VIRGINIA BEACH, Va. (WVEC) -- On a daily basis, millions of people monitor their health, checking their blood pressure at home.

The "at-home" approach gives patients an idea of where their blood pressure measurements stand in between visits to the doctor’s office.

Blood pressure monitors, however, are not always as accurate as they should be.

“Some are good and some are not so good,” said Dr. Deepak Talreja.

Talreja is a cardiologist in Virginia Beach. He and other health care providers rely, in part, on home measurements to help them figure out how much blood pressure medication to prescribe to patients.

VIDEO: Differences between hospital and at-home blood pressure monitors

“We really need to work with reliable information as to what a patient’s blood pressure is doing throughout the day,” explained Talreja.

Joshua Walton, who works at ABC13, has been checking his blood pressure regularly for years. High blood pressure runs in his family, and he wanted to make sure he was staying on top of his health. He often would use the machines at pharmacies and grocery stores. Walton quickly found out many of the grocery stores and even home blood pressure monitors were not calibrated correctly. That’s the case for many at-home blood pressure monitors as well.

“The machine was saying everything was fine and all,” he said.

Doctors told Walton everything was not fine, and they diagnosed him with high blood pressure.

Talreja told 13News Now mistakes like that happen often and can have very serious consequences.

“The real dangers are if we believe someone’s blood pressure is high when it’s not actually high. We might overmedicate them and make them feel worse, even putting them at risk for passing out,” Talreja told 13News Now.

So how can you protect yourself from this situation?

Talreja said it is important for people to bring the at-home devices to their doctor’s office to have them calibrated and see how accurate they really are. Doing that can prevent mistakes that could lead to serious health issues.

VIDEO: How is blood pressure measured?

"Untreated high blood pressure is the leading cause of stroke and cardiovascular deaths, shared Talreja. "Over-treated high blood pressure risks side effects from medications."

As for Walton, he said he is glad he was able to catch things when he did.

“It was kind of scary. It definitely was. I’m glad I was given the opportunity to go and correct the situation," he shared.

When it comes to deciding which at-home blood pressure monitor to buy, Talreja recommended going with something that is priced moderately.

“Don’t go with the cheapest or most expensive. Pick one that’s priced in the middle, and, of course, don’t forget to take it to your doctor’s office to be calibrated,” offered Talreja.