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Regularly waking up between 2 and 4 a.m. can be related to many factors, from stress and lifestyle habits to health and sleep problems. Photo: Magnific . |
According to CHTV , a 2025 survey by the Chinese Sleep Research Association showed that 18.2% of adults experience frequent nighttime awakenings or waking up too early, ranking third among sleep problems.
In the same year, the Sleep Health Research White Paper also noted that 39% of adults wake up at least twice a night, while 65% experience sleep disturbances 1-2 times a week.
Specifically, waking up between 2 and 4 a.m. and being unable to fall back asleep is not simply a matter of poor sleep. In medicine, waking up earlier than desired and being unable to continue sleeping is called early-onset insomnia or late-stage insomnia. This condition may be related to circadian rhythms, prolonged stress, anxiety, depression, or other medical conditions.
Why do you usually wake up between 2 and 4 in the morning?
Sleep is not a state of stillness but is made up of several cycles, each lasting about 90 minutes, including light sleep, deep sleep, and rapid eye movement (REM) sleep.
During the first half of the night, deep sleep predominates, allowing the body to repair tissue and secrete growth hormone. In the second half, the duration of deep sleep gradually decreases while REM sleep increases, resulting in lighter sleep.
Around 3-4 AM is when the body transitions from deep sleep to light sleep. This is a natural "window" that makes it easier for people to wake up.
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Sleep occurs in multiple cycles, each lasting approximately 90 minutes, alternating between light sleep, deep sleep, and the REM stage. Photo: Magnific. |
In addition, cortisol (a hormone that plays a crucial role in the stress response) also fluctuates according to the circadian rhythm. Levels of this hormone typically drop to their lowest point between midnight and 1 AM, then begin to rise around 2-3 AM in preparation for waking up.
After waking up, cortisol levels continue to rise sharply during the first 20-30 minutes. This is the cortisol Awakening Response (CAR), a normal physiological phenomenon in healthy individuals.
The problem arises when this process occurs earlier or more intensely than normal. In people experiencing prolonged stress, anxiety, or chronic insomnia, the hypothalamic-pituitary-adrenal (HPA) axis may be overactivated. This causes the nighttime cortisol trough to become shallower, and the hormone to surge earlier, potentially causing the brain to enter a state of alertness in the middle of the night.
A 2023 clinical study published in Sleep Medicine noted that the more severe the insomnia, the higher the morning cortisol levels, and the higher the scores for depression and anxiety.
Meanwhile, a 2020 review also considered HPA axis dysfunction as one of the common physiological findings in people with chronic insomnia.
Factors that cause the body to wake up early.
The 3 AM "alarm clock" isn't always caused by stress. Waking up early is just one symptom; there could be many other factors behind it that sleepers often overlook.
One often overlooked factor is blood sugar. When blood sugar drops too low at night, the body may release cortisol and adrenaline to bring it back to a safe level. This reaction can potentially cause someone who is sleeping to suddenly wake up.
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Eating a lot of refined carbohydrates in the evening or drinking alcohol can contribute to disrupted sleep. Photo: Magnific. |
In addition, a diet high in refined carbohydrates in the evening or drinking alcohol can also contribute to disrupted sleep. Notably, after alcohol is metabolized, cortisol levels can rise again several hours later, precisely when many people enter the latter half of their sleep cycle and are more likely to wake up.
Sleep deprivation can also prolong this cycle. Studies show that just one night of 4-6 hours of sleep can result in baseline cortisol levels the following day being 20-37% higher than those who get a full 8 hours of sleep. In this case, sleep deprivation and increased stress response can interact, further deteriorating sleep quality.
Besides stress, waking up early can also occur in many other conditions such as depression, anxiety, night terrors, obstructive sleep apnea (OSA), hyperthyroidism, or certain neurological diseases like Parkinson's disease.
With OSA, awakenings can occur when the upper airway becomes obstructed during sleep, forcing the brain to trigger short bursts of wakefulness to restore breathing. Sleeping partners may notice signs such as loud snoring, choking or shortness of breath, or even intermittent cessation of breathing.
Signs that require a doctor's visit
If waking up early occurs three or more times per week, lasts for more than a month, and is accompanied by daytime fatigue, decreased concentration, impaired memory, or low mood, the patient should be evaluated for the cause.
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Persistent early awakenings, occurring three or more times per week and affecting daytime health, are signs that require an assessment of the underlying cause. Photo: Magnific. |
If your sleep partner notices you snore very loudly, frequently choke or gasp for breath, or even stop breathing intermittently, while daytime sleepiness affects your work or driving, your doctor may order polysomnography to assess your risk of sleep apnea.
If a person wakes up with a rapid heartbeat, sweating, feelings of panic, or a prolonged state of depression and loss of interest, they should be evaluated for mental health issues.
If you wake up with chest pain or tightness, shortness of breath, cyanosis, sudden confusion, slurred speech, or profuse sweating with tremors that don't improve after eating or drinking, call emergency services immediately. These could be signs of a cardiovascular emergency or severe hypoglycemia.
Sleep aids
In the book "What to Eat to Stay Young ," the author emphasizes: "Insomnia is no joke." Just one week of sleep deprivation (less than 5 hours per night) can lead to health problems comparable to those of smokers, people with diabetes, or those with coronary artery disease. Despite this, over 25% of the population still sleeps less than 6 hours a night.
To remedy this, a meta-analysis of numerous clinical trials suggests an effective little trick: Soak your feet or take a warm bath (40-42°C) for 10 minutes, 1-2 hours before bedtime.
Warm water dilates the blood vessels in the soles of the feet, allowing heat from the internal organs to dissipate more quickly. Immediately after stepping out of the warm water, the sudden drop in body temperature stimulates the brain to release sleep signals, helping you fall asleep about 15 minutes faster and sleep more soundly.
For insomnia, cognitive behavioral therapy for insomnia (CBT-I) is an important treatment option. This approach helps establish a consistent wake-up time, regulate time spent in bed, re-establish a connection between bed and sleep, and change anxiety-inducing thoughts about insomnia.
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Limiting blue light exposure from phones and computers before bed can help your body maintain a more stable sleep-wake cycle. Photo: Magnific. |
In addition, lighting can be adjusted to support circadian rhythms. For those who frequently wake up too early, evening light therapy can help regulate sleep-wake cycles. Reducing exposure to blue light from screens before bedtime is also recommended.
Additionally, it's recommended to maintain about 150 minutes of moderate-intensity aerobic exercise per week, limit caffeine intake in the late afternoon, avoid alcohol as a way to fall asleep, and keep the bedroom quiet, dark, and cool.
These medications can be used in some cases but require a doctor's prescription. Some groups, such as dual orexin receptor antagonists and low-dose doxepin, can help treat insomnia, while Z-drugs should be used with caution due to the risk of tolerance and dependence with long-term use.
People who frequently wake up between 2 and 4 a.m. can start keeping a sleep diary for 2-4 weeks, tracking their sleep times, number of awakenings, and daytime state. If the condition persists and affects their health, they should bring their diary to a medical facility for evaluation.
Source: https://lifestyle.zingnews.vn/vi-sao-co-hien-tuong-thuong-xuyen-giat-minh-tinh-giac-luc-2-4h-sang-post1685015.html
