It is the level of intensity of cardio during cardio exercise and has different ranges. 60% to 70% ,low intensity this is a warm up for beginners. 70%-80% moderate intensity, it is in this zone that improves body's ability to transport oxygen throughout the body and conditioning one's heart.80% - 90% it in this zone also that allows us to burn more calories.
it's hard for people to concentrate because they always have that one person on there mind and there always thinking about them so they get so distracted with that .