Some people are always on time, while others are always late. The human body is also like this in many aspects. A recent study by the National Institute of Environmental Health Sciences (NIEHS) of the United States found that the due date of delivery is meaningless to a large extent, because women’s gestation periods vary, and few people will give birth just before the due date of delivery. The British Daily Mail published an article entitled “12 health passwords” which can reflect the life span of the human body and can be summarized by many experts.
1. Digestion of food: 24 hours
Food can be swallowed in three seconds, but the digestion time in the human body will last for a whole day. Dr. Anton Emmanuel, an expert in gastroenterology at University College London, said that when food enters the stomach, it will be decomposed at a rate of 3-4 calories per minute with the help of gastric acid, and greasy food will take longer to digest. A 600 calorie dinner takes only 2-3 hours to digest in the stomach, and then 20 hours later, the food will enter the intestine for digestion.
However, the time to digest food varies from person to person, and basically 16-30 hours are within the health range. A study by the University of Hawaii in the United States found that the digestion time of foods such as hamburgers can be as long as 3 days, while fruit only takes 1 hour. The digestion speed of women, the elderly and patients taking antihypertensive drugs and antidepressants is relatively slow. In addition, bad emotions such as anxiety can also cause digestion to slow down. And intestinal inflammation such as irritability will shorten the food digestion time to less than 16 hours.
2. Wound healing: up to 2 years
A study by Columbia University found that the healing process starts after the wound is injured, but it takes 2 years for the wound such as surgical wound to fully heal. Studies have found that less than one second after the wound occurs, the blood vessels tighten to reduce bleeding. Platelets coagulate to help seal the wound. Calcium, vitamin K, fibrinogen and other substances will start immediately to form scabs. Scar tissue was formed in the following 3 months, and in the following 2 years, the scar tissue was enhanced, but it could only reach 80% of the initial strength of skin tissue. Scientists say that diabetes, adrenal ketones, ibuprofen and other factors can inhibit wound healing. Factors such as aging and sleep apnea will hinder wound healing. Vitamin C plays a key role in wound healing. If vitamin C is insufficient, the wound will be more difficult to heal.
3. Gain weight: 3 hours
A study by the University of Oxford in the UK found that dietary fat can enter the blood one hour after a meal, and most of it can enter fat tissues such as the waist three hours later. If the total fat of a meal is 30g, the waist fat will increase by 2-3 teaspoons within 3 hours after the meal. These fats are only temporary energy stores. But if you eat too much fat, it is easy to lead to fat accumulation in the waist, which will lead to obesity over time.
4. Orgasm: 20 minutes for women and 3 minutes for men
Many studies have shown that the duration of orgasm varies from a few seconds to half a minute. However, there are gender differences in the time to orgasm: the average time for women is 10-20 minutes, and that for men is only 2-3 minutes. Professor John stad, a gynaecologist at London premenstrual syndrome and menopause clinic, said that the brain, heart and hormones can all affect sexual desire and orgasm, so there are many variables in the time of orgasm for men and women.
5. Blood compensation: 6 weeks
After losing or donating about 568 ml of blood, it takes about 24 hours to replenish plasma, but 4-6 weeks to replenish red blood cells. The whole blood replenishment process starts from the kidney. After sensing the decrease of blood oxygen, the cells around the renal tubules begin to secrete erythropoietin. Male and female blood donors need to wait at least 12 weeks and 16 weeks between two blood donations, respectively, because the blood iron level in men is relatively high. (China stipulates that the interval between two whole blood donations shall not be less than 6 months)
6. Fertilization: 30 minutes
A study by the University of California found that it only takes half an hour for sperm to go upstream to the cervix and combine with eggs in the fallopian tube. NIEHS research in the United States found that once an egg is fertilized, the gestational time will vary from 37 to 42 weeks. Older pregnant women and women who gain too much weight during pregnancy will have a longer pregnancy, and the specific mechanism is still unclear.
Dr Victoria Beckett, an expert from the Royal College of Obstetrics and Gynecology, said that when the fetal lungs are developed, they will send a contraction command signal to the uterus to prepare for childbirth. But in some cases, this signal will be earlier, leading to premature birth. For example, the uterus is large, twins are pregnant, pregnancy diabetes or inflammation around the uterus. Although 37-42 weeks of gestation is normal, a study published in the British Medical Journal last year found that children born at 37-38 weeks of gestation are more likely to develop asthma and gastrointestinal diseases. A study in the Netherlands found that children born after 42 weeks of gestation (usually due to technology) were more likely to suffer from ADHD. The cause may be fetal enlargement or insufficient placental oxygen supply and nutrition.
7. Nail growth rate: 2-4 mm per month
A study by the University of North Carolina in the United States found that the average nail growth rate of people today is 3.55 mm / month, compared with 3 mm / month in 1938, which is related to the rich protein and various nutrients in the diet of modern people. Too slow nail growth is a sign of poor diet. The study also found that due to the difference in blood circulation, the growth rate of middle finger nails was the fastest, and that of little finger nails was the slowest. Because of hormones, men’s nails grow faster than women’s. Because of sufficient sunshine and more vitamin D, nails grow faster in summer.
8. Urinate after drinking water: 1 hour
Roland Reis, an expert in urology at Hampshire hospital in England, said that after drinking water (or other fluids), it enters the blood flow through the intestine, and then is filtered by the kidney and sent to the bladder, and then it is excluded from the body. The whole process takes about one hour. After drinking coffee, the process seems to accelerate. But this is only a misunderstanding. The real reason is that caffeine stimulates the bladder and causes more urination. Alcohol is a diuretic. After drinking alcoholic beverages, you will have more urine and urinate more frequently. Generally, the normal urination is once every 3-4 hours. Prostatic hypertrophy and other conditions will increase the frequency of urination. Reis said that waiting for urine and frequent urination may be signals of bladder hyperactivity. The reason is that there is an error in the signal between the brain and the bladder, causing the brain to send urination instructions to the bladder when it is not full.
9. Brain growth period: 25 years
David price, Professor of developmental neurobiology at the University of Edinburgh in the UK, said that before the age of three or four, the key period of brain development is just like the “main line” of the telephone system has been laid, but some branch telephone lines have yet to be connected. After 4 years old, the brain will lose the ability to form “branch telephone lines”. By adolescence, the brain is basically fully developed except for the prefrontal lobe. Brain development was not completely completed until the age of 25. A study found that the prefrontal lobe of the brain in adolescents was significantly less than that in adults, and the tissue in this area gradually increased with age. Prefrontal cortex is closely related to thinking, planning and impulse control. Adolescents are more likely to take risks, which is related to the fact that the prefrontal lobe of the brain is not fully developed.
10. Adolescence: 3-8 years
Dr Mark vandepamp, an endocrinologist at the Royal Free London NHS Foundation, said that puberty in girls usually starts at the age of 9-12 and lasts for 3-5 years. No longer growing is usually a sign of the end of puberty, and women usually have menarche for 2 years. Puberty in boys usually starts at the age of 10-13 and lasts for 5-8 years.
The latest research found that, because of estrogen, girls who develop earlier are at greater risk of breast cancer in the future than girls who start to develop at the age of 16. The later the puberty of girls, the greater the risk of osteoporosis. Early adolescence seems to have little effect on boys. However, studies in the United States show that early puberty may lead to early sexual activity and increased risk-taking behavior of boys.
11. Lung development: 18-22 years
In adolescence and early 20s, the lung capacity reached its peak, and then gradually decreased. John Henderson, a professor of pediatrics at the University of Bristol in the UK, said that the development of the human respiratory system began in the uterus and was basically completed by the 16th week of pregnancy. After birth, the respiratory tract becomes wider, and the air bag will continue to develop with the increase of the lungs. This process continues throughout childhood. Because women reach puberty earlier than men, the peak time of their lung function is also earlier than men. Before the age of 20 for women and after the age of 20 for men.
Professor Henderson said that some factors would prevent the development of lung function from peaking. Parental smoking, maternal smoking during pregnancy, premature birth, low birth weight, repeated lung infection, childhood asthma, etc. will directly affect the normal development of the lungs. These children are at greater risk of developing lung diseases such as chronic obstructive pulmonary disease (COPD) in the future.
12. Menopause: 2-10 years
The average age at menopause is 51 years old, but it is normal to enter menopause at 40-55 years old. Because of estrogen, menopause increases the risk of breast cancer too late. Cancer Research UK found that compared with menopausal women aged 45, menopausal women aged 55 had a 30% increased risk of breast cancer. And premature menopause means that the protection of estrogen is lost too early, which leads to increased risk of osteoporosis, heart disease and stroke.
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