This is where Zone 2 cardio enters the chat. Zone 2 should constitute the majority of your cardiovascular training because it provides a solid aerobic base essential for overall endurance and health. When 80% of your cardio workouts are in Zone 2, it allows your body to develop the efficiency needed for longer, more intense sessions without overtraining. This approach, often referred to as the 80/20 rule in endurance sports, balances the high-intensity workouts (20%) with lower-intensity efforts (80%), ensuring sustainable progress and reducing the risk of injury. In contrast, relying solely on High-Intensity Interval Training (HIIT) can lead to burnout, increased risk of injury, and inadequate recovery. HIIT is great for improving anaerobic capacity and burning calories quickly, but without the foundation provided by Zone 2 cardio, you will likely find yourself constantly fatigued, overtrained, and more susceptible to injuries and illnesses.