The 220-minus-age formula is wrong for most people. Three better ways to set your heart rate zones, and how to know which zone you are actually training in.
By Coach Voris, NASM-CPT · AI Fitness · heart rate zones, cardio, wearables, vo2 max, training
Your watch puts you in zone 4 on an easy jog and zone 2 on a hard hill. That is almost never your effort being wrong. It is your zones being wrong. Zones are only useful if the ceiling they are calculated from is close to your real maximum heart rate. Most devices start from a formula, and that formula is off by 10 to 20 beats for a large share of people. The 220-minus-age rule came from a loose fit across a small data set. Its standard deviation is roughly 10 to 12 beats per minute. That means a 45-year-old with a "predicted" max of 175 could easily have a true max of 163 or 187. Ten beats of error moves every zone boundary. If your true max is lower than predicted, every session feels harder than the label says and your easy days quietly become moderate days. That is the single most common reason people stop improving while training more. After a 10 minute warm-up, run or ride 3 minutes hard, recover 2 minutes easy, then go 3 minutes all out, finishing with everything you have in the last 45 seconds. The highest number you see is a realistic working max. Do this only if you are already training regularly and have no cardiac risk factors. If you are new, unwell, or over 50 and unt…