Two nights of broken sleep is enough to make people feel years older, according to researchers who said that consistent, restful slumber is a key factor in helping to ward off the feeling of one’s true age.
Psychologists in Sweden found that volunteers felt more than four years older on average when they were restricted to just four hours of sleep for two consecutive nights, with some claiming that the sleepiness made them feel decades older.
The opposite was seen when people were allowed to stay in bed for nine hours, although the effect was more modest, with study participants claiming to feel three months younger than their actual age on average after getting enough rest.
“Sleep has a big impact on how old you feel and it’s not just your long-term sleep patterns,” says Dr Leonie Balter, a psychoneuroimmunologist at the Karolinska Institute in Stockholm and first author of the study. “Even when you only get two nights less sleep, it has a real impact on how you feel.”
Beyond just feeling more decrepit, the perception of being many years older can affect people’s health, Balter said, by encouraging unhealthy eating habits, reducing physical exercise and making people less willing to socialize and have new experiences. go.
The researchers conducted two studies. In the first, 429 people aged 18 to 70 answered questions about how old they felt and about how many nights, if any, they had slept badly in the past month. Their sleepiness was also rated according to a standard scale used in psychology research.
For each day of poor sleep, the volunteers felt an average of three months older, the scientists found, while those who reported no bad nights in the preceding month felt, on average, almost six years younger than their true age. However, it was unclear whether poor sleep made people feel older or the other way around.
In the second study, the researchers asked 186 volunteers aged 18 to 46 about how old they felt after two nights of abundant sleep, in which they stayed in bed for nine hours each night, and two nights when they slept just four hours a night. slept . After two nights of restricted sleep, the participants felt an average of 4.44 years older than when they had enough sleep. Feeling older was, not surprisingly, linked to feeling sleepier.
“If you want to feel young, the most important thing is to protect your sleep,” Balter said.
Write in Proceedings of the Royal Society B, the psychologists describe differences in people’s reactions to sleep loss depending on whether they were a morning person, who woke up and went to bed early, or an evening person who got up late and retired late. Evening types generally felt older than their true age, even after plenty of sleep, but morning types were hit harder in how old they felt when their sleep was disrupted.
Balter says the findings, if confirmed, could be put to good use. “It’s important to realize how malleable subjective age is,” she said. “If we can make people feel younger, they may have the associated benefits, such as being more willing to take on new experiences and be socially active and physically active.”
Dr Serena Sabatini, a psychologist at the University of Surrey who was not involved in the study, called the results “promising” but said investigating whether this holds up in older people should be a priority for future research be.
“Another important thing to consider in future research is an exploration of these mechanisms over time,” she added. “This study tells us that a bad night’s sleep can have an impact on how we feel the day after, but what are the cumulative effects of bad sleep over months and years?”
Dr Iuliana Hartescu, a senior lecturer in psychology at Loughborough University, who was also not involved in the study, said insufficient or poor sleep quality is important for lifestyle behaviors that ultimately affect long-term health.
“Sleep is one modifiable behavior that has an immediate, noticeable effect on health,” she said. “The effects of poor diet and low physical activity take a while to notice. The effect of a poor night’s sleep is immediate and affects all other 24-hour lifestyle behaviors.”
In separate work, a 10-year study of more than 4,000 Europeans found that those who consistently exercised two to three times a week were significantly less likely to suffer from insomnia than inactive people, and were better able to recommended six to nine hours of sleep each night.
The international team of researchers analyzed questionnaires from people enrolled in the European Community Respiratory Health Survey about their exercise habits, how well and how long they slept and how sleepy they felt during the day. Volunteers at 21 sites in nine countries were followed for a decade.
Those who exercised two or more times a week, for at least an hour a week, were 42% less likely to have trouble falling asleep than inactive people, the study found, and 55% more likely to to be “normal sleepers” who get a healthy amount of shut-eye every night.
“This study has a long follow-up period, 10 years, and strongly suggests that consistency in physical activity may be an important factor in optimizing sleep duration and reducing the symptoms of insomnia,” the authors said. writes in BMJ Open.
