You wake up in the middle of the night. You look at the clock and discover that it says more or less 4 in the morning. Even though you stay in bed, from that moment on you can’t get back to that deep, restful sleep.
If you have identified with that situation, you should know that you are not the only one. In fact, executives like Howard Schultz, the director of Starbucks, or Apple’s Tim Cook, have said that they get up around 5 in the morning. They probably do it to take advantage of those hours when most people are still in bed, but also because they wake up around 4 in the morning and can’t get any more sleep.
What happens to our brain at 4 in the morning?
Middle-of-the-night awakenings become more common as we grow older. In fact, over the years it is increasingly difficult to sleep straight through. However, the explanation for the tendency to wake up at 4 in the morning is not only found in age, it also depends on other factors.
First of all, you have to know the physiology of sleep, which follows different phases throughout the night. We are not always in a deep sleep phase. Every night we complete two or three sleep cycles, but starting with the first one, which lasts approximately three hours, our level of alertness increases, which means that any stimulus can wake us up.
Each of the sleep cycles includes three phases: a first slow and superficial, a second slow deep and a third known as the REM phase. The first two repair physical fatigue, while the REM phase restores cognitive functions.
The first sleep cycle usually lasts a maximum of three hours. From that moment on, our alert level is higher, so a faint noise or any discomfort can wake us up. We generally enter the second cycle naturally and, in some cases, also the third. However, since we have already slept a few hours and our need for rest is less than when we went to bed, those other sleep cycles are likely to be lighter.
Therefore, it is normal for us to wake up approximately four or five hours after falling asleep. If we go to bed around 11 at night, it is likely that we will open our eyes at 4 in the morning. If we get nervous because we have woken up and want to sleep or we start thinking about our worries, falling back into the arms of Morpheus will become an impossible mission.
How to sleep better? The answer could be in the diet
We can’t do much to influence sleep cycles, but we can focus on our hormonal balance. In fact, waking up at 4 in the morning also depends on hormones.
Sleep is guided by our internal clock or circadian rhythm. One of the most important circadian rhythms is precisely the one that regulates the sleep-wake cycle, which largely depends on the levels of two hormones: melatonin and cortisol, which follow a regular 24-hour pattern.
Melatonin helps us fall asleep, while cortisol helps us get up and stay awake. To synthesize melatonin, our body needs tryptophan, an essential amino acid that we acquire through food.
If we have not produced enough serotonin, we can fall asleep when we go to bed, but it is likely that we will wake up around 4 in the morning and from that moment on we will fall into a state of sleep.
The good news is that we can reinforce foods rich in tryptophan in our diet, such as chicken and turkey, oily fish, eggs, especially the yolk, dairy products, nuts and whole grains such as oats. In this way we can produce the appropriate amount of serotonin and improve the quality of sleep.
In addition, it is advisable that we develop habits that help our brain reduce the state of nervous excitement before going to bed, such as reading, listening to relaxing music, practicing relaxation techniques or taking a hot bath.
Likewise, we must forget about our cell phone at least two hours before going to bed because the blue light from electronic devices suppresses the production of melatonin, which will affect the quality of sleep and increase the risk of waking up at 4 in the morning and never going back to sleep.
Poza, J. J. et. Al. (2018) Melatonina en los trastornos de sueño. Neurología; 10.1016.
Zhu, L. & Zee, P. C. (2012) Circadian Rhythm Sleep Disorders. Neurol Clin; 30(4): 1167–1191.