Fatigue is a common and potentially debilitating side effect of radiation therapy , which is commonly employed in cancer treatment, exposing patients to a daily dose of ionizing radiation . It is well established that when exposed to ultraviolet radiation, the skin releases β-endorphin, a "feel-good" hormone, which causes opiate-like behavior and addiction to sun exposure. This led to the question whether the radiation-induced increase in β-endorphin levels could contribute to the fatigue that cancer patients experience after radiation therapy.
Researchers from Massachusetts General Hospital tested this hypothesis by irradiating the rats’ tails to model radiation therapy treatments and observed the change in the levels of β-endorphin over the six weeks of the radiation treatment course. The rats exhibited behavior associated with opiate use, such as increased pain threshold, fatigue…
