Heart rate reserve is a fitness indicator and a more accurate way to find your target heart rate, especially for exercise. Heart rate reserve is the difference between your maximum (peak) heart rate and your resting heart rate. Your maximum heart rate is the number of beats per minute your heart can reach during exercise. Your resting heart rate is the number of beats per minute when you’re fully rested on a bed, preferably right after waking up in the morning.
To calculate your resting heart rate right after waking up, gently place your index and middle fingers on your neck to the side of your windpipe; once you feel your heartbeat, count the beats for 60 seconds. Then enter the information in the calculator below to find your estimated maximum heart rate and aerobic zones.
This is using the updated Karvonen formula 206.9 – (0.67 x age).