exercise

While mild exercise like walking is better than none, it takes more vigorous exercise to have strong anti-aging benefits.

Run to Stay Young - NYTimes.com (well.blogs.nytimes.com)

In fact, when the researchers compared their older runners’ walking efficiency to that of young people, which had been measured in earlier experiments at the same lab, they found that 70-year-old runners had about the same walking efficiency as your typical sedentary college student. Old runners, it appeared, could walk with the pep of young people.

Older walkers, on the other hand, had about the same walking economy as people of the same age who were sedentary. In effect, walking did not prevent people from losing their ability to walk with ease.

...

The researchers speculate that this difference resides deep within their volunteers’ muscle cells. Intense or prolonged aerobic exercise, such as running, is known to increase the number of mitochondria within muscle cells, said Justus Ortega, now an associate professor of kinesiology at Humboldt University, who led the study. Mitochondria help to provide energy for these cells. So more mitochondria allow people to move for longer periods of time with less effort, he said.

Runners also may have better coordination between their muscles than walkers do, Dr. Ortega said, meaning that fewer muscles need to contract during movement, resulting in less energy being used.

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The good news for people who don’t currently run is that you may be able to start at any age and still benefit, Dr. Ortega said. “Quite a few of our volunteers hadn’t take up running until they were in their 60s,” he said.

Could less exercise be more beneficial for weight loss? NYT's "Well" blog reports:
For Weight Loss, Less Exercise May Be More

On the other hand, the men who had exercised the most, working out for 60 minutes a day, had managed to drop some flab, losing an average of five pounds each. The scientists calculated that that weight loss, while by no means negligible, was still about 20 percent less than would have been expected given the number of calories the men were expending each day during exercise, if food intake and other aspects of their life had held steady.

Meanwhile, the volunteers who’d worked out for only 30 minutes a day did considerably better, shedding about seven pounds each, a total that, given the smaller number of calories that they were burning during exercise, represents a hefty 83 percent “bonus” beyond what would have been expected, says Mads Rosenkilde, a Ph.D. candidate at the University of Copenhagen who led the study.

Several bits of good advice for strength training here, from the NYT's "Well" blog.
A Safer Shoulder Workout (Well)

Poor form or technique can turn shoulder workouts into a fast track to physical therapy.

Randall Munroe, of xkcd fame, once noted that "The role of gender in society is the most complicated thing I've ever spent a lot of time learning about, and I've spent a lot of time learning about quantum mechanics." The LA Times reports on the role of gender in the Olympics: Olympic Games and the tricky science of telling men from women (Los Angeles Times Articles)

Once it's agreed that men and women should compete separately, how should officials divide them up?

It's not a rhetorical question. Though most people fall neatly into "male" and "female" categories, some do not. The fact that there are people with physical or genetic traits of both sexes prompted the IOC to rethink its gender test.

Well Weight Training May Lower Diabetes Risk (Well)

After controlling for many variables, including age, body mass and alcohol intake, the researchers found that engaging in aerobic exercise for at least 150 minutes a week lowered the risk of developing the disease by 52 percent. Doing the same amount of weight training, meanwhile, was associated with a 34 percent lower risk, independent of any aerobic exercise. But doing both led to the greatest reduction in risk. Dr. Willett said the mechanism behind weight training’s beneficial effect on diabetes most likely stems from its effect on insulin receptors.

The New York Times reports on research showing that several shorter periods of exercise may as beneficial -- or even moreso -- than one longer workout: