Short sampling durations of 2 min, 1 min, and 30 s provided valid and reliable measures of resting MSNA compared to a 5-min control, being highly correlated (r = 0.69-0.93; P<0.001).
Observational (n=53)
Are short sampling durations (2 min, 1 min, 30 s, 15 s) valid and reliable for measuring resting muscle sympathetic nerve activity compared to a standard 5-min control in healthy humans?
Short sampling durations of 2 min, 1 min, and 30 s provide valid and reliable measures of resting muscle sympathetic nerve activity, though epochs ≤30 s may require larger sample sizes due to poorer reliability.
Effect estimate: r = 0.69-0.93
p-value: p=<0.001
Resting muscle sympathetic nerve activity (MSNA) demonstrates high intraindividual reproducibility when sampled over 5-30 min epochs, although shorter sampling durations are commonly used before and during a stress to quantify sympathetic responsiveness. The purpose of the present study was to examine the intratest validity and reliability of MSNA sampled over 2 and 1 min and 30 and 15 s epoch durations. We retrospectively analyzed 68 resting fibular nerve microneurographic recordings obtained from 53 young, healthy participants (37 men; 23 ± 6 yr of age). From a stable 7-min resting baseline, MSNA (burst frequency and incidence, normalized mean burst amplitude, total burst area) was compared among each epoch duration and a standard 5-min control. Bland-Altman plots were used to determine agreement and bias. Three sequential MSNA measurements were collected using each sampling duration to calculate absolute and relative reliability (coefficients of variation and intraclass correlation coefficients). MSNA values were similar among each sampling duration and the 5-min control (all P > 0.05), highly correlated (r = 0.69-0.93; all P 0.05). A consistent proportional bias (P < 0.05) was present for MSNA burst frequency (all sampling durations) and incidence (1 min and 30 and 15 s), such that participants with low and high average MSNA underestimated and overestimated the true value, respectively. Reliability decreased progressively using the 30- and 15-s sampling durations. In conclusion, short 2 and 1 min and 30 s sampling durations can provide valid and reliable measures of MSNA, although increased sample size may be required for epochs ≤30 s, due to poorer reliability.
Notay et al. (Fri,) conducted a observational in Healthy (n=53). Short sampling durations (2 min, 1 min, 30 s, 15 s) vs. Standard 5-min control was evaluated on MSNA values (burst frequency and incidence, normalized mean burst amplitude, total burst area) (r = 0.69-0.93, p=<0.001). Short sampling durations of 2 min, 1 min, and 30 s provided valid and reliable measures of resting MSNA compared to a 5-min control, being highly correlated (r = 0.69-0.93; P<0.001).