Estimate target heart-rate zones for cardio, fat loss, Zone 2 training, and conditioning after 40.
Build aerobic conditioning with controlled intensity.
Train endurance and work capacity.
Use intervals carefully when recovery is good.
Cardio after 40 should be planned, not guessed. Heart-rate zones give users a simple way to control intensity instead of turning every session into a max-effort grind.
For fat loss, health, and conditioning, Zone 2 work can be a useful base. Harder intervals still have a place, but they should be used intelligently and recovered from properly.
Zone 2 can help build a sustainable conditioning base, but fat loss still depends heavily on calories, protein, and consistency.
Intervals can be useful, but they should be added based on recovery, joint tolerance, and training level.
A monitor helps, but perceived effort can also guide intensity.
Fitness calculators are educational estimates and coaching tools. They are not medical diagnosis or treatment. If you have pain, symptoms, medications, medical conditions, or injury concerns, consult a qualified professional.