Heavy Drinking And Sedentary Lifestyle Pose Risks To Brain Health But Aerobic Exercise Can Help
Aerobic exercise can slow cognitive decline, and decrease negative neural changes associated with normal aging and several diseases. A new study investigates if aerobic exercise may also prevent or repair alcohol-related neurological damage, finding that it may in fact protect white matter integrity from alcohol-related damage.
Results will be published in the September 2013 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.
"Engaging in regular aerobic exercise has been found to improve learning, memory, and self-control," said Hollis C. Karoly, a graduate student at the University of Colorado at Boulder as well as the corresponding author for the study. "This seems to be particularly true among older adults who exercise regularly, which suggests that exercise may prevent a natural loss in cognitive functions that occurs as people age. Additionally, exercise has been shown to protect white matter in the brain from damage associated with aging and various diseases."
Karoly added that heavy long-term alcohol consumption leads to neural damage that looks similar to the decline in neurocognitive functioning observed as people age. "Given that exercise is protective against some of the neural and cognitive effects of aging, it seemed likely that aerobic exercise may also work to reverse or prevent some of the damage to the brain caused by chronic alcohol consumption."
Susan F. Tapert, chief of psychology at the VA San Diego, and professor of psychiatry at University of California, said the researchers' focus on the effects of aerobic exercise/heavy alcohol use on white matter is highly significant. "Heavy drinking has been linked to problems in the brain's white matter," she said, "and it is unclear why the effects are more prominent in some individuals than in others."
"Additionally, aerobic exercise is associated with greater white matter integrity," said Karoly. "Thus, examining the relationship between exercise and alcohol use on white matter was a logical next step."
Karoly and her colleagues had 60 participants (37 men, 23 women), drawn from a larger database designed to share common brain and clinical data collected across studies on alcohol and nicotine use, undergo a diffusion tensor imaging session. All participants also completed measures of alcohol consumption, loss of control over drinking, and aerobic exercise participation. Study authors then examined relationships among exercise, alcohol, and fractional anisotropy in the superior longitudinal fasciculus, external capsule, fornix and superior and anterior corona radiata, as well as self-reported loss of control over drinking.
"This study found that the relationship between alcohol consumption and white matter depends upon how much people exercise," said Karoly.
"For individuals with low levels of aerobic exercise, heavy drinking was linked to poorer white matter health, but for those with greater exercise involvement, the relationship between alcohol and white matter health was not as strong," added Tapert. "Although we don't know yet if the exercise is protecting against alcohol-related damage, or if it is a sign of factors linked to brain health, this is a very compelling study. This suggests that individuals who have experienced alcohol-related brain problems could possibly use exercise to help recover those effects; studying people over time will tell us if this is in fact the case."
More specifically, alcohol was related to decreases in white matter integrity in the external capsule and superior longitudinal fasciculus among low exercisers. "White matter is a crucial part of the nervous system," explained Karoly, "relaying information between areas of the brain. In general, white matter damage can lead to motor deficits, sensory problems, and cognitive difficulties. Both the external capsule and superior longitudinal fasciculus connect important brain areas, so damage to these tracts may have a host of more specific implications for negatively impacting cognitive, behavioral, and emotional functioning."
"In particular, the superior longitudinal fasciculus is linked to the relay of information across relatively long distances in the brain: frontal to parietal connectivity," added Tapert. "Compromised white matter integrity in these areas has been linked to poorer performance on cognitive tests."
"These findings represent a first step in better understanding the relationship between alcohol, exercise, and the brain," said Karoly. "We already know that heavy, chronic alcohol exposure is associated with widespread damage to the brain, but little is known about how this damage could be reversed or prevented. Aerobic exercise appears to be a promising candidate for decreasing alcohol-related brain damage. Certainly clinicians could use these findings to support prescribing aerobic exercise programs as an adjunct treatment for individuals dealing with psychological or physiological problems related to a heavy alcohol-use history."
Tapert agreed. "These are compelling findings that I hope will drive more research into the potential for aerobic exercise to improve functioning, particularly in people recovering from histories of heavy drinking. On the flip side, it looks like the combination of heavy drinking and a sedentary lifestyle poses risks to brain health and should probably be avoided. From a neurobiological perspective, it will be very interesting to see how aerobic exercise could potentially mitigate inflammatory, oxidative, and other sources of neural injury produced by heavy alcohol use."