What do researchers say?

Sleep isn’t simply resting. It’s an essential biological process in which the body repairs its cells, regulates hormones, eliminates toxins accumulated in the brain, and balances its energy metabolism. When we don’t get enough sleep, even after just one night, significant changes occur: blood sugar increases due to decreased insulin sensitivity, hunger hormones become dysregulated ( ghrelin increases and leptin decreases), muscles lose efficiency, the liver becomes inflamed, and intestinal flora is altered, generating systemic inflammation.

Furthermore, the body enters a state of oxidative stress. Free radicals accumulate, damaging tissues such as the liver, brain, and muscle, promoting accelerated aging. A key finding from clinical studies is that sleep deprivation directly affects mitochondrial function, especially in the liver and brain. Inhibition of essential Krebs cycle enzymes, reduced ATP production, and alterations in the antioxidant system were observed. Changes in the expression of genes controlling glucose transporters, insulin receptors, and proteins involved in cell apoptosis have also been identified. In animal studies, just three nights of reduced sleep were enough to cause transient liver dysfunction and insulin resistance in muscle.