There is no doubt that getting out and taking a walk is much better than sitting on the couch all day. Getting out and moving is a necessary and important part of a healthy lifestyle, whether you're seeking to normalize your blood pressure or diabetes, reduce your risk of cardiovascular disease or joint problems, or simply to improve your mental health.

But that still leaves many questions to be answered -- for optimum health, how much should you exercise, for how long, and how strenuous does it really need to be?

Just as I've mentioned in previous articles, the Japanese study mentioned above once again confirms that the higher the intensity of the exercise, the greater the overall health benefits. That is why high-intensity interval walking produced more results than moderate walking. The other major benefit of this approach is that it take MUCH less time to exercise this way. You simply don't have to do one hour of aerobics or running to get fit. That can be a major waste of time and actually counter productive.

If you're looking to lose or maintain weight, remember that the key to weight loss is not just about how many calories you burn, but how many calories you burn over a unit of time (in other words, the difference between your basal metabolic rate and your activity.)

Vigorous exercise burns calories immediately, AND helps reset your internal thermostat to keep burning calories even while you're at rest. Less intense exercise does not have this effect. So what's the right amount of intensity? You should exercise vigorously enough so that it's difficult to have a conversation with someone next to you. If you find yourself huffing and puffing to where you can't talk at all, then it's too strenuous.