Exercise Heart Rate Calculator — Intensity Reference
Explore general AHA percent-maximum ranges and your own entered reserve percentages
Exercise heart rate intensity reference
AHA ranges are general averages based on estimated maximum heart rate. Reserve percentages below are entered by you and use a different denominator.
Table of Contents
What this intensity reference means
The term “fat-burning zone” describes a popular idea, but a percentage of heart rate does not establish an optimal range for fat loss. This worksheet shows the AHA's general moderate and vigorous exercise intensity ranges.
The AHA calls its figures averages and a general guide. They do not measure your own maximum heart rate or predict calories or fat loss.
Source: American Heart Association, Target Heart Rates Chart (reviewed August 12, 2024)
How the ranges are calculated
The AHA's general estimate is maximum heart rate ≈ 220 − age. Its moderate range is about 50–70% of that estimate; vigorous is about 70–85%. For age 40, the estimate is 180 bpm, moderate is 90–126 bpm, and vigorous is 126–153 bpm.
The optional reserve worksheet uses your entered resting heart rate: reserve = estimated maximum − resting heart rate; target = resting heart rate + reserve × your entered percentage ÷ 100. At age 40 and rest 60 bpm, chosen 60–70% HRR gives 132–144 bpm. Those are user-selected HRR percentages, not the AHA's 50–70% MHR guidance.
Source: American Heart Association, Target Heart Rates Chart (reviewed August 12, 2024)
Keep the denominator visible
A percentage of estimated maximum heart rate (MHR) and a percentage of heart rate reserve (HRR) can give different bpm values. This calculator labels which denominator each result uses.
The estimated maximum is an average arithmetic reference, not a measured individual ceiling or a safety threshold. Conditions and medications may change an appropriate target; the AHA advises discussing targets with a health professional in those cases.
Source: American Heart Association, Target Heart Rates Chart (reviewed August 12, 2024)
Why the old fat-burning label can mislead
The AHA intensity chart identifies moderate and vigorous effort. It does not identify an optimum zone for fat loss. A result here cannot establish which fuel you used or how your body weight will change.
Use the calculated range to understand the percentage arithmetic, not as a promise of a particular outcome.
Source: American Heart Association, Target Heart Rates Chart (reviewed August 12, 2024)
Interpreting exercise effort
The AHA suggests using its age-based numbers as a general guide and checking your pulse during activity. It notes that medications and heart conditions can alter heart rate responses.
If you use the reserve option, choose percentages for a separate reason relevant to your own plan. The calculator does not prescribe an HRR training interval.
Source: American Heart Association, Target Heart Rates Chart (reviewed August 12, 2024)
Frequently asked questions
Are 50–70% and 70–85% reserve percentages? No. The AHA states those bands as percentages of estimated maximum heart rate. Reserve percentages in the second method are entered by you.
Can I treat 220 − age as my safe upper limit? No. It is an age-group estimate, and the AHA presents averages as a general guide.
Why are inputs limited to ages 20–70? Those are the ages in the AHA chart used here. The limit prevents silent extrapolation beyond the displayed chart.
Source: American Heart Association, Target Heart Rates Chart (reviewed August 12, 2024)