The only known remedy for radiation-induced fatigue is exercise
- lots of it! I know it's the last thing he'll feel like doing, but it's the first thing he should be doing. Well-meaning friends will encourage him to "take it easy," which is exactly the worst advice he could take. Instead of relaxing, get him a trainer at the gym during his radiation therapy.
This has been proven in randomized clinical trials:
"Men who followed advice to rest and take things easy if they became fatigued demonstrated a slight deterioration in physical functioning and a significant increase in fatigue at the end of radiotherapy. Home-based, moderate-intensity walking produced a significant improvement in physical functioning with no significant increase in fatigue. Improved physical functioning may be necessary to combat radiation fatigue."A randomized, controlled trial of aerobic exercise for treatment-related fatigue in men receiving radical external beam radiotherapy for localized prostate carcinoma
"In the short term, both resistance and aerobic exercise mitigated fatigue in men with PCa receiving radiotherapy. Resistance exercise generated longer-term improvements and additional benefits for QOL, strength, triglycerides, and body fat."Randomized Controlled Trial of Resistance or Aerobic Exercise in Men Receiving Radiation Therapy for Prostate Cancer
Not only does it alleviate fatigue, but it helps the radiation work better and reduces its toxicity. It also helps combat depression. Modulation of Blood Flow, Hypoxia, and Vascular Function in Orthotopic Prostate Tumors During ExerciseThe effect of aerobic exercise on treatment-related acute toxicity in men receiving radical external beam radiotherapy for localised prostate cancer.