Variable physical functions in individuals in response to sensory stimuli

Abstract

Abstract PURPOSE: Sensory stimulation affects physical functions; however, the type and range of physical function change remain unclear. This study aimed to evaluate the type and extent of changes in the simple physical functions resulting from exposure to color and taste stimuli. METHODS: Five basic colors (red, blue, yellow, green, and black) and foods representative of five basic tastes (sweet, sour, salty, bitter, and umami) were used as stimuli. Three different physical function tests, muscle strength (grip strength), flexibility (bending length), and balance (stabilometer trajectory area) were measured while wearing color-tinted goggles or after tasting food stimuli. Tests were repeated for six successive days in a controlled environment. RESULTS: Each stimulus had different effects on participants. For color stimulation, the median change ratio between the minimum and maximum effects was 5.68% (4.14%–8.07%) for muscle strength, 8.52% (5.11%–13.39%) for flexibility, and 30.60% (26.81%–36.18%) for balance. The corresponding values in taste stimulation were 4.96% (3.67%–7.89%), 6.11% (4.37%–8.86%), and 28.92% (21.38%–34.01%). The rate of change in balance was the highest among the three physical tests and was significantly different from the rate of change in the other physical functions (balance vs. muscle power, P < 0.001; balance vs. flexibility, P < 0.001). CONCLUSION: Color and taste stimuli have differential effects on physical function. The extent of physical change to stimuli differed among the participants, suggesting individual-level differences in sensitivity to stimuli. Sensory stimuli affect physical functions individually and affect balance more than any other physical function.