However , you can improve your ' anaerobic threshold ' -- the point of exhaustion -- by planning drills during which you work at 70 - 80 and 80 - 90 % of your maximum heart rate .
That can only be maintained for four or five seconds .
You can improve your ' anaerobic threshold ' -- the point of exhaustion -- by planning drills during which you work at 70 - 80 and 80 - 90 % of your maximum heart rate .
That can only be maintained for four or five seconds .