Next time you’re at the gym, hop on that treadmill. A study of wheel-running hamsters has shown that exercise may effectively reduce alcohol intake in humans. The key is circadian timing which, in mammals, is regulated not only by light but also by other influences such as food, social interactions, and exercise.

"Alcohol abuse, characterized by routine craving for and consumption of alcohol as well as an inability to function normally without it, disrupts both the timing and consolidation of daily circadian rhythms -- when to sleep, eat, and mate -- driven by the brain circadian clock," corresponding author J. David Glass, professor of biological sciences at Kent State University, was quoted as saying. "With continual alcohol use, one may go to bed too early or late, not sleep across the night, and have an unusual eating regime, eating little throughout the day and/or overeating at night. This can lead to a vicious cycle of drinking because these individuals, in response, will consume more alcohol to fall asleep easier only to complain of more disrupted sleep across the night and additionally have a greater craving for alcohol."

In other words, according to Alan M. Rosenwasser, professor of psychology at the University of Maine, chronic alcohol abuse and circadian disruption become reciprocally destructive and result in negative effects on physical and emotional health. "It is, therefore, very interesting that access to running wheels or other forms of voluntary exercise in animal experiments has emerged as a powerful environmental factor influencing brain health, circadian rhythms, and emotional well-being," Rosenwasser was quoted as saying.

Glass agreed, noting that exercise is important in the non-photic regulation of circadian timing. "Restricting animals from exercising, such as blocking access to a running wheel as we did in this study, had a significant stimulatory effect on alcohol consumption," he said.

"In this study, we found that the more the hamsters ran, the less they consumed alcohol," said Glass. "The 'lazier' hamsters that did not run as much had a greater craving for and consumption of alcohol, suggesting that exercise may be an effective, beneficial, and non-pharmacologic treatment option for alcoholism."

"Many members of the general public, and indeed, many medical professionals, continue to view alcohol abuse and alcohol addiction as character flaws and as failures of 'willpower,'" said Rosenwasser. "Findings such as these help put alcohol abuse disorders in a broader biological context and show that both physiological and environmental factors contribute to excessive alcohol intake. Accordingly, these physiological and environmental factors will need to be addressed in order to effectively control alcohol abuse and other forms of excessive behavior."

Glass noted that exercise appears able to alter the chemical environment of the brain in a manner similar to alcohol. "Dopamine is the primary chemical released within the brain in response to any type of reward, including exercise, drugs, food, and sex," he said. "For humans, exercise may be an effective, beneficial, and naturally-rewarding substitute for any type of addiction. It may also reduce the risk of addiction in individuals who have a family history of it, in addition to significantly reducing the risk of cardiovascular disease and mood disorders. But like all rewards, exercise should be used in moderation and not interfere with an individual's normal daily functioning."


SOURCE: Alcoholism: Clinical & Experimental Research, online June 21, 2010, and in print September, 2010