Hormonal responses to the six-minute walk test in women (W) and men (M) with coronary artery disease (CAD)

We determined efficacy of the 6-min walk test (exercise) as a stimulus for release of hormones associated with sympathetic activation and fluid/electrolyte regulation in W and M with CAD. Nine W and 9 M with arteriographically-documented CAD and normal LV ejection fractions were matched for age (66 ± 8 yrs) and hypertension; none of the subjects had diabetes mellitus. Maintenance drugs included ACE inhibitors (2W;3M), B-blockers (7W;1M), Ca-channel blockers (1W;2M), diuretics (2W;0M), and nitroglycerin (3W;3M). After venipuncture and 30 min of supine rest, basal blood samples were drawn. Subjects then walked for 6 min to cover as much distance as possible. Post-exercise blood samples were drawn. Basal levels of vasopressin (VP) were significantly higher in M (1.02 ± 0.17 pg/ml) than in W (0.61 ± 0.01 pg/ml). There were no gender differences for basal levels of atrial natriuretic peptide (ANP), plasma renin activity (PRA), norepinephrine (NE), epinephrine (E), cortisol or aldosterone. Exercise for W and M combined significantly increased VP (0.81 ± 0.09 basal to 1.05 ± 0.12 pg/ml post-exercise), ANP (84 ± 20 to 134 ± 25 pg/ml), and NE (240 ± 23 to 448 ± 54 pg/ml) but not PRA (4.40 ± 1.84 to 6.14 ± 2.79 ng/ml/hr) or E (23 ± 1 to 26 ± 2 pg/ml). There were no gender differences for the magnitude of exercise-induced increases for VP, ANP, PRA, NE or E. Conclusions: a gender difference occurred only for basal VP levels; the 6-min walk test is an exercise stressor of sufficient intensity and duration to significantly increase VP, ANP and NE in both W and M with CAD.