The effect of sex and body weight on lung volumes during sleep

Abstract

Study Objectives Low lung volumes are thought to contribute to obstructive sleep apnea (OSA). OSA is worse in the supine versus lateral body position, men versus women, obese versus normal-weight (NW) individuals and REM versus NREM sleep. All of these conditions may be associated with low lung volumes. The aim was to measure FRC during wake, NREM, and REM in NW and overweight (OW) men and women while in the supine and lateral body positions. Methods Eighty-one healthy adults were instrumented for polysomnography, but with nasal pressure replaced with a sealed, non-vented mask connected to an N2 washout system. During wakefulness and sleep, repeated measurements of FRC were made in both supine and right lateral positions. Results Two hundred eighty-five FRC measures were obtained during sleep in 29 NW (body mass index [BMI] = 22 ± 0.3 kg/m2) and 29 OW (BMI = 29 ± 0.7 kg/m2) individuals. During wakefulness, FRC differed between BMI groups and positions (supine: OW = 58 ± 3 and NW = 68 ± 3% predicted; lateral OW = 71 ± 3, NW = 81 ± 3% predicted). FRC fell from wake to NREM sleep in all participants and in both positions by a similar amount. As a result, during NREM sleep FRC was lower in OW than NW individuals (supine 46 ± 3 and 56 ± 3% predicted, respectively). FRC during REM was similar to NREM and no sex differences were observed in any position or sleep stage. Conclusions Reductions in FRC while supine and with increased body weight may contribute to worsened OSA in these conditions, but low lung volumes appear unlikely to explain the worsening of OSA in REM and in men versus women.

The 3% Oxygen Desaturation Index is an Independent Risk Factor for Hypertension Among Children with Obstructive Sleep Apnea

“…Previous studies have suggested that pediatric hypertension increases along with childhood obesity, 16 and that hypertension further contributes to the clustering of obesity-related cardio-metabolic risk factors. 17 Moreover, obesity increases fat accumulation in the parapharyngeal space 18 and reduces lung volume, 19 which can also cause or aggravate OSA. Notably, pediatric OSA, obesity, and hypertension are likely to persist into adulthood and then further increase the risks of cardiovascular diseases and mortality.…”

Overnight variation in tidal expiratory flow limitation in COPD patients and its correction: an observational study

“…The likelihood of developing EFL T is markedly increased by postural change when EELV falls [ 5 , 6 ]. Lung volume falls further in a state-dependent fashion with the onset of sleep [ 7 , 8 ], but to date, we lack data about how this impacts EFL T .…”

Muscling Up Pharyngeal Airflow,

“…10 Movement of the hyoid and laryngeal apparatus will also alter the resting lengths of attached muscles, such as the sternohyoid and sternothyroid muscles, and may reduce muscle effectiveness under some conditions, such as lower lung volumes. 11 Body position influences lung volume in both awake 12 and sleeping 13 individuals. In awake individuals the postural changes in lung volume are less in obese than in healthy weight individuals.…”

“…12 In supine nonrapid eye movement sleep, lung volumes can fall to approximately 60% predicted in healthy weight individuals, with even greater reductions in overweight individuals. 13 Sleeping subjects with OSA, who are obese and supine, are likely to have even lower lung volumes, with displacement of the hyoid cranially. This suggests the lung volume at which ACS occurs may be important in determining its efficacy.…”