What is the clinical evidence from this study?

Study design: Observational. Population: Sleep-disordered breathing (n=108). Intervention: Central apnea vs. Obstructive apnea, mixed apnea, and hypopnea. Primary outcome: Heart rate variability indices (SDSD, RMSSD, SD1) and heart rate (estimate -11.67, 95% CI -18.78 to -4.59, p=<0.001).

What does this research mean for the field?

Central apnea events exert the most profound effects on autonomic function among sleep respiratory events, significantly reducing ultra-short-term heart rate variability compared to obstructive apnea, mixed apnea, and hypopnea. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This study aims to investigate how different types of respiratory events affect heart rate variability and autonomic nervous system function.

June 10, 2026Open Access

Differential Effects of Sleep Respiratory Event Types on Heart Rate Variability: Central Apnea as the Most Significant

Q: What are the key findings of this study?

Central apnea events were associated with significantly reduced heart rate variability compared with obstructive apnea during NREM sleep (SDSD estimate -11.67; 95% CI -18.78 to -4.59; p<0.001).

Q: What does this research mean for the field?

Central apnea events exert the most profound effects on autonomic function among sleep respiratory events, significantly reducing ultra-short-term heart rate variability compared to obstructive apnea, mixed apnea, and hypopnea. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

Q: What question did this study set out to answer?

This study aims to investigate how different types of respiratory events affect heart rate variability and autonomic nervous system function.

Key Result

Central apnea events were associated with significantly reduced heart rate variability compared with obstructive apnea during NREM sleep (SDSD estimate -11.67; 95% CI -18.78 to -4.59; p<0.001).

Key Points

This study aims to investigate how different types of respiratory events affect heart rate variability and autonomic nervous system function.
108 patients with sleep-disordered breathing underwent overnight polysomnography (PSG) to analyze 19,862 respiratory events.
Linear mixed-effects models (LMMs) evaluated differences in heart rate variability and ECG-derived features between event types.
Sidak-adjusted pairwise comparisons analyzed HRV metrics before, during, and after respiratory events.
Central apnea (CA) significantly reduced heart rate variability metrics (SDSD, RMSSD, SD1) compared to other events (all p < 0.05).
HRV changes were consistent before, during, and after respiratory events (all p < 0.001).
During NREM sleep, SDSD was significantly lower in CA compared to obstructive apnea (estimate = −11.67, p < 0.001) and hypopnea (estimate = −11.38, p < 0.001).

Study Design

Type

Observational (n=108)

Structured PICO

Do central apnea events have a more profound immediate effect on heart rate variability compared to other sleep respiratory events in patients with sleep-disordered breathing?

Population

108 patients with sleep-disordered breathing undergoing overnight polysomnography, contributing 19,862 respiratory events for analysis.

Exposure

Central apnea (CA) events

Comparator

Other respiratory event types (obstructive apnea [OA], mixed apnea [MA], and hypopnea [HYP])

Outcome

Immediate effects on ultra-short-term heart rate variability (HRV) and heart rate indices (SDSD, RMSSD, SD1, HR)surrogate

Central apnea events exert the most profound immediate suppressive effects on autonomic function and heart rate variability among sleep respiratory events, suggesting they may serve as a biomarker for cardiovascular risk in sleep-disordered breathing.

Main Result

Mean Difference: -11.67 (95% CI -18.78–-4.59)

p-value: p=<0.001

Abstract

Background: Sleep-disordered breathing (SDB) is frequently accompanied by autonomic nervous system (ANS) dysfunction, which is closely associated with an increased incidence of cardiovascular diseases and elevated mortality risk. Heart rate variability (HRV) serves as a classic metric for evaluating sympathovagal balance; however, the specific impacts of four distinct types of respiratory events—obstructive apnea (OA), central apnea (CA), mixed apnea (MA), and hypopnea (HYP)—on HRV remain underinvestigated. Utilizing ultra-short-term HRV analysis, this study aimed to evaluate the immediate effects of different respiratory events on ANS function, while further exploring the modulatory roles of arousal, Apnea–Hypopnea Index (AHI) severity and sleep stages (non-rapid eye movement NREM vs. rapid eye movement REM). Methods: A total of 108 patients with SDB undergoing overnight polysomnography (PSG) were included. A total of 19,862 respiratory events, including obstructive apnea (OA), central apnea (CA), mixed apnea (MA), and hypopnea (HYP), were analyzed using 15 s ECG segments. Linear mixed-effects models (LMMs) and estimated marginal means (EMMs) with Sidak-adjusted pairwise comparisons were constructed to evaluate differences in ECG-derived features and to analyze differences between event types. Results: Central apnea (CA) was associated with significantly reduced HRV and heart rate indices, including Standard Deviation of Successive Differences (SDSD), Root Mean Square of the Successive (RMSSD), Standard Deviation 1 (SD1), and heart rate (HR), compared with other respiratory event types (all p 0.05). Conclusions: This study is the first to elucidate the differential impacts of four distinct types of sleep respiratory events on ultra-short-term HRV, confirming that CA events exert the most profound effects on autonomic function. These findings suggest that the proportion of CA occurrences could serve as a more precise biomarker for identifying individuals at high risk for cardiovascular diseases within the SDB population.