Is it harmful to wash your hair with cold water in the weather of 5 to 15 degrees?

As the saying goes, "If you want to be healthy, take a cold bath every day". Many people feel refreshed after taking a cold shower, and even insist on washing all year round. So, how about a cold bath? For most people, if the method is correct, taking a cold bath is good for health. This is because, in the first minute or two, the skin epidermis will shrink and blood will flow to the internal organs. But after two or three minutes, the body will adapt to this temperature, and the blood will be redistributed and returned to the skin epidermis. The whole process is like "gymnastics" for blood vessels, which can not only enhance the resistance, but also enhance the elasticity of blood vessels and prevent arteriosclerosis. Secondly, bathing with cold water will obviously stimulate the nervous system, leading to faster heartbeat, deeper breathing and faster blood flow, which can not only promote metabolism, but also make the skin soft and elastic. In addition, taking a cold bath also helps to enhance the digestive function, and has a certain auxiliary therapeutic effect on chronic gastritis, gastroptosis, constipation and other diseases. However, in order to "enjoy" the benefits of taking a cold bath to the maximum extent, we must adopt scientific and reasonable methods, as follows: starting from summer, stick to it and step by step; Do a "warm-up" exercise before each cold shower: rub your skin for a few minutes until you feel red and hot; When taking a bath, first pour water on the limbs, and then rinse the chest and back for a few minutes to let the body have a gradual adaptation process; The water temperature should not be too low, 5℃-25℃ is appropriate, and the time should not be too long, 10- 15 minutes or so, and the longest time should not exceed half an hour. In addition, it should be noted that it is not advisable to take a cold bath after strenuous exercise, because the capillaries on the body surface are dilated at this time. If you suddenly "encounter" cold water, it will increase the burden on your heart and cause discomfort such as palpitation, shortness of breath and dizziness. In the process of bathing, if there are symptoms such as persistent whitening and dizziness, stop immediately to avoid accidents. A cold bath is not for everyone. The following people should "relax" when taking a cold bath: infants and elderly people over 60 years old are best not to wash, and women should not wash during menstruation and pregnancy, so as to avoid excessive water temperature; For people with poor immunity due to long-term continuous overtime or illness, bacteria and viruses are easy to enter, causing diseases such as colds and pharyngitis; Sensitive person should not be washed with cold water, otherwise it will have a rash; Taking a cold bath in patients with hypertension will increase blood pressure, and even lead to cerebrovascular bleeding, stroke, coma and so on. Taking a cold bath in patients with heart disease will increase the burden on the heart, induce angina pectoris, acute myocardial infarction and even sudden death; Patients with rheumatism and sciatica who are stimulated by cold water will aggravate local pain and should not take a cold bath. Precautions for taking a cold bath; 1. Women shouldn't take cold showers. When taking a cold bath, because the water temperature is too low, the human body will feel cold and produce a series of stress reactions, such as rapid heartbeat, high blood pressure, muscle contraction and nervous tension. It can not only eliminate fatigue, but also easily cause colds and should be avoided as much as possible. Because of its special physiological reasons, especially when female friends are in menstruation, lactation and pregnancy, the stimulation of cold water will cause endocrine disorders, amenorrhea and abdominal pain, and many bacteria will also enter the vagina to cause gynecological diseases such as vaginitis, which will seriously affect women's future pregnancy and health. 2. People with coronary heart disease should not take a cold bath! ! Cold water bath can promote the blood circulation of blood vessels in the whole body and enhance the opening and closing function of skin pores. Long-term adherence to cold water bath can improve the cold resistance of the body, thus helping to prevent diseases such as colds. Cold bath is really good for healthy people, but it is not suitable for patients with coronary heart disease. Because cold water stimulation can induce angina pectoris, even acute myocardial infarction or sudden death. According to clinical research, the peak of acute myocardial infarction is from 1 1 to April of the following year, and the main reasons may be related to cold stimulation and sudden climate change. Because the patient is stimulated by cold, the α adrenergic receptor of the body is excited, the arterioles of the whole body are contracted, the ejection resistance of the heart is increased, and the oxygen consumption of the myocardium is increased. Coronary artery disease in patients with coronary heart disease, coronary blood flow can not be increased accordingly, which eventually leads to myocardial ischemia and angina pectoris. Therefore, patients with coronary heart disease should pay special attention to cold and warmth in cold season, and avoid taking a cold bath to avoid an acute attack of coronary heart disease. 3. Don't take a cold bath in after making love. In the process of "sharing the same bed", the blood circulation of the whole body is accelerated, which is manifested by increased blood pressure, accelerated heartbeat, accelerated gastrointestinal peristalsis, flushed skin, sweat gland pores opening and sweating. Therefore, after * * is over, you will feel irritable and thirsty. Some people are eager to drink cold drinks or take a cold bath to sweat, which is not good for their health. Because during sexual life, the blood vessels in the gastrointestinal tract are dilated, drinking cold drinks will suddenly damage the gastrointestinal mucosa and even cause gastrointestinal discomfort or colic before the congestion of the gastrointestinal mucosa returns to normal. Similarly, in the process of * *, the skin blood vessels of the whole body are also congested and dilated, and the pores of sweat glands are in an open state of perspiration. At this time, if the skin is blown by cool wind or bathed in cold water, the blood vessels of the skin will suddenly contract, so that a large amount of blood will return to the heart and increase the burden on the heart; At the same time, it will also cause the sweat gland drainage hole to suddenly close, so that sweat is stored in the sweat gland, which is harmful to health.