Want a workout that's just as effective but can be done in less time? Combine multiple exercises into one. For example, do a lunge and shoulder press.
Stand with your feet hip width apart holding a dumbbell in each hand with elbows bent in a 45 degree angle, above your shoulders and palms facing forward.
Take a large step forward with one foot; bend your knees to lower into a lunge until your front thigh is parallel to the floor.
Reverse to return to the start position and press the dumbbells up above your shoulders.
Repeat to 10 reps and switch leg for another 10 reps.