Final answer:
According to the given information, the indicator of pain intensity is the patient's self-report of pain.
Step-by-step explanation:
An indicator of pain intensity according to the given information is the patient's self-report of pain. This means that the patient verbally expresses or rates their pain level. It is a subjective measure as it relies on the patient's perception and description of their pain. Other options mentioned, such as sleep, stimulation, and exhaustion, can be associated with pain but are not direct indicators of pain intensity.