How heart-rate zones work
One signal among many.
Heart rate changes with effort, fitness, fatigue, temperature, medication and other factors. A zone estimate can help you recognise broad intensity levels, but it is not exact for everyone. Your coach can help you interpret the display alongside breathing, perceived effort and how you feel.
The five zones
From recovery to peak.
Each zone has a job. Most sessions spend time in several of them.
Z1
Recover
Very light effort
A comfortable pace that supports recovery between harder efforts. You should be able to speak easily.
Z2
Build
Light to moderate
A sustainable pace for developing aerobic consistency. Conversation should still feel manageable.
Z3
Strengthen
Moderate to challenging
A focused working pace where breathing becomes more noticeable and effort requires attention.
Z4
Challenge
Hard effort
A demanding intensity used for structured intervals. Follow the session plan and your coach’s guidance.
Z5
Peak
Very hard effort
Short, high-intensity efforts for appropriate participants and programming. Not a target to chase in every workout.
Your heart-rate estimate
Use estimates as a guide, not a diagnosis.
Some training systems estimate maximum heart rate from age, but formulas are only rough population-level estimates and can be inaccurate for individuals. Kraventis does not use a simple calculation to prescribe medical advice. If you have a health concern or are unsure about exercise intensity, seek guidance from a qualified healthcare professional.
Uses the common 220 minus age formula. It is a rough population estimate, not a personal prescription or medical advice.