Any athlete or person wanting to maximize their workouts knows the feeling of all-out exertion. Lifting weights until muscle failure, sprinting all-out for 100 meters, and simply going until you can’t go anymore are ways to increase exercise performance.
Your workouts can only be as intense as your body’s ability to deliver oxygen and nutrients to working muscles while removing waste products. The transport of these metabolic materials throughout your body comes down to your circulatory system.
Do you remember the last time you sprinted at an all-out pace or lifted weights until failure? You may recall having noticed a distinct “burning” in your working muscles that caused you so much pain that you couldn’t continue. At this point, you stopped to rest.