Table 4.

Forearm haemodynamics at rest and increasing exercise intensity during normoxia and hypoxia with each drug condition. Δ from normoxia rest: absolute change from normoxia rest within each drug infusion

				Δ from normoxia rest
	Rest	10%	20%	10%	20%
Forearm blood flow (ml min−1)
Control
Normoxia†	62 ± 11	189 ± 23	350 ± 40	126 ± 16	287 ± 35
Hypoxia*†	76 ± 13	231 ± 39	409 ± 46	169 ± 30	346 ± 40
Phentolamine
Normoxia†	224 ± 20‡	356 ± 31‡	502 ± 44‡	131 ± 21	286 ± 41
Hypoxia*†	378 ± 39‡	509 ± 46‡	669 ± 33‡	306 ± 43‡	466 ± 57‡
Phentolamine/propranolol
Normoxia†	280 ± 40‡	420 ± 51‡	593 ± 61‡	139 ± 25	312 ± 45
Hypoxia*†	382 ± 46‡	494 ± 50‡	751 ± 42‡§	213 ± 25§	450 ± 43‡
Forearm vascular conductance (ml min−1 (100 mmHg)−1)
Control
Normoxia†	73 ± 12	213 ± 26	387 ± 43	139 ± 18	314 ± 38
Hypoxia*†	89 ± 16	263 ± 43	450 ± 47	190 ± 32	377 ± 40
Phentolamine
Normoxia†	265 ± 24‡	411 ± 36‡	570 ± 53‡	147 ± 25	315 ± 50
Hypoxia*†	448 ± 46‡	591 ± 55‡	759 ± 69‡	354 ± 53‡	521 ± 63‡
Phentolamine/propranolol
Normoxia†	325 ± 47‡	477 ± 58‡	652 ± 65‡	152 ± 29	326 ± 51
Hypoxia*†	443 ± 55‡	565 ± 54‡	825 ± 52‡	240 ± 27§	479 ± 53‡

Values are mean ±s.e.m.

^*Main effect of hypoxia, P < 0.05

^†main effect of exercise, P < 0.05

^‡P < 0.05 vs. control

^§P < 0.05 vs. phentolamine.