Thermography-derived Skin Temperature Metrics Reflect Physiological And Perceptual Recovery

Monitoring recovery following fatiguing exercise requires tools that are sensitive to both physiological and perceptual stress while remaining practical for applied settings. Infrared thermography has emerged as a promising, non-invasive technique, yet its association with established recovery outcomes has not been fully elucidated. PURPOSE: To investigate the association between thermography-measured skin temperature with physiological and perceptual recovery metrics. METHODS: Eight recreationally active individuals (mean ± standard deviation; age: 29 ± 5yrs, height: 174.3 ± 7.7, weight: 72.5 ± 7.1kg) completed a whole-body fatiguing exercise protocol with either pre-exercise sauna, post-exercise sauna, or no sauna bathing in a randomized and counterbalanced order. Recovery was assessed at baseline and 24-, 48-, and 72-hours post-exercise using physiological testing (range of motion [ROM], Landing Error Scoring System [LESS], bilateral and unilateral counter-movement jumps [CMJ], and a lactate threshold [LT] test) and perceptual measures (Fatigue and Soreness Visual Analog Scales [VAS] and Short Recovery and Stress Scale [SRSS]). Whole-body front-and-back thermographic images were captured at each time point, quantifying right-left average asymmetries (RLAsy), absolute average asymmetry (AbsAsy), global temperature (GbT), and a whole-body asymmetry quantity and severity measurement (TRI). Linear mixed-effect models were used to examine associations between recovery outcomes and thermography variables, with subject as a random effect to account for repeated measures and intervention as a fixed effect. RESULTS: For physiological measures, hip flexion asymmetry was negatively associated with GbT (estimate=-1.268, p=0.045). For perceptual outcomes, Emotional Balance was positively associated with GbT (estimate=0.281, pCONCLUSION:Thermographic surface temperature measures were significantly associated with both physiological and perceptual recovery measures, supporting the potential use of thermography as a complementary measure for assessing recovery status.