Fig. 2
Time-course changes in baroreflex sensitivity. A 4-h interval changes in baroreflex sensitivity for ascending (BrrA) and descending (BrrD) across all vigilance states. B 4-h interval changes in BrrA and BrrD during awake (AW), quiet sleep (QS), and paradoxical sleep (PS) phases in the control, 10s-30c, and 5s-60c groups under and after intermittent hypoxia (IH) exposure. The black bar indicates the period of IH exposure. The gray background indicates the dark phase. BrrA reflects baroreflex sensitivity for sequences where mean arterial blood pressure (MAP) and RR intervals ascend concurrently, and BrrD reflects descending sequences. Line and symbol conventions: a solid line with circles represents the room-air control group (RA); a dashed line with squares represents the 10s-30c group; and a dotted line with diamonds represents the 5s-60c group. Groups: control (room air); 10s-30c (10-s episodes duration at 30 cycles/hour; and 5s-60c (5-s episodes duration at 60 cycles/hour). IH exposure was administered for 8 h per day over 21 consecutive days. Sample sizes: control (n = 8), 10s-30c (n = 8), and 5s-60c (n = 8). Statistical significance: *p < 0.05 for 10s-30c vs. control; #p < 0.05 for 5s-60c vs. control; $p < 0.05 for 5s-60c vs. 10s-30c (one-way analysis of variance [ANOVA] followed by Fisher’s least significant difference [LSD] post hoc test)
