Daily lifestyle factors beyond hydration status may be associated with malaise risk during summer training in male collegiate lacrosse players: An exploratory prospective field study

Non-specific symptoms such as malaise, headache, nausea, dizziness, exercise-associated muscle cramps, and syncope, which are monitored in relation to exertional heat illness (EHI) but are not specific to it, may interrupt athletic participation during summer training. Prospective evidence regarding their associations with daily lifestyle, health-related, and hydration-related factors is limited. This exploratory study examined these associations in male collegiate lacrosse players. Twenty-four Division III players were monitored across 46 practice sessions over two summers (2023–2024; 187 athlete-day observations). Sleep, diet, health condition, perceived training conditions, and symptoms were assessed after each session. Urine specific gravity and pre- to post-training body mass change were measured as hydration-related indicators. Environmental conditions were evaluated using wet-bulb globe temperature (WBGT) obtained from the nearest monitoring station. Malaise was reported in 9 of 187 observations and headache in 6. Perceived mental stress showed the strongest association with malaise (odds ratio [OR], 29.55; 95% confidence interval [CI], 7.19–168.81; p < 0.001), followed by illness, sleep deprivation, sleep duration of <5 h, reduced breakfast consumption, breakfast skipping, and impaired sleep quality. Electric fan use during sleep was negatively associated with headache (OR, 0.10; 95% CI, 0.00–0.84; p = 0.031). Pre-training hypohydration was common but was not significantly associated with symptom occurrence. Symptoms were reported across maximum session WBGT values of 20.5–30.8°C. Beyond hydration status, simple pre-training assessments of perceived mental stress, sleep, and nutrition may improve early risk identification and training load adjustment. The small number of symptom events and insufficient statistical power warrant further validation in larger prospective studies.