Using HIIT to help you workout during a busy week https://www.acefitness.org/resources/everyone/blog/7993/benefits-of-hiit-for-a-busy-schedule The human body expends about 5 calories of energy to consume 1 liter of oxygen. When an activity uses multiple muscle groups at a high level of intensity, more oxygen is needed, and more calories are burned. HIIT workouts that involve both the upper […]