Heart rate variability and electrocardiographic parameters among workers exposed to chronic intermittent hypobaric hypoxia in the Peruvian Andes: A cross-sectional study Cardiac autonomic function in Andean workers

Q: What are the key findings of this study?

Chronic intermittent hypobaric hypoxia exposure was not associated with significant differences in resting heart rate variability (SDNN p=0.273) or ECG parameters (PR p=0.879, QTc p=0.809).

Q: What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Occupational exposure to chronic intermittent hypobaric hypoxia (n=96). Intervention: Chronic intermittent hypobaric hypoxia (rotational shifts at >=3,000 m with rest at <2,500 m) vs. Permanent work at lower altitude (<2,500 m). Primary outcome: Resting heart rate variability (SDNN) and standard 12-lead electrocardiographic parameters (PR and QTc intervals) (p=0.273).

Elizbet Susan Montes-Madariaga; Jhon Brando Ortiz-Saavedra; Julio Samuel Mamani Castillo; Anel Ivonne Valencia-Pacheco; Jorge Ballón‐Echegaray; Irmia Luz Paz Torres; Ricardo A. J. Leon-Vasquez

doi:10.64898/2026.10.15.26365599

October 16, 2026Open Access

Heart rate variability and electrocardiographic parameters among workers exposed to chronic intermittent hypobaric hypoxia in the Peruvian Andes: A cross-sectional study Cardiac autonomic function in Andean workers

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Key result

Chronic intermittent hypobaric hypoxia exposure is not associated with altered resting HRV or ECG parameters.

P=0.273
n=96

Why the study?

Does occupational exposure to chronic intermittent hypobaric hypoxia alter resting heart rate variability and standard electrocardiographic parameters in healthy male Andean workers compared to working permanently at lower altitude?

Key Points

To compare heart rate variability and standard electrocardiographic parameters between workers exposed to chronic intermittent hypobaric hypoxia and controls working permanently at lower altitudes in Arequipa, Peru.
Observational cross-sectional study in 96 healthy male workers aged 20–60 years (median age 34 years) in Arequipa, Peru.
The exposed group included 53 workers performing rotational shifts at altitudes ≥3,000 m above sea level with rest periods at <2,500 m, compared to a control group of 43 workers permanently at <2,500 m.
Heart rate variability was assessed using a Polar® H10 sensor after 15 minutes of rest during the morning rest period at approximately 2,300 m, alongside standard 12-lead electrocardiography.
Electrocardiographic intervals did not differ significantly between the exposed and control groups for PR interval (p = 0.879) or corrected QT interval (p = 0.809).
Time-domain heart rate variability parameters showed no statistically significant differences, including SDNN (p = 0.273), coefficient of variation of NN intervals (p = 0.150), RMSSD (p = 0.830), pNN50 (p = 0.735), standard error of the mean (p = 0.224), and sample entropy (p = 0.180).
Frequency-domain heart rate variability parameters were comparable between groups, with no significant differences in low-frequency power (p = 0.608), high-frequency power (p = 0.948), or the LF/HF ratio (p = 0.992).

Study Design

Type

Cross-Sectional (n=96)

Multicenter

No

Structured PICO

Does occupational exposure to chronic intermittent hypobaric hypoxia alter resting heart rate variability and standard electrocardiographic parameters in healthy male Andean workers compared to working permanently at lower altitude?

P

Population

96 apparently healthy male workers aged 20-60 years in Peru (53 exposed to rotational high-altitude shifts >=3,000 m for at least 6 months and 43 permanent low-altitude controls), free of cardiovascular, metabolic, or pulmonary disease.

E

Exposure

Occupational exposure to chronic intermittent hypobaric hypoxia, defined as performing rotational shifts at high altitudes (≥3,000 m above sea level) alternating with rest periods at lower altitudes (<2,500 m above sea level) for at least 6 consecutive months.

C

Comparator

Control workers performing permanent work schedules continuously at lower altitudes (<2,500 m above sea level).

O

Outcome

Resting heart rate variability (time-domain parameters: SDNN, CV of NN intervals, RMSSD, pNN50, SEM, sample entropy; frequency-domain parameters: LF power, HF power, LF/HF ratio) assessed during a 10-minute morning recording after 15 minutes of rest using a Polar H10 sensor, and standard 12-lead electrocardiographic parameters (cardiac axis, PR interval, QT interval, corrected QT interval) evaluated during the rest period at approximately 2,300 m above sea level.surrogate

Main Result

p-value: p=0.273

In apparently healthy male Andean workers evaluated during their rest period at moderate altitude, occupational exposure to chronic intermittent hypobaric hypoxia was not associated with significant alterations in resting heart rate variability or standard 12-lead ECG parameters compared to permanent lower-altitude controls.

Limitations

Cross-sectional design precludes causal inference or assessment of temporal changes
Measurements were performed during the rest period at moderate altitude (2,300 m) rather than during active high-altitude exposure
Sample included only male workers, limiting generalizability to females
Potential residual confounding from work intensity, rotation schedule, sleep, diet, hydration, caffeine intake, stress, and breathing patterns
Heart rate variability was assessed during a single short-term (10-minute) resting recording
Cross-sectional design does not allow causal inference or assessment of temporal changes
Measurements were performed during the rest period at moderate altitude (~2,300 m) rather than during active exposure at high-altitude worksites, which may have attenuated detectable differences
Sample included only male workers, limiting generalizability to female workers
Residual confounding related to work intensity, rotation schedule, sleep, diet, hydration, caffeine intake, psychological stress, breathing pattern, and recent physical activity cannot be ruled out
HRV was assessed during a single short-term resting recording

Implication

No association in this cross-sectional cohort; leaves open effects during active ascent or in other populations.

Abstract

Chronic intermittent hypobaric hypoxia is an occupational exposure experienced by workers who alternate between high-altitude worksites and lower-altitude resting locations. Its effects on cardiac autonomic modulation and electrocardiographic parameters remain insufficiently characterized in Andean workers. This study aimed to compare heart rate variability and electrocardiographic parameters between workers exposed to chronic intermittent hypobaric hypoxia and controls working permanently at lower altitude in Arequipa, Peru. An observational cross-sectional study was conducted in 96 male workers aged 20–60 years. The exposed group included 53 workers performing rotational shifts at altitudes ≥3,000 m above sea level with rest periods at <2,500 m, while the control group included 43 workers working permanently at <2,500 m. Heart rate variability was assessed during the morning rest period in Arequipa, at approximately 2,300 m above sea level, using a Polar® H10 heart rate sensor after 15 minutes of rest. Participants also underwent standard 12-lead electrocardiography. Vital signs were clinically similar between groups. No statistically significant differences were observed in PR interval, corrected QT interval, time-domain heart rate variability parameters, or frequency-domain heart rate variability parameters. In this sample of apparently healthy male workers evaluated during their rest period at moderate altitude, exposure to chronic intermittent hypobaric hypoxia was not associated with significant differences in resting heart rate variability or standard electrocardiographic parameters.

Discussion

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Cite This Study

Montes-Madariaga et al. (2026) conducted a cross-sectional in Occupational exposure to chronic intermittent hypobaric hypoxia (n=96). Chronic intermittent hypobaric hypoxia (rotational shifts at >=3,000 m with rest at <2,500 m) vs. Permanent work at lower altitude (<2,500 m) was evaluated on Resting heart rate variability (SDNN) and standard 12-lead electrocardiographic parameters (PR and QTc intervals) (p=0.273). Chronic intermittent hypobaric hypoxia exposure was not associated with significant differences in resting heart rate variability (SDNN p=0.273) or ECG parameters (PR p=0.879, QTc p=0.809).

synapsesocial.com/papers/6ae28e75cbadf70daf6c424a https://doi.org/10.64898/2026.10.15.26365599

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Heart rate variability and electrocardiographic parameters among workers exposed to chronic intermittent hypobaric hypoxia in the Peruvian Andes: A cross-sectional study Cardiac autonomic function in Andean workers

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

Heart rate variability and electrocardiographic parameters among workers exposed to chronic intermittent hypobaric hypoxia in the Peruvian Andes: A cross-sectional study Cardiac autonomic function in Andean workers

Key Points

Study Design

Structured PICO

Main Result

Limitations

Implication

Abstract

Discussion

Cite This Study

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