In the summertime, it is time to play. If you are just beginning an exercise routine, this time of year is the best time to start with a walking program. I have always walked. You can do it too!
Beginning a Walking Program:
Start out with a plan to walk some time every day. I enjoy walking in the morning. Walk for at least 15 minutes. It sounds like you should do more- but just 15 minutes in the AM and 15 in the PM can really make a difference in how you feel for the day.
In you plan consider how you will increase your pace:
Start out just walking at a normal pace, and then after the first week, begin to increase your pace to a comfortable, but strenuous clip!
The next week begin to swing you arms a bit and take larger steps. The goal being to walk faster and faster until you can feel that your heart rate is beginning to be affected. When I first started some fast walking programs, I would wear a monitor so that I could be at my target heart rate while I was walking. This is the most effective way of a good walking program.
Before you know it, you have taken up a new way of life. You will begin to look forward to your new found exercise plan and maybe talk someone else into going along with you!
Good luck and ask you MD before starting any vigorous exercise program.