Cardio training zones are defined by which heart rate ranges?

• A. 65-75% HRmax
• B. 50-60% HRmax
• C. 30-40% HRmax
• D. 90-100% HRmax

Answer: (A)

Cardio training zones target a moderate, sustainable effort that keeps the heart rate in the aerobic range. Hitting about 65-75% of HRmax provides enough challenge to elevate heart and lung activity while still allowing you to continue the activity for an extended period. This level promotes improvements in endurance and cardiovascular fitness because you’re working hard enough to stress the system but not so hard that you can’t maintain the pace.

Lower ranges, around 50-60%, are generally more suitable for warm-ups, cool-downs, or very light activity, where cardiovascular adaptations are minimal. Very high ranges, near 90-100%, are maximal efforts that aren’t sustainable for long workouts and are used for intervals or sprints, not steady cardio. So the defined cardio training zone sits in the moderate range of roughly two-thirds of maximum heart rate.