Submaximal 2-day cardiopulmonary exercise testing to assess exercise capacity and [PESE] in people with long COVID 2025 Thomas et al

[Andy]

Full title: Submaximal 2-day cardiopulmonary exercise testing to assess exercise capacity and post-exertional symptom exacerbation in people with long COVID.

Abstract​

Long COVID has a complex pathology and a heterogeneous symptom profile that impacts quality of life and functional status. Post-exertional symptom exacerbation (PESE) affects one-third of people living with long COVID, but the physiological basis of impaired physical function remains poorly understood.

Sixty-eight people (age (mean ± SD): 50 ± 11 years, 46 females (68%)) were screened for severity of PESE and completed two submaximal cardiopulmonary exercise tests separated by 24 h. Work rate was stratified relative to functional status and was set at 10, 20 or 30 W, increasing by 5 W/min for a maximum of 12 min.

At the first ventilatory threshold (VT1), V̇O2 was 0.73 ± 0.16 L/min on Day 1 and decreased on Day 2 (0.68 ± 0.16 L/min; P = 0.003). Work rate at VT1 was lower on Day 2 (Day 1 vs. Day 2; 28 ± 13 vs. 24 ± 12 W; P = 0.004). Oxygen pulse on Day 1 at VT1 was 8.2 ± 2.2 mL/beat and was reduced on Day 2 (7.5 ± 1.8 mL/beat; P = 0.002). The partial pressure of end tidal carbon dioxide was reduced on Day 2 (Day 1 vs. Day 2; 38 ± 3.8 vs. 37 ± 3.2 mmHg; P = 0.010). Impaired V̇O2 is indicative of reduced transport and/or utilisation of oxygen. V̇O2 at VT1 was impaired on Day 2, highlighting worsened function in the 24 h after submaximal exercise. The data suggest multiple contributing physiological mechanisms across different systems and further research is needed to investigate these areas.

Highlights​

• What is the central question of this study?
  
  Can a submaximal 2-day cardiopulmonary exercise test (CPET) protocol suggest why people living with long COVID experience post-exertional symptom exacerbation (PESE)?
• What is the main finding and its importance?
  
  A submaximal 2-day CPET protocol revealed a reduction in oxygen uptake, oxygen pulse and partial pressure of end tidal carbon dioxide, suggesting dysfunctional oxygen transport, utilisation or both may contribute to long COVID PESE. Provided that there are appropriate and detailed screening processes that exclude people living with moderate–severe-risk post-exertional malaise, submaximal CPET offers a safe and informative option to investigate long COVID pathophysiology.

Open access

 

[Trish]

I'm puzzled by their use of the terms PESE and PEM to mean possibly different things.

 

[InitialConditions]

I'm puzzled by their use of the terms PESE and PEM to mean possibly different things.

I've seen this elsewhere online with people stating that PEM is unique to ME/CFS whereas PESE is a more general feature of other conditions.

However, scanning this paper, I'm not even sure that's what the authors are doing as they've not clearly stated that they are two different things, and in fact 'PESE/PEM' is used throughout the paper. It's all a bit confused.

 

[Utsikt]

The only included the healthier patients:

Exclusion criteria comprised the following: <18 years of age, admitted to or received treatment from intensive care units, unconfirmed COVID-19 test or no retrospective clinician diagnosis, no confirmed long COVID diagnosis from a healthcare professional, reporting a grade 0 or 1 on the Post-COVID-19 Functional Status (PCFS) scale, and reporting a 3 or 4 for symptom frequency and severity on the DePaul symptom screening questionnaire (Cotler et al., 2018).

They were supposed to use an app for tracking symptoms, but it didn’t really work for technical reasons:

2.4.2 Symptom app reporting​

A mobile device app developed by Sheffield Hallam University was used daily to report symptom severity and overall health a week prior to CPET Day 1, and for a week following CPET Day 2. Participants were asked to rate their overall health on a 0–100 scale (100 = best health, 0 = worst health), and the severity of several commonly associated long COVID symptoms such as fatigue, breathlessness, and difficulty thinking on a 0–100 scale (100 = high severity, 0 = symptom not present).

Symptom app data​

Nineteen participants provided responses via the mobile symptom app. Forty-nine participants did not use the symptom app due to technical issues and non-compliance with reporting symptoms. No adverse responses were reported or identified during the 7-day symptom-reporting and there were no differences in individual symptom severity between baseline and 7 days post-CPET Day 2. Overall health had decreased 7 days post-CPET Day 2 compared with baseline; however, this was non-significant when Bonferroni corrected (Day 1 vs. Day 2 [n = 19]; 46 ± 11% vs. 41 ± 16%; P = 0.027).