This story in Sunday's New York Times says that long-distance exercise builds the brain:

The story gives more evidence that aerobic fitness is correlated with a faster, more flexible brain, an effect that's been shown in senior citizens as well as in children. Adam Campbell reported similar evidence in this story in Men's Health last year.

But toward the end, I noticed something curious:

Tennis isn't an endurance sport. It's a start-stop activity, meaning that the actions -- sprinting, lunging, striking the ball -- are anaerobic.

And that brings up the biggest question I have about all this: Is it better for your brain to trudge along on a treadmill at a gym while watching ESPN, or to participate in a sport or exercise activity that doesn't increase your aerobic fitness but does challenge your brain to make adjustments?

Without any evidence to offer, I have to think that hiking, playing basketball, or even working your way through 18 holes of golf would stimulate your brain in ways that riding a stationary bike wouldn't.

If the only neuron-generating variable that matters is how much blood circulates through your brain, the answer is "no." Riding the stationary bike might be the best option.

But if there's something else involved in this equation -- coordination, strategy, competition, proprioception and balance, visual stimulation (in the case of the hike) -- then maybe a more interesting activity would have a more beneficial effect.

None of which suggests that strength training would be a brain-building activity.

So is the development of strength and muscle mass a no-brainer, literally?

I don't know of any research showing a direct link between strength training and intelligence or neurogenesis. But some studies have hinted at other benefits that might have a peripheral effect on brain power. For example, this study shows that increased strength increases the rate of force production -- that is, it speeds up the nervous system.

Does that translate to brain power?

Not that I could tell. But in clicking around a bit on PubMed, I did come across this study, which looked at geriatric patients and tried to figure out which was more important for their long-term mobility: physical activity, or leg strength.

Mobility, I think, is a pretty good stand-in for quality of life in the elderly. If you can't get up and get around, you're at the mercy of whoever is in charge of pushing your wheelchair. Family activities are planned around your inability to move yourself from place to place. Not only does your life change as your physical abilities decline, but so do your interactions with everyone you encounter.

The researchers found that total physical activity does indeed matter: "[E]ach additional hour of physical activity at baseline was associated with an approximately 3 percent decrease in the rate of mobility decline."

But for strength, the effect is much more dramatic: "[E]ach additional unit of leg strength at baseline was associated with an approximately 20 percent decrease in the rate of mobility decline."

I don't know what they mean by a "unit of strength," but let's just take a wild guess and assume that an hour of strength training a week would produce a unit of strength. So an hour of physical activity -- let's say brisk walking -- would mean you slow the loss of mobility by 3 percent. But an hour of strength training would slow it down by 20 percent.

I have no idea if that's a fair comparison or a reasonable assessment. But it does seem clear that if you compare general physical activity with targeted strength development, strength comes out ahead.

This study, however, shows something that's even more interesting:

The researchers looked at elderly Mexican-Americans to see what factors exacerbated or mitigated cognitive decline. They found that handgrip strength was powerfully associated with keeping your marbles. That is, the people who lost the most brainpower also lost the most strength over the seven-year study period. The people whose strength declined the least showed the highest cognitive ability.

Since losing cognitive ability is associated with an inability to participate in "activities of daily living," or ADLs, you see some interesting connections: The weaker your brainpower, the weaker your muscles. The weaker your muscles, the fewer things you can do.

I don't know if this works in reverse, if building strength also builds brainpower. But the researchers do note that the link between cognitive decline and fewer ADLs can be mitigated by handgrip strength -- stronger people can keep on doing normal things, even if their brains are leaking neurons.

For now, I guess that's the best we muscleheads can hope for: Strength training may not build our brains along with our muscles, but it does guarantee we'll be able to use our bodies to move our brains around well into old age.

Is that enough of a benefit for you?

Monday blog meat

• Here's a weirdly intriguing story: A researcher believes that anorexia is genetic, and that it could be the female equivalent of Asperger's disorder, which is most commonly diagnosed in males.
• If you have a few minutes, check out this Salon story on the biochemistry of love.
• According to this lawsuit, Barry Bonds sold steroids to nuns. This is either is a whole new form of surreal personal expression -- litigation as performance art -- or a tragic example of life imitating The Onion. (Hat tip: Viva El Birdos.)