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Objectives To examine the thermoregulatory and fluid‐electrolyte responses of firefighters ingesting ice slurry and carbohydrate–electrolyte solutions before and after firefighting operations. Methods Twelve volunteer firefighters put on fireproof clothing and ingested 5 g/kg of beverage in an anteroom at 25°C and 50% relative humidity (RH; pre‐ingestion), and then performed 30 minutes of exercise on a cycle ergometer (at 125 W for 10 minutes and then 75 W for 20 minutes) in a room at 35℃ and 50% RH. The participants then returned to the anteroom, removed their fireproof clothing, ingested 20 g/kg of beverage (post‐ingestion), and rested for 90 minutes. Three combinations of pre‐ingestion and post‐ingestion beverages were provided: a 25℃ carbohydrate–electrolyte solution for both (CH condition); 25℃ water for both (W condition); and a −1.7℃ ice slurry pre‐exercise and 25℃ carbohydrate–electrolyte solution post‐exercise (ICE condition). Results The elevation of body temperature during exercise was lower in the ICE condition than in the other conditions. The sweat volume during exercise was lower in the ICE condition than in the other conditions. The serum sodium concentration and serum osmolality were lower in the W condition than in the CH condition. Conclusions The ingestion of ice slurry while firefighters were wearing fireproof clothing before exercise suppressed the elevation of body temperature during exercise. Moreover, the ingestion of carbohydrate–electrolyte solution by firefighters after exercise was useful for recovery from dehydration.

Two kinds of 3D printers were developed in our group. One is bathtub-type gel printer named SWIM-ER. The other is ink-jet-type food printer named E-CHEF NO.1. Using Meso-Decorated gels and agar, 3D printing of the soft materials was carried out. The valve of blood vessel, which is difficult to build by soft materials, is printed successfully by SWIM-ER. Their dimensions became almost the same as the designed. We also succeeded in printing food by E-CHEF NO.1, while a few bubbles are found in the sample.

The market of care food is growing for aging society and the personal version of care food will be needed for improving a fun of meal. On this occasion, 3D printing technologies have been developed and are being applied for food creation. In the present study, we prepare food ink for the world-first 3D gel printer designed by our group. The hardness of food is one of the most important factors that influence the texture of food. So that the jelly foods made by the 3D gel printer is designed being soft and easy to chew. Here four kinds of jelly food samples are prepared by using agar and gelatin as gelation agents. The mechanical strength of the jelly foods is evaluated by a compression test for foods. We measured the hardness (maxmum stress) of the jelly foods and succeeded in the preparation of various jelly foods of 8 ~ 45kPa in hardness. The gelation of agar is possibly controlled by temperature change. Thus by using the temperature change, the jelly foods are easily printed by the 3D gel printer. We hope these printed jelly foods will make it possible for elder persons to enjoy their fun of everyday meal and improve the quality of life for the elder persons.