Objective: In the present study, we investigated the effects of enveloping-airflow air conditioner on health maintenance and fatigue in healthy volunteers. The enveloping airflow is that of gently holding the whole room space along the ceiling, wall, and floor.
Design: In a randomized placebo-controlled crossover trial, 10 healthy women who had feeling cold, stiff shoulder and knee pain very often under air conditioner working, participated in the study. They performed fatigue-inducing desk work for 2 hours, and rested for 30 minutes in the air conditioned room controlled by enveloping airflow or direct airflow.
Methods: We evaluated subjective sensation by Visual Analogue Scale (VAS), peripheral blood flow by laser-Doppler flowmetry, and body temperature.
Result: The enveloping airflow prevented hypothermia, increased blood flow, moreover attenuated feeling of cold, knee pain and fatigue, increased sensation of comfort as compared with the direct air flow.
Conclusion: Enveloping-airflow air conditioner is effective in maintaining health and attenuating fatigue.

Objective Enveloping airflow, as opposed to direct airflow, warms the room by gently circulating the airflow along the floor, wall, and ceiling, thereby uniformly warming the entire room. The objective of our study was to determine the effects of air-conditioned heating by enveloping-airflow on sense of fatigue and comfort in healthy volunteers.
Design Eight healthy women, who often felt discomfort in an air-conditioned heating environment, participated in a randomized placebo-controlled crossover trial. Subjects rested for 30 minutes in a room air-conditioned either by enveloping airflow or by direct airflow, and then performed fatigue-inducing tasks for 2 hours.
Methods We evaluated the sense of fatigue by visual analogue scale (VAS), peripheral blood flow by laser-Doppler flowmetry, and sympathetic nerve activity by urinary vanillylmandelic acid level.
Result Air conditioning by enveloping-airflow, as compared to direct airflow, enhanced peripheral blood flow and attenuated sympathetic nerve hyperactivity caused by performing fatigue-inducing tasks. Moreover, it helped to maintain subjective levels of motivation and comfort, as well as to alleviate sense of fatigue and cold.
Conclusion Air-conditioned heating by enveloping-airflow is effective for attenuating sense of fatigue and discomfort as well as health maintenance.