Walking is fantastic exercise. Great for helping keep healthy and for burning calories. And with no need to change or shower afterwards. Depending on your speed and bodyweight, a 30 minute brisk walk can burn around 150 to 200 calories. It should be part of everybody's exercise regime.
The only thing it will not generally do - unless you are pretty overweight/unfit/going uphill/carrying a backpack - is get your heart rate up to the optimum level for good cardiovascular exercise. You don't necessarily need to go to the other extreme though and be pushing your heart rate to its maximum, but you do need to reach a level up from walking.
There are lots and lots of ways to get good cardiovascular exercise - and doing something you really enjoy is by far the best way to keep it going long term. Particularly sport, or maybe dancing, cycling, swimming, jogging or gym classes perhaps. Gym cardio machines certainly work, but not many people have the motivation to use them for more than a few months.
and many of them are totally surprised to find they really enjoy it! So please keep an open mind. People usually try and go much too fast to start with and then unsurprisingly find it too hard. So slow right down, build up your distance and speed really gently and you'll be amazed at what you can do three months later - even if you're 60 and haven't run anywhere since school! (medical conditions permitting) Of course you don't have to try it if you don't want to.
Including resistance training as part of your programme just gets more and more important the older we get. Use it or lose it! For example, don't let everyday tasks become more difficult - lifting, carrying, opening, etc - keep core muscles and back muscles strong to help avoid back problems and posture problems, improve bone density and lower osteoporosis risk, reduce the risk of injury, improve your lean tissue mass and so raise your metabolic rate, and simply look and feel so much better with well toned muscle!
My studio is very well equipped (210 sq ft), with everything needed for a complete workout. So whether you want to do some serious weight training to turn heads on the beach or just keep your body in good shape for a healthy retirement, I've got everything you need.