Central and peripheral haemodynamics in individuals with paraplegia during light and heavy exercise.

The purpose of this study was to analyse lower leg skin blood flow (laser Doppler flowmetry) in five individuals with high-level paraplegia (T5-T9), six participants with low-level paraplegia (T10-T12) and six able-bodied controls during 3-minute light and heavy arm-cranking exercises (approximately 15% and 80% peak power output, respectively). Throughout light exercise, cutaneous vasoconstriction was shown for the control group (-20%), but not the low-level (+62%) or the high-level paraplegic group (+33%). During heavy exercise, vasoconstriction was initially found for controls followed by an increase in skin blood flow during the last 2 minutes, whereas the participants with paraplegia demonstrated skin blood flow increases. Skin blood flow responses were not related to lesion level. Metabolic parameters were not different among the three groups, but heart rates for participants with paraplegia were higher during heavy exercise than in controls. These results suggest impaired sympathetic vasoconstriction in individuals with paraplegia during exercise.