In a report from December 15, 2025, you may have experienced or often woken up a few minutes before the alarm clock goes off. For example, you set your alarm for 6 a.m., but you wake up automatically at 5:55 a.m. If you are one of these people, is your body normal? Let’s see what experts have to say.
Professors Yaqoot Fatima, a sleep health expert at the University of the Sunshine Coast in Australia, Alexandra Metse, a senior lecturer in psychology, and Danielle Wilson, a sleep scientist, wrote in an article on The Conversation website that waking up like this is not a coincidence; it’s your body’s internal clock at work. But how does this internal alarm clock function?
They explained that deep within the brain, there is a small group of neurons called the suprachiasmatic nucleus, which is often considered the “master clock” of the human body. These neurons track time through coordinating physiological rhythms, such as the circadian rhythm, to regulate functions like sleep, body temperature, hunger, and digestion.
The circadian rhythm influences the times when we naturally feel sleepy and awake each day. Our bodies naturally set this circadian rhythm, so differences in people’s sleep and wake times are entirely normal.
Why do some people prefer going to bed and waking up early, while others are “night owls” who go to bed and wake up late? This is because their circadian rhythms differ.
Establishing regular sleep and wake times, as well as habits around eating and exercise, can regulate our circadian rhythm, allowing it to predict when these activities occur each day and release relevant hormones to cope accordingly.
For example, when we wake up in the morning, we experience something called the cortisol awakening response, which is a significant increase in cortisol levels—a hormone that helps us prepare for the day ahead and maintain energy levels.
For individuals with a regular wake-up time exposed to morning sunlight, the circadian rhythm remembers their typical wake-up time. Before the alarm goes off, the circadian rhythm gently prepares the body—body temperature rises, melatonin (a sleep hormone) levels drop, and cortisol levels begin to rise.
By the time the alarm sounds, the body is already in an alert state. You can think of this as a hormone-driven “wake-up service,” similar to a wake-up call when staying in a hotel.
These scholars point out that if you regularly wake up a few minutes before the alarm goes off feeling refreshed, it indicates that your circadian rhythm is well-coordinated. It has learned to anticipate your daily routine, helping you transition smoothly from sleep to wakefulness.
However, if you wake up before the alarm feeling groggy or restless, it may suggest poor sleep quality rather than a well-functioning circadian rhythm.
Developing regular daily routines helps train the body’s circadian rhythm, especially when consistent with natural cues in the environment such as changes in light and temperature throughout the day. This can make falling asleep easier and waking up feeling refreshed.
On the other hand, irregular sleep patterns disrupt the circadian rhythm, leading to fatigue, difficulty concentrating, and challenges in completing mentally demanding tasks.
If you lack a regular sleep schedule, you rely on the alarm clock to wake you up, which may disturb deep sleep stages, leaving you feeling groggy; this situation is known as sleep inertia.
In today’s society, waking up naturally without the use of an alarm clock can be challenging. But if achieved, it means you have received sufficient rest, and your circadian rhythm is healthy and functioning well.
These scholars summarize that by implementing the following strategies, training your body to wake up without an alarm clock is feasible—(1) maintaining regular sleep times, sleeping 7 to 8 hours per day (including weekends); (2) avoiding disruptions in sleep due to caffeine, alcohol, or consuming heavy meals at night; (3) creating a dark sleep environment and avoiding electronic screens before bedtime; (4) ensuring exposure to natural sunlight in the morning.
It is worth noting that Dr. Mathias Basner, a professor of psychiatry at the University of Pennsylvania, previously stated that hitting the snooze button and indulging in a few extra minutes of sleep when the alarm goes off can affect sleep quality and even be harmful to the body.