title: Effect of age on long-term facilitation and chemosensitivity during NREM sleep.
abstract: The reason for increased sleep-disordered breathing with a predominance of central apneas in the elderly is unknown. We speculate that ventilatory control instability may provide a link between aging and the onset of unstable breathing during sleep. We sought to investigate potential underlying mechanisms in healthy, elderly adults during sleep. We hypothesized that there is 1) a decline in respiratory plasticity or long-term facilitation (LTF) of ventilation and/or 2) increased ventilatory chemosensitivity in older adults during non-, this should be hyphenated, non-rapid rapid eye movement (NREM) sleep. Fourteen elderly adults underwent 15, 1-min episodes of isocapnic hypoxia (EH), nadir O2 saturation: 87.0 ± 0.8%. Measurements were obtained during control, hypoxia, and up to 20 min of recovery following the EH protocol, respectively, for minute ventilation (VI), timing, and inspiratory upper-airway resistances (RUA). The results showed the following. 1) Compared with baseline, there was a significant increase in VI (158 ± 11%, P < 0.05) during EH, but this was not accompanied by augmentation of VI during the successive hypoxia trials nor in VI during the recovery period (94.4 ± 3.5%, P = not significant), indicating an absence of LTF. There was no change in inspiratory RUA during the trials. This is in contrast to our previous findings of respiratory plasticity in young adults during sleep. Sham studies did not show a change in any of the measured parameters. 2) We observed increased chemosensitivity with increased isocapnic hypoxic ventilatory response and hyperoxic suppression of VI in older vs. young adults during NREM sleep. Thus increased chemosensitivity, unconstrained by respiratory plasticity, may explain increased periodic breathing and central apneas in elderly adults during NREM sleep.
authors: Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan schowdh@med.wayne.edu.
authors: Susmita
authors: S
authors: Chowdhuri
authors: Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan.
authors: Sukanya
authors: S
authors: Pranathiageswaran
authors: Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan.
authors: Rene
authors: R
authors: Franco-Elizondo
authors: Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan.
authors: Arunima
authors: A
authors: Jayakar
authors: Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan.
authors: Arwa
authors: A
authors: Hosni
authors: Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and.
authors: Ajin
authors: A
authors: Nair
authors: Medical Service, John D. Dingell Veterans Affairs Medical Center, Detroit, Michigan; and Division of Pulmonary/Critical Care and Sleep Medicine, Department of Medicine, Wayne State University School of Medicine, Detroit, Michigan.
authors: M Safwan
authors: MS
authors: Badr
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D002628:Chemoreceptor Cells / Q000502:physiology*; D005260:Female; D006801:Humans; D017774:Long-Term Potentiation / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000379:methods; D012123:Pulmonary Ventilation / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology*; D055815:Young Adult
keywords: aging; episodic hypoxia; hypoxic ventilatory response; intermittent hypoxia; peripheral chemoreceptor activity; ventilation