Effects of an individualized exercise training program on severity markers of obstructive sleep apnea syndrome: a randomised controlled trial

Highlights

• Individualized exercise did not decrease AHI compared to controls

• Individualized exercise improved AHI in REM sleep and objective daytime sleepiness

• Adding personalized exercise training to the management of patients with OSA should be considered

Abstract

Objective

Obstructive sleep apnea (OSA) is a high prevalent disorder with severe consequences including sleepiness, metabolic, and cardiovascular disorders. The aim of this study was to assess the effect of an individualized exercise-training (IET) program with educational sessions vs educational sessions alone on severity markers of OSA over an eight-week duration.

Methods

This was a randomised, controlled, parallel-design study. In sum, 64 patients with moderate-to-severe OSA (apnea-hypopnea index AHI 15–45/hour), low physical activity level (Voorrips<9), body-mass index (BMI) <40 kg/m² were included in intervention group (IG) or control group (CG), and 54 patients finished the study. All underwent polysomnography (PSG), multiple sleep latency test (MSLT), constant workload exercise test, blood samples and fulfilled questionnaires twice. The primary endpoint was the change in apnea-hypopnea (AHI) at eight weeks from baseline. Main secondary endpoints were daytime sleepiness assessed by questionnaire and objective tests.

Results

No significant between-group differences were found for changes in AHI. A reduction in AHI was found in IG only (p = 0.005). Compared to CG, exercise training leads to a greater decrease in AHI during REM sleep (p = 0.0004), with a significant increase in mean daytime sleep latency (p = 0.02). Between-group differences were significant for weight reduction, severity of fatigue, insomnia and depressive symptoms with trend for sleepiness symptoms.

Conclusions

In adult patients with moderate-to-severe OSA, IET did not decrease AHI compared to the control group but improved markers of severity of OSA, in particular AHI in rapid eye movement (REM) sleep and objective daytime sleepiness. Adding personalized exercise training to the management of patients with OSA should be considered.

ClinicalTrials.gov identifier

NCT01256307.

Introduction

Obstructive sleep apnea (OSA) is a common sleep breathing disorder characterized by recurrent episodes of upper airway obstruction leading to intermittent hypoxia, arousals, increasing of sympathetic activity, oxidative stress, systemic inflammation and changes in intrathoracic pressure [1]. Excessive daytime sleepiness (EDS) is a cardinal symptom of OSA and is also associated with impaired quality of life, increased risk for accidents and metabolic and cardiovascular diseases [[2], [3], [4], [5]].

Continuous positive airway pressure (CPAP) is the first-line treatment of OSA resulting in decrease of apnea-hypopnea index (AHI), EDS, and improvement of sleep quality. However, long-term CPAP effectiveness remains limited by low adherence [6] and no randomized controlled trial has demonstrated a key protective effect in prevention of cardiovascular diseases [7]. CPAP therapy showed no effect on weight loss, energy expenditure, and no clinical significant impact on metabolic disorders or biomarkers associated with OSA [8]. Other treatments such as oral appliances or upper airway surgery only partially correct OSA, may have side effects, and their efficacy on the metabolic and cardiovascular consequences of OSA are poorly studied [9].

OSA is closely related to being overweight/obese, with a bidirectional link. Obesity is the most important risk factor for OSA [10] and OSA by itself can contribute to weight gain [11]. Moreover, patients with OSA present a decreased level of physical activity [12]. Lifestyle modification including diet and exercise training may be effective in reducing weight and severity of OSA, and are therefore recommended for the management of OSA [13,14].

Currently, few studies addressed the impact of non-pharmacological strategies such as hypocaloric diets and exercise training on severity of OSA. Recent meta-analysis showed a significant decrease in AHI and subjective sleepiness after exercise training regardless of weight loss [15,16]. The mechanisms underlying such improvement remain unclear; however a reduction of adipose tissue and in fluid shift in the upper airway area, an increase in oropharyngeal muscle strength, a change in humoral mediators of inflammation and metabolism, and a modification of sleep architecture with increased slow wave sleep associated with an increased respiratory stability may attenuate the propensity towards airway collapse during sleep [15,16]. The benefits of exercise training may also reduce severity of comorbidities associated with OSA (eg, diabetes, hypertension or cardiovascular diseases) and increasing physical activity is recommended to prevent cardiovascular diseases [15]. We previously showed positive effects of exercise training on cardiometabolic parameters and subjective EDS assessed by the Epworth Sleepiness Scale (ESS) in OSA patients [17], but its impact on objective sleepiness had not been evaluated.

The aim of this randomized, parallel-design study was to evaluate the efficacy of an individualized exercise training (IET) program with educational sessions compared to educational sessions only in patients with low physical activity level and moderate-to-severe OSA over an eight-week duration on severity markers of OSA: (1) change in AHI at endpoint vs baseline, (2) changes in EDS assessed by questionnaire and objective tests, and (3) subgroups analyses of patients according to their age, gender, BMI, ESS and AHI levels.