Understanding Why Some People Need Less Sleep: The Role of Gene Variations

Have you ever wondered why some individuals seem to function perfectly after just a few hours of sleep, while others require a full eight hours or more? A fascinating area of research suggests that genetics may play a significant role in these differences.

Take Margaret Thatcher, for example—she was known for sleeping only four hours a night yet remained mentally sharp and physically healthy. While this might seem exceptional, most people cannot sustain such a sleep pattern without negative effects. For the majority, chronic sleep deprivation leads to cognitive impairments, mood disturbances, and long-term health risks.

Certain individuals are naturally short sleepers—people who function optimally with just four to six hours of sleep and do not experience the typical signs of tiredness or sleepiness. This trait, known as the natural short sleep phenotype, appears to be rooted in genetic differences. Researchers have identified rare gene variants that enable these individuals to sleep less without adverse consequences. For instance, a 2025 study highlighted a woman in her seventies carrying such a mutation; despite sleeping only six hours nightly throughout her life, she remained active and healthy, indicating her body was biologically wired to need less sleep.

However, it's important to distinguish between genetic short sleepers and those who are simply sleep-deprived. Many people believe they are short sleepers, but in reality, they are often experiencing the effects of chronic sleep deprivation due to work demands, social commitments, or lifestyle choices. Sleep debt accumulates over time, leading to impaired concentration, mood swings, micro-sleeps, and increased risk of obesity, diabetes, high blood pressure, and cardiovascular disease. While some attempt to compensate by catching up on sleep during weekends, this practice doesn't fully offset the health risks associated with irregular sleep patterns.

Research shows that frequent disruptions to sleep schedules can affect the body's internal clock, making it harder to fall asleep and wake up naturally. Over time, this can increase the risk of early death and various health issues more than the total hours of sleep. Therefore, maintaining consistent, high-quality sleep throughout the week is critical for health.

As to whether historical figures like Thatcher were true natural short sleepers is uncertain. Some reports suggest she napped during the day, possibly compensating for poor nighttime sleep.

Various factors influence individual sleep needs—age, health conditions, lifestyle, and underlying medical issues. Older adults, for example, often experience changes in circadian rhythms and may sleep less or have fragmented sleep due to arthritis or cardiovascular problems. Despite these differences, most people require between seven to nine hours of sleep per night to support optimal health and functioning.

In summary, while genetics can predispose some to need less sleep, for most individuals, prioritizing regular, sufficient sleep is essential. Sleep should not be viewed merely as a luxury but as a vital component of overall health, making it crucial to establish healthy sleep habits.