Which of the following is a sign of chronic stress?

Insomnia is a well-documented sign of chronic stress. When individuals experience ongoing stress, their body remains in a heightened state of alertness, disrupting normal sleep patterns. This can lead to difficulties in falling asleep, staying asleep, or experiencing restful sleep. Chronic stress can cause a myriad of physiological and psychological responses, one of which is the inability to relax enough to achieve a good night's rest.

In contrast, options such as increased energy levels and improved concentration are generally associated with a lack of stress or effective stress management, while emotional resilience denotes the ability to bounce back from challenges and is not indicative of chronic stress. Therefore, insomnia serves as a clear indicator of the negative impact that persistent stress can have on an individual's health and well-being.