Sleep disorders and systemic arterial hypertension: implications of heart rate variability and cardiovascular autonomic modulation

Abstract

Sleep disorders constitute a significant public health problem and show a consistent association with the development and progression of systemic arterial hypertension, a condition strongly related to dysfunction of the autonomic nervous system. In this context, heart rate variability (HRV) stands out as a widely used non-invasive marker to assess cardiovascular autonomic modulation and prognostic risk in hypertensive individuals. Alterations in sleep quantity and quality, especially sleep fragmentation and sleep-related breathing disorders, have been associated with sympathetic predominance, reduced vagal tone, and the loss of nocturnal blood pressure dipping. Thus, the present study aimed to synthesize recent evidence regarding the relationship between sleep disorders, heart rate variability, and systemic arterial hypertension, with an emphasis on the underlying pathophysiological mechanisms. This is a systematic literature review conducted in the PubMed database over the past five years, using the descriptors “Sleep Disorders” AND “Heart Rate Variability” AND “Hypertension” NOT “Animals”, with filters applied to full-text articles published in English or Portuguese. Unlike previous reviews, systematic reviews were included. Initially, nine studies were identified, of which four met the eligibility criteria after screening titles, abstracts, and full texts. The results indicated that sleep disorders, particularly obstructive sleep apnea and sleep fragmentation, are associated with HRV alterations consistent with increased sympathetic activation, reduced parasympathetic modulation, and poorer blood pressure control. Integrated approaches, such as cardiopulmonary coupling, have shown promise in characterizing sleep stability and its relationship with nocturnal blood pressure. Furthermore, inflammatory and oxidative mechanisms, as well as changes in vascular aging biomarkers such as Klotho and sirtuins, were implicated in mediating these effects. It is concluded that sleep disorders exert a significant influence on cardiovascular autonomic modulation and the control of systemic arterial hypertension, constituting modifiable risk factors, although methodological heterogeneity among studies highlights the need for future investigations with greater standardization and longitudinal designs.