Natural short sleepersThere is a small group of people who don’t need much sleep. Scientists call this the natural short sleep phenotype – a biological trait that allows people to get all the benefits of sleep in less time. Not everyone who sleeps less is a natural short sleeperBut here’s the catch: most people who think they’re natural short sleepers aren’t. The effects of short sleep build up over time, creating what’s known as a “sleep debt”. A recent large study suggested weekend catch-up sleep may not offset the cardiovascular risks associated with chronic short sleep.