Research on dynamic comfort maintenance by measuring lower limb edema and seat pressure during simulated seated sleep in flight.

Seated sleep during flight can bring significant discomfort to passengers. The objective of this research was to study passengers' dynamic comfort maintenance strategies in lower limb postural shifting during seated sleep in flight. Studies on seated sleep postures and sitting comfort were conducted. First, 40 participants were recruited to the observational research for collecting typical leg postures during seated sleep. Then, an experiment was conducted with the participants simulating seated sleep in the aircraft seat. The changes in lower limb edema and seat pressure in different postures were measured with a bioelectrical impedance device, near-infrared spectroscopy device and pressure mapping device. Six postures were selected through the observational research. The experiment showed that tissues of the thighs and buttocks suffer alternate higher compression by shifting between the six postures. Lower limb edema is higher when the shanks are forward, while the tissue under the ischial tuberosity suffers higher compression when the shanks are neutral. Six motivations for passengers to shift each sitting posture to achieve dynamic comfort were summarized, which helps obtain alternating rest in different body parts. The suggestion of a leg position adjustment system was also proposed.