Cardiopulmonary examinations of athletes returning to high-intensity sport activity following SARS-CoV-2 infection

Babity M, Zámodics M, König A, et al. Cardiopulmonary examinations of athletes returning to high-intensity sport activity following SARS-CoV-2 infection. Scientific Reports. 2022;12(1). doi:10.1038/s41598-022-24486-x

Link to Original Article: https://www.nature.com/articles/s41598-022-24486-x

- The study evaluated the long-term effects of SARS-CoV-2 infection on athletic performance in 165 asymptomatic elite athletes.

- The athletes underwent cardiopulmonary exercise testing (CPET) after returning to maximal-intensity training following their infection.

- The majority of athletes had satisfactory fitness levels during CPET, achieving high heart rates, maximal oxygen uptake, and ventilation.

- Some athletes experienced exercise-induced arrhythmias, ST-depression, hypertension, slightly elevated pulmonary pressure, and troponin increase.

- Among athletes with previous CPET data, exercise capacity increased in most athletes after SARS-CoV-2 infection, but decreased in a few athletes.

- Some athletes with ongoing symptoms or cardiac abnormalities were diagnosed with myocarditis, ischemic heart disease, anomalous coronary artery origin, and arrhythmias.

Introduction

Short-term effects of Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) showed athletes had mild to moderate symptoms of COVID-19 while some athletes showed serious complications, including myocarditis, thromboembolism, severe pneumonia, and sudden death. Initial return-to-sport protocols included ECG, cardiac torponin level, and echocardiographic examinations, but later literatures revealed the occurrence of severe cardiac involvement to be rare. As a result, a thorough examination for athletes was deemed unneccessary for asymptomatic or mild-symptomatic athletes. However, moderate-to-severe COVID-19 negatively affected vital organs and fitness level 2 to 3 months after the initial infection. This research studied the long term alterations in physic al fitness and the probable time interval until re-achieving the peak-performance of the athletes after the initial diagnosis of COVID-19.

Methods

The Methods section of the research paper describes the study design and procedures for a one-year investigation into the cardiac effects of SARS-CoV-2 infection in athletes. A total of 183 athletes who had experienced a SARS-CoV-2 infection were included in the study, with asymptomatic elite athletes and those with positive findings or ongoing symptoms invited to participate. Athletes with known cardiovascular diseases or musculoskeletal symptoms were excluded. The participants underwent cardiology control examinations and cardiopulmonary exercise testing (CPET) at least 2-3 weeks after their infection and again 2-4 months later. Prior to the study, informed consent was obtained, and ethical approval was received. Various assessments were conducted, including physical examinations, ECGs, blood pressure measurement, cardiac enzyme level measurement, echocardiography, and CPET on a treadmill. Anaerobic threshold and blood lactate levels were also determined. Statistical analyses were performed to evaluate the data. The researchers also noted that additional examinations were conducted for some athletes based on previous CPET data or indications from pre-infection examinations.

Results

Results of asymptomatic elite athletes

In this study, 165 asymptomatic elite athletes were analyzed to assess the effects of SARS-CoV-2 infection. The athletes were predominantly male, with an average age of 20 years and trained for 16 hours per week. The analysis was conducted approximately 93.5 days after the initial signs of infection and after 21 days of training cessation. During the acute phase, 17% of the athletes were asymptomatic, 82.4% experienced mild symptoms, and only 0.6% had moderate symptoms.

One athlete showed slightly elevated levels of high-sensitive Troponin T (hs Troponin T) four months after infection, but all other laboratory measurements and tests were negative. This elevation was considered sports-related as the levels normalized after a two-week break from training. Two athletes had slightly increased pulmonary pressure, which returned to normal in follow-up examinations.

Most of the asymptomatic athletes had satisfactory fitness levels according to cardiopulmonary exercise testing (CPET) results, with a resting heart rate of 70 BPM and a maximum heart rate of 187 BPM. The athletes achieved a maximal relative aerobic power of 50.9 ml/kg/min and reached their anaerobic threshold at 87% of their maximal values.

Overall, this study suggests that asymptomatic elite athletes can experience minimal to mild symptoms during SARS-CoV-2 infection, and most maintain satisfactory fitness levels.

Comparison of CPET results before and after a SARS-CoV-2 infection in elite athletes

In this study, the researchers compared the results of cardiopulmonary exercise testing (CPET) before and after a SARS-CoV-2 infection in 62 elite athletes. They found that after the infection, the athletes had longer exercise times, higher values of VȮ2max (maximal oxygen uptake) and ventilation, and similar maximal blood lactate levels. The athletes also had a higher heart rate ratio to the maximal heart rate and similar oxygen uptake ratio to VȮ2max at the anaerobic threshold. There was a slight decrease in maximal heart rate after the infection, but when corrected for age, this change was not significant. Additionally, no significant differences were observed in VE/CO2 slopes before and after the infection. However, some athletes experienced a decrease in exercise capacity, with more than a 10% decrease in VȮ2max compared to previous exams. Eight athletes exhibited resting or exercise-induced arrhythmias or ST-T changes, but no structural cardiac abnormalities were found. Some athletes required new antihypertensive therapy or treatment for cardiovascular pathologies discovered through further examinations. Based on the findings, the researchers recommended close follow-up and evaluation to rule out any potentially malignant arrhythmias or cardiac pathologies.

Results of athletes with positive findings or ongoing symptoms during the second visit

The section discusses the results of athletes who had positive findings or ongoing symptoms during the second visit. Out of 18 athletes, 11 were still symptomatic, with symptoms including decreased exercise capacity, palpitations, exercise-induced shortness of breath, worsening symptoms of asthma, and peripheral skin symptoms. One athlete had elevated levels of hs Troponin T without any symptoms, indicating an individual characteristic. Another athlete experienced long-standing mild chest pain, which was later determined to be a sign of previous myocarditis caused by COVID-19. A non-elite athlete with ST-depression in the precordial leads was found to have anomalous right coronary artery origin and significant coronary artery disease. An elite athlete with asthma experienced worsened symptoms and decreased exercise capacity following the infection. Another athlete had palpitations and fatigue, and multiple cardiac abnormalities were detected through testing. These cases highlight the importance of cardiology screening and early evaluation in athletes at higher risk for cardiac diseases. Further examinations, restrictions in sports activity, and follow-up were recommended for athletes with symptoms or cardiac pathologies.

Discussion

The researchers aimed to investigate the cardiopulmonary status of elite athletes after returning to maximal intensity training following a SARS-CoV-2 infection. They found that most asymptomatic elite athletes had satisfactory fitness levels more than 3 months after infection. However, 2.8% of elite athletes were still experiencing COVID-19-related symptoms. The study suggests that there is no connection between training after the first negative examinations and the presence of long-standing symptoms. Another study by Martinez et al. examined 789 athletes, 58% of whom had prior symptomatic COVID-19. They found that 0.6% had cardiac MRI findings indicating inflammatory heart disease, along with changes in troponin levels, ECG, and echocardiography. In the current study, no new onset of inflammatory heart disease was observed during the long-term follow-up, but one athlete showed evidence of previous myocarditis. The overall results suggest that cardiac involvement after asymptomatic or mildly symptomatic SARS-CoV-2 infection in athletes is rare.

Treatments

This research paper examines the effects of SARS-CoV-2 infection on elite athletes and their subsequent recovery. The study finds that in a group of asymptomatic or mildly symptomatic athletes, most athletes showed satisfactory aerobic capacity (VȮ2max) three months after the infection. Some athletes even showed an increase in exercise time, VȮ2max, ventilation, and heart rate at anaerobic threshold compared to their pre-infection measurements. The paper also highlights the findings of other studies that support these results, with no major alterations in cardiac or pulmonary function observed in asymptomatic athletes after recovering from SARS-CoV-2 infection. However, there were some cases where a decrease in fitness values was observed, exceeding the expected decrease from detraining. The authors recommend conducting routine cardiac and exercise stress testing in elite athletes, especially after infections like SARS-CoV-2, to reduce the risk of sudden cardiac death. The paper acknowledges limitations such as the small sample size and the need for further long-term follow-up to assess the lasting impact of the infection on athletes' performance.

Conclusions

The study found that after more than 3 months post-infection with SARS-CoV-2, most athletes had satisfactory fitness levels and intensive sport activity was generally safe. Cardiopulmonary exercise test (CPET) results showed improvements in VȮ2max and maximal ventilation compared to pre-infection levels. However, some athletes with symptoms or positive clinical findings required further examinations and follow-up, such as arrhythmias. The percentage of long-symptomatic elite athletes and positive findings related to SARS-CoV-2 infection was low. Additionally, the detailed screening revealed significant diseases unrelated to SARS-CoV-2 infection. Overall, asymptomatic athletes can safely continue their training after COVID-19 infection with appropriate cardiovascular examinations. With well-designed training plans, most athletes achieved good exercise fitness within three months, and the infection did not have long-term restrictions on their sports career.

Opportunities for Future Research

1. Investigate the long-term effects of SARS-CoV-2 infection on athletic performance by conducting longitudinal studies that follow athletes for an extended period of time (e.g., 6 months to 1 year) after recovery from the infection.

2. Explore the prevalence and impact of exercise-induced arrhythmias and ischemic heart disease in athletes who have returned to maximal-intensity training after SARS-CoV-2 infection.

3. Examine the role of cardiac troponin level measurements and echocardiographic examinations in the assessment and monitoring of athletes after SARS-CoV-2 infection.

4. Investigate the relationship between COVID-19 symptoms and changes in exercise capacity in athletes, with a focus on understanding the factors that contribute to long-term symptoms and decreased training capacity.

5. Assess the cardiovascular status of athletes with ongoing minor long post-COVID symptoms, pathological ECG findings, or laboratory abnormalities, to identify potential cardiac pathologies that may require further examination, treatment, or follow-up.

6. Conduct comparative studies to evaluate the impact of different training phases (e.g., off season, preparation period, peak performance) on the cardiopulmonary status and fitness levels of athletes after SARS-CoV-2 infection. This could provide insights into optimal training strategies for athletes recovering from the infection.