For each of the HIIT workouts listed in this routine, aim to get your heart rate up to 80% of your maximum during the work set and down to 60% for the recovery period. If unable to keep your heart rate in this range, adjust the intensity of the workout accordingly. Day Workout Monday HIIT Sprinting Sprint for 30 seconds and take a two minute rest between runs. Complete two sets of four sprints with an eight-minute rest between sets. Tuesday Rest Wednesday HIIT Biking Bike for a minute hard and take a minute rest. Complete a total of 12 sprints. Thursday Rest Friday HIIT Rowing Row hard for a minute and take a minute rest. Complete 12 sets in total. Saturday Rest Sunday Rest *Notes: * Rest means rest from HIIT training. You may want to add weight training on some rest days * To find maximum heart rate, use this formula: Maximum Heart Rate = 220-Age