I highly recommend aqua jogging as an entry level exercise for people over the age of 30. If you haven’t exercised in quite some time or never exercised, aqua jogging is a place to start with low risk of injury.
With the aqua jogging belt (easily purchased online, at Wal-Mart, your local sporting goods, or pool store) you are floating upright in the pool with your feet not touching the bottom of the pool. Because you are floating, the shock from weight bearing (walking on the ground on the bottom of the pool) isn’t present. When you walk make sure you work just as much on your hip extension (knee behind the hip) as you do the hip flexion (knee toward the chest). The more equal range of motion (flexion & extension) the better. If it’s been a long time since you have exercised, start out at ten minutes. If you become sore over the next two days, reduce the time of exercise to five minutes. If you did not get sore, keep exercising two to three days a week for at least a month. Make sure you do not exercise two days in a row. You want to allow time for your muscles to recover. It is more important that you continue to aqua jog than it is how fast you start out. Once you get to a 30 minutes per session, don’t go longer just increase your intensity. It’s the consistency that pays off in the long run.