Zone 2 training refers to moderate-intensity cardio exercise where you work at 60 to 70 percent of your maximum heart rate for long durations. This is considered a “sweet spot” for improving overall health and fitness because it allows you to stay at an intensity for fat oxidation (burning more fat for energy), reduce lactate build-up, and improve your stamina for more exercise all through the growth of your mitochondria. Training in these intensities tends to be the most helpful for endurance athletes, individuals wanting to improve their cardiovascular fitness, and those with weight loss goals because of its effect on the cell’s mitochondria and aerobic pathways.