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. 2021 Jun 16;321(2):R197–R207. doi: 10.1152/ajpregu.00202.2020

Table 2.

Carotid body chemosensitivity

Parameter CW
TN
PRE D80 D160 PD PD60 Pre D80 D160 PD PD60
CBCO2, L·min·mmHg−1 8.29 (6.38) 10.41 (6.66) 11.42 (9.61) 9.88 (11.61) 12.60 (9.40) 9.62 (7.71) 6.56 (2.90) 7.09 (3.65) 10.76 (6.02) 11.77 (4.66)
HR response to hypercapnia, beats·min−1·mmHg−1 0.32 (0.22) 0.40 (0.38) 0.41 (0.43) 0.51 (0.36) 0.66 (0.81) 0.19 (0.09) 0.32 (44) 0.26 (0.18) 0.55 (0.61) 0.51 (0.39)
MAP response to hypercapnia, mmHg·mmHg−1 1.11 (0.21) 0.42 (0.19)* 0.37 (0.13)* 0.86 (0.56) 0.75 (0.17)* 0.66 (0.03)# 0.49 (0.13)* 0.47 (0.16)* 0.84 (0.28) 0.92 (0.19)*#
CBO2, L·min·mmHg−1 5.30 (2.75) 5.17 (4.75) 5.43 (4.29) 7.03 (5.41) 7.80 (4.93) 5.93 (3.65) 2.47 (1.45) 3.17 (1.25) 6.94 (3.36) 7.27 (4.26)
HR response to hypoxia, beats·min−1·mmHg−1 149.2 (53.3) 144.7 (52.4) 105.8 (59.8)* 183.1 (37.2)* 180.4 (63.1)* 144.0 (46.4) 116.6 (44.7) 135.7 (71.9) 167.4 (68.2) 159.2 (60.1)
MAP response to hypoxia, mmHg·mmHg−1 362.0 (61.1) 311.2 (92.3) 228.2 (90.2) 286.8 (66.5)* 240.9 (65.7)* 358.9 (60.9) 284.4 (65.3)* 269.5 (94.8)* 297.4 (88.4) 277.0 (46.3)*

Values are presented as mean (SD); n = 13 (all males). Carotid body chemosensitivity to hypercapnia (CBCO2) and carotid body chemosensitivity to hypoxia (CBO2) values were multiplied by a factor of 100 for readability. CW, cold water; D80 and D160, 80 and 160 min into the dive; HR, heart rate; MAP, mean arterial pressure; PD, postdive; PD60, 60 min postdive; PRE, predive; TN, thermoneutral water. Two-way repeated-measures analysis of variance (time × water temperature). If a significant interaction or main effect was found, post hoc multiple comparisons were completed with the least squared differences (LSD) procedure. *P < 0.05 from pre-dive; #P ≤0.05 CW vs. TN.