Heart rate for interval training

Estimating your maximum heart rate

The well-known 220 minus age formula wasn’t built from much data. Researchers who pooled hundreds of studies and then tested adults in the lab found that 208 minus 0.7 times age fits better, especially for older adults ³. Cero uses this formula. It’s still an estimate: your own maximum can be a fair way above or below it.

Age	Max HR	90 to 95%
20	194 bpm	175 to 184 bpm
30	187 bpm	168 to 178 bpm
40	180 bpm	162 to 171 bpm
50	173 bpm	156 to 164 bpm
60	166 bpm	149 to 158 bpm

Heart rate during hard intervals

In a trial with moderately trained men, four 4-minute intervals at 90 to 95% of maximum heart rate, with 3 minutes of jogging at about 70% between them, improved VO2max more than steady running at lower intensities ¹. Patients with heart failure, exercising under supervision, improved more with the same kind of intervals than with moderate exercise ².

Heart rate lags behind effort. In very short intervals, such as 20 or 30 seconds, it keeps rising after the interval ends, so judge those by effort, not by your heart rate.

Heart rate during rest

Rest is where heart rate is most useful. Waiting until it falls to a set level means each round starts from a similar place, rather than starting tired because the clock said so.

• Choose a recovery target, such as 60 to 70% of your maximum.
• Rest until you reach it, with a cap so a slow recovery doesn’t end the session.
• In Cero, Adaptive HR does this for you, and warns you if a hard interval is too easy or too hard.

Sources

1. Helgerud J, Høydal K, Wang E, et al. Aerobic High-Intensity Intervals Improve VO2max More Than Moderate Training. Med Sci Sports Exerc. 2007;39(4):665-671. doi.org/10.1249/mss.0b013e3180304570
2. Wisløff U, Støylen A, Loennechen JP, et al. Superior Cardiovascular Effect of Aerobic Interval Training Versus Moderate Continuous Training in Heart Failure Patients. Circulation. 2007;115(24):3086-3094. doi.org/10.1161/CIRCULATIONAHA.106.675041
3. Tanaka H, Monahan KD, Seals DR. Age-predicted maximal heart rate revisited. J Am Coll Cardiol. 2001;37(1):153-156. doi.org/10.1016/S0735-1097(00)01054-8