title: Hypothalamic-pituitary-adrenal axis response and recovery from high-intensity exercise in women: effects of aging and fitness.
abstract: This study tested the hypotheses that aging is associated with prolonged recovery after a challenge to the hypothalamic-pituitary-adrenal axis (acute exercise) and that aerobic fitness is associated with a blunting of the age-related loss of negative feedback sensitivity. Young (27 +/- 2.8 yr, n = 9), older (64.6 +/- 1.4 yr, n = 11), and older-fit women (66.3 +/- 2.2 yr, n = 11) underwent a short bout of treadmill exercise at high (but submaximal) intensity. The exercise trial elicited significant increases in heart rate, blood pressure, ACTH, and cortisol (P < 0.001). Although the young and the older women exhibited similar cortisol response to the trial and throughout the recovery period, the older women had a slower decrease of ACTH levels (P < 0.05), suggesting reduced negative feedback sensitivity with aging. Between the two groups of older women, the older-fit group had significantly greater rate of recovery of ACTH levels (P < 0.05) compared with the older unfit women. However, older fit women had greater cortisol production during the recovery period (P < 0.05), suggesting greater adrenal sensitivity to ACTH. These results suggest that aging is associated with changes in the dynamic function of the hypothalamic-pituitary-adrenal axis and that these changes are attenuated by aerobic fitness.
authors.affiliation: Stress and Neuroendocrine Research Center, Exercise and Sport Research Institute, Department of Kinesiology, Arizona State University, Tempe, AZ 85287-0404, USA.
authors.forename: Tinna
authors.initials: T
authors.lastname: Traustadóttir
authors.forename: Pamela R
authors.initials: PR
authors.lastname: Bosch
authors.forename: Timasue
authors.initials: T
authors.lastname: Cantu
authors.forename: Kathleen S
authors.initials: KS
authors.lastname: Matt
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood / Q000502:physiology*; D019540:Area Under Curve; D001794:Blood Pressure; D015444:Exercise / Q000502:physiology*; D025461:Feedback, Physiological; D005260:Female; D006339:Heart Rate; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000502:physiology*
chemical_list: D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone