From habits to harm: the effects of lifestyle, sleep, and fitness on injury risk in students using a structural equation modeling approach

Background University students often deal with a mix of challenges — from frequent sports and recreational injuries to habits like smoking, drinking alcohol, or consuming energy drinks, along with irregular sleep and different levels of physical activity. This study examines the links between lifestyle habits, sports participation, sleep quality, self-perceived fitness, and the likelihood of getting injured. Methods In a cross-sectional survey of 933 first-year students (mean age 20.1 ± 2.5), participants reported lifestyle indicators (cigarettes, alcoholic drinks, energy drinks), sports activity (training volume, athlete/competitive status, sport diversity), sleep quality, self-rated fitness, and the number of injuries causing class absence. Partial least squares structural equation modeling evaluated the measurement properties and the structural paths. Results Sports activity had a strong, positive association with perceived physical fitness. The interaction of lifestyle and sports activity is negatively associated with fitness, indicating that unhealthy habits attenuate sport-related fitness gains. Lifestyle was negatively associated with sleep quality, while better sleep quality positively predicted fitness. Physical fitness did not show a significant direct association with injury counts. Poorer sleep quality was associated with a higher number of injuries. Conclusion In this large student sample, sleep quality emerged as a pivotal, modifiable protector—linked positively to fitness and negatively to injury risk—whereas sports participation improved fitness, but its benefits were undermined by unhealthy lifestyle behaviours. Injury prevention efforts in student populations should therefore combine promotion of healthy lifestyle choices, sleep hygiene interventions, and safe sport practices.