5 Common Medical Myths Debunked

Do you truly need 8 glasses of water a day? An MRI for your knee pain? Eye drops for pink eye? House Call Doctor debunks five common medical myths.

Sanaz Majd, MD
5-minute read
Episode #243

Myths can be frustrating for those of us practicing medicine. In the age of the internet, it's a challenge to compete with Google University. Unfortunately, much of what you read online is inaccurate. Therefore, medical myths tend to spin out of control, more rapidly than we can sometimes control as physicians.

Here are five of the most common medical myths debunked:

Myth #1: Drink 8 glasses of water a day

Who decided that we need to specifically consume 8 glasses of water a day? And how large of a glass are we talking about anyway? The truth is: this number is arbitrary.

We absorb a good portion of our bodily fluid intake from our foods. And drinking excessive amounts of water can mess with our cellular electrolyte balance. Recently I saw a patient with a very low sodium level in her routine blood work. I was a tad surprised, because she was healthy and not on any medications. I repeated it, and it was still low. We worry about sodium levels when it’s too low, it can make us feel fatigued, confused and can potentially land us in the hospital.

So I asked her to come in to my office. Believe it or not, in addition to excessive fluid intake, dehydration is a cause for low sodium. (Confusing, right?) Quantifying the amount of fluid intake is very useful in these situations.

After inquiring about her fluid intake, she revealed that she drinks 6 bottles of 32 oz water bottles each day. If we assume that each “glass” of water is about 8 oz, this means she was drinking 24 glasses of water a day.

"I’m trying to shed just a few extra pounds. And I hear from the ‘Dr. So and So’s show’ that water is good for you," she told me.

Yes, water is certainly required for the functioning of each one of our cells and organs. However, there’s no need for excess. And in fact it can do harm. So I told her what I tell all my patients – drink to thirst. Your body will let you know when you need water. You don’t need more than that.

After some fluid restriction, this particular patient’s sodium level went back to the normal range.

I have to admit, for whatever reason, I see this much more commonly in my elderly patients.

Myth #2: You can catch a virus from the cold weather

You may have heard it over and over again from your mother: “Put on a jacket! You’re going to catch a cold!” This is a phrase I heard frequently in my household growing up. And to be honest, it still baffles me when patients reiterate it in my office after so many years.

To be fair, it’s not 100% incorrect. Viruses tend to survive, flourish, and reproduce more efficiently in lower temperatures. This is why we tend to see them spike in the wintertime. However …you can’t catch it simply from the “cold” weather. Viruses are contracted from another carrier who is infected with one. Think of that the next time you shake hands, kiss, or hug. Or more than likely, you will catch a virus from someone in your vicinity who coughed or sneezed in the open air.

Viruses jump from host to host, and that is the only way they survive. Sure, when an infected person sneezes or coughs in the air, it releases those viral particles; but without being exposed to those droplets, you can’t really “catch” a cold otherwise.


Medical Disclaimer
Please note that all content here is strictly for informational purposes only. This content does not substitute any medical advice, and does not replace any medical judgment or reasoning by your own personal health provider. Please always seek a licensed physician in your area regarding all health related questions and issues.

About the Author

Sanaz Majd, MD

Dr. Sanaz Majd is a board-certified Family Medicine physician who graduated from Drexel University College of Medicine in Philadelphia. Her special interests are women's health and patient education. 

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