidance on how much healthy fluid your body really requires.
Both Mayo Clinic and Harvard Health base their hydration recommendations on the National Academies of Sciences, Engineering, and Medicine (NASEM) guidelines, developed by a committee of MDs, PhDs, and health experts. These evidence-based targets are that:
Men should aim for about 15.5 cups (3.7 liters) of fluids per day.
Women should aim for about 11.5 cups (2.7 liters) of fluids per day.
These totals include all hydrating fluids—plain water, coffee or tea in moderation, lightly flavored water with natural fruit, and the water naturally present in foods. Juice is generally the only other source that can meaningfully contribute to these recommendations.
Why You Can Trust These Guidelines
The NASEM recommendations were developed by a diverse committee of experts, including MDs, PhDs, and specialists in nutrition, physiology, epidemiology, and dietetics. This composition ensured that the guidelines would be comprehensive, evidence-based, and trustworthy. The panel carefully reviewed extensive research on hydration, fluid needs, and related health outcomes to provide population-level guidance that is both realistic and practical. Their goal was to establish daily fluid targets that support overall health, prevent dehydration, and reduce the risk of kidney, urinary, and cardiovascular issues. Importantly, these recommendations take into account all sources of water, including beverages and the natural water content in foods.
The committee specifically focused on linking adequate water and electrolyte intake to reducing the risk of dehydration, kidney stones, urinary tract problems, and cardiovascular complications. They also emphasized the role of water in body temperature regulation, metabolism, and overall cellular function, highlighting that proper hydration is fundamental to maintaining long-term health.
But don’t worry, these totals aren’t just about plain drinking water. They include all fluids—water, other beverages (tea and coffee), and even foods that naturally contain water.
Water From Food: The Hidden Source
On average, about 20% of daily fluid intake comes from food. That means:
Men: ~3 cups from food, ~12.5 cups (3 L) from beverages
Women: ~2.3 cups from food, ~9.2 cups (2.1 L) from beverages
Translation: If your diet is rich in water-packed fruits and vegetables, you could get up to 25–30% of your fluids from food—meaning you might need to drink 2–3 fewer cups of water than the standard daily recommendation.
Some foods are almost as good as a glass of water:
Fruits: watermelon (92% water), strawberries (91%), oranges (86%)
Vegetables: cucumber (96%), lettuce (96%), zucchini (95%), tomatoes (94%)
Other foods: soups, yogurt, and even cooked grains contribute to hydration
Hydration and Fascial Health
Your fascia—the connective tissue that surrounds muscles, bones, and organs—relies on proper hydration to stay flexible, resilient, and functional. Fascial tissue is composed of collagen, elastin, and a gel-like ground substance that is 70–80% water, along with proteoglycans and glycosaminoglycans that help it absorb shock, glide smoothly, and transmit forces efficiently. Adequate water intake supports this intricate network, helping maintain elasticity, reduce stiffness, and promote overall mobility. While hydration isn’t a cure-all for musculoskeletal issues, staying well hydrated is a simple and powerful way to nourish your fascia and support the body’s natural movement and resilience.
Hydration After Bodywork
Following treatments like Counterstrain therapy, hydration becomes even more important. As the body releases restrictions and tissues reset, drinking enough healthy fluids can help flush out metabolic waste products and support recovery. Encouraging post-session hydration ensures the benefits of treatment are reinforced and discomfort is minimized.
Listen to Your Body
Guidelines provide a benchmark, but your needs vary depending on activity level, climate, and health. A simple rule of thumb: if you’re thirsty, drink water or other healthy fluids. Your body is usually a reliable guide.
Why Dehydration Sneaks Up on Us (and It’s Not Just Mom)
Aging and Thirst
As we age, our sense of thirst diminishes, meaning many older adults don’t feel thirsty until they’re already dehydrated—which, by then, is potentially dangerous.ER Visits & Hydration
Dehydration contributes significantly to hospital admissions in seniors:In one study, 17–28% of older adults in the U.S. were chronically dehydrated.
Another showed dehydration as a primary or complicating reason in up to 30–40% of older patients admitted to hospital, and around 9% of hospitalizations in those over 65 included dehydration as a secondary diagnosis. ScienceDirect
A UCLA study highlighted that dehydration led to a 5% increase in preventable ER visits, particularly affecting those over 65.
Mild Dehydration Hurts Performance
Even losing just 1–2% of body water—yes, just a couple of pounds—can impair cognitive performance, mood, and focus.
The Takeaway
Instead of fixating on “eight glasses,” aim for about 11–15 cups of healthy fluids daily, knowing that a good portion will come from food. Pairing beverages with water-rich foods is a natural, balanced way to stay hydrated—benefiting not just your overall health, but your skin and recovery after therapeutic care.
Hydration isn’t just about water—it’s about what’s on your plate, your skin health, and keeping you out of the ER. And yes, even if it makes you roll your eyes, reaching for healthy fluids is worth it.