1. Just waking up
It is thought that taking a bath right after waking up will help the body wake up and have a day full of energy. However, this is not a good choice for health.

After a night of sleep, the body is in a state of rest and relaxation, blood circulation is slower, heart rate and blood pressure are relatively lower. If you take a bath at this time, especially a hot bath, it can cause blood to flow quickly to the skin surface, while the amount of blood supplied to internal organs such as the heart and brain is reduced. This change can cause fatigue, dizziness, and even fainting in people with large fluctuations in blood pressure.

Additionally, the morning is the time when blood sugar levels in the body are lower, especially for those who eat dinner early or do not eat at night. Bathing in this situation, especially hot water baths, can reduce blood sugar and increase the risk of hypoglycemia.

Because of this, after waking up, you should wait for your body to gradually adapt to the state of being awake or exercise, and then take a bath.

2. Just had a full meal
This is the habit of many people. However, after eating, the digestive system needs a large amount of blood to help the digestive tract absorb and digest food.

When you bathe right after eating, the change in water temperature will cause blood to flow to the surface of the body, impacting the blood supply to the digestive tract, thereby adversely affecting the digestion process. This can cause problems such as indigestion and bloating, and may even affect digestive health in the long term. Especially after eating foods high in fat and protein, the digestion process is more complicated and needs more blood supply. So, it’s advisable to wait at least 30 minutes to 1 hour after a meal to wait for the food to be initially digested before bathing to avoid putting a burden on the digestive system.

3. Take a late bath and go to bed immediately

People are advised not to bathe after 10 pm. Because if you bathe during this time, the body will constrict or dilate blood vessels to retain or release heat. This can easily lead to sudden blood vessel spasms, making the body susceptible to high blood pressure or even stroke.

Additionally, it’s not advisable to sleep immediately after bathing. Bathing too close to bedtime, especially hot baths, will cause the body temperature to increase, and the human body needs to lower its body temperature when falling asleep to achieve the best sleep state.

From a physiological perspective, the human body requires a lower body temperature to promote the secretion of melatonin, an important hormone that regulates sleep. Therefore, you are advised to shower 1 to 2 hours before going to bed so that the body has time to gradually return to the appropriate sleeping temperature. Moreover, the water temperature should not be too high to avoid stimulating the nervous system and making people more alert.

4. After exercise
The body will sweat a lot after exercise. Many people want to shower immediately to remove sweat.

However, the heart rate and blood pressure will increase during exercise, blood flow increases rapidly and the body will be in a state of “fight or flight” excitement. Showering right after exercise, especially cold showers, will cause blood vessels to suddenly constrict, affecting blood circulation and can lead to cardiovascular problems, even stroke.

Furthermore, after exercise, the body needs time to detoxify through sweat and dissipate heat through the skin in order to regulate body temperature. If you take a bath right after finishing exercise, especially a hot bath, it can interrupt the body’s natural cooling process and increase the burden on the cardiovascular system. Thus, after strenuous exercise, you had better cool down and rest properly in order that your heart rate and body temperature gradually return to normal before bathing.