Myth: I Have to Train for an Hour in Order to Have Any Exercise Benefit. Reality: Absolutely not! It all depends on the type of workout you’re doing. If you’re doing a HIIT (high intensity interval training) workout, you can accomplish all your goals in 15 to 20 minutes — or less. Tabata training (eight sets of 20 seconds of hard work followed by 10 seconds of rest) is only four minutes, but an incredible aerobic and anaerobic workout. So it’s not just the time you work. More importantly, it’s what you’re doing, your exertion level and the overall structure of your training plan.