Original ArticleHeart rate variability and cardiorespiratory coupling in obstructive sleep apnea: elderly compared with young
Introduction
Obstructive sleep apnea (OSA) is a respiratory disorder characterized by recurrent airflow obstruction caused by total or partial collapse of the upper airways [1], [2]. Aging is associated with increased apnea prevalence and is thus known to be a major factor contributing to the risk of OSA [3], [4]. Moreover, elderly adults with OSA are at greater risk for cardiovascular disease (i.e. coronary artery disease, congestive heart failure, ischemic disease, and stroke) [5], [6].
Cardiac autonomic function can be non-invasively assessed by analyzing the heart rate variability (HRV), which quantifies the changes in beat-to-beat intervals influenced by the combined effects of the sympathetic and parasympathetic nervous systems on the heart rate [7]. Clinical studies have consistently reported that decreased HRV is associated with sleep disorders [8], [9], [10]. During sleep, HRV is influenced by direct modulation of vagal efferent activity resulting from baroceptor responses to respiratory blood pressure fluctuations and from mechanical sinus node stretch determined by respiration-related changes in venous return [11].
Respiration undergoes important modifications during sleep and HRV is affected by sleep stage organization and by the presence of apnea events [12]. However, it is not known whether the effects of OSA on cardiac autonomic modulation in elderly subjects are different from those in young subjects, both during wakefulness and sleep. It is not known whether different effects are likely to be observed during specific sleep stages. Since OSA as it relates to the senescence process is considered a risk factor for cardiac autonomic impairment, we hypothesized that HRV and cardiorespiratory coupling (CRC) would be worse in elderly subjects with OSA.
Therefore, the aim of the study was to contrast HRV and CRC during wakefulness and sleep in young and elderly subjects with OSA. Further, we aimed to determine whether the presence of OSA in young and elderly subjects has a different impact on HRV and CRC during different stages of sleep.
Section snippets
Methods
This was a cross-sectional study, by analysis of medical records involving young and elderly patients referred to our sleep medicine clinic between January 2011 and December 2012 for evaluation of excessive daytime somnolence, snoring, and suspected OSA. The study protocol was approved by the Ethics Committee of Federal University of São Carlos (N.401/2010 opinion) and was registered as a clinical trial (RBR-3jbm6d). All participants signed informed consent prior to the polysomnography. The
Sample characteristics
One hundred examinations meeting the inclusion criteria for this study were selected: 50 young subjects (20 young and 30 OSA young) and 50 elderly subjects (20 elderly and 30 OSA elderly) (Table 1). Body mass index (BMI) was influenced by age and OSA, with an interaction between both. As expected, AHI was higher in OSA groups. Nadir saturation was lower in elderly + OSA subjects, and time spent with oxygen saturation <90% (T90) was influenced by both age and OSA (P <0.05). Likewise, the
Main results
The main results of our study may be summarized as follows: (i) the presence of OSA influenced HRV in young subjects to a greater degree, with a reduction in autonomic modulation during wakefulness and different sleep stages, whereas changes in HRV were only apparent during wakefulness in elderly subjects; (ii) age influenced HRV during wakefulness and sleep in elderly people; (iii) the presence of OSA influenced cardiorespiratory coupling only during wakefulness in both young and elderly
Conclusions
Our study reveals that the presence of OSA influenced HRV in young and elderly individuals, with reduced autonomic modulation during wakefulness and REM sleep. Age per se appeared to influence HRV during wakefulness and REM sleep in elderly subjects. Finally, the presence of OSA and age had an unfavorable impact on CRC during wakefulness and sleep. Thus, whereas OSA has negative effects on HRV and CRC across the lifespan, there seems to be an age-dependent influence with respect to how these
Funding sources
This study was supported by FAPESP 2009/01842-0 and CAPES 12883-12-3.
Conflict of interest
The ICMJE Uniform Disclosure Form for Potential Conflicts of Interest associated with this article can be viewed by clicking on the following link: http://dx.doi.org/10.1016/j.sleep.2014.05.028.
References (37)
- et al.
Obstructive sleep apnea syndrome in the São Paulo epidemiologic sleep study
Sleep Med
(2010) - et al.
Heart rate variability, sleep and sleep disorders
Sleep Med Rev
(2012) - et al.
Sleep in the elderly patient
Clin Chest Med
(1993) - et al.
Vegetative background of sleep: spectral analysis of the heart rate variability
Physiol Behav
(1997) - et al.
Sleep apnea and heart failure. Part I: obstructive sleep apnea
Circulation
(2003) - et al.
Aging and sleep: physiology and pathophysiology
Semin Respir Crit Care Med
(2010) - et al.
Sleep disordered breathing and mortality: a prospective cohort study
PLoS Med
(2009) - et al.
Associations of symptoms of sleep apnea with cardiovascular disease, cognitive impairment, and mortality among older Japanese-American men
J Am Geriatr Soc
(1999) - et al.
Sleep disorders in the elderly
Indian J Med Res
(2010) - et al.
The effect of aging and severity of sleep apnea on heart rate variability indices in obstructive sleep apnea syndrome
Psychiatry Investig
(2012)
Correlation between the severity of obstructive sleep apnea and heart rate variability indices
J Korean Med Sci
Polysomnography underestimates altered cardiac autonomic control in patients with obstructive sleep apnea
Herzschrittmacherther Elektrophysiol
Contribution of tonic chemoreflex activation to sympathetic activity and blood pressure in patients with obstructive sleep apnea
Circulation
Altered cardiovascular variability in obstructive sleep apnea
Circulation
Technical review of polysomnography
Chest
What every clinician should know about polysomnography
Respir Care
The scoring of respiratory events in sleep: reliability and validity
J Clin Sleep Med
The visual scoring of sleep in adults
J Clin Sleep Med
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