In 2020, the rapid spread of SARS-CoV-2 (COVID-19) created a global pandemic that resulted in quarantines and limited in-person contact. For undergraduate students in the United States (U.S.), this led to an unexpected cancelation of in-person classes or transition to remote, virtual learning to mitigate contraction of the highly contagious virus. Most universities returned to in-person learning, with precautions in place, during the 2021–2022 school year. Despite efforts to reduce the spread of the virus, the Centers for Disease Control and Prevention (CDC) reported over 100 million COVID-19 cases total in the U.S. at the end of 2022 (1) with college campuses serving as the grounds for super spreader incidences (2).

The coronavirus family is responsible for acute respiratory tract infections, with SARS-CoV and MERS-CoV viruses resulting in severe acute respiratory syndrome (SARS) that can lead to respiratory failure (3, 4). Common symptoms of COVID-19 present as fever, cough, fatigue, dyspnea, and sputum (5); though, the virus also impacts the cardiovascular system (6). Endothelial dysfunction, damage to the myocardium, and changes to the right and left ventricular structures result in reduced cardiovascular function leading to poor health outcomes especially in individuals with elevated cardiovascular risk factors (e.g., pre-existing cardiometabolic disease, auto-immune diseases, and cancer, etc.) (7). At least one coronary heart disease risk factor has been reported among more than one half of young adults aged 18–24 years (8). As a result, there is a need to understand the effects of acute COVID-19 infections on cardiovascular function and fitness across the college years, even in the absence of pre-existing risk factors. A review of available post-COVID-19 infection studies demonstrates a reduction in cardiorespiratory fitness (CRF) brought about by a sequelae of physiological changes, such as reduced lung diffusion of gasses, cardiac output and stroke volumes, in addition to peripheral changes in oxygen extraction and mitochondrial function (9). COVID-19 infections resulting in reduced cardiovascular function may lead to increased risk for cardiovascular disease (CVD), decreased quality of life, and increased risk of all-cause mortality throughout the lifespan. There is limited information about the impact of COVID-19 on CRF of young individuals despite evidence that COVID-19 may result in limitations in and damage to the cardiovascular system in this population.

Irrespective of the cardiorespiratory factors associated with COVID-19 infection, low CRF is associated with greater risk for all-cause mortality, CVD events, and cancer mortality in adults as well as associated with cardiometabolic risks in adolescents (10–12). A nationally representative sample in the U.S. demonstrated that only 42% of adolescents aged 12–15 years old had healthy CRF (13). Additionally, a decline in mean CRF of 0.9 mL/kg/min per decade has been reported between 1995 and 2013 in children in the U.S. aged 9–17 years (14). Physical activity is also a significant factor in the health status of children and adults, associated with cardiorespiratory fitness (15, 16). Low CRF can be prevented with lifestyle modifications, such as an increase in physical activity levels (17). In the context of college students transitioning from childhood into young adulthood, there is a reported decline in physical activity when enrolling in university (18, 19). Regular moderate-to vigorous physical activity and elevated CRF levels are promoted as preventative measures of CVD, especially with the concern of pervasive physical inactivity and sedentary behaviors worldwide (20). Since the start of the COVID-19 pandemic, patients with CVD increased sedentary time by 28% and decreased recreational physical activity by 33% (20). An early systematic review of university students of different countries reported a significant decline in physical activity levels, with a decrease in mild physical activity between 32.5 and 366% and a decrease in vigorous physical activity between 2.90 and 52.8%, during the COVID-19 pandemic when compared to pre-pandemic physical activity levels (21).

Therefore, the purpose of this study was to investigate among college freshman in the two academic years following the post-COVID lock-down: (1) differences in CRF (self-reported and measured), physical activity, anthropometrics by COVID-19 incidence; (2) associations between COVID-19 incidence and perceived CRF; and (3) to explore among those who perceived that COVID-19 incidence impacted their CRF, whether there were any differences in their measured CRF, physical activity, or anthropometrics.

First year undergraduate students (n = 151; 80% female; 18.9 ± 0.4 yrs.; 23.4 kg/m² female vs. 23.0 kg/m² male) from the 2021–2022 (n = 71) and 2022–2023 (n = 80) cohorts were included in this study and completed the FRESH Survey (Table 1). Twenty-eight (n = 28) of these students (18.9 ± 0.4 yrs.; 25.3 kg/m² female vs. 24.1 kg/m² male) also participated in the laboratory-based sub-study to measure CRF and anthropometrics. (In-person laboratory data was conducted post COVID-19 pandemic when university facilities reopened under restricted activity guidelines, which limited student participation in the laboratory portion of the study.) The study included 58.3% of participants identifying as Caucasian/White, 17.9% as Asian, 9.3% as Hispanic/Latino, 15.2% as African American/Black, and 5.3% as multiracial.

Our findings demonstrate that the majority of college students with a history of COVID-19 infection generally did not have any differences in perceived CRF, PA engagement, or weight status. Although not statistically significant, participants who had COVID-19 had lower odds of having a positive perception of their CRF compared to those never infected. Furthermore, although we hypothesized that contracting COVID-19 may have a more perceptible impact on CRF of those who are less fit and less physically active college students, students who perceive a negative impact of COVID-19 infection on their CRF are actually more physically active. Thus, detecting any negative impact of COVID-19 incidence on optimal post-infection physical activity engagement is likely affected by the pre-infection physical activity baseline and CRF perception. Those who engaged in greater physical activity are more likely to notice a change in their CRF and associated physical activity limitations post-COVID-19 contraction than those who are not as physically active and less perceptive about their aerobic fitness.

The Physical Activity Guidelines for Americans recommends that healthy adults ages 18–65 years old engage in moderate intensity physical activity for at least 30 min five days per week or vigorous intensity physical activity for at least 20 min three days per week (36). In this study, 58% of participants reported exceeding the minimum recommended weekly levels of physical activity, however, the majority of participants who completed voluntary laboratory testing were categorized as very poor to poor based on their CRF and aerobic capacity results. The discrepancy between high levels of physical activity engagement and low values of estimated maximal aerobic capacity may be attributed to participants miscalculating or overestimating physical activity engagement (37). Low levels of estimated maximal aerobic capacity may be due to participants attaining a VO₂peak rather than a VO₂max (38). Though 85% of their age-predicted maximum heart rate was achieved, the testing protocol may have captured a symptom-limited peak rather than an upper functional limit due to the limited exposure to higher intensity physical activity in this population.

The reported physical activity engagement of participants in the current study is similar to Spring 2022 data reported by the American College Health Association (ACHA), where approximately 69% of undergraduate students reported meeting the Physical Activity Guidelines for aerobic activity (39). However, the ACHA survey does not include measures or perceptions of CRF, nor does it provide stratified data by year of college enrollment (39). A discrepancy between college students’ self-reported physical activity and accelerometer-measured physical activity has been reported, with self-reported data classifying 66.7% of students as sufficiently physically active compared to accelerometer-measured data classifying only 33.8% of students as sufficiently physically active (37). Therefore regardless of reported physical activity levels, it is likely that students over report their activity levels and attention to the continued promotion of physical activity in this population is warranted. It is further noteworthy that a cohort study of adult patients at Kaiser Permanente with a positive COVID-19 diagnosis reported a higher incidence of hospitalization and poor COVID-19 outcomes among patients classified in lower physical activity engagement categories (40). Therefore, pre-infection physical activity participation may be a significant determinant in the severity of COVID-19 outcomes. Additionally, our study included a predominance of female participants (80%), potentially reducing the generalizability of our findings across genders, though the GWU student body in 2022 was predominantly women (62.3%) (24). Data collection for this study is ongoing for future research to draw stronger causal inferences about the impact of COVID-19 on CRF in a longitudinal manner.

At the time of this study, there have been over 700,000 COVID-19 cases among undergraduate students in the U.S. since the start of the pandemic (41). Data before the pandemic also indicates a high prevalence of CVD risk factors among college students, which may exacerbate the impact of COVID-19 infection in this population (8). Cardiorespiratory exercise testing research reveals that COVID-19 infection impacts the cardiorespiratory system through limitations in exercise tolerance post-contraction (42), specifically referencing depressions in cardiopulmonary responses to maximal exercise and reduced carbon monoxide diffusing capacity of the lungs (43). A decline in cardiorespiratory health due to COVID-19 infection alongside lower physical activity levels and reduced CRF, may significantly increase the risk of CVD development and incidence of cardiopulmonary-related events in younger populations (44). Symptoms of COVID-19 are exacerbated by CVD risk factors, including hypertension, diabetes, weight, and physical inactivity (45). In our research, we found that students who did not perceive a post-viral negative impact on their CRF tended to exercise less frequently and, though not statistically significant, had higher % BF via body composition measurement. The presentation of CVD risk factors that have been reported to exacerbate COVID-19 symptoms raises concern in the college student population, particularly in instances when CRF effects are not perceived. COVID-19 infection will likely increase the risk of developing CVD in the lower physical activity engagement group due to greater difficulty increasing physical activity levels post-infection. Additionally, students who did not previously have high CVD risk but increased risk factor development as a result of the COVID-19 pandemic will also expedite the likelihood of CVD development compared to others in their age group.

The impact of COVID-19 infection may be perceptually less in those who are physically inactive and who deem themselves as having lower CRF due to their lack of exposure to more challenging activities and, as a result, a limited understanding of their general CRF limitations. Concerningly, the lower CRF impact perception of COVID-19 infection in this population may have a greater and longer lasting impact on their cardiorespiratory health in the absence of recognizable symptoms or significant changes in daily life functional capacities. Post-COVID-19, a cross-sectional study of U.S. adults reported reduced physical activity engagement among previously active participants compared to no change in physical activity engagement among previously inactive participants (46). The reported associations may coincide with a perception or lack of perception of negative impacts due to COVID-19. In the context of our population throughout the COVID-19 pandemic, students likely experienced a decrease in opportunities to engage in physical activity, with campuses and recreational facilities closing, and an increase in screen time, with learning moved to a virtual format.

To our knowledge, there is limited information examining COVID-19’s impact on CRF and associated health markers (physical activity and weight status/adiposity) among college students. Other studies have examined relationships between general physical activity and fitness levels post-COVID-19, yet there is still a deficiency of information surrounding COVID-19 incidence and impact on CRF (21, 47, 48). While we utilized survey questions from several validated instruments, there are inherent limitations to self-reported data including COVID-19 incidence and health metrics, which may be potentially skewed due to participants overreporting or underreporting health markers, such as height, weight, and physical activity engagement. Our results could be strengthened by improving representation of the student body and as well as increasing the sample size of participants that participated in laboratory fitness testing. Unfortunately, laboratory testing opportunities were initially more limited due to COVID-19 restrictions, such as mask mandates and restricted in-person activity on campus, as we worked through and emerged from the pandemic. While the sample size of laboratory assessment participants was small, it is a noted strength that we collected both objective and subjective measures of CRF and weight status during the pandemic. These measures together allowed us to formulate a more comprehensive picture of how COVID-19 infection may affect CRF among college students.

Further research regarding the impact of COVID-19 incidence on college student CRF with low levels of physical activity and aerobic fitness is necessary, particularly when their perceived CRF is self-reported as healthy. Following COVID-19 infection, college students require the proper resources and knowledge to make informed decisions about optimal and safe strategies to engage or re-engage in exercise and physical activity. This is specifically vital for inactive or sedentary populations with limited exercise frequency as COVID-19 symptoms may act as another barrier, exacerbating the chronic cardiorespiratory health implications (44). Additionally, it is necessary to develop testing and programming strategies that facilitate an optimal return to physical activity and exercise for the overall population. Our research demonstrates that even participants who were physically active with above average CRF perceived a challenge when returning to physical activity post-COVID-19 infection. Our research provides data post-COVID-19 infection detailing the health experiences of first-year college students to pinpoint areas that need to be addressed with future research.

Our findings demonstrate that those who perceived greater impacts of COVID-19 incidence on CRF were more physically active. However, the lack of perceived COVID-19 infection impact on CRF by less active participants does not indicate that this population was unaffected. Though not statistically significant, participants who did not perceive an impact of COVID-19 on their CRF tended to have higher percent body fat and lower aerobic capacity compared to those who perceived a greater CRF impact. Further research examining the effects of COVID-19 incidence on perceived versus measured CRF among college students should be facilitated in larger cohorts. In this manner, the impact of COVID-19 symptoms on cardiorespiratory health must be better understood to assist with cardiovascular risk factor mitigation in college-aged populations. Additionally, information from the current study may inform public health strategies concerning post-COVID-19 infection return to activity protocols for college students to reduce long-term implications on cardiorespiratory health and provide methods to optimize return-to-activity timelines. The decision to re-engage in physical activity should be encouraged to reduce the severity of COVID-19 infection and delay the onset of CVD risk factors. In doing so, we can mitigate additional risk factors for chronic diseases, such as CVD, commonly linked to COVID-19 infection in young adults.