Effects of ice-pack application on hand skin temperature and subjective thermal sensation and comfort in healthy young men: a randomised, parallel-group controlled trial

Ice packs are widely used in sports medicine and acute care, yet few studies have concurrently quantified objective hand skin cooling and subjective responses (thermal sensation, thermal comfort and pain) during and after a typical clinical application. Immediate post-cooling changes in somatosensory thresholds (e.g., mechanical detection threshold [MDT], vibration detection threshold [VDT]) are also sparsely characterised. In addition, heterogeneous protocols/outcomes limit comparability across studies. To determine the effects of a standardised 15-min ice-pack application on hand skin temperature (Tsk) and on thermal sensation, thermal comfort and pain intensity in healthy young men, and to examine immediate post-cooling changes in mechanical and vibration detection thresholds. In a randomised, parallel-group superiority trial (1:1), thirty-nine healthy male participants (mean age 23.0 ± 1.4 years; BMI 24.9 ± 2.7 kg/m 2 ) were allocated to an experimental group (n = 20; ice pack) or a control group (n = 19; thermoneutral water pack). The prespecified primary endpoint was the nadir dorsal-hand skin temperature during rewarming (time points IV-X) measured by infrared thermography (ROI mean), analysed as the between-group mean difference with 95% CI. Hand Tsk was also tracked with resistance thermometry; subjective outcomes were assessed with validated scales; quantitative sensory testing (QST) endpoints included MDT and VDT. Cooling produced a marked fall in Tsk, with the experimental group reaching a minimum of 22.6 ± 2.9 °C by IRT (primary endpoint) and 17.5 ± 2.2 °C by RT; Tsk did not return to baseline within 30 min post-application (p < 0.001). Discomfort and pain intensity increased during cooling. MDT showed an immediate post-cooling change (p < 0.01), whereas VDT did not (p = 0.617). A typical clinical ice-pack application markedly lowers hand skin temperature without full recovery in the early rewarming period. Concurrently, discomfort and pain increase, mechanical detection thresholds shift, and vibration detection remains unchanged. These findings address key gaps and provide an empirical basis for individualising cryotherapy dose to balance efficacy and tolerability in clinical practice. Trial registration: ClinicalTrials.gov, NCT07254182 (retrospectively registered on 15/10/2025).