COVID-19's Impact on Athletes: Reduced Cardiorespiratory fitness after a SARS-CoV-2 Infection.

Objective: This study aimed to identify potential changes in cardiorespiratory fitness among athletes who had previously been infected with SARS-CoV-2.

Methods: In this prospective observational multicenter hybrid study (CoSmo-S), cardiopulmonary exercise testing on treadmills or bicycle ergometers involving 2314 athletes (39.6% female) was conducted. German federal squad members (59.6%) and non-squad athletes were included in the study. 1170 (37.2% female) subjects were tested positive for SARS-CoV-2 via PCR from which we had pre-SARS-CoV-2 infection examinations available for 289 subjects. Mixed effect models were employed to analyze amongst others the following dependent variables: Power output at individual anaerobic threshold (POIAT/kg), maximal power output (POmax/kg), measured V̇O2max/kg, heart rate at individual anaerobic threshold (HRIAT) and maximal heart rate (HRmax).

Results: A SARS-CoV-2 infection was associated with a decrease in POIAT/kg (-0.123 W/kg, p < 0.001), POmax/kg (-0.099 W/kg, p = 0.002), measured V̇O2max/kg (-1.70 ml/min/kg, p = 0.050) and an increase HRIAT (2.50 b/min, p = 0.008), HRmax (2.59 b/min, p < 0.001) within the first 60 days after SARS-CoV-2 infection. Using the pandemic onset in Germany as longitudinal reference point, the healthy control group showed no change over time in these variables respectively an increase in POmax (+0.126 W/kg, p = 0.039) during the first 60 days after the reference point. Subgroup analyses showed that both squad members and endurance athletes experienced greater decreases in cardiorespiratory fitness compared to non-squad members respectively athletes from explosive power sports.

Conclusions: A SARS-CoV-2 infection is associated with a decline in cardiorespiratory fitness in athletes for approximately 60 days. Potential factors contributing to this outcome seem to be cardio-pulmonary and vascular alterations in consequence of SARS-CoV-2. A minor effect on cardiorespiratory fitness has training interruption due to acute symptoms and/or quarantine.