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Wearable HRV monitoring indicates autonomic dysfunction and delayed sympathovagal recovery after exercise above VT1 in long COVID patients, suggesting increased risk of post-exertional malaise.

Continuous multi-day HRV recordings showed lower HRV in long COVID patients compared to healthy controls during daily activities and sleep (p=0.027). Nighttime HRV decreased with intense exercise and longer durations in patients (p=0.018), indicating exercise-induced autonomic disturbances. The delayed recovery of sympathovagal balance after exercise close to and above VT1 suggests that the risk of PEM rises above this threshold.

Last updated: Jul 28, 2026•0 RCTs•📖 Read as article →

Evidence Score

Evidence Score32/100
Human RCT☆☆☆☆☆
Meta-analysis☆☆☆☆☆
Mechanism★★★★★
Safety★★★★☆
Confidencelow

Study Evidence

Study 1. Wearable Heart Rate Variability Monitoring, Autonomic Dysfunction and Post-exertional Malaise in Long COVID: An Observational Study.

observational

Ruijgt TM, Slaghekke A, Ellens A, Janssen KW, Wüst RCI · Sports medicine (Auckland, N.Z.) (2026)

Participants: N/A
Duration: Multi-day continuous monitoring with single exercise test
Intervention: Continuous wearable HRV monitoring during daily activities and after (sub)maximal cardiopulmonary exercise testing to determine heart rate at VT1.
Outcome: Heart rate variability (HRV) during daily activities, sleep, and 24 hours post-exercise at various intensities relative to VT1.
Effect Size: N/A
Population: 121 patients with long COVID (mean age 43±11 years, 32% male) and 21 healthy controls (mean age 42±13 years, 48% male).

Result:

PubMed: 42501245DOI: 10.1007/s40279-026-02487-4

Mechanism Graph

Long COVID patients have lower baseline HRV indicating autonomic dysfunction.
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Exercise close to or above VT1 further reduces HRV in patients.
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Nighttime HRV decreases after intense or prolonged exercise in patients.
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Delayed recovery of sympathovagal balance increases risk of post-exertional malaise.

Limitations

  • ⚠Small sample size of healthy controls (n=21) relative to patient group (n=121).
  • ⚠Observational design cannot establish causality between HRV changes and PEM.
  • ⚠Potential confounding by daily activity differences not fully controlled.

Frequently Asked Questions

What is the main finding of this study?▼

The study found that long COVID patients have lower heart rate variability (HRV) than healthy controls, and after exercise near or above the first ventilatory threshold, their HRV remains lower for 24 hours, suggesting autonomic dysfunction and increased risk of post-exertional malaise.

How was HRV measured in this study?▼

HRV was continuously measured using wearable devices over multiple days in 121 long COVID patients and 21 healthy controls, with daily activities tracked in a logbook.

What is the significance of the first ventilatory threshold (VT1) in this context?▼

VT1 marks the exercise intensity at which the risk of post-exertional malaise (PEM) appears to increase in long COVID patients, as HRV recovery is delayed above this threshold.

Can wearables help manage long COVID symptoms?▼

Yes, the study suggests that wearable HRV monitoring can assess autonomic function and help patients avoid overexertion by identifying exercise intensities that lead to prolonged autonomic disturbances.

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References

  1. 1.Ruijgt TM, Slaghekke A, Ellens A, Janssen KW, Wüst RCI. "Wearable Heart Rate Variability Monitoring, Autonomic Dysfunction and Post-exertional Malaise in Long COVID: An Observational Study.." Sports medicine (Auckland, N.Z.), 2026. PMID: 42501245 DOI: 10.1007/s40279-026-02487-4
Disclaimer: This content is for educational purposes only and is not medical advice. Evidence scores reflect the quality and quantity of available research, not clinical recommendations. Always consult a healthcare professional before starting any supplement or intervention.