Table 2.

Individual and mean cardiovascular response to the cold pressor test

Variable	Astronaut	Pre-flight					In-flight
		BL	CPT1	CPT2	R1	R2	BL	CPT1	CPT2	R1	R2
SBP (mmHg)	1	135	136	148	145	132	149	159	176	165	151
	2	151	161	172	165	160	153	168	188	188	174
	3	127	132	136	128	117	145	154	165	157	140
	4	133	145	145	133	129	140	143	160	150	140
	5	137	145	145	138	132	—	—	—	—	—
	Mean	136	143	150*	143	134	147†	156*	172**‡	165*†	151
	±s.e.m.	±5	±6	±8	±8	±9	±3	±5	±6	±8	±8
DBF (mmHg)	1	64	69	78	74	65	77	83	94	86	75
	2	76	79	87	82	80	73	81	90	85	74
	3	69	71	74	68	65	76	81	89	84	78
	4	68	71	75	70	73	72	78	88	83	75
	5	68	67	71	67	62	—	—	—	—	—
	Mean	69	73*	78*	74	71	75	81*†	90**†	85*†	76
	±s.e.m.	±2	±2	±3	±3	±4	±1	±1	±1	±1	±1
MAP (mmHg)	1	88	91	101	98	87	101	108	122	113	100
	2	101	107	115	110	107	100	110	123	119	108
	3	88	91	95	88	83	100	105	115	108	98
	4	90	96	98	91	91	94	99	112	105	97
	5	91	93	96	91	85	—	—	—	—	—
	Mean	92	96*	102**	97*	92	99	106*†	118*†	111*†	101
	±s.e.m.	±3	±4	±4	±5	±5	±2	±2	±3	±3	±2
HR (beats min−1)	1	46	48	39	44	41	50	50	48	47	50
	2	56	59	53	56	61	50	53	53	52	51
	3	62	63	62	65	62	57	60	60	57	56
	4	57	57	59	58	63	59	62	59	60	62
	5	52	53	53	52	53	—	—	—	—	—
	Mean	55	57	53	56	57	54	56	55	54	55
	±s.e.m.	±3	±3	±5	±4	±5	±2	±3	±3	±3	±3

Means ±s.e.m. Data from five astronauts pre-flight and from four astronauts in-flight SBP, systolic blood pressure; DBF, diastolic blood pressure; MAP, mean arterial pressure; HR, heart rate; BL, baseline; CPT₁, first minute of cold pressor test; CPT₂, second minute of cold pressor test; R₁ first minute of recovery; R₂, second minute of recovery.

^*P < 0.05

^**P < 0.01, compared with baseline

^†P < 0.05

^‡P < 0.01, compared with pre-flight.