Effects of COVID-19 infection on maximal oxygen consumption, gas exchange, and substrate oxidation in young adults who are overweight or obese

Introduction: The impact of COVID-19 on maximal oxygen consumption (V̇O2max), gas exchange, and substrate oxidation in individuals who are overweight or obese remains uncertain and warrants investigation. Objective: To investigate the effects of prior COVID-19 infection on V̇O2max, gas exchange, and substrate oxidation in overweight and obese young adults. Methodology: Ninety young men and women who were overweight or obese were enrolled in the study and divided into two groups: those previously infected with COVID-19 (COVID) and those with no history of COVID-19 infection (NCOVID). Anthropometry, resting heart rate (RHR), blood pressure, and health questionnaire data were collected. V̇O2max, oxygen consumption (V̇O2), estimated fat oxidation (FO), carbohydrate oxidation (CHO), respiratory exchange ratio (RER), and minute ventilation (V̇E) were assessed during an incremental treadmill V̇O2max test. Differences between the groups were assessed using paired and independent sample t-tests. Associations between the parameters were examined using the Pearson product-moment correlation coefficient. Results: Among the women, the V̇O2, V̇CO2, CHO, FO, and RER peaks were significantly different in the COVID group compared with the NCOVID group (all, p < .05). There was no statistically significant difference in V̇O2max between the COVID and NCOVID groups. However, in both groups V̇O2max differed significantly by sex, with higher values in the men than women. In the men, V̇O2max, V̇O2, and V̇CO2 were correlated with the participants’ body mass, BMI, and exercise frequency. In the NCOVID group, RHR was found to be moderately correlated with V̇O2max, V̇O2, V̇CO2, and V̇E in the men, while in the NCOVID women, V̇CO2 was associated with the RHR, exercise frequency, and exercise duration. Conclusion: Women who were overweight or obese and who had a history of COVID-19 infection exhibited altered gas exchange and substrate oxidation responses during maximal exercise compared with their never-infected peers, despite showing no difference in V̇O2max.