Is hitting the snooze button really a bad idea? Study sheds light on the impact of morning alarms on sleep and cognition

By Dr. Sushama R. Chaphalkar, PhD.Oct 23 2023Reviewed by Benedette Cuffari, M.Sc.

In a recent study published in the Journal of Sleep Research, researchers determined the predictors and effects of using intermittent morning alarms on sleep, cognition, cortisol awakening response (CAR), and mood.

Study: Is snoozing losing? Why intermittent morning alarms are used and how they affect sleep, cognition, cortisol, and mood. Image Credit: Generated with DALL.E 3

Background

While ‘snoozing’ is a common behavior among people throughout the globe, little is understood about its causes and potential effects on an individual’s physical, emotional, and cognitive health. To date, few studies have examined snoozing; however, evidence suggests that fragmented sleep due to snoozing may impact daily life, such as a weak CAR leading to sleepiness and deficits in cognitive performance and mood.

About the study

The current study was conducted in two parts.

The focus of Study 1 was to examine the characteristics of individuals who snooze and their reasons for snoozing. A total of 1,732 individuals with a mean age of 34 years from Sweden, the United States, the United Kingdom, Finland, and Australia were included in the Study 1 cohort. About 66% of the participants were women, and 33% were men.

These individuals were surveyed on their sleeping and waking habits using an online questionnaire. These data were analyzed to compare snoozers with non-snoozers using t-tests and chi-square tests to assess the potential link between snoozing and the quality and duration of sleep.

Study 2 was a laboratory experiment conducted to understand the effects of snoozing on cortisol levels, mood, sleep architecture, and cognition post-waking up. This crossover study involved 31 habitual snoozers with a mean age of 27.5 years, 18 of whom were women.

Individuals with difficulty sleeping, insomnia symptoms, heavy snoring, or other physical or mental ailments were excluded from the study. All study participants slept in the laboratory for three nights wearing polysomnography gear.

Study participants were subjected to two waking conditions of snoozing or no snoozing. The experimental protocol was adjusted according to their regular sleep and wake times.

In the snoozing cycle, the participants were asked to set their alarms 30 minutes prior to their regular wake time, with three snooze events of 10 minutes each before waking. In the no-snoozing condition, participants were asked to set their alarm at their regular waking time and were not permitted to snooze.

The participants’ saliva samples were collected after waking and after 40 minutes to measure their cortisol levels. Cognition was evaluated using Karolinska WakeApp (KWA) tests. The KWA test lasted an average of 13 minutes and tested the participants for arithmetic speed, Stroop, and episodic and working memory.

All study participants self-rated their sleepiness, performance, mood, and effort.

Study findings

In Study 1, 69% of participants reported snoozing their morning alarm sometimes, whereas about 60% fell asleep between the two alarms. An average of 22 minutes were spent snoozing, with each interval about eight minutes long.

Interestingly, the snoozers were about six years younger than the non-snoozers, and most were likely to be “evening types.” No significant difference was observed in sleep quality; however, those who snoozed were three times more likely to feel drowsy upon waking up.

No gender-based differences were observed. The most common reasons for snoozing were “feeling too tired to wake up,” “wanting to wake up slowly,” and “it feels good” among 25%, 17%, and 17% of the cohort, respectively.

In Study 2, no significant effect of snoozing was observed on self-rated mood, sleepiness, CAR, or sleep architecture. However, a brief snoozing period may help reduce sleep inertia and slightly improve cognition right after waking, as the participants in the no-snooze condition showed an inertia effect in all the tests except the Stroop test compared to those in the snooze condition.

Snoozing was found to prevent awakening from slow-wave sleep (SWS), as none of the participants in the last 30 minutes of sleep in the snoozing condition had SWS as compared to 30% in the no-snooze condition.

Importantly, the Bayes factors determined in the overall study show varying strengths of evidence.

Conclusions

The study findings provide novel insights into the use of intermittent morning alarms and their effects on people’s overall well-being, with important implications for their work efficiency. Further research must include more representative samples, longer snooze times, and non-habitual snoozers.

It would also be interesting to investigate the effect of daylight, the long-term impact of snoozing, and the mechanisms underlying the observed effects to further improve our understanding of this behavior.