By GRETCHEN REYNOLDS
November 22, 2016
The holiday season is a good time for a reminder that alcohol can do bad things to the brain. Studies on animals suggest that it reduces the number of neurons in the hippocampus, the brain’s memory center, and weakens mitochondria there. Because mitochondria help produce energy within cells, their impairment can damage or kill brain cells. But two new animal studies offer some succor: Aerobic exercise, it turns out, may meliorate some of the impacts of heavy drinking on the brain.
Both studies were presented earlier this month at the annual Society for Neuroscience meeting in San Diego. The first, conducted by physiologists at the University of Louisville, involved adult male mice. Every day for 12 weeks — the equivalent of several human years — groups of mice received either injections of alcohol or salt water. Half the animals in each group were then put through daily treadmill workouts. These exercise sessions were short but intense: roughly two-tenths of a mile run at a strenuous pace.
The second study focused on binge drinking. Researchers from the University of Houston inserted tubes into the stomachs of female rats to provide consistent doses of either alcohol or nonalcoholic liquid every Monday night for 11 weeks. Half the rats in each of these two groups were then kept idle in their cages for the rest of the week, while the other half ran on wheels for up to two hours, three days a week.
In each study, the brains of the rodents that exercised after receiving alcohol were substantially different from those of their sedentary counterparts. The inactive mice had weakened mitochondria in many neurons; the runners had hardy mitochondria. The sedentary rats given alcohol had almost 20 percent fewer neurons in their hippocampi than the control animals. The rats who were made to work out, though, had as many neurons as the controls, even if they were given alcohol.
“It’s well known that running increases neurogenesis” — that is, the creation of new brain cells — according to J.L. Leasure, the associate professor of psychology at the University of Houston who oversaw the rat study. So it seems likely that running stabilized the total number of brain cells in the bingeing rats, she says, even if some neurons died as a side effect of alcohol consumption. Exercise is also known to improve mitochondrial health in the brain.
This does not mean working out is a license to be a lush, Leasure says, adding that alcohol probably has other undesirable effects within the brain that are not countered by exercise. Nor has research shown how much or what types of exercise provide the best protection — or even whether animal studies like these translate to people. There is also your liver to consider, along with other bodily consequences. Still, if you overdo it this holiday season, Leasure says, going for a run is “probably wise.”