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.