Maximum Heart Rate and Target Zones

How is maximum heart rate calculated?

Maximum heart rate describes the highest rate reached during intense effort. An age-based estimate is not a measurement of your actual maximum. This tool uses the Tanaka equation as its main method rather than assuming an average of several formulas is more accurate.

Estimated maximum heart rate = 208 − 0.7 × age. At age 40, the estimate is 180 beats per minute.

The comparison section also shows 220 − age (Fox) and 211 − 0.64 × age (Nes). Different numbers at the same age do not tell you which is your true maximum. The calculator does not establish a rate up to which exercise is guaranteed safe.

Target zones: percent of maximum or Karvonen?

If resting pulse is blank, zones use percentages of estimated maximum heart rate. There is no hidden default of 70 bpm. If you enter a resting rate, the Karvonen method uses heart rate reserve. The two approaches should not be expected to give the same bpm at the same percentage.

Heart rate reserve = maximum − resting rate.
Karvonen target = resting rate + intensity × heart rate reserve.

At age 40 with a resting rate of 60, reserve is 120. The 60–70% reserve zone is 132–144 bpm. Without a resting input, 60–70% of maximum gives 108–126 bpm. This is a difference in the definition of intensity, not an arithmetic error.

How to read the five zones

The table shows 50–60%, 60–70%, 70–80%, 80–90% and 90–100% bands. They are mathematical ranges under the chosen method, not a ready-made weekly training prescription. Watches and training systems can use names such as Zone 2 for differently defined ranges.

During running, walking or cycling, heat, fatigue, hydration and the measuring device can affect heart rate. The talk test and perceived effort help add context. The American Heart Association’s target heart rate guide explains a general framework; a personal plan also needs your experience and health circumstances.

Is there one best fat-burning heart rate?

A larger proportion of energy coming from fat at lower-to-moderate intensity does not mean long-term fat loss is automatically greatest in that band. Duration, total expenditure, recovery and consistency matter too. The tool does not label one zone the fastest fat-loss range for everyone.

The cardio and HIIT guide compares different approaches to exercise. The daily calorie calculator addresses energy needs separately: one heart-rate zone is not a complete weight-management plan.

Measuring resting heart rate

Measure when you are calm rather than just after exercise. Several measurements under similar conditions help identify an unusual one-off reading. If a watch value seems unexpected, check sensor contact and measurement conditions.

A resting rate equal to or higher than the estimated maximum cannot produce a meaningful positive reserve. The tool does not generate reversed zones. Inputs outside its adult calculation ranges also require correction.

Medication, health and age

Age-based formulas may be unsuitable when medication changes heart rate. In particular, there is no universal adjustment of 20 or 30 bpm for beta-blocker use; personal assessment is needed. With heart disease or symptoms during exercise, this table cannot establish a safe effort limit.

The calculation is for adults. The main Tanaka equation is the same for women and men; individual differences still exist. For strength-training loads, explore the one-rep max estimate. The water intake guide covers the basics of fluid planning.