Pace should be increased comfortably yet a person should work to become slightly out of breath so metabolism continues to increase. Do not reach the point where rapid breathing makes conversation too difficult.
Use of fat compared to use of carbohydrates for energy:
An intensity under 25% of maximum oxygen consumption will result is much less aerobic conditioning benefit but still utilize fat oxidation as the body\’s main source of energy. Aerobic exercise intensity of 25% to 65% of oxygen consumption will increase the amount of aerobic oxidative energy production by both carbohydrates and fat. However, fat burning potential is greatest in moderate intensity aerobic exercise done at a rate of 65% of the maximum oxygen consumption. This intensity maximizes aerobic oxidative energy production for the body (9).