Effects of Clothing Pressure Caused by Different Types of Brassieres on Autonomic Nervous System Activity Evaluated by Heart Rate Variability Power Spectral Analysis
Journal of Physiological Anthropology and Applied Human Science
The present study was designed to investigate the effects of clothing skin pressures exerted by two different types of brassieres (a conventional higher skinpressured brassiere and a newly devised low skinpressured brassiere) on the autonomic nervous system (ANS) activity. Six healthy young women (22.8 ± 1.4 yrs.) with regular menstrual cycles participated in this study. The ANS activities were assessed by means of heart rate variability power spectral analysis. The skin pressures exerted by
... sures exerted by the brassieres were measured with an air-pack type contact surface pressure sensor at five different points. The total amount of clothing pressure, and the pressures at the center and the side regions of the brassieres were significantly greater in the high than in the low skin-pressured brassiere (Total 9816.1 ± 269.0 vs. 05). Concerning the ANS activity, the Total power, and the very low frequency (VLF) and the high frequency (HF) components were significantly decreased in the high skin-pressured brassiere than those in the low skin-pressured brassiere (Total 531.6 ± 57.3 vs. 770.5 ± 54.2 ms 2 , P<0.01; VLF 60.7 ± 14.6 vs. 179.2 ± 38.1 ms 2 , P<0.05; HF 209.5 ± 33.2 vs. 283.2 ± 61.5 ms 2 , P<0.01). Our data indicate that the higher clothing pressures exerted by a conventional brassiere have a significant n e g at iv e i mp ac t o n t h e A N S a c t i v i t y , w h ic h is predominantly attributable to the significant decrease in the parasympathetic as well as the thermoregulatory sympathetic nerve activities. Since the ANS activity plays a n i m p o r t a n t r o l e i n m o d u l a t i n g t h e i n t e r n a l environment in the human body, excess clothing pressures caused by constricting types of foundation garments on the body would consequently undermine women's health.