Exertional intolerance and dyspnea with preserved lung function: an emerging long COVID phenotype?

Abstract

The COVID-19 pandemic has resulted in significant acute morbidity and mortality worldwide. There is now a growing recognition of the longer-term sequelae of this infection, termed “long COVID”. However, little is known about this condition. Here, we describe a distinct phenotype seen in a subset of patients with long COVID who have reduced exercise tolerance as measured by the 6 min walk test. They are associated with significant exertional dyspnea, reduced health-related quality of life and poor functional status. However, surprisingly, they do not appear to have any major pulmonary function abnormalities or increased burden of neurologic, musculoskeletal or fatigue symptoms.

Respiratory muscle dysfunction in long-COVID patients

“…The most commonly reported symptoms include persistent dyspnea and fatigue in up to 51% and 63% of cases, respectively, which are also among the longest lasting sequelae [ 3 , 5 ]. As recently reported, exertional intolerance and dyspnea can also be observed in Long COVID patients with preserved lung function [ 6 ]. In this light, in addition to a growing body of evidence regarding pulmonary parenchymal and cardiac sequelae, exercise intolerance in Long COVID patients might have additional causes related to respiratory muscular dysfunction.…”

The effectiveness of pulmonary rehabilitation for Post-COVID symptoms: A rapid review of the literature

“…Comparator: 213 (51) Hypertension: n = 54 (54); Intervention: 99 (100). Comparator: NR Intervention: 65 (66) Sepsis: n = 37 (37); NR Smokers or Ex-Smokers: n = 27 (27); Delirium: n = 36 (35); Adiposities: n = 25 (25); ARDS severe: n = 27 (27); Musculoskele-tal disease: n = 25 (25); ICU acquired weakness: n = 24 (24); Dyslipidemia: n = 20 (20.2); Anemia: n = 24 (24); Neurological disease: n = 20 (20); Electrolyte disturbance: n = 18 [ 18 ]; Chronic renal failure: n = 19 (19); Acute renal failure: n = 14 [ 14 ]; Coronary artery disease: n = 18 (18.2); Atrial Fibrillation: n = 13 [ 13 ] Malignancy: n = 15 [ 15 ]; Myocarditis 12 [ 12 ] COPD: n = 11 [ 11 ] Tozato (2021) Brazil Case series 4 Range: 43-72 2 (50) Hypertension: n = 3 (75); 4 (100) 2 (50) Kidney injury: n = 1 (25) Dyspnea: n = 3 (75); Previous smoker: n = 1 (25); Fatigue: n = 1 (35); HIV: n = 1 Tetraparesis: n = 1 (25); Prostate cancer: n = 1 (25) Cardio-respiratory deficits: n = 1 (25) a Numbers or proportions not reported; COPD: chronic obstructive pulmonary disease; COVID-10: Coronavirus Disease 2019; CPAP: continuous positive airway pressure; NR: not reported; PR: pulmonary rehabilitation; SD: standard deviation. …”

“…Further, patients with post-COVID symptoms may have different rehabilitation needs compared to the usual patients participating in PR. For instance, some COVID-19 survivors experience persistent dyspnea and diminished exercise capacity, despite no substantial impairment in pulmonary function [ 18 ]. While the need for post-COVID rehabilitation is recognized, PR may not be the solution and differences in presentation between post-COVID and chronic respiratory patients suggest value in a more specific “post-COVID rehabilitation”.…”

Impaired systemic oxygen extraction long after mild COVID-19: potential perioperative implications

“…But how does this affect that relatively young person who admits to being sedentary and unfit but has no objective evidence of cardiopulmonary disease, and whose only other notable medical history is mild COVID-19 a year earlier? A recent report proposed the existence of a specific “long COVID phenotype” with exertional intolerance and dyspnoea despite normal pulmonary function 11 , raising the question of whether there is more to this patient than meets the eye.…”