Figure 2.

Increase in forearm blood flow is due largely to an increase in skin, rather than skeletal muscle, blood flow. Iontophoresis of adrenaline completely arrests the skin circulation but has little to no effect on skeletal muscle circulation. There was little to no increase in forearm blood flow during heat stress following iontophoresis of adrenaline to the right forearm (filled symbols) compared to the substantial increase in forearm blood flow to the control limb (open symbols). Adapted, with permission, from Edholm et al.¹³