What is the clinical evidence from this study?

Study design: Cross-Sectional. Population: Hypertensive adults aged 35-70 years with varying nighttime sleep durations and daytime napping habits, from rural Fasa, Iran (n=1338). Intervention: Regular daytime napping combined with long nighttime sleep (≥9 hours) vs. No daytime napping or non-long nighttime sleep ( 450 ms in men and >460 ms in women (Bazett's formula) (OR 3.54, 95% CI 1.29-9.71, p=0.014).

What question did this study set out to answer?

To explore the relationship between sleep patterns and QTc prolongation in hypertensive adults.

March 6, 2026BMC Cardiovascular DisordersOpen Access

The interactive effect of long nighttime sleep and daytime napping on QTc prolongation in hypertensive adults

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Why the study?

Hypertension is strongly associated with QTc abnormalities, but the influence of habitual sleep patterns remains underexplored.

Does the combination of prolonged nighttime sleep and daytime napping increase the risk of QTc prolongation in hypertensive adults?

Population

1,338 hypertensive participants from the Fasa Adult Cohort Study

Comparison

Different nighttime sleep durations and daytime napping patterns

Design

Cross-sectional analysis

Key result

Regular daytime napping combined with prolonged nighttime sleep (≥9 hours) increased odds of QTc prolongation by 3.54-fold compared to other sleep patterns in hypertensive adults.

Authors

ZMZahra Mohammadi SBSina Bazmi MAMohsen Ahmadi

Discussion

Member takes

Overview

May warrant sleep pattern review in hypertensives with QTc prolongation; hypothesis-generating and should not yet change practice.

Key Points

To explore the relationship between sleep patterns and QTc prolongation in hypertensive adults.
Cross-sectional analysis of 1,338 hypertensive participants from the Fasa Adult Cohort Study.
Sleep parameters assessed using the Pittsburgh Sleep Quality Index.
QTc calculated from 12-lead electrocardiograms using Bazett’s formula.
Logistic regression models used to evaluate associations of sleep behaviors and QTc prolongation.
QTc prolongation was observed in 20.5% of participants.
Combination of prolonged nighttime sleep (≥ 9 h) and daytime napping significantly increased the risk (OR = 3.54).
Statistical interaction confirmed between prolonged nighttime sleep and daytime napping (OR = 4.36).
Short nighttime sleep accompanied by daytime napping showed no significant association with QTc prolongation.

Study Design

Type

Cross-Sectional (n=1,338)

Structured PICO

Does the combination of prolonged nighttime sleep and daytime napping increase the risk of QTc prolongation in hypertensive adults?

Population

1,338 hypertensive adults aged 35 to 70 years from the Fasa Adult Cohort Study (FACS), mean age 54.79, 24.1% male, 75.9% female.

Intervention

Prolonged nighttime sleep (≥ 9 hours) combined with regular daytime napping (≥ 3 times per week).

Comparator

Adequate (6-9 hours) or short (≤ 6 hours) nighttime sleep, and/or no regular daytime napping.

Outcome

QTc prolongation (> 450 ms in men and > 460 ms in women using Bazett’s formula).surrogate

Main Result

Effect estimate: OR 3.54 (95% CI 1.29-9.71)

p-value: p=0.014

Excessive total sleep duration, characterized by prolonged nighttime sleep combined with regular daytime napping, is independently associated with an increased risk of QTc prolongation in hypertensive adults.

Limitations

Cross-sectional design limits causal inference
Small subgroup of long sleepers with limited QTc events
No sex-stratified analysis due to limited power
QTc calculated only by Bazett's formula primarily; Fridericia formula yielded non-significant associations
ECG measures lacked formal inter- and intra-observer reliability assessments
Sleep duration and napping based on self-reported PSQI data
Wide confidence intervals indicating limited precision
Small size of certain exposure subgroups
Potential unmeasured confounding by sleep-disordered breathing such as obstructive sleep apnea

Cite This Study

Mohammadi et al. (2026) conducted a cross-sectional in Hypertensive adults aged 35-70 years with varying nighttime sleep durations and daytime napping habits, from rural Fasa, Iran (n=1,338). Regular daytime napping combined with long nighttime sleep (≥9 hours) vs. No daytime napping or non-long nighttime sleep (<9 hours) was evaluated on QTc prolongation defined as >450 ms in men and >460 ms in women (Bazett's formula) (OR 3.54, 95% CI 1.29-9.71, p=0.014). Regular daytime napping combined with prolonged nighttime sleep (≥9 hours) increased odds of QTc prolongation by 3.54-fold compared to other sleep patterns in hypertensive adults.

synapsesocial.com/papers/69aa7048531e4c4a9ff59f38 https://doi.org/10.1186/s12872-026-05670-7

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March 6, 2026BMC Cardiovascular DisordersOpen Access

The interactive effect of long nighttime sleep and daytime napping on QTc prolongation in hypertensive adults

View Full Paper

Ask AI

Bookmark

Why the study?

Hypertension is strongly associated with QTc abnormalities, but the influence of habitual sleep patterns remains underexplored.

Does the combination of prolonged nighttime sleep and daytime napping increase the risk of QTc prolongation in hypertensive adults?

Population

1,338 hypertensive participants from the Fasa Adult Cohort Study

Comparison

Different nighttime sleep durations and daytime napping patterns

Design

Cross-sectional analysis

Key result

Regular daytime napping combined with prolonged nighttime sleep (≥9 hours) increased odds of QTc prolongation by 3.54-fold compared to other sleep patterns in hypertensive adults.

Authors

ZMZahra Mohammadi SBSina Bazmi MAMohsen Ahmadi

Discussion

Member takes

Overview

May warrant sleep pattern review in hypertensives with QTc prolongation; hypothesis-generating and should not yet change practice.

Key Points

To explore the relationship between sleep patterns and QTc prolongation in hypertensive adults.
Cross-sectional analysis of 1,338 hypertensive participants from the Fasa Adult Cohort Study.
Sleep parameters assessed using the Pittsburgh Sleep Quality Index.
QTc calculated from 12-lead electrocardiograms using Bazett’s formula.
Logistic regression models used to evaluate associations of sleep behaviors and QTc prolongation.
QTc prolongation was observed in 20.5% of participants.
Combination of prolonged nighttime sleep (≥ 9 h) and daytime napping significantly increased the risk (OR = 3.54).
Statistical interaction confirmed between prolonged nighttime sleep and daytime napping (OR = 4.36).
Short nighttime sleep accompanied by daytime napping showed no significant association with QTc prolongation.

Study Design

Type

Cross-Sectional (n=1,338)

Structured PICO

Does the combination of prolonged nighttime sleep and daytime napping increase the risk of QTc prolongation in hypertensive adults?

Population

1,338 hypertensive adults aged 35 to 70 years from the Fasa Adult Cohort Study (FACS), mean age 54.79, 24.1% male, 75.9% female.

Intervention

Prolonged nighttime sleep (≥ 9 hours) combined with regular daytime napping (≥ 3 times per week).

Comparator

Adequate (6-9 hours) or short (≤ 6 hours) nighttime sleep, and/or no regular daytime napping.

Outcome

QTc prolongation (> 450 ms in men and > 460 ms in women using Bazett’s formula).surrogate

Main Result

Effect estimate: OR 3.54 (95% CI 1.29-9.71)

p-value: p=0.014

Limitations

Cross-sectional design limits causal inference
Small subgroup of long sleepers with limited QTc events
No sex-stratified analysis due to limited power
QTc calculated only by Bazett's formula primarily; Fridericia formula yielded non-significant associations
ECG measures lacked formal inter- and intra-observer reliability assessments
Sleep duration and napping based on self-reported PSQI data
Wide confidence intervals indicating limited precision
Small size of certain exposure subgroups
Potential unmeasured confounding by sleep-disordered breathing such as obstructive sleep apnea

Cite This Study

synapsesocial.com/papers/69aa7048531e4c4a9ff59f38 https://doi.org/10.1186/s12872-026-05670-7

Also Consider

Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context:

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