Which theory posits that sleep's primary function is to restore energy and repair tissue?

• A. Restoration theory
• B. Memory consolidation theory
• C. Activation-synthesis theory
• D. Evolutionary theory

Answer: (A)

Sleep's restorative role—restoring energy and repairing tissue—is the focus of this theory. It suggests that during sleep the body carries out metabolic repair, replenishes energy stores, and supports immune function. Growth hormone release during deep sleep and observed improvements in tissue healing after adequate sleep are often cited as supporting evidence. This stands in contrast to memory consolidation theories that emphasize learning and memory stabilization, activation-synthesis theories that explain dreams as byproducts of brain activity, and evolutionary theories that frame sleep as an adaptation for energy conservation. So, the primary function described here is the restoration of the body.