Here’s what this health metric really indicates, according to cardiologists. Fact checked by Isaac Winter Reviewed by Vivek Cherian, MD Heart rate variability (HRV) is the difference in the timing ...

That tension becomes especially clear with heart rate zone training, a popular five-tier system that endurance athletes use to measure effort and fine-tune performance. The well-known formula is ...

Heart rate variability (HRV) is the variation in the time between two consecutive heartbeats over a specific period. Doctors may use HRV as an indicator for certain aspects of a person’s health, ...

It’s been known for decades that heart rate variability (HRV) during labor signals how a fetus is responding to stress. Lower HRV—a lower variation in heartbeats—is even a risk factor for sudden ...

It may sound dramatic, but the rate at which your heart is beating plays a key role in how long you’re likely to live. According to expert cardiologists and academic researchers, resting heart rate ...