In a recent episode of the ZOE podcast, Bryan Johnson – a man famous for trying pretty much every supposed longevity booster going – spoke with the gut health company’s co-founder Dr Tim Spector and CEO Jonathan Wolf.

Bryan said that his progress was being measured with a “few different modalities,” adding that it’s possible to “measure the biological age of the heart anatomically.” 

Though many of the methods the controversial millionaire uses to track, preserve, and even try to reverse his body’s age are experimental, researchers have found that one of the metrics he uses – resting heart rate – really can be linked to mortality. 

How does resting heart rate affect longevity?

Harvard’s site says that measuring your resting heart rate, or the number of times your heart beats in a set period while you’re relaxed, is “one of the easiest, and maybe most effective” health markers we have.

Dr Jason Wasfy, director of quality and analytics at Massachusetts General Hospital Heart Center, said: “A lower resting heart rate can mean a higher degree of physical fitness, which is associated with reduced rates of cardiac events like heart attacks”.

Meanwhile, a higher resting heart rate could belie an increased risk of cardiac risk “as the more beats your heart has to take eventually takes a toll on its overall function”.

A 2013 study found that men who had a resting heart rate between 81 and 90 had double the risk of premature death than those with a lower heart rate (<50 bpm), while those with a resting heart rate above 90 had triple the risk. 

With every 10 added beats per minute, they found, the likelihood of premature death upped by 16%. 

What’s an ideal resting heart rate?

The British Heart Foundation says an ideal resting heart rate is between 60-100 BPM (beats per minute). 

Sometimes, very fit people have a lower heart rate than 60 BPM. A lower resting heart rate warrants a GP visit if it’s accompanied by symptoms like dizziness, fainting, and fatigue. 

Your heart rate can dip as low as 40 BPM when you sleep without any cause for cencern.

A heart rate over 100 BPM is too fast for most of us. See a doctor if you notice palpitations, dizziness, fatigue, or fainting. 

How can I measure my resting heart rate?

It takes about 30 seconds to measure your resting heart rate. You just need to make sure you’re really, well, rested when you check it; soon after waking up is a great time to check your resting heart rate.

Put your index and middle fingers on your wrist or neck – anywhere you can feel a pulse.

Don’t use your thumb, because that has its own pulse.

Measure the beats across 30 seconds and then double it to get your beats per minute (BPM).

You should repeat it a few times to make sure your reading is accurate, making sure it’s not within an hour of either drinking caffeine or taking exercise (those elevate your heart rate).

For the most accurate stats, take your resting heart rate multiple times across that week at different times of day.