Individuals who naturally stay up late are not inherently more prone to premature mortality compared to early risers—provided they do not engage in excessive drinking and smoking during those extended nighttime hours, a 37-year-long study suggested on Friday (16).
Previous research has indicated that night owls, who typically stay awake later and find it challenging to wake up early, have a higher likelihood of experiencing various health issues.
In 2018, a significant study conducted in the UK observed that individuals who classified themselves as evening people faced a 10 per cent higher risk of dying compared to those identifying as morning people, over a span of 6.5 years.
Although the previous research raised concerns for night owls worldwide, it did not consider various factors, such as alcohol consumption, that might have contributed to the observed mortality rates.
To delve deeper into this topic, researchers in Finland conducted a study, published in the peer-reviewed journal Chronobiology International, aiming to gain further insights and understanding.
Conducted on a sample of nearly 24,000 same-sex twins in Finland, the study tracked participants who were surveyed in 1981 to determine whether they identified as morning or evening individuals.
Of the participants, approximately one-third indicated being somewhat inclined towards being evening people, while 10 per cent firmly classified themselves as evening individuals. Most of the participants identified as morning people.
The findings indicated that the evening-oriented participants tended to be younger in age and exhibited a higher prevalence of alcohol consumption and smoking habits compared to their morning-oriented counterparts.
When the researchers followed up in 2018, more than 8,700 of the twins had died.
Over the 37 years, the researchers found that the definite night owls had a nine per cent higher risk of death from all causes -- a similar rate to the 2018 study.
But that difference was "mainly due to smoking and alcohol", the study said.
For example, it found that non-smoker night owls who were light drinkers were no more likely to die earlier than morning people.
- Night owls and drugs -
Christer Hublin, the lead author of the study from the Finnish Institute of Occupational Health, told AFP that the study's findings highlighted the potential for night owls to take action in order to reduce their risk of premature death.
"Clearly evening people should critically think about the amount of alcohol and tobacco they are using," he said.
Independent of other factors, the time when people tend to sleep, known as their chronotype, has "little or no" contribution to their mortality, Hublin added.
Jeevan Fernando, a chronotype researcher from Cambridge University who was not involved in the study, said that although the findings were reliable, the research had its limitations.
Fernando pointed out that relying solely on self-identification of participants as morning or evening individuals was "unsatisfactory" since it lacked objective information, unlike more contemporary approaches that employ advanced methods to determine chronotypes.
Fernando further noted that the study's limitations extended to its exclusion of substances other than alcohol and tobacco. Specifically, he highlighted the potential impact of cocaine, which has been associated with shifts from being an early riser to a late riser.
In his previous research, Fernando led a study that revealed night owls to have poorer mental health, particularly in terms of anxiety, and emphasized that drug use could potentially exacerbate these issues.
(AFP)
