One- and two-year stability salivary alpha-amylase diurnal rhythm and overall daily output
Free Communication
salivary alpha-amylase, chronic stress, sympathetic nervous system, diurnal rhythm, daily output, stability
Rohleder, Nicolas; Jungmann, Franziska, Kirschbaum, Clemens; Miller, Gregory E.
Department of Psychology, Brandeis University, Waltham, MA, USA; Department of Psychology, Technische Universität Dresden, Dresden, Germany; Department of Psychology, University of British Columbia, Vancouver, BC, Canada
Salivary alpha-amylase (sAA) has been shown to have a pronounced diurnal rhythm with a sharp decrease after waking and increasing concentrations in the afternoon. Recent studies have shown that total daily output and slope of the diurnal curve are associated with chronic stress. However, long-term stability of diurnal sAA secretion has not been investigated.
We assessed diurnal rhythm and output of sAA secretion in n=74 healthy young women (15-19 years) by collecting saliva in three assessment waves spaced one year apart (mean interval length: 404 and 343 days, resp.). At each assessment wave, participants provided samples during two consecutive days, with six daily samples scheduled at 0, 0.5, 1, 4, 9, 14 hours after waking. Indices for diurnal slope and daily output were computed.
Data confirmed the daily pattern of sAA observed in earlier studies. Diurnal slope of sAA showed good stability with a correlation of r=.45; p<0.001 over the first, and r=0.33; p<0.01 over the second one-year period. Stability over two years was low (r=-.07; p=.61). Daily output was relatively stable over the first r=.31; p<0.01 and the second one-year period (r=.44; p<0.001), as well as over the entire two-year period (r=.52; p<0.001).
These findings document a reasonable stability of daily sAA secretion over a one-year period for diurnal slope, and over a two-year period for daily output. This confirms our earlier findings of a relative robustness against short-term influences, and it underscores the usefulness of diurnal sAA activity for assessment of long-term stress system activity.
Dr.
Nicolas
Rohleder
Brandeis University
Assistant Professor
Dr.
rohleder@brandeis.edu
781 736 3319
Department of Psychology
415 South Street
MS062 PO Box 549110
Waltham
MA
02454
USA
