Figure 2: Changes in baroreflex sensitivity (BRS), number of baroreflex estimates per minute, and tau (optimal time delays) during HDBR in the fainters and the nonfainters. Nonfainters, the median values [25th, 75th percentiles] are shown as dots, ; fainters, the absolute individuals values are shown as diamonds, ; BDC, 14 days before head-down bed rest; HDT2, the 2nd day of bed rest; HDT7, the 7th day of bed rest; HDT21, the 21st day of bed rest; HDT41, the 41st day of bed rest; HDT56, the 56th day of bed rest; , the 6th day during recovery; , the 12th day during recovery. compared with baseline before HDBR.