We feel sleepy in spring, tired in autumn and nap in summer. What should we do if we feel sleepy in spring?

I feel sleepy in spring, tired in autumn, nappy in summer, and unable to wake up in winter.

As a qualified worker, no matter what happens, we will say ⬇️

But when we feel sleepy after a meal, we can only ⬇️

Why is it so difficult to “refuse” to feel sleepy after a meal? Today, let’s take a look with Pangke!

How do people feel sleepy?

Sleep is an indispensable instinct for humans and the most basic physiological need for living things. The core feature of sleep behavior is "sleep homeostasis regulation" , that is, as the wakefulness time increases, sleepiness gradually increases, eventually leading to sleep, and insomnia is the process of sleepiness being gradually eliminated. But where does "sleepiness" come from?

Previously, the top academic journal Science published a research report on sleep online, revealing that sleepiness is related to the continuous accumulation of a molecule called "adenosine". Adenosine is a "byproduct" of the cell energy molecule adenosine triphosphate (ATP) . The longer you stay awake, the more ATP is consumed, and the more adenosine molecules there are outside the cells. They bind to the corresponding receptors, inhibiting neural activity, and people will become more and more sleepy.

By observing the part of the mouse brain that controls the sleep/wake center, it was found that neuronal activity is closely related to changes in adenosine concentration, and two types of neurons that complexly regulate adenosine release were found: acetylcholinergic neurons and glutamatergic neurons . When the researchers managed to destroy the glutamatergic neurons in the basal forebrain of mice, they found that the mice's wakefulness time increased significantly. Therefore, it can be seen that the activity of glutamatergic neurons is the main cause of extracellular adenosine accumulation.

The researchers pointed out that in the process of accumulating sleepiness due to long-term wakefulness, glutamatergic neurons in the basal forebrain region of the brain not only maintain and promote wakefulness, but also increase sleepiness by stimulating the release of adenosine.

In addition, the lack of energy substances in the human body (such as muscle glycogen, liver glycogen, etc.), the accumulation of substances that can cause fatigue (such as lactic acid, pyruvate, etc.) and the protective inhibition of the cerebral cortex will also cause fatigue and drowsiness.

What causes drowsiness after meals?

Now that we understand the principle of drowsiness, let's look at the reasons for "drowsiness after meals". Perhaps the most common explanation you have heard before is that after eating, in order to facilitate digestion, the blood flow to the digestive system will increase, which will lead to a decrease in blood flow to the brain, which will cause cerebral ischemia and hypoxia, and people will become more prone to drowsiness. This logic seems to be reasonable in general, but it does not stand up to scrutiny!

The brain is the highest center of the human nervous system and can be said to be the most important organ in the human body. The body has a unique mechanism to ensure a stable blood supply to the brain. In physiology, there is a major principle that "no matter how hard life is, the brain must not suffer", so the blood supply to the brain must be guaranteed first.

Since the reason is not blood supply, then why do people feel sleepy after eating? Maybe we can find some clues from the process of food digestion!

No matter it is meat or vegetarian food, after entering the human body, the first stop is the mouth . In the process of chewing, the food is actually being simply and roughly decomposed for the first time; then it goes along the esophagus to the stomach , where gastric acid and digestive enzymes will decompose the food for the second time; depending on the food, they stay in the stomach for different times, and then they will go to the small intestine . After decomposition and absorption in the small intestine, the remaining residue enters the large intestine through the ileal valve; after the large intestine absorbs the final nutrients, it will form feces with other material residues, useless cells, etc. and excrete them.

What do you feel after reading about the changes that food undergoes in our body throughout its life?

In fact, to put it simply, after food enters our digestive system, it will be broken down into extremely small substances. The nutrients in them will be repeatedly absorbed and then transported to all parts of the body. The most important ingredient among them is glucose, which can be said to be equivalent to a "gas station" in our body.

In order to keep all parts of the body "filled up" at all times and places, the glucose content in the blood (that is, blood sugar) has always remained stable. However, after ingesting food, the glucose obtained from the decomposition of food will also be absorbed into the blood, and the blood sugar concentration will rise. Insulin, the only hormone in the body that can lower blood sugar, comes into play!

When blood sugar rises, the body will increase the secretion of insulin, prompting the conversion of excess glucose into glycogen, inhibiting the conversion of glycogen into glucose, and effectively adjusting blood sugar concentration. Therefore, the formation of insulin is one of the reasons for "feeling sleepy after a meal".

The synthesis of insulin promotes the synthesis and storage of proteins. In this process, tryptophan (a type of protein) forms 5-hydroxytryptamine (also known as serotonin) in the brain , which further forms a hormone that can regulate the biological clock - melatonin . I believe everyone is familiar with melatonin, which is an amine hormone produced by the pineal gland and can make the human body feel sleepy.

Another reason is related to serotonin . Serotonin can bind to receptors on the surface of neurons to enhance human sleep (emphasis here), promote memory, etc. After eating, the serotonin content increases, and serotonin promotes sleep, so after eating, you will feel sleepy.

In addition, this sleepiness after meals is also related to a substance in our body called cholecystokinin . It is a polypeptide hormone composed of 33 amino acids, which can stimulate the secretion of gastric acid, promote the digestion of fat, carbon water and protein, stimulate the secretion of insulin, and also travel to the brain to hypnotize the brain. In this process, did you see a familiar word "insulin" again? Therefore, the secretion of cholecystokinin can also cause us to feel sleepy after meals.

In addition to the above reasons, if you have the habit of taking a nap, then feeling sleepy after a meal is related to your biological clock . In addition, liver diseases, high blood sugar and other diseases can also cause feeling sleepy after a meal.

How to effectively relieve drowsiness after meals?

Here, Pang Ke will start with the cause and give you two suggestions: First, avoid eating high-sugar foods , such as bread, rice cakes, milk tea, etc., to reduce the secretion of insulin from the source; second, avoid eating foods with high tryptophan content , such as bananas, milk, nuts, etc., thereby reducing the synthesis of serotonin and further reducing melatonin.

Starting from lifestyle habits , you can also do appropriate exercise. Of course, it is not strenuous exercise such as running. Instead, when you feel sleepy after a meal, you can take a walk outdoors to adjust your body condition and allow your body to receive more visual stimulation. If you do this often, you can gradually improve your biological clock for a nap after a meal and relieve sleepiness.

Starting from tactile stimulation , you can choose to brush your teeth, wash your face, etc. to increase the excitement of the body's nervous system, thereby achieving the purpose of eliminating drowsiness.