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Acute sleep fragmentation decreases skeletal muscle blood flow during exercise

In a randomized crossover study of 20 adults, one night of fragmented sleep (induced by audio alarms every 30 minutes) significantly reduced brachial artery dilation and forearm blood flow during rhythmic handgrip exercise compared to habitual sleep. Peak and total hyperemic responses to single contractions were not affected, and endothelial sensitivity to shear rate was similar between conditions.

Last updated: Aug 12, 2026•1 RCTs•📖 Read as article →

Evidence Score

Evidence Score42/100
Human RCT★★☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. The impact of acute sleep fragmentation on muscle blood flow responses to handgrip exercise.

observational

Narvaez G, Gonzales JU · Journal of applied physiology (Bethesda, Md. : 1985) (2026)

Participants: N/A
Duration: 2 nights (one habitual, one fragmented) with exercise testing the following morning
Intervention: One night of fragmented sleep induced by audio alarm every 30 minutes
Outcome: Forearm blood flow (FBF) and brachial artery dilation during handgrip exercise
Effect Size: N/A
Population: Twenty healthy adults (10 females, 10 males)

Result:

PubMed: 42566231DOI: 10.1152/japplphysiol.00509.2026

Mechanism Graph

Sleep fragmentation increases nightly awakenings and wake after sleep onset
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Reduced sleep duration leads to impaired vascular function
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Brachial artery dilation is reduced during rhythmic exercise
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Result: Lower muscle blood flow during exercise, potentially blunting oxygen delivery

Limitations

  • ⚠Only acute (one night) sleep fragmentation was studied, not chronic sleep disruption
  • ⚠Exercise was limited to handgrip contractions; findings may not generalize to whole-body exercise
  • ⚠Sleep was assessed at home via actigraphy, not polysomnography, which may not capture all sleep architecture changes

Frequently Asked Questions

Does sleep fragmentation affect blood flow during single muscle contractions?▼

No, peak FBF and total hyperemic responses following single contractions were similar between sleep conditions (all p > 0.05).

What was the effect of sleep fragmentation on brachial artery dilation during rhythmic exercise?▼

Brachial artery dilation was significantly reduced after fragmented sleep (5.5 ± 4.8% vs. 3.3 ± 3.7%, p=0.01).

Was endothelial sensitivity to shear rate altered by sleep fragmentation?▼

No, endothelial sensitivity to shear rate was similar between habitual and fragmented sleep conditions (0.039 ± 0.024 vs. 0.042 ± 0.031 %/s-1, p=0.77).

How was sleep fragmentation induced in this study?▼

An audio alarm sounded every 30 minutes during the night to increase arousals from sleep.

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References

  1. 1.Narvaez G, Gonzales JU. "The impact of acute sleep fragmentation on muscle blood flow responses to handgrip exercise.." Journal of applied physiology (Bethesda, Md. : 1985), 2026. PMID: 42566231 DOI: 10.1152/japplphysiol.00509.2026
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