In 2014, former training instructor Daniel Green was in for a shock when, at age 81, he went to his doctor in Sussex. His resting heart rate (RHR) was 36 beats per minute.

The doctor tested again, and it was down to 26 BPM, one beat lower than the all-time low entered in the Guinness World Records.

Green credits walking an hour every morning, using the elliptical regularly and lifting weights.

While you don't need to bring your BPM down to one beat every three seconds, if you have a high resting heart rate, it's a good idea to lower it.

One study of men ages 40 to 59 found that an RHR of 81 to 90 (as opposed to an RHR of 65 to 80) doubled the chance of death over the course of the 16-year study, while an RHR higher than 90 tripled it.

A high RHR also increased the chance of heart attack, and recent studies have found that elevated RHR is associated with an increased risk of death in patients with colorectal, pancreatic, and non-small cell lung cancer, as well as being predictive of colon cancer recurrence.

Ask what your ideal RHR is based on your age and gender. If you need to bring it down, try the following: 10 minutes of mindful meditation daily; stay well-hydrated; limit alcohol intake (seven drinks weekly for women, 14 for men); shoot for at least 150 minutes of exercise a week; take 10,000 steps a day; and get seven to nine hours of sleep nightly.