I started a new workout in December that is 6 days a week for about 30 minutes to complete. Day 1, 3, and 5 I do three circuits with dumbells that are only multijoint or compound exercises. One or two minutes of rest between circuits. On days 2, 4, and 6, I do a high intensity cardio on a treadmill for 20 minutes with alternating speeds that gets my heart rate up to 90%. So far so good. I feel great.