FUNCTIONAL HIIT F45 is specifically designed to provide a functional full-body workout while improving energy levels, metabolic rate, strength, and endurance. TEAM TRAINING The team mentality at F45 Training helps members transform their lifestyle physically and mentally while encouraging community growth and a no-ego attitude. 45 MINUTES F45 is one of the most time-efficient ways of training. We aim to burn up to 750 calories per 45-minute session.