Walking regularly can strengthen your bones, tone your muscles, and trim your waist. It also may reduce your risk of some cancers, and lower your risk of depression.
Check out this advice from Christy.

No need for the monthly fee to walk the treadmill at a local gym.
Go for free, grab a friend or co-worker and take a quick 15 minute walk around the parking lot at work or nearest park.
You would be surprise how quick it goes when you’re just talking with a friend, and 15 minutes a day can really keep the weight off and tone the hips, and butt.
Your friend can’t join you one day, make it a speed walk. Go until your heart rate increases and stop when you get out of breath. It may be less than 15 minutes, but great for your heart health.
Walking at lunch also relieves the day to day stress of the office and will put you in a smooth mood ready for the rest of your day. So give it a try, 15 minutes is not very long and so easy to do.