Can fidgeting make you more fit?

That nervous-looking guy on the plane next to you with the jittery leg could be doing a lot more than irritating you for two hours? He might just be burning extra calories that are helping him get or stay fit.

Little activities we do daily, research is showing, could really add up, particularly during a time when people are moving less throughout their waking hours. Now scientists are digging in to see if nervous habits and movements as simple as walking to the coffee machine are helping lean people stay lean and could help obese people get fit.

Researchers have looked critically at these "incidental physical activities" to first judge how much they boost our cardiorespiratory fitness, which has recently been ranked as critical as blood pressure and cholesterol in predicting long-term health. Cardiorespiratory fitness is gauged by the most amount of oxygen a person can take in while working out, otherwise known as the VO2 max.

A recent study of participants who are overweight and sedentary but still in good health found that those who had little bursts of activity but did not formally exercise had greater a VO2 max than those people who moved slower or did not do even light activity for hours on end.

This is supported by an earlier study that compared lean and obese women's incidental activity. The leaner ladies were far more likely to fidget and to have bursts of movement, even as simple as standing up, leading authors to assert that the obese participants could burn up to 300 extra calories per day mimicking this lifestyle.

Scientists also weighed in that fitness levels -- and that golden VO2 -- can be boosted with incidental physical activities. This might make that cliche that you can get fit simply by opting to take the stairs rather than the elevator more valid.

Celebrity trainer Jillian Michaels has repeatedly said this attitude is indicative of a culture of lethargy, and that a commitment to push hard, even for short periods of time is necessary for people getting in shape or trying to lose weight. While that may be very true, perhaps it is also important to consider that our hourly walk to the water cooler or running down the stairs to answer the bell are keeping our bodies in tune, too. Incidental activity, these studies seem to be saying, doesn't replace a sweaty run or abs workout. But standing up and parking at the far end of the lot might just add to the formal exercise we are doing.

So drum your fingers upon your desk. Play air drums on the steering wheel. Put a skip in your step when you get out of bed. If these studies are right, our bodies cannot afford to lose those movements.