Severe loss of mechanical efficiency in COVID‐19 patients

Abstract

Background There is limited information about the impact of coronavirus disease (COVID‐19) on the muscular dysfunction, despite the generalized weakness and fatigue that patients report after overcoming the acute phase of the infection. This study aimed to detect impaired muscle efficiency by evaluating delta efficiency (DE) in patients with COVID‐19 compared with subjects with chronic obstructive pulmonary disease (COPD), ischaemic heart disease (IHD), and control group (CG). Methods A total of 60 participants were assigned to four experimental groups: COVID‐19, COPD, IHD, and CG ( n = 15 each group). Incremental exercise tests in a cycle ergometer were performed to obtain peak oxygen uptake (VO 2 peak). DE was obtained from the end of the first workload to the power output where the respiratory exchange ratio was 1. Results A lower DE was detected in patients with COVID‐19 and COPD compared with those in CG ( P ≤ 0.033). However, no significant differences were observed among the experimental groups with diseases ( P > 0.05). Lower VO 2 peak, peak ventilation, peak power output, and total exercise time were observed in the groups with diseases than in the CG ( P < 0.05). A higher VO 2 , ventilation, and power output were detected in the CG compared with those in the groups with diseases at the first and second ventilatory threshold ( P < 0.05). A higher power output was detected in the IHD group compared with those in the COVID‐19 and COPD groups ( P < 0.05) at the first and second ventilatory thresholds and when the respiratory exchange ratio was 1. A significant correlation ( P < 0.001) was found between the VO 2 peak and DE and between the peak power output and DE ( P < 0.001). Conclusions Patients with COVID‐19 showed marked mechanical inefficiency similar to that observed in COPD and IHD patients. Patients with COVID‐19 and COPD showed a significant decrease in power output compared to IHD during pedalling despite having similar response in VO 2 at each intensity. Resistance training should be considered during the early phase of rehabilitation.

Decreased Fatty Acid Oxidation and Altered Lactate Production during Exercise in Patients with Post-acute COVID-19 Syndrome

“…They should provide impetus for further investigations into the molecular mechanisms linking COVID-19 to metabolic reprogramming and mitochondrial dysfunction. Our report is consistent with that by Pleguezuelos and colleagues, who also showed that patients with PACS that followed acute COVID-19 requiring admission to the ICU suffered from reduced exercise efficiency ( 10 ) and with that of Rinaldo and colleagues showing that disease severity does not impact exercise capacity in COVID-19 survivors; however, the study focused on peak values and cardiorespiratory peak values and not on metabolic/cellular adaptations as we did in our study ( 11 ).…”

From heart to muscle: pathophysiological mechanisms underlying long-term physical sequelae from SARS-CoV-2 infection

“…Data from Szekely et al are reported in L/min. Studies in figure are Baratto et al ( 66 ), Pleguezuelos et al ( 67 ), and Szekely et al ( 68 ).…”

“…Besides cardiorespiratory fitness, mechanical efficiency (i.e., the ratio between total energy expenditure and external work), may also account for some of the deleterious effects of COVID-19 hospitalization on exercise tolerance. For example, delta efficiency during cycling was significantly lower (20%) in patients with COVID-19 8 wk after hospital discharge compared to age-matched healthy controls (27%) ( 67 ). The use of short duration increments during the exercise test and the severity of the acute phase of illness (12 days in ICU) of the recruited patients should be considered when interpreting the results of this study.…”

Phenotyping long COVID

“…These results are in agreement with those of 8 previous mostly smaller studies on a total of 203 patients. (15)(16)(17)(18)(19)(20)(21)(22). When grouped together thus on a total of 581 patients, mean values of FEV 1 of 97 % predicted, DL CO of 83 % predicted, VO 2 max of 82 % predicted with an anaerobic threshold of 50 % of VO 2 max, V E /VCO 2 slope of 30, preserved breathing reserve and moderately decreased max heart rate altogether offer a CPET profile of deconditioning on the recovery of an acute inflammatory process, prolonged bed rest, and post-traumatic syndrome and depression.…”