K 's Key Ideas from Why We Sleep
by Matthew Walker

• Routinely sleeping less than six or seven hours a night demolishes your immune system, more than doubling your risk of cancer.

• Insufficient sleep is a key lifestyle factor determining whether or not you will develop Alzheimer’s disease.

• Inadequate sleep—even moderate reductions for just one week—disrupts blood sugar levels so profoundly that you would be classified as pre-diabetic.

• Short sleeping increases the likelihood of your coronary arteries becoming blocked and brittle, setting you on a path toward cardiovascular disease, stroke, and congestive heart failure.

• Sleep disruption further contributes to all major psychiatric conditions, including depression, anxiety, and suicidality.

• Too little sleep swells concentrations of a hormone that makes you feel hungry while suppressing a companion hormone that otherwise signals food satisfaction.

• The shorter your sleep, the shorter your life span.

• Sleep reforms the body’s metabolic state by fine-tuning the balance of insulin and circulating glucose.

• Human beings are in fact the only species that will deliberately deprive themselves of sleep without legitimate gain.