Q: My New Year's resolution was to get more exercise and

Q: My New Year's resolution was to get more exercise and, I hope, lose a few pounds. Walking is an activity I know I can stick with, but I keep hearing that I should aim for 10,000 steps a day. Where does that number come from, and am I wasting my time if I do less?

A: Walking is a great option - it's easy, inexpensive and low-impact, and can be done just about anywhere. Best of all, walking has multiple health benefits. Walking will do more than just help you control your weight. In fact, even if you don't lose any weight at all, you'll still come out ahead. People who are physically active lower their risk of stroke, heart disease, type 2 diabetes, depression and even some cancers. Bottom line - they live longer. For optimal health benefits, the Centers for Disease Control and Prevention say we should spend at least 150 minutes per week doing a moderately paced aerobic activity for no less than 10 minutes at a stretch. (Or 75 minutes per week of vigorous physical activity.)

Those 150 minutes of moderate activity can absolutely be spent in your chosen method - walking - as long as it's at a brisk pace. Three to four miles per hour is about right for most of us. That's fast enough so that your heart gets pumping, yet you're still able to carry on a conversation. Which brings us to the question of distance, and the mystery of the 10,000 steps. 10,000 steps - that's about five miles - have a toehold in science. A study found that men who burned 2,000 calories per week through exercise measurably lowered their risk of heart disease. Since a 5-mile walk uses roughly 300 calories, to burn 2,000 calories per week takes 10,000 steps.

Is 10,000 steps a make-or-break number from the outset? The short answer is no. Any amount of physical activity above and beyond what you're presently doing is beneficial. The main thing is to ease into your new exercise program in a way that's both safe and sustainable.

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