Whole-body norepinephrine kinetics (means ± SE). Arterial plasma norepinephrine concentration (A), norepinephrine plasma clearance (B), and calculated NE spillover rate (C) before and after 12 weeks of lifestyle intervention with weight loss by caloric restriction (WL, n = 20), weight loss by caloric restriction and aerobic exercise (WL+EX, n = 18), or no treatment (control, n = 17). *P < 0.05, **P < 0.01, and ***P < 0.001 versus baseline. Plasma NE: time effect, P = 0.004; group × time interaction, P = 0.006. NE plasma clearance: no significant time, group, or interaction effects. Whole-body NE spillover: time effect, P = 0.002; group × time interaction, P = 0.004.