[Influence of physical responses due to controlled frequency breathing during exercise]

The purpose of this study was to examine the influence of respiratory responses due to controlled frequency breathing (CFB) during steady state cycle ergometric exercise (50% of Peak VO2, 60rpm) and to compare their responses between long distance (L), badminton (B), Swimming (S) and untrained (C; Control) group. Twenty-two (n = 6; L, B, C.n = 4; S) female university students were forced to take CFB for 1 min every 3 min during 20 min exercise. The breathing frequencies (BR) were 10, 12, 15, 20 and 30 frequencies in a minute. They were represented by CFB10, CFB12, CFB15, CFB20 and CFB30 respectively. In addition, CFB5, and 40 were given in a separate series. Ventiratory volume (VE) decreased significantly, (P < 0.05) when BR decreased less than about 50% of normal breathing (NB), CFB15 in (B) and (C). It showed to be less than CFB12 in (S), and CFB10 in (L). According to the decrease of VE, tidal volume and O2 pulse increased during CFB10 and 15 in all groups to maintain a constant O2 consumption for a given workload. End tidal partial pressure of O2 (PETO2) significantly decreased during less than CFB15 in (B) and (C), during CFB10 in (L). PETCO2 increased during less than CFB15 in (B), less than CFB12 in (L) and (C). However in (S) during every CFB, neither PETO2 nor PETCO2 changed significantly. Talking about the main differences shown between the four groups, (S) and (L) significantly exceeded (C) in maintaining of VE during CFB. However, in consideration of a ratio of the frequency of CFB to that of NB, (L) could maintain VE against more strictly controlled of breathing than other groups. (B) showed similar tendencies as (C) about some responses. It is considered that these differences in respiratory responses to CFB may result from difference of the duration and the level of breathing control that were forced during their daily training rather than whether their breathing frequency during each exercise is high or low.