Zone 1 (Very Light): 50-60%. Ideal for warm-ups, cool-downs, and active recovery.
Zone 2 (Light): 60-70%. The "fat-burning" zone. Good for long, slow endurance training.
Zone 3 (Moderate): 70-80%. Improves cardiovascular fitness and builds aerobic capacity.
Zone 4 (Hard): 80-90%. Increases your lactate threshold and anaerobic endurance. Tough but effective.
Zone 5 (Maximum): 90-100%. For short, intense bursts to boost peak performance. Use sparingly.