MAF Heart Rate (Aerobic Base)

The formula

MAF heart rate = 180 − age + adjustment

180 − 35 = 145, and with the default adjustment of zero the result is 145 bpm.

Worked examples

Age 25, no adjustment → 155 bpm
Age 35, no adjustment → 145 bpm
Age 45, no adjustment → 135 bpm
Age 60, no adjustment → 120 bpm
Age 35, +5 (returning from illness) → 150 bpm
Age 35, −5 (training consistently for years) → 140 bpm
Age 35, −10 (on regular medication) → 135 bpm

What the adjustment is for

The bare 180-minus-age number is a starting point, and the adjustments are the part that makes it individual. Add five if you are recovering from illness, injury or a long layoff, or if you are new to training. Subtract five if you have trained consistently for more than two years without injury. Subtract another five if you take prescription medication that affects heart rate. Those directions matter: the same age can legitimately sit ten beats apart.

How the number is meant to be used

• It is a ceiling, not a target. Aerobic base work sits at or just under it, not above.
• Slow down to stay under. Most people find the pace that keeps them there embarrassingly easy at first — that is the point of the method.
• Use the talk test as a cross-check. Full sentences should be possible; if they are not, the effort is above the aerobic band.
• It is a training heuristic, not a physiological measurement. Laboratory thresholds and heart-rate drift with heat will disagree with it, and that is expected.
• A medical condition changes the picture. Heart rate formulas are general guidance, not clinical advice.

Recheck the number when your training history changes, and judge the band by how aerobic effort actually feels over a few weeks rather than by the formula alone.

Frequently Asked Questions