Glossary
Stress reactivity
What is stress reactivity?
Stress reactivity describes the size and duration of a person's response to a stressor. It can refer to physiological changes, such as heart rate or cortisol, or to the person's reported distress.
How it varies
These measures need not move together. Someone can report distress without showing the same pattern on every physiological measure. Responses also depend on history, current circumstances, and the systems being measured.
Example
Imagine two employees receiving similar critical feedback in a study. One person’s measured heart rate rises more above their own resting baseline and takes longer to return; the other person shows a smaller, shorter increase. That would illustrate a difference in cardiovascular reactivity and recovery.
The researchers separately ask both people how distressed they feel. They might report similar distress despite different heart-rate patterns. Neither report reveals cortisol levels; those would require their own measurements and sampling times. This hypothetical contrast describes particular measured responses, not proof that one person is generally more resilient or that their circumstances are identical.
Why it matters
Reactivity helps describe individual differences in responding to demands. Lower is not automatically better: a response may be useful in its context. McEwen's review examines both the adaptive and potentially harmful effects of stress responses.