3.1. Biochemical stress parameters
A mixed-design ANOVA with Time (T1 to T6 time points) as a
within-participant factor and Group (control group vs. stress group) as
a between-participant factor was conducted on the collected salivary
cortisol. Results (see Figure 2) showed significant main effects of
Time, F (5, 305) = 6.07, p < .001,\(\eta_{p}^{2}\) = 0.09, and of Group, F (1, 61) = 26.06, p< .001, \(\eta_{p}^{2}\) = 0.30. A significant interaction
effect of Time × Group was also observed, F (5, 305) = 9.92,p < .001, \(\eta_{p}^{2}\) = 0.14. Simple effects
analyses (Bonferroni corrected) found that salivary cortisol levels in
the stress group were significantly higher than that in the control
group at T3 (p = .002), T4 (p = .001), T5 (p< .001), and T6 (p < .001). Salivary cortisol
concentrations taken after the MIST in the stress group were also
significantly higher than those at baseline, supporting the notion that
stress was successfully induced.