By sport
Biathlon Training Zones
The same I1–I5 model as XC skiing, plus controlling heart rate on the shooting range.
Max Heart Rate Calculator
Your maximum heart rate is the highest your heart can beat at all-out effort. Age formulas estimate it: Tanaka gives 208 − 0.7 × age, the classic 220 − age runs high. At age 35 that is 184 and 185 bpm, but true values vary by ±10–12 bpm, so test it.
Heart Rate Zone Calculator
Heart-rate zones are percentages of your maximum heart rate: Zone 1 is 50–60%, Zone 2 60–70%, Zone 3 70–80%, Zone 4 80–90% and Zone 5 90–100%. At a max of 185 bpm, Zone 2, the aerobic-base zone, is 111–130 bpm. Most easy training belongs in Zones 1–2.
XC Skiing & Biathlon Heart Rate Zones (I1–I5)
Cross-country skiing and biathlon use the Norwegian/FIS I1–I5 scale: I1 is 60–72% of maximum heart rate (<2 mmol/L lactate), I2 72–82% (~2), I3 82–87% (2.5–4), I4 87–92% (4–6) and I5 92–100% (>6). At 190 bpm maximum, I1 is 114–137 bpm and I3 156–165 bpm.