Body Temperature Regulation, Cold Exposure, Thermal Comfort Perception
Conditions
Keywords
Skin Temperature, Infrared Thermography (IRT), Thermal Sensation, Local Cooling
Brief summary
This randomized, parallel-group study looked at how a standard 15-minute ice pack applied to the back of the hand affects skin temperature and how cold and comfortable the hand feels, compared with a room-temperature water pack. Healthy young men were randomly assigned to one of the two groups during a single laboratory visit. Skin temperature was measured before, during, and after the application, and participants rated their thermal sensation (how cold/warm they felt) and overall comfort. The main outcome was the change in hand skin temperature right after the 15-minute application. Additional outcomes included comfort and cold-feeling ratings and how quickly skin temperature returned toward baseline during recovery. This was a minimal-risk study; expected short-term effects included temporary cold, numbness, redness, or mild discomfort. No medicines or invasive procedures were used.
Interventions
OTHERIce Pack (Localized Cryotherapy)
Single 15-minute application of a reusable plastic Mueller ice bag (Ø 22.86 cm, 946 mL). The bag was filled with 400 g pre-portioned cylindrical ice and placed on the dorsal side of the dominant hand, \ 1 cm proximal to the wrist-joint line, fully covering the fingers. Participants were supine with the treated hand slightly elevated; ambient temperature and humidity were controlled (≈22.5 ± 1.0 °C; 55.3 ± 6.5% RH). Subjective thermal sensation/comfort (and pain) were recorded at minutes 7 and 15 during application. Arm: Experimental - Ice Pack
OTHERThermoneutral Water Pack (Control)
Identical 15-minute application using the same Mueller bag, filled with thermoneutral water (within ±0.5 °C of limb skin temperature), mass-matched to 400 g. Placement, posture, room conditions, and timing of subjective assessments (minutes 7 and 15) mirrored the experimental arm: bag on the dorsal side of the dominant hand, \ 1 cm proximal to the wrist-joint line, fully covering the fingers; participants supine with the hand slightly elevated. Arm: Active Comparator - Thermoneutral Water Pack.
Sponsors
Poznan University of Physical Education
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Outcomes Assessor)
Masking description
Blinding of outcomes assessors only. Thermographic image analysis and statistical analyses were performed by personnel not involved in data collection and blinded to group assignment; data were labeled by study ID without treatment identifiers. Participants and intervention administrators were unblinded due to perceptible cooling
Eligibility
Sex/Gender
MALE
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* Healthy male volunteers (university student population). * Good general health with no history of neck or upper-quadrant pain. * Able to provide written informed consent. * Willing to comply with pre-visit restrictions on the study day (abstain from tobacco, coffee, alcohol; no hand ointments for 24 h; wash/degrease hands ≥1 h before testing; refrain from vigorous exercise/physical treatments for 24 h).
Exclusion criteria
* Diabetes * Thyroid or other endocrine dysfunction * Significant spinal pain * Generalised neurological or rheumatological disorders * Regular use of pain medications or psychotropic medications
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Minimum dorsal-hand skin temperature during rewarming (IV-X), by infrared thermography | From immediately after pack removal (0 minutes; time point IV) to 30 minutes after pack removal (time point X). | Region-of-interest (ROI) mean skin temperature (Tsk; °C) on the dorsal hand measured with infrared thermography (IRT; FLIR SC640). The primary estimand is the between-group mean difference (Ice - Thermoneutral) in the nadir (minimum) across rewarming time points IV-X, with 95% confidence intervals (CI). Lower values indicate greater cooling. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Mechanical Detection Threshold (MDT) from baseline to immediately post (I → IV) | Baseline (after acclimatisation; time point I) and 0 minutes after ice-pack removal (time point IV). | MDT (g) via Semmes-Weinstein monofilaments using an up-down procedure; analysed as IV - I. Higher values indicate reduced tactile sensitivity. |
| Change in Vibration Detection Threshold (VDT) from baseline to immediately post (I → IV) | Baseline (after acclimatisation; time point I) and 0 minutes after ice-pack removal (time point IV). | VDT using a 64-Hz Rydel-Seiffer tuning fork (0-8/8 scale); analysed as IV - I. Higher values indicate reduced vibration sensitivity. |
| IRT-RT temperature offset at matched time points I-X | Baseline (after acclimatisation) and at 0, 5, 10, 15, 20, 25, and 30 minutes after ice-pack removal. | Difference between infrared-thermography-derived skin temperature (TskIRT) and resistance temperature detector-derived skin temperature (TskRT), in degrees Celsius (°C), at each matched time point (I-X). IRT values represent ROI averages; resistance temperature (RT) values are point skin temperature readings from a RTD placed between the 3rd and 4th metacarpal bones. Positive values indicate that TskIRT is greater than TskRT. Between-group comparisons across time. |
| Thermal Comfort (CS) during cooling and immediately post | Baseline (after acclimatisation; time point I), 7 minutes after ice-pack application (time point II), 15 minutes after ice-pack application (time point III), and 0 minutes after ice-pack removal (time point IV). | 5-point comfort scale (1 comfortable … 5 extremely uncomfortable) at I-IV; peak during cooling prespecified as the maximum at II or III. |
| Pain Intensity (Visual Analogue Scale; VAS) during cooling and immediately after ice-pack removal | Baseline (after acclimatisation; time point I), 7 minutes after ice-pack application (time point II), 15 minutes after ice-pack application (time point III), and 0 minutes after ice-pack removal (time point IV). | 0-100 mm visual analogue scale; peak during cooling prespecified as the maximum at II or III. |
| Thermal Sensation (TSS) during cooling and immediately post | Baseline (after acclimatisation; time point I), 7 minutes after ice-pack application (time point II), 15 minutes after ice-pack application (time point III), and 0 minutes after ice-pack removal (time point IV). | 9-point TSS (-4 very cold … +4 very hot) at I-IV; peak during cooling prespecified as the maximum at II or III. Between-group comparison of peak and trajectory. |
Countries
Poland
Outcome results
None listed