Cutaneous vasomotor adjustments during arm-cranking in individuals with paraplegia

Skin blood flow (SKBF) was evaluated during arm-cranking exercise in able-b odied control subjects (AB; n = 6) and in individuals with low- (LP; T10-T1 2 lesions; n = 6) and high-level paraplegia (HP; T5-T9 lesions; n = 6), usi ng laser Doppler flowmetry (LDF). During moderate exercise SKBF decreased t o [mean (SD)] 82 (15)% of the pre-exercise resting level in AB, whereas it increased to 158 (52)% in LP and to 112 (51)% in HP (the LP:AB difference, P < 0.05). During intense exercise SKBF increased to 366 (180)% of the rest ing level in AB, whereas it increased only moderately [147 (68)%] in both p araplegic groups (the paraplegic:AB difference, P < 0.05). The paraplegics developed a higher esophageal and leg skin temperature, which was attribute d to the lack of active vasodilation and evaporative cooling over the legs. The results indicate that individuals with paraplegia suffer from impaired cutaneous vasoconstriction at the onset of arm exercise, and possess only a limited vasodilatory capability in the paralyzed regions. During intense exercise, thermoregulation depends critically on active cutaneous vasodilat ion and skin cooling.