Heart rate recovery, or HRR, measures how quickly your heart rate returns to a normal rate after a bout of peak effort exercise. It’s used as a measure of fitness, to track how athletes are improving, and is also associated with risks of serious disease and even mortality.
Your HRR gives you valuable information about the function of your autonomic nervous system, which controls vital functions like breathing, says Mike Nelson, Ph.D., C.S.C.S., an associate professor at the Carrick Institute. To understand why HRR is important for this, he says, think of your autonomic nervous system like a race car.
The sympathetic (fight-or-flight) side of your nervous system is like the gas pedal — the harder you push it, the faster it goes. The parasympathetic (rest-and-digest) side is like the brakes. The harder you push on the brakes, the faster the car slows down, Nelson says. Your HRR measures how well your brakes are working. And that’s important: “If you’re all gas, no brakes all the time, odds are you’re eventually going to blow your engine.”