Booze Is Bad For Your Brain But Jogging Helps

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 neutrons in the hippocampus, the brain’s memory centre, and weakens the mitochondria there. As 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 effects 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. 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 a nonalcoholic liquid one night for 11 weeks. Half the rats in each group 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% fewer neurons in their hippocampi than the control animals. The rats that were made to work out, though, had as many neurons as the controls.