Respiratory effort during obstructive sleep apnea: role of age and sleep state

Chest. 1997 Oct;112(4):875-84. doi: 10.1378/chest.112.4.875.


Objective: To evaluate the patients' individual characteristics predictive of the degree of respiratory effort developed during obstructive sleep apneas (OSAs).

Design: Prospective consecutive sample, collection of clinical and polysomnographic data.

Setting: University teaching hospital.

Patients: One hundred sixteen consecutive OSA patients with clinical symptoms of OSA and more than 20 apneas per hour of sleep.

Measurements: Anthropomorphic data, daytime blood gas values, and polysomnographic data. From esophageal pressure measurements during sleep, three indexes of respiratory effort during OSAs were derived: the maximal end-apneic esophageal pressure swing (PesMax), the increase in esophageal pressure swing (deltaPes) during the apnea, and its ratio to apnea duration (RPes).

Results: The indexes of respiratory effort were significantly lower in rapid eye movement (REM) than in non-REM sleep (PesMax: 50.9+/-2.5 vs 39.6+/-1.9 cm H2O, p<0.001; deltaPes: 30.9+/-1.7 vs 23.4+/-1.4 cm H2O, p<0.001; RPes: 1.05+/-0.05 vs 0.53+/-0.03 cm H2O/s, p<0.001); therefore, a separate analysis was conducted in non-REM and in REM sleep. Indexes were also significantly lower in subgroups of older as compared to younger patients (PesMax: 55.6+/-3.5 vs 40.0+/-2.2 cm H2O, p<0.001; deltaPes: 34.2+/-2.3 vs 24.1+/-1.6 cm H2O, p=0.001; RPes: 1.21+/-0.08 vs 0.8+/-0.05 cm H2O/s, p<0.001). The three indexes were closely correlated with each other and only PesMax correlation data are reported. In non-REM sleep, age was the most important single independent correlate of PesMax (r=-0.37, p=0.000). In REM sleep, the apnea-related hypoxemia, apnea duration, and age were the main contributors to the variance of PesMax.

Conclusions: Respiratory effort in response to upper airway occlusion in OSA patients is lower in REM than in non-REM sleep and decreases with increasing age.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Age Factors
  • Aged
  • Aging / physiology*
  • Body Mass Index
  • Carbon Dioxide / blood
  • Esophagus / physiopathology
  • Female
  • Forecasting
  • Humans
  • Hypoxia / blood
  • Hypoxia / physiopathology
  • Inhalation / physiology
  • Male
  • Middle Aged
  • Oxygen / blood
  • Polysomnography
  • Pressure
  • Prospective Studies
  • Regression Analysis
  • Respiration / physiology*
  • Sleep Apnea Syndromes / physiopathology*
  • Sleep Stages / physiology*
  • Sleep, REM / physiology
  • Tidal Volume / physiology
  • Time Factors


  • Carbon Dioxide
  • Oxygen