This is another story I've been meaning to get to, a health story this time.
It turns out that exercise feeds the brain, and does other good things as well that weren't understood before. It all has to do with discoveries in the relationship between exercise, the brain and glycogen.
Glycogen is one of the ways the body stores food — glucose — for ready use. (The other way is in "adipose tissue" — where you don't want it.) Unlike food stored as fat (which most bodies have to be trained to later access), glycogen is starch — like sugar, but longer molecules. Glycogen is stored in the liver and in muscles, which means glycogen is easy to access.
To a lesser degree, glycogen is also stored and used in the brain (my emphasis and some reparagraphing throughout):
In petri dishes, when neurons, which do not have energy stores of their own, are starved of blood sugar, their neighboring astrocytes [support cells for neurons that store glycogen] undergo a complex physiological process that results in those cells’ stores of glycogen being broken down into a form easily burned by neurons. This substance is released into the space between the cells and the neurons swallow it, maintaining their energy levels.But while they knew that glycogen was used in the brain, they didn't know when, until now.
■ Last year, scientists in Japan learned the following:
In the first of their new experiments, published last year in The Journal of Physiology, scientists at the Laboratory of Biochemistry and Neuroscience at the University of Tsukuba gathered two groups of adult male rats and had one group start a treadmill running program, while the other group sat for the same period of time each day on unmoving treadmills. The researchers’ aim was to determine how much the level of brain glycogen changed during and after exercise.So during exercise, the brain "eats" its glycogen, plus any glycogen it gets from the rest of the body. When all the glycogen is all used up, marathoners call it "hitting the wall."
Using their [new] glycogen detection method [don't ask], they discovered that prolonged exercise significantly lowered the brain’s stores of energy, and that the losses were especially noticeable in certain areas of the brain, like the frontal cortex and the hippocampus, that are involved in thinking and memory, as well as in the mechanics of moving.
So far so good; comports with "what we know."
■ Now for what we don't know. A follow-up study by the same group, published this year, looked both at brain glucose levels after single, isolated exercise sessions, and also after exercise performed as part of a four-week exercise program.
First, the brain after an isolated exercise session:
After the single session on the treadmill, the animals were allowed to rest and feed, and then their brain glycogen levels were studied. The food, it appeared, had gone directly to their heads; their brain levels of glycogen not only had been restored to what they had been before the workout, but had soared past that point, increasing by as much as a 60 percent in the frontal cortex and hippocampus and slightly less in other parts of the brain. The astrocytes had “overcompensated,” resulting in a kind of brain carbo-loading. The levels, however, had dropped back to normal within about 24 hours.Good news for sure. A 60% increase in food to the brain, especially the frontal cortex, after exercise can only aid the higher brain functions.
Now for the brain after exercise that's part of a program:
In those rats that ran for four weeks, the “supercompensation” became the new normal, with their baseline levels of glycogen showing substantial increases compared with the sedentary animals. The increases were especially notable in, again, those portions of the brain critical to learning and memory formation — the cortex and the hippocampus.In other words, you can make your higher-performing brain "the new normal."
■ There's even better news from unpublished studies from the same lab. The lead scientist says that:
“glycogen supercompensation in some brain loci” is "enhanced in rats receiving carbohydrates immediately after exhaustive exercise."All good reasons to exercise. And be sure to eat that banana (or add carbs to your protein shake) afterwards.
My recommendation — If you can't make yourself exercise for long periods (I get horribly bored myself), do something really hard for short stretches; but do it regularly, like 4-5 days per week, every week.
My personal favorite is stair-walking. There are 20 stories in my building. One round at a walking pace takes no more than 12 minutes, up and down. If you have a five-storey building, do four rounds; it's the same.
Once you get your calves (and wind) used to one round, just stick with it, 4–5 days a week, every week. Twelve minutes isn't that long. Then increase the rounds to the number you want to hold at, and you're done. (I worked up to five rounds, but one or two, done regularly, is enough to do you a whole lot of good. Just get to a level you can hold to and maintain it.)
The good news is that (1) you can take an iPod and listen to anything you want (I listen to lectures — feeds the brain that other food); and (2) you'll be dead-alone, since everyone else on the planet, not to mention your building, will be riding those elevators.
You can even bring a buddy and chat.
(To follow on Twitter or to send links: @Gaius_Publius)