Between-day reliability of local thermal hyperemia in the forearm and index finger using single-point laser Doppler flowmetry.

OBJECTIVE: To assess between-day reliability for LTH in glabrous and nonglabrous index finger skin and nonglabrous forearm skin, with single-point laser Doppler flowmetry.

METHODS: Part-1: In healthy, habitually active males (n=10), LTH was examined twice (~7-10 days apart) for both skin types on the index finger. Part-2: Identical testing was performed on the volar forearm. Local heating (33-42°C at 1°C·20 s-1  + 20 minutes at 44°C) was performed at all skin sites and baseline, initial peak, and plateau phases were identified. Data were expressed as raw CVC (laser-Doppler flux/MAP), and as CVC normalized to baseline (%CVC33°C ) and maximum heating (%CVC44°C ). Reliability was assessed using between-day mean difference, %CV, and ICC.

RESULTS: Reliability (%CV) was poor at baseline for all forms of data presentation and for other phases with %CVC33°C . At the initial peak and plateau, reliability was moderate-poor (20%-26%) for CVC and good-moderate (6%-18%) for %CVC44°C . Reliability was good-moderate for vasodilatory onset time (10%-23%) and time to initial peak (6%-13%).

CONCLUSIONS: For all sites, LTH reliability was acceptable for the timing, and for the initial peak and plateau using CVC or %CVC44°C .