During the summer in Japan, it is often so hot and humid that just walking outside is enough to break out in perspiration. At night, the heat can make it difficult to get to sleep. Fortunately Japanese researchers and companies have used their ingenuity to devise a plethora of products that help to keep people comfortable even at the height of summer.

Enhancing a Natural Cooling Effect

The summer heat can make outdoor activities uncomfortable, whether it is work, gardening, or just going for a walk. This need not be the case, however, thanks to "air-conditioned" clothing that is claimed to be "cooler than having no clothes on." An air-conditioned shirt features two small fans fitted to either side of the waist. The fans draw in air, which is then blown over the surface of the body, helping sweat to evaporate. Thus, this elegant solution to summer discomfort promotes the body's natural cooling mechanism - perspiration. The battery-powered fans can be switched on and off, and the strength of the air flow can be adjusted as desired.

The system was originally developed to make workmen's clothes more comfortable in summer. Men's long- and short-sleeved shirts, as well as ladies' short-sleeved blouses, were subsequently developed for office wear. These garments are in line with the Government of Japan's "Cool Biz" campaign to promote the wearing of cool, light clothes in the workplace in order to reduce electricity consumption by room air conditioners. Scrubs for operating rooms, motorcyclists' jackets, and trousers are among the other air-conditioned garments that have been developed.

Turning Sleepless Nights into Sweet DreamsUse of this air-conditioning system is not restricted to clothes; one of the latest applications of the technology is in a mat designed to be laid over the mattress of a bed. The mat consists of sheets of soft plastic mesh layered in a manner that allows air to flow from the head end to the foot end; a fan fitted at the foot end of the mat draws a steady stream of air into the head end and out of the foot end. Like in the air-conditioned clothes, the air flow promotes the evaporation of sweat, producing a cooling effect. Even using one of the mats for eight hours a day consumes considerably less electricity than a room air-conditioner. Cushions made with this mesh material are also available. Sitting for long periods in summer can be sweaty and uncomfortable, but these air-conditioned cushions allow you to stay cool by blowing the heat away.

Meanwhile, several companies have developed bed sheets that utilize the heat-absorbing properties of xylitol, a natural sweetener, to cool the skin. The sheets are treated with a specially processed version of xylitol that absorbs heat on reacting with moisture. The heat-absorbing effect is repeated every time the skin comes into contact with the sheets, resulting in a cool feeling. When the perspiration evaporates from the xylitol its heat-absorbing effect is immediately recovered.

Odor-Busting NanotechnologyAnother summer concern is the body odor that can be generated by perspiration. People concerned about body odors can now opt to wear odor-free underwear. This product is made from a textile originally developed for use in the medical and nursing field, but which is now available for general use. The fibers of the cloth incorporate particles of a porous ceramic material with holes measuring just 500-800 nanometers across. These particles capture the odor-causing molecules in sweat which are then broken down by metallic ions. The instantaneous odor-destroying effect of this technology had already been proved in the nursing field. All that was needed to apply it in underwear was a little attention to design and color.

Garments using this technology include men's undershirts and boxer shorts, women's panties and camisoles, and unisex T-shirts, as well as bags for carrying home items such as trainers, and handkerchiefs. (October 2009)