A study in Switzerland found that workplace interruptions affect stress levels in unimaginable ways. The participants in the control group accomplished a simple additional task with the HR staff.
Those in two “stress condition” groups finished a task that involves psychosocial stress. The stress was in a form of being questioned and appraised when they were applying for a promotion while finishing their “regular” work.
The participants in the “stress condition” groups had an increased heart rate and increased cortisol production. Between the two, the second group had a better mood and felt less stressed and threatened.