The hypothalamic-pituitary-adrenal (HPA) axis is a hormonal system that defends against stress, starvation and illnesses. New findings of alterations in adrenocorticotropic hormone (ACTH) and cortisol secretion in alcoholic patients, which reflect changes in the HPA axis, prompt recommendations that alcoholics avoid excessive stress - both physical and psychological - during early abstinence.
Results are published in the May issue of Alcoholism: Clinical & Experimental Research.
"The HPA axis provides the metabolic fuel for the reaction of the brain, muscles and heart against psychological and physical distress," said Vittorio Coiro, aggregate professor in internal medicine at the University of Parma, Italy. "In previous research, tests with psychological and physical challenging stimuli - such as operative traumata, hyperthermia, cold-pressor and public-speaking stress - have shown a deficient HPA reactivity in abstinent alcoholics. However, none of these studies has established a time course of HPA failure during abstinence or has shown the time needed for a possible recovery."
"The HPA axis is an exquisitely sensitive system triggered physiologically by a wide range of psychological and physical stressors," remarked Cristiana Di Gennaro, research doctor at the University of Parma. "A rise in plasma ACTH and cortisol are considered good markers of stress, in terms of both acute reaction and of chronic exposure to stressful situations. An impaired function of HPA axis is well known in alcoholics," she added, "and it has been suggested that a blunted HPA axis responsiveness plays a role in early alcohol relapse following detoxification in alcoholics."
Researchers recruited two groups of males: 10 recently abstinent alcoholics 33 to 45 years of age; and 10 age-matched healthy controls. All participants exercised on a bicycle ergometer for approximately 15 minutes to a workload gradually increased at three-minute intervals until exhaustion (considered a highly reproducible and reliable form of stress). The alcoholics were tested at three time points: four, six and eight weeks after alcohol withdrawal. The controls were tested only once.
Results indicate an only slight ACTH/cortisol response to physical exercise among alcoholics after four weeks of abstinence, returning to near-normal levels at eight weeks.
This means, said Coiro, that not only did his group establish a time course of HPA failure during abstinence, but they also found that physical exercise among abstinent alcoholics may not always be a good thing.
"Guidelines for recovery from alcoholism attribute an important role to physical activity and sport," he said. "Exercise is included in many rehabilitation programs, because it produces physical and emotional effects that benefit the alcohol-dependent subjects during early abstinence. However, in the absence of HPA reactivity, exercise until exhaustion may produce stressful deleterious effects, because alcohol-dependent subjects are more vulnerable to relapse during early abstinence."
"Given that the HPA axis remains 'stunned' for at least one month from withdrawal, with a full functional recovery only after two months," said Di Gennaro, "caution is to be recommended for patients in rehabilitation programs that include stressful physical exercise. However, since physical activity has been found to be an important therapeutic tool for early alcohol-withdrawing patients, it should be included in treatment even during the first eight weeks of abstinence, albeit mild at the beginning, with a slight progressive increase of physical activity during the first and the second month of abstinence."
"From a research perspective," said Coiro, these results help us to understand entity and time of the effects of alcohol in the central nervous system as ACTH/cortisol measurements represent a 'window' through which we can evaluate alcohol damage in central nervous transmission. Practically speaking, guidelines for alcohol-rehabilitation programs should take into account these observations for a better programming of physical exercise and therapeutic follow up. Furthermore, readers should be aware of the increased vulnerability of alcohol-dependent subjects, particularly during the first two months of abstinence, when physical and psychological stress should be absolutely avoided."