Influence of Sex and Obesity on Plasma Catecholamine Response to Isometric Exercise

The effects of obesity and gender on plasma catecholamine levels were studied in 10 lean men, 10 lean women, and 10 obese women. Measurements (mean ± SE) were obtained sequentially after 30 min of bedrest, 10 min of standing, and 5 min of sustained handgrip, and following 15 min of rest while standing. The supine plasma norepinephrine (NE) levels were comparable among the 3 groups, whereas plasma epinephrine (E) was lowest in obese women (14 ± 2 pg⁄ml), intermediate in lean women (19 ± 2 pg⁄ml), and highest in lean men (29 ± 5 pg⁄ ml). Peak plasma levels were reached during handgrip. E valuesin men (139 ± 27 pg⁄ml) exceeded those in lean women (71 ± 9 pg⁄ml; P< 0.05), and both were higher than the E response in obese women (38 ± 7 pg⁄ml; P< 0.01). While peak plasma NE levels in lean women (654 ± 62 pg⁄ml) and obese women (524 ± 46 pg⁄ml) were comparable, both were significantly lower than the NE response in lean men (1014 ± 114 pg⁄ml; P < 0.02). Increments in plasma FFA during handgrip were 21‰ and 28‰ ab...