title: Lactate and heart rate variability threshold during resistance exercise in the young and elderly.
abstract: This purpose of this study was to: 1) determine the intensity corresponding to anaerobic threshold (AT) during a discontinuous resistance exercise protocol in healthy young and elderly subjects by analyzing heart rate variability (HRV) and blood lactate (BL) and 2) investigate the effect of aging on these variables. A total of 28 individuals, 14 young and 14 elderly healthy men underwent one-repetition maximum (1RM) testing to determine maximum load on the leg press. Discontinuous resistance exercise testing was initiated at 10% of the 1RM with subsequent increases of 10%. The load corresponding to AT was approximately 30% 1RM in both groups. The determination of AT by HRV was associated with BL responses (p<0.01). While HRV indexes decreased with increasing of loads in both groups, the elderly had lower values at loads below AT (p<0.05). Additionally, BL increased sharply after the load corresponding to AT in both groups, although elderly subjects showed the lowest values (p<0.05). In conclusion, HRV is an effective tool for determining AT, which was approximately 30% 1RM under the testing procedures included in the present study. Furthermore, there was a marked change in autonomic function, with gradual vagal withdrawal followed by sympathetic activation. These responses were lower in elderly subjects.
authors.affiliation: Department of Physiotherapy, Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of Sao Carlos, Sao Carlos, Brazil.
authors.forename: R P
authors.initials: RP
authors.lastname: Simões
authors.forename: V
authors.initials: V
authors.lastname: Castello-Simões
authors.forename: R G
authors.initials: RG
authors.lastname: Mendes
authors.forename: B
authors.initials: B
authors.lastname: Archiza
authors.forename: D A
authors.initials: DA
authors.lastname: Santos
authors.forename: H G
authors.initials: HG
authors.lastname: Machado
authors.forename: J C
authors.initials: JC
authors.lastname: Bonjorno
authors.forename: C R
authors.initials: CR
authors.lastname: Oliveira
authors.forename: M S
authors.initials: MS
authors.lastname: Reis
authors.forename: A M
authors.initials: AM
authors.lastname: Catai
authors.forename: R
authors.initials: R
authors.lastname: Arena
authors.forename: A
authors.initials: A
authors.lastname: Borghi-Silva
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D015308:Anaerobic Threshold / Q000502:physiology*; D001341:Autonomic Nervous System / Q000502:physiology; D015444:Exercise / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D008875:Middle Aged; D055070:Resistance Training / Q000379:methods*; D013564:Sympathetic Nervous System / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology; D055815:Young Adult
chemical_list: D019344:Lactic Acid