We've been conditioned to think if we can't get a solid 30-minute workout in a day, it's a waste of our time, and this is especially true from former athletes who spent hours exercising per day in their youth. What can 15 minutes a day really do? The answer is a lot.
A small study by the Pennington Biomedical Research Center showed that a group of 464 women who walked 72 minutes a week for six months had improved heart health and fitness. Seventy-two minutes in a week is just over 10 minutes in a day - that's it! The women who were picked for the study were all considered overweight or obese and did not exercise prior to their participation.
In addition to this study's findings, it's important to note that just 10-15 minutes of strength training or cardiovascular exercise can burn 100 calories or more depending on intensity. One-hundred extra calories a day is approximately one pound a month, or 12 pounds a year, you're keeping off your body.
Don't forget you also burn calories after you're done working out. We all know you burn calories while you exercise, but you also burn a fair amount of calories recovering from exercise. In fact, your metabolism can be elevated from 24 to 72 hours after a workout. This mostly occurs when you complete interval or high-intensity exercise. The higher your heart rate during exercise (even small bursts of elevated heart rate), the more it helps with the "after burn" of additional calories. By exercising more frequently, you keep your metabolic rate constantly elevated, making it easier to stay in a healthy BMI range.
Another thing to note is frequent short workouts may lessen injury risk. Trained athletes may be able to handle two-hour runs or bike rides, but the average person is going to face extreme muscle soreness and fatigue if they extend their workouts too long. Fatigued muscles are more prone to acute and chronic injuries. Injuries and soreness are listed among the top factors for people who don't exercise. By building in frequent short workouts, you may lower your injury risk and raise your chances of getting into a consistent workout schedule.