Why do so many people hit snooze? This global smartphone study uncovers surprising patterns and raises questions about how repeated alarms may be impacting our sleep health.
Study: Snooze alarm use in a global population of smartphone users. Image Credit: Andrey_Popov / Shutterstock
Harvard Medical School researchers conducted a study on users of a sleep monitoring smartphone application to explore the prevalence and characteristics of snooze alarm use, a typical but poorly understood human behavior. The findings are published in the journal Scientific Reports.
Background
Sleep is a complex and dynamic physiological process for maintaining health and well-being. Internal circadian rhythms, together with time spent awake, influence the timing and duration of sleep. However, humans often subdue these biological regulatory processes for personal or professional reasons.
The recommended duration of night sleep for adults ranges from 7 to 9 hours. However, over the past several decades, a trend of not meeting this recommendation has been observed in global populations, which may increase the risk of both physical and mental health complications.
Although humans naturally wake after sufficient sleep, they often require assistance, such as the use of an alarm clock, to meet a desired wake time under conditions of insufficient sleep duration. The “snooze” function commonly available in alarm clocks is designed to repeatedly alert the sleeper in fixed intervals following the initial alarm. However, according to sleep experts, a sleeper should set an alarm for the last realistic wake time instead of setting a snooze alarm to get as much consolidated, uninterrupted, high-quality sleep as possible.
Using a snooze alarm is a typical but poorly understood human behavior. Only a few studies have investigated the health impact of snooze alarms and reported that this practice is associated with short and poor-quality sleep and feelings of drowsiness upon waking.
In the current study, researchers analyzed a large dataset to explore the prevalence and characteristics of snooze alarm use across countries, cultures, and climates.
Study design
The study analyzed a large pool of data from the users of a sleep monitoring smartphone application called “SleepCycle.” The database included six months of data from 21,222 app users and more than 3 million sleep sessions from users across four continents. The dataset included users who elected to use the traditional snooze feature, logged sleep sessions 50% or more of the nights in each month of the monitoring interval, used the app on an iPhone as opposed to an Android device, and consented for their data to be used in research.
Study findings
The analysis of sleep sessions opted by users at night revealed that more than half (specifically, 55.6%) of sessions end up with a snooze alarm. Of all users, about 45% were heavy snooze alarm users, 28% were moderate users, and 27% were light users.
Compared to light and moderate users who used snooze alarm less frequently and demonstrated more consistent sleep times, heavy snooze alarm users, who used the alarm almost every day and multiple times within each day, demonstrated erratic sleep/wake times.
Overall, users pressed the snooze alarm approximately 2.4 times daily and spent on average 10.8 minutes snoozing. This is equivalent to a monthly loss of nearly one 6-hour night of sleep. Heavy users chose the snooze alarm approximately 4 times daily, resulting in about 20 minutes of snoozing duration. On the other hand, light users chose the snooze alarm on average 1.2 times a day, resulting in 3 minutes of snoozing duration.
The use of a snooze alarm was more frequent during weekdays (Monday to Friday) and less frequent on weekends (Saturday and Sunday). Fewer commitments on weekends among employees and students might be the reason for this less frequent use.
The duration of snooze alarm use was significantly longer among women than men. The researchers suggest that this could stem from factors such as additional childcare and household duties over professional duties or an increased risk for insomnia among women, which might be the reason for women's higher reliance on the snooze alarm.
Month-to-month variations in snooze alarm use were minimal in the study population. Users in the Northern hemisphere exhibited slightly higher usage in December and less usage in September, while users in the Southern hemisphere exhibited the opposite trend. These variations might be associated with changes in seasonal sleep patterns due to factors like less access to natural light during winter months, potentially causing a delay in circadian rhythms.
The frequency of snooze alarm use was also higher among long sleepers (more than 9 hours of sleep) compared to that among short sleepers (less than 7 hours of sleep) or those meeting the recommended sleep duration (7 to 9 hours of sleep). As researchers mentioned, higher snooze alarm usage observed after long sleep sessions could be indicative of hypersomnia or compensatory sleep to recover from sleep deficiency.
The snooze alarm usage frequency was also higher among sleepers who went to bed later than usual compared to those who went to bed earlier. An unusual sleeping time is more common among shift workers who may have inadequate time in bed, and hence, more reliance on the snooze alarm. Furthermore, users with misaligned sleep may experience more fragmented sleep, and thus, greater reliance upon the snooze alarm.
While the study provides valuable insights from a large, international dataset using objective snooze alarm data, the researchers acknowledge certain limitations. These include the sleep data being app-derived, which may overestimate actual sleep duration as it doesn't account for time taken to fall asleep or awakenings during the night. Additionally, it was not certain if users were actually sleeping between alarms, and the sample of app users may not be fully representative of the general global population. The study also did not have information on the age of participants or self-reported feelings of grogginess upon waking.
Overall, the study findings highlight that a higher frequency of snooze alarm use might be indicative of a poor sleep pattern and potentially part of the phenotype of poor sleep health. Given that snooze alarm use is discouraged by experts to avoid sleep fragmentation, researchers highlight the need for future investigations to understand the impact of snooze alarm use on daytime performance and overall health. They also suggest that public health messages encouraging individuals to set their alarm for the latest possible wake time, rather than relying on the snooze button, could be a viable strategy to promote better sleep habits.