" A Columbia University Study conducted in New York suggests that “watching late night television may put people in a state of heightened alertness and physiological arousal, preventing them from falling asleep with ease. In addition, being exposed to many hours of the bright light of the television screen may throw people off their sleep-wake cycle, while too little physical activity may cause people to become restless and struggle with sleep. "

― Mark Sisson , The Primal Blueprint: Reprogram Your Genes for Effortless Weight Loss, Vibrant Health, and Boundless Energy