Short and Sweet
If a full schedule prevents you from getting all the exercise you would like, you may want to consider “high-intensity interval training” (HIIT). As some studies suggest that as little as 30 minutes of the right kind of exercise per week can provide health benefits, HIIT involves exercising at full intensity for a short burst (usually 20 to 30 seconds), followed by an active recovery (easy pace for a minute or two) for a total time of about 20 minutes. Both seasoned athletes and couch potatoes can benefit due to the fact that intensity is relative. In fact, some research suggests that those who benefit most from HIIT are the unfit. In any case, warmup and stretching are important.