title: Effects of age, adiposity, and fitness level on plasma catecholamine responses to standing and exercise.
abstract: The plasma norepinephrine (NE) and epinephrine (E) responses to a variety of stressors are influenced by age, adiposity, and exercise training status. The objectives of this study were to 1) compare basal levels as well as posture- and exercise-induced changes in plasma NE and E concentrations in young [25 +/- 1 (SE) yr; n = 24] and older (64 +/- 1 yr; n = 106) people and examine the associations of the responses with adiposity and maximal O2 uptake (VO2max) and 2) determine the extent to which the NE and E responses are altered by exercise training in older people. We found no significant differences in basal NE and E levels between young and older subjects. However, the NE response to standing was exaggerated in older people (696 +/- 39 vs. 512 +/- 61 pg/ml; P < 0.05), whereas NE and E responses to exercise requiring approximately 78% of VO2max were attenuated in older people (NE: 1,444 +/- 74 vs. 1,983 +/- 222 pg/ml; E: 109 +/- 10 vs. 228 +/- 29 pg/ml; both P < 0.01). Increments in NE and E during exercise were more closely associated with age (NE: r = -0.38; E: r = -0.46; both P < 0.05) and VO2max (NE: r = 0.43; E: r = 0.52; both P < 0.05) than with adiposity (NE: r = -0.29; E: r = -0.25; both P < 0.05). In 48 older subjects who completed 9 mo of exercise training, the increases in NE and E during exercise at the same absolute intensity were 39 and 57% lower, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
authors.forename: W M
authors.initials: WM
authors.lastname: Kohrt
authors.forename: R J
authors.initials: RJ
authors.lastname: Spina
authors.forename: A A
authors.initials: AA
authors.lastname: Ehsani
authors.forename: P E
authors.initials: PE
authors.lastname: Cryer
authors.forename: J O
authors.initials: JO
authors.lastname: Holloszy
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D000328:Adult; D000375:Aging / Q000502:physiology*; D002395:Catecholamines / Q000097:blood*; D004837:Epinephrine / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D010806:Physical Education and Training; D010807:Physical Endurance / Q000502:physiology; D010809:Physical Fitness / Q000502:physiology*; D011187:Posture / Q000502:physiology*; D012044:Regression Analysis; D012727:Sex Characteristics
chemical_list: D002395:Catecholamines; D009638:Norepinephrine; D004837:Epinephrine