Endurance exercise training is associated with elevated basal sympathetic nerve activity in healthy older humans

A. V. Ng, R. Callister, David G Johnson, D. R. Seals

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Abstract

We tested the hypothesis that endurance training is associated with altered basal levels of muscle sympathetic nerve activity (MSNA) and responses to acute stress in healthy older adults. MSNA (peroneal microneurography) and plasma norepinephrine (NE) concentrations were measured during supine rest, a cold pressor test, and isometric handgrip (40% maximal voluntary force to exhaustion) in 16 older masters endurance athletes [10 men, 6 women; 66 ± 1 (SE) yr] and 15 healthy normotensive untrained control subjects (9 men, 6 women; 65 ± 1 yr). The athletes had higher levels of estimated daily energy expenditure and maximal oxygen uptake and lower levels of resting heart rate and body fat than the control subjects (all P < 0.05). MSNA during supine rest was elevated in the athletes whether expressed as burst frequency (43 ± 2 vs. 32 ± 3 bursts/min, respectively; P < 0.05) or burst incidence (75 ± 4 vs. 52 ± 5 bursts/100 heartbeats, respectively; P < 0.01). These whole group differences were due primarily to markedly higher levels of MSNA in the athletic vs. untrained women (48 ± 4 vs. 25 ± 3 bursts/min, 82 ± 3 vs. 38 ± 3 bursts/100 heartbeats, respectively, P < 0.001). In contrast, basal plasma NE concentrations were not significantly different in the athletes vs. control subjects. The MSNA and plasma NE responses to acute stress tended to be greater in the athletes. These findings indicate that vigorous regular aerobic exercise is associated with an elevated level of MSNA at rest and a tendency for an enhanced response to acute stress in healthy normotensive older humans.

Original languageEnglish (US)
Pages (from-to)1366-1374
Number of pages9
JournalJournal of Applied Physiology
Volume77
Issue number3
Publication statusPublished - 1994
Externally publishedYes

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Keywords

  • aging
  • autonomic nervous system
  • endurance training

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

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