We need sleep to recharge our body and brain. That much scientists agree on; but why we need 7 to 8 hours of sleep to get the job done and precisely how sleep or lack of sleep impact our physical and mental health is still the subject of vigorous scientific debate. In an article on physorg.com, sleep expert David Prober, an assistant professor of biology at the California Institute of Technology who studies the sleep-regulating properties of genes and neurons, explained the four current hypotheses about why we need sleep:
- Sleep as bandaid. During the day, our bodies create free radicals, metabolic byproducts that cause cellular damage associated with cancer and chronic disease. Sleep increases production of the genes that repair damaged cells. The higher a species’ metabolic rate, the more free radicals its body produces and the more sleep it requires.
- Sleep as fuel. Sleep appears to replenish the fuel our cells burn during our waking hours. Prober has found that as our bodies use ATP (Adenosine Tri-Phosphate), a primary energy-carrying molecule, they increase production of adenosine, a molecular compound that triggers sleep.
- Sleep as housekeeper. Like running a program to free up disk space on your computer’s hard drive, sleep consolidates new learning, cleaning out fractured and duplicate synapses.
- Sleep as teacher. During sleep we replay daily events, reinforcing learning and strengthening memory in the process.
Scientist may not agree on why, but they do agree that sleep is essential to good health.