By sport
Cycling Training Zones
Power is king. Anchor your zones to FTP from a 20-minute test, then verify with heart rate. Coggan's 7-zone model is the standard.
Max Heart Rate Calculator
Your maximum heart rate is the highest your heart can beat in all-out effort. Age formulas estimate it: Tanaka gives 208 − 0.7 × age; the classic 220 − age tends to run high. At age 35 that is roughly 184 and 185 bpm, but the real value varies by ±10–12 bpm, so test it to be sure.
Heart Rate Zone Calculator
Your 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 key aerobic-base zone, runs about 111–130 bpm. Spend most easy training in Zones 1–2.
Karvonen Heart Rate Reserve Calculator
The Karvonen formula sets zones from your heart-rate reserve: maximum minus resting heart rate. Target = intensity% × (HRmax − RHR) + RHR. With a max of 185 and resting of 50 bpm (reserve 135), 70% gives 0.70 × 135 + 50 ≈ 145 bpm. Because it uses your resting heart rate, it personalises zones to your fitness.
LTHR Heart Rate Zone Calculator
LTHR zones anchor to your lactate-threshold heart rate, the heart rate you can hold for about an hour, instead of an age-estimated maximum. Find LTHR from the final 20 minutes of a 30-minute time trial. Friel's model then sets Zone 4 (threshold) at 94–99% of LTHR for cycling and 95–99% for running.
FTP Calculator & Cycling Power Zones
Functional Threshold Power (FTP) is the highest power you can hold for about an hour. The Coggan model sets seven zones from it: Endurance (Z2) is 56–75% FTP and Threshold (Z4) is 91–105%. At an FTP of 250 W, Z2 is 140–188 W, Z4 is 228–263 W, and Sweet Spot is 220–235 W.
Critical Power Calculator (CP & W′)
Critical Power (CP) is the asymptote of the power–duration curve, the highest power you can sustain almost indefinitely. From two maximal efforts, CP = (P1·t1 − P2·t2) ÷ (t1 − t2) and W′ = (P1 − CP)·t1. A 300 W 3-minute and 250 W 10-minute effort give CP ≈ 229 W with a W′ of about 12.9 kJ.