<< Back
Do You Need 8 Glasses of Water a Day? 6 Health Myths Explained
August 28, 2026
If you’ve ever searched a health question online, you’ve probably walked away with more questions than answers.
Do you really need eight glasses of water every day? Will you catch a cold if you go outside with wet hair? Is that detox actually going to help you lose weight?
“Health misinformation is incredibly common because many myths contain a small grain of truth,” says Suelen DeOliveira, APRN, with Hartford HealthCare Medical Group. “But health is rarely black and white. Most topics are more nuanced than a simple headline or social media post can capture.”
Many common health myths stick around because they sound believable or have been repeated for generations.
So what’s fact, and what’s fiction? Let’s clear up some of the most common health myths once and for all.
1. Myth: You need to drink eight glasses of water every day
Somewhere along the way, eight glasses became the magic number. But hydration isn’t that simple.
The amount of water you need depends on your age, activity level, climate, health conditions and even the foods you eat.
“Everyone’s hydration needs look different,” says DeOliveira. “If you’re exercising outdoors in the summer, you’ll need a lot more water than someone spending most of their day inside.”
Luckily, your body is usually pretty good at letting you know when it needs more water.
“Thirst, urine color and overall energy levels can all provide clues about hydration status,” DeOliveira adds.
Try: Carrying a water bottle and aiming for pale yellow urine rather than obsessing over a specific number of glasses.
> Related: This Is What Dehydration Actually Looks Like
2. Myth: Cracking your knuckles causes arthritis
Despite decades of concern, research has never shown a connection between knuckle cracking and arthritis.
“Knuckle cracking might be annoying to the people around you, but it hasn’t been proven to cause arthritis,” says DeOliveira. “The sound comes from changes in pressure within the joints, not from damage occurring inside them.”
But you still shouldn’t ignore symptoms in your joints.
“If you experience pain, swelling or reduced movement in a joint, that’s worth discussing with a provider regardless of whether you crack your knuckles,” DeOliveira adds.
Try: Paying attention to joint pain and stiffness, not sounds.
> Related: Can Exercise Prevent Arthritis?
3. Myth: You can sweat toxins out of your body
This one has fueled everything from detox teas to extreme sauna challenges.
But the reality is that your liver and kidneys do most of the heavy lifting when it comes to removing waste products from your body.
“Sweating helps regulate your body temperature, but it’s not a major detoxification system,” says DeOliveira.
That doesn’t mean you should skip exercise.
“Physical activity supports overall health in countless ways, but detoxifying the body through sweat is not one of its primary functions,” DeOliveira adds.
This is one of those common health myths that can make expensive products or extreme routines sound more effective than they really are.
Try: Focusing on hydration, exercise and balanced nutrition instead of expensive detox products.
> Related: 7 Common Causes of Night Sweats (and When to Worry)
4. Myth: You only need sunscreen on sunny days
If it isn’t 85 degrees and sunny, you might be tempted to skip sunscreen. But ultraviolet rays don’t take the day off when the sun disappears behind the clouds.
“UV radiation can penetrate clouds and still damage your skin,” says DeOliveira. “That’s why skin cancer prevention recommendations apply year round, not just during beach season.”
Even short exposures can add up over time.
Try: Applying sunscreen every morning as part of your routine, regardless of the weather.
5. Myth: If you’re thin, you’re healthy
Body weight only tells a small part of the story.
Blood pressure, cholesterol, blood sugar, fitness level, sleep quality and mental health all contribute to overall wellness.
“You can’t tell anyone’s health by looking at them,” DeOliveira notes.
That’s why preventive care is so important.
“Regular checkups can uncover issues that aren’t visible from the outside,” DeOliveira adds.
Try: Scheduling routine visits even if you feel healthy and maintain a healthy weight.
> Related: Diet vs. Exercise: What Matters More for Your Health?
6. Myth: Natural means healthy
Poison ivy is natural. So are many substances that can be harmful to humans.
“The word natural is a marketing term, not a guarantee of safety or effectiveness,” says DeOliveira. “Many natural products can interact with medications or cause side effects.”
That’s why supplements deserve the same scrutiny as other health products.
Try: Reading labels carefully and talking with your doctor before starting new supplements.
> Related: 7 Foods That Sound Healthy but Really Aren’t
The healthiest habit? Stay informed
Health advice changes. New research emerges. And sometimes, long-held beliefs turn out to be wrong.
That’s why common health myths can be difficult to recognize, especially when they appear repeatedly online or come from someone you trust.
One of the most important health habits is to maintain a healthy dose of skepticism, especially when you’re reading things online.
“Whenever you hear a health claim that sounds too good to be true, it’s worth taking a closer look,” says DeOliveira.
And when in doubt, ask an expert.
“Your healthcare provider can help you sort through the noise and focus on recommendations that are actually supported by evidence,” DeOliveira adds.