Calyx Physical Therapy
Cristina Shupe, PT -- Physical Therapist and Fascial Counterstrain Provider in San Francisco: Specializing in the treatment of chronic pain, injuries and conditions

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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. Even mild dehydration—losing just 1–2% of your body’s water—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 glasses of water 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 modern research shows that hydration needs are 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 water your body really requires.

According to Mayo Clinic and Harvard Health (citing the National Academies of Sciences, Engineering, and Medicine):

  • 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.

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 (0.7 L) from food, ~12.5 cups (3 L) from beverages.

  • Women: ~2.3 cups (0.6 L) from food, ~9.2 cups (2.1 L) from beverages.

If you eat lots of fruits and vegetables, you might get closer to 25–30% of your fluids from food. With a low-produce diet, it may be closer to 10–15%.

Foods That Help Hydrate You

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 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. Your body is usually a reliable guide.

The Takeaway

Instead of fixating on “eight glasses,” aim for about 11–15 cups of 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.

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. Mayo ClinicMDPI

  • 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. PMCVerywell HealthUCLA

    • 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. ScienceDirectjarlife.net

    • A UCLA study highlighted that dehydration led to a 5% increase in preventable ER visits, particularly affecting those over 65. UCLA

  • 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. Wikipedia

Cristina