How do you fit all this exercise into your life? If you are not exercising at all, here is a good starting plan. Try to start with 30 minutes of exercise three times each week. It is best to start walking two of those days, and do some strength training one day. Target all the major muscle groups with one set each. Always include some stretching at the end of every workout.
What is most important first is establishing the habit of exercise! After you have accomplished this for three months, lengthen one of your walking sessions to include both walking and weights. This will give you one day of walking, one day of weights and one day of both. Follow this for up to six weeks.
Your next goal should be to increase your walking time on the your walking only day. Increase it in five minutes increments to 45 minutes or one hour, depending on your time availability. Follow this schedule another six weeks. Next, on your lifting only day, increase the intensity (weight) of your exercises. Work to momentary muscle fatigue within 8-12 reps. Follow this for two to six weeks, then increase the volume on this day by adding a second set to your exercises. At this time you may feel that you can add another day of exercise or try a yoga class.