The Karvonen method personalizes your training heart rate by using your resting heart rate, not just your age. Enter your age, resting heart rate, and desired intensity to find your target.
Sample input: Age (years): 30, Resting heart rate (bpm): 60, Intensity (% of heart-rate reserve): 70
Target heart rate: 149 (70% intensity (Karvonen))
Training at 70% of your heart-rate reserve gives a target of about 149 bpm (your estimated max is 187 bpm). Use this as a guide during cardio.
The Karvonen formula uses heart-rate reserve, the gap between your maximum and resting heart rate. Target equals reserve times intensity plus resting heart rate, giving a more personal target than percent-of-max alone.
Measure your pulse for 60 seconds first thing in the morning before getting up, ideally averaged over several days. A typical adult resting rate is 60 to 100 beats per minute, and fitter people often sit lower.
The American Heart Association suggests moderate intensity around 50 to 70 percent and vigorous intensity 70 to 85 percent of heart-rate reserve. Beginners should start at the lower end.
Two people the same age can have very different fitness. Including resting heart rate makes the target reflect your conditioning, so well-trained people get appropriately higher targets.