Saliva
Cortisol
Salivary cortisol
was measured before, during, and after the commute on each study day
(10 min prior to the commute; 45 min into the commute; 10 min postcommute;
and 80 min postcommute). The timing of measurements was consistent
across days for each participant to control for diurnal patterns.
Participants could not eat, drink, or chew gum for 30 min before giving
a saliva sample or ingesting a large meal less than 1 h before the
saliva sample. Samples were collected using Salivette swabs (Nümbrecht,
Germany). Participants rolled the swab in their mouths for 60 s and
returned the swab to the Salivette tube. Samples were kept on ice
during transport and stored at −20 °C. The saliva was
analyzed with a high-sensitivity enzyme-linked immunosorbent assay
kit from Salimetrics (State College, PA), and all samples were analyzed
in duplicate, with the average of the duplicates used for statistical
analyses.