Depression and anxiety disorders are two common mental health conditions worldwide. College students are considered a high-risk population for the development of these conditions. Improved cardiorespiratory fitness (CRF) has been shown to decrease depression and anxiety risk, symptoms, and severity but this relationship and the extent to which improved CRF can reduce these risks has yet to be examined in the college student population. Validated and reliable non-exercise estimated cardiorespiratory fitness (eCRF) algorithms could be used to identify relationships and associations with depression and anxiety severity levels among college students. The purpose of this study was to assess eCRF and its association with depression and anxiety from a sample of college students. The specific aims of this study were to (1) assess the association of a non-exercise estimated cardiorespiratory fitness algorithm with depression in college students, (2) assess the association of a non-exercise estimated cardiorespiratory fitness algorithm with anxiety in college students, (3) determine which college student demographic and performance variables are significant predictors of depression scores, (4) determine which college student demographic and performance variables are significant predictors of anxiety scores, and (5) evaluate the agreement between self-reported and laboratory-measured variables of the non-exercise estimated cardiorespiratory fitness algorithm.

During the spring semester of 2023, a total of 44 students attending a large, diverse, southwestern university visited the Sports Injury Research Center on the University of Nevada, Las Vegas (UNLV) campus and completed a questionnaire and laboratory data collection. The questionnaire included demographic and student status information, anthropometric variables, the frequency, duration, and intensity of weekly physical exercise, and responses to questions from a validated depression instrument (Patient Health Questionnaire (PHQ-9)) and anxiety instrument (Generalized Anxiety Disorder (GAD-7)). The laboratory data collection included participant anthropometric variables measured by a research technician, height, weight, waist circumference, and resting heart rate. The relationship between depression, anxiety, and fitness was assessed using results from the PHQ-9, GAD-7, and a validated non-exercise eCRF algorithm. To investigate the associations between eCRF with depression and anxiety, parametric tests using the independent samples t-test were conducted. Conversely, non-parametric tests using the chi-square test of independence test were also conducted. To identify potential predictors of depression and anxiety, linear regression and multiple regression analyses were performed. Lastly, to evaluate and quantify the level of agreement and differences between two methods for obtaining variables to be calculated within the eCRF algorithm, a Bland Altman Analysis was conducted. There were no statistically significant findings among all analyses including 1) assessment of the association of eCRF with depression, 2) assessment of the association of eCRF with anxiety, 3) determination of relationships and potential predictors of PHQ-9 and GAD-7 scores, and 4) evaluation of the level of agreement between self-reported and laboratory-measured variables of eCRF algorithm. However, moderately strong effect sizes were found for associations between depression and anxiety severity levels with independent variables including 1) eCRF, 2) sex, 3) sexual orientation, 4) race, and 5) class standing. The results from the Bland Altman Analysis indicated no significant differences between the two methods for obtaining variables calculated within the eCRF algorithm, suggesting acceptable use of selfreported variables for the non-exercise algorithm. Further evidence is needed to support improvements in CRF to have a significant association with antidepressant and antianxiety effects among college students.