Donald Trump is reportedly a natural short sleeper, functioning on just four hours of sleep per night.

The ability to function as a natural short sleeper is often linked to a rare mutation in the DEC2 gene, also known as BHLHE41. In 2009, researchers at the University of California, San Francisco—led by Dr. Ying-Hui Fu and Dr. Louis Ptáček—first identified this genetic variation. People carrying this mutation can maintain peak cognitive performance on just four to six hours of sleep per night.In a typical brain, the glymphatic system clears metabolic waste and neurotoxins during deep sleep. In people with the DEC2 mutation, this "cleaning" process is significantly more efficient, allowing the brain to complete eight hours of maintenance work in roughly four hours. This efficiency prevents the buildup of adenosine, the chemical responsible for sleepiness.Beyond DEC2, scientists discovered a second mutation in the ADRB1 gene in 2019 that also contributes to short sleeping. People with these mutations often display high energy levels and a more optimistic temperament, sometimes described as a "hypomanic" personality trait. While only about 1% of the population are true natural short sleepers, research into these individuals helps scientists understand how to improve sleep quality and efficiency for everyone.