Two studies on snoozing habits found that morning drowsiness and shorter sleep were more common among individuals who snooze. On the other hand, 30 minutes of snoozing either improved or did not affect cognitive performance after arising compared to rough awakening. There were no effects of snoozing on cortisol awakening response, morning sleepiness, mood, or characteristics of overnight sleep. The study was published in the Journal of Sleep Research.
Since the early 1950s, most alarm clocks have featured a snooze button, allowing the alarm to be delayed for a brief period after its initial activation. This function enables users to employ intermittent alarms to postpone their final awakening, a practice commonly known as snoozing. Surveys conducted in 2017 and 2022, involving 20,000 activity-tracking wristwatch users and working professionals respectively, found that approximately 50% of individuals hit the snooze button at least once each morning. Women, individuals with a less pronounced conscientiousness trait, and those who prefer staying up late are more likely to engage in snoozing.
Despite the widespread practice of snoozing, its effects on daily functioning have been largely understudied by scientists. Essentially, snoozing shortens overall sleep duration compared to setting the alarm for a later time, when one would immediately rise after the alarm. This practice could potentially increase the risk of various negative effects associated with sleep loss, such as cognitive deficits, mood disturbances, and others. Conversely, delaying the final wake-up time might allow an individual to complete their sleep cycle and reach a lighter sleep stage before having to wake up.
Tina Sundelin, an assistant professor at the Stress Research Institute and Department of Psychology at Stockholm University, and her colleagues wanted to learn more about snoozing behavior and its effects. “I was interested in the topic of snoozing partly because it seemed to be such a common behaviour and partly because I kept hearing that it was bad without it having been properly studied,” she explained.
The researchers conducted two studies; the first aimed to identify the characteristics of people who snooze and their reasons for postponing awakening. The second study examined the effects of snoozing on sleep quality, sleepiness, cognitive ability, mood, and the cortisol awakening response.
The cortisol awakening response is a natural increase in cortisol levels occurring within the first hour of waking, playing a critical role in preparing the body and mind for the day ahead. Cortisol, a steroid hormone produced by the adrenal glands, is integral to various physiological functions, including metabolism regulation, immune response, and the body’s stress response.
In the first study, 1,732 individuals responded to a survey conducted by the study authors via Qualtrics. Eighty percent of the respondents were from Sweden, with others hailing from the USA, Finland, the UK, and Australia. Sixty-nine percent of the participants reported occasionally using the snooze function or setting multiple alarms. Most did so only on workdays, but 23% used it on both workdays and days off. Among snooze users, 60% reported falling asleep between alarms.
On average, snoozers were six years younger than non-snoozers, four times more likely to stay up late at night (evening types), and had shorter sleep durations on workdays (but not on days off). The most common reasons for snoozing included feeling too tired to wake up, enjoying the sensation, and preferring a slower, more gradual awakening.
The second study involved 31 habitual snoozers, averaging 27.5 years of age, including 18 women. All participants slept in a laboratory equipped with a polysomnography device for three nights. The first night involved practice tests to minimize learning effects. The subsequent nights included one with snoozing and another without. Participants maintained their regular sleep schedules but either woke up at their usual time or 30 minutes earlier, using the snooze button every 9-10 minutes until their final awakening.
Immediately upon waking, the researchers turned on the lights, collected saliva samples (to measure cortisol levels), and conducted a series of cognitive tests using the Karolinska WakeApp. Participants also rated their sleepiness, effort, and performance after each cognitive test, as well as their mood.
The results indicated that sleep characteristics were similar on nights with and without morning snoozing. Sleep architecture, the organization and structure of sleep stages, differed only during the snooze period, with participants experiencing lower sleep efficiency and more arousals. There was also a variation in sleep stages during this period. Participants exhibited signs of sleep inertia, or drowsiness, immediately after awakening in both conditions.
Cognitive performance generally improved over time after waking. Right after waking, those who snoozed showed somewhat better performance on two cognitive tests, although the effect of snoozing on one test dissipated 40 minutes later. Both sleepiness and mood improved sometime after waking, regardless of snoozing. Furthermore, snoozing had no impact on cortisol levels.
The findings indicate “that snoozing is common and probably not that bad for you, as long as you are getting the sleep you need beforehand,” Sundelin told PsyPost. “I was surprised that the effects of 30 minutes of snoozing had such little impact on the full night’s sleep. And that participants were a bit more quick-thinking after having snoozed.”
The study provides valuable insights into the effects of snoozing. However, it also has limitations that must be considered. Notably, the second study only included habitual snoozers, meaning the results may not be applicable to individuals who do not usually snooze. Research on such individuals might yield different outcomes. Additionally, the study exclusively used a 30-minute snooze duration, suggesting that shorter or longer snoozing periods could have varying effects.
“It is a rather small study and we only focus on one morning of snoozing,” Sundelin said. “I would be interesting to look at snoozing (vs not snoozing) over time and also to focus on different types of snoozing – different durations and intervals etc.”
The paper, “Is snoozing losing? Why intermittent morning alarms are used and how they affect sleep, cognition, cortisol, and mood”, was authored by Tina Sundelin, Shane Landry, and John Axelsson.
