Could knowing your heart rate variability improve your health?
Dr Malcolm Finaly, a consultant cardiologist and electrophysiologist at Barts Health, explains the science behind some recent health technology headlines.
“You might have seen in the news recently that some doctors are suggesting that ‘checking your pulse every day could improve your sleep, beat stress and help spot early signs of illness’.
“How you ask? By monitoring something called your heart rate variability (HRV) using a wearable device like a smart watch. Sounds good right. But is it true?
The jury is still out
“There is evidence to suggest that wearable technology like smart watches can help monitor and manage your health. In fact, we’re researching this ourselves. It’s still early days for this whole area of research but it’s showing promise.
“Things are less clear when it comes to how useful it is to measure and monitor your HRV. It might be a good metric for measuring how stressed or relaxed you are, but it has little use to doctors when we’re assessing and treating patients.
“Part of the reason for this is because HRV monitoring offers only a general picture. It’s been shown to be a good overall indicator of stress or relaxation levels across large groups but looking more closely at the individuals, it does not always correlate reliably with people’s real stress or relaxation. To put it another way you might have a high HRV and still be stressed.
Research is being done into how wearable tech could help us manage our health - but it's early days
We need to delve deeper
“When researchers are developing new ways to diagnose and treat conditions, they assess them through clinical trials – the best type being a randomised double-blind clinical trial. They do this first in small groups of people (100-200 people), then larger ones (we’re talking thousands of people), testing for things like safety and how well things work. Once this is done, their results are reviewed by experts in the field and then published so other people can learn about what they did.
“In the case of information being shared by one doctor, as of now, these trials haven’t been done to prove the theory. Instead, we’re told that the theory has been tested in just 198 people who we don’t know anything about (how old they were, do they have health problems etc.).
The helpful bits
“However, there is some information being shared as part of the discussions around HRV which is helpful – tips for improving your health in general. Reminders that things like having a good night’s sleep, eating well, reducing how much you drink, not smoking etc. can improve your health.
“But some people are putting the cart before the horse and are suggesting that improving your HRV can directly improve your health. Instead, it’s a case of improvements in your health can change your HRV. So don’t worry too much about what that number is, and instead focus on getting more exercise and eating well.
“There is a lot of work being done to see how wearable technology like smart watches can help us monitor and manage our health and how information gleaned from them might help doctors in caring for patients. But for now, it’s a big stretch to say that the ‘secret to spotting the early signs of illness’ and being happy lies solely in them.”