I’ve seen a few patient now because they’ve been worried about their Fitbit heart rate reports.

The Fitbit is an amazing bit of kit that can constantly monitor your heart rate. It’s worn on the wrist and is a step up from the older chest strap monitors that are widely used in sport, mainly because their convenience means they can be worn all the time.

This means the Fitbit is generating huge amounts of data on heart rate that we simply have never seen before as doctors. We’ve had the ability to accurately record continuous heart rate and ECG monitors for some years but these are complex devices put on by medical professionals and simply aren’t as widely used as a Fitbit. They are also mostly used in people with a high probability of heart rhythm problems rather than the healthy fitness focussed population.

Some people who feel well otherwise may see their heart rate is outside the normal range and unsurprisingly worry about it.

Most people who see me are worried that their heart rate is too slow at times. They can google it and find lots of information about fast heart rates but not necessarily slow heart rates.

Most people will have nothing to worry about, especially if they have no symptoms like feeling faint or fatigued; and if their heart rate goes up normally with exercise.

There are diseases such as sick sinus syndrome or heart block that can cause slow heart rates – these usually are picked up because of fainting or a constant very slow heart rate in the 30-40’s. This can be successfully treated with a pacemaker. More difficult is people who have a generally slow rate even on exercise – something known as chronotropic incompetence which can also be treated with a pacemaker.

Constantly rapid heart rates are worth investigating – some rhythms such as atrial fibrillation or slow atrial tachycardia can occur without symptoms and cause impaired heart function simply as a function of a rapid rate (over 100beats per minute) for weeks on end.

So the Fitbit is a helpful piece of technology which can certainly help to motivate and inform exercise programs. I’m sure it will pick up people who do have concerning heart rhythm problems but this will be a rare event!

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