There are so many reasons why we keep delaying that workout – everyday life, the unexpected, stress. For all those lacking time or motivation to build a regular fitness routine, workout stacking is a great way to fit some exercise into a busy day. Also known as fitness stacking, the method is aimed at making it easier to introduce exercise into your daily routine. And the best part is: You don’t need a gym membership. Ten-minute exercise units Fitness stacking means “stacking” up a workout out of different building blocks by exercising in shorter intervals throughout the day, according to Sven…