 Cortisol levels rise slowly over time and take a while to return to base level, indicating that cortisol is more associated with chronic stress levels.Alpha amylase, on the other hand, spikes quickly when confronted with a stressor and returns to baseline soon after the stress has passed, making salivary amylase measurement a powerful tool for psychological research studying acute stress responses.Samples are usually collected from participants by having them drool through a straw into a collection tube while experiencing a stimulus, with samples taken every few minutes to record the gradual change in stress hormone levels.