Dados do Trabalho

Título

Exercise and Sleep-Induced Oxygen Desaturation in Individuals with Chronic Obstructive Pulmonary Disease

Introdução

It is known that exercise-induced oxygen desaturation (EIOD) is fairly prevalent among individuals with chronic obstructive pulmonary disease (COPD) and has been associated with arterial stiffness, reduced exercise capacity and increased risk of mortality. Factors associated with EIOD include obesity, airflow limitation and low resting oxygen saturation (SpO2). Individuals with COPD also experience a drop in SpO2 during sleep, resulting from being on the steep part of the oxyhemoglobin dissociation curve. However, it is not yet known whether EIOD associates with nocturnal sleep characteristics in this population.

Objetivo

To compare sleep between groups of individuals with COPD with and without EIOD.

Métodos

In this cross-sectional study, individuals with COPD underwent pulmonary function assessment, continuous SpO2 monitoring using pulse oximetry during maximum isometric voluntary contraction of the quadriceps femoris (QF) and during the sit-to-stand (STS) test, with a cutoff point of SpO2<90% to indicate EIOD. Sleep was objectively assessed using the Actiwatch monitor over 7 consecutive days and also by polygraphy during one night. Statistical analysis was performed using SPSS 20.0 software, and the Shapiro-Wilk and Mann-Whitney tests were applied.

Resultados

Thirty-six individuals with COPD were evaluated (age: 70 [64-72] years; BMI: 27 [24-31] kg/m²; FEV1 54 [44-70]% predicted). The group with EIOD during the QF muscle strength test showed lower mean and minimum SpO2, as well as greater number of apneas in the polygraphy exam (p<0.05 for all). Additionally, individuals with EIOD during the STS test had greater sleep latency (p=0.031), lower sleep efficiency (p=0.025), higher % of wake time after sleep onset (p=0.047), more wake blocks (p=0.046) and lower total sleep time both in minutes and in % (p=0.038 and 0.047, respectively). In the polygraphy exam, worse results were also observed in those with EIOD in terms of mean SpO2 (p=0.023), baseline SpO2 (p=0.012), SpO2<85% (p=0.012), and SpO2<80% (p=0.012).

Conclusões

Individuals with COPD and exercise-induced oxygen desaturation exhibit poorer outcomes in sleep quantity, quality and respiratory performance during nocturnal sleep. Identifying factors associated with impaired sleep in this population is crucial for developing strategies aimed at a more comprehensive disease management.

Palavras -chave

Chronic obstructive pulmonary disease; Sleep; Peripheral oxygen saturation.