Heart Rate Zones: How to Train Smarter, Not Harder

Calculators do the heavy lifting, but knowing what is going on underneath is what saves you money — or stress — later. Same hour of exercise can produce wildly different results depending on intensity. Heart rate zones are the cleanest way to control that.

Max heart rate estimate

MHR ≈ 220 − age (rough). 30-year-old → ~190. More accurate: 207 − (0.7 × age).

The 5 zones

Z1: 50–60% MHR (recovery). Z2: 60–70% (endurance base). Z3: 70–80% (tempo). Z4: 80–90% (threshold). Z5: 90–100% (VO2 max).

80/20 rule

Elite endurance athletes spend ~80% of training time in Z1–Z2 and only ~20% in higher zones. Most amateurs flip this and stall.

When to push to Z4–Z5

1–2 sessions/week. Builds aerobic ceiling. Painful but high-leverage.

Pro tips

• Buy a chest strap monitor — wrist-based is fine for steady state but unreliable for intervals.
• Track resting heart rate weekly. Rising trend = overtraining or sickness.

Frequently asked questions

Are heart rate calorie estimates accurate? Within ±15%. Treat as a trend, not the truth.

What's a healthy resting heart rate? 60–80 bpm for most adults. Athletes can be in the 40s. Sudden changes matter more than absolute values.

Bookmark the calculator linked above — you will need it more often than you think.