Free weights, spinning, Jacob's Ladder and belly crunches notwithstanding, the best exercise for many is still the first one they engaged in as wee toddlers--the simple act of walking.
For so many people, finding the motivation and time to actually go to the gym or plug into a DVD or fitness program is so overwhelming to them that they actually stop working out all together. Legitimate concerns about the intensity of these workouts as well as the business and demands of daily life can bring an hour or two hours of getting there, doing the full workout, and then cooling down and cooling off to an absolute full stop.
What seems, psychologically if not in all other ways as well, less daunting and fearsome, is simply walking.
Putting one foot in front of the other doesn't require much in the way of equipment, psyching oneself up, or even time. Forty minutes or more is glorious if the weather is fine and you're in the company of, say, your own child, significant other or lovely pet. Walking is free. What's more, if the weather isn't so nice, using the shopping mall as an exercise track can bring you to places you've never been as well. Plus, it's a place in your mind where window shopping is all you'll do because you're there for the company of people, whomever you're with, and to get your walking in, not to spend money you can't really afford to spend on clothes and gadgets you could do without.
Walking is wonderful whether you are 5 or 75 years of age. It's a lifelong skill, one we normally reserve for functional use, like breathing, but, like breathing, (think yoga and meditation) we can take it to whole new levels with practice and patience.
Walking is also easier on the body over the long term than many other high impact forms of exercise.
You should always stretch, even prior to walking - but funnily enough, longer strides will actually cause your Achilles tendons and hamstrings to stretch as you are walking.
The benefits of walking are the same as they are for every regular exercise; lower weight and blood pressure, lower cholesterol and enhanced oxygenation of the blood, better mood, and stronger muscles.