Research Background and Objectives
In ancient Japan, warm stones ("onjaku") were used to warm the body during cold weather. Onjaku retains heat well and is considered the prototype of modern portable heat pads. Talc, pagodite, serpentinite, and hornblende were suitable for this purpose. We created arm supporters from serpentine-containing fibers and examined their effectiveness and safety.
Participants and Methods
Participants were young, healthy Japanese adults who were asked to enter a 25 °C room and stay there for approximately 30 min. The arm support was worn for 30 min, and we measured forearm temperature and the median venous vessel diameter of the forearm before and after wearing the arm support. Data are presented as means ± standard errors. A p < 0.05 indicated statistical significance. All research experiments were approved by the Ethics Committee of Komatsu University (approval number IRIN2219-2).
Results
We recruited ten Japanese female undergraduate students (age: 20.3 ± 0.2 years, body mass index: 20.4 ± 0.6 kg/m2). No adverse events, such as burning, redness, and swelling, or complaints of discomfort occurred during or after the 30-min period where the arm support was worn. We observed significant increases in forearm temperature (32.47 ± 0.29 °C to 34.59 ± 0.32 °C) and in median venous vessel diameter (2.65 ± 0.2 mm to 3.56 ± 0.14 mm) while the arm supporter was worn.
Discussion
Warming devices, such as modern disposable heat pads, often lead to burns and dermatitis. In this study, we used non-self-heating arm supports, which are considered extremely safe. Wearing the serpentine-containing arm supports for 30 min did not cause any adverse events, thus demonstrating their safety.
Moreover, we observed an increase in skin temperature and dilation of the median vein owing to the use of arm supports. Because the median vein is usually targeted during blood collection and infusion, increasing venous dilation might be beneficial for collecting blood or placing an intravenous line. Our novel, serpentine-containing arm supports have the potential for implementation in clinical practice.
Conclusion
Our results confirm the heat retention properties and safety of serpentine-containing arm supports.