How your body functions

Food digestion takes 24 hours.

After food is swallowed, it reaches the stomach within 3 seconds. With the help of stomach acid, it is gradually broken down at a rate of consuming 3-4 calories per minute. High-fat foods need to stay in the stomach for 2-3 hours before entering the next passage - the small intestine. In the small intestine, food is further broken down, and nutrients are fully absorbed and utilized by the body. After about 20 hours, the remaining portion completes its journey slowly in the large intestine.

Wound healing takes up to 2 years.

Researchers at Columbia University found that the body begins the healing process within seconds after an injury: blood vessels quickly constrict to reduce blood flow, platelets accelerate blood clotting, and the wound starts to scab. However, it takes about 2 years for deeper wounds to heal, and the wounded area will only regain 80% of its original skin strength.

Weight gain occurs 3 hours after a big meal.

If you're feeling satisfied after a hearty meal, you'll start to feel the consequences about 3 hours later, as fat accumulates around your waist. Harvard University research found that dietary fats enter the bloodstream after 1 hour, and after 3 hours, most of them become part of the fatty tissues.

Rest is needed for 6 weeks after donating 500 milliliters of blood.

After a decrease in blood volume, plasma returns to normal within 24 hours, while oxygen-carrying red blood cells require a longer rest period, about 4-6 weeks. Therefore, doctors recommend a minimum interval of 12 weeks for blood donation for males and 16 weeks for females, as males typically have higher iron levels than females.

Fertilization of an egg takes only 30 minutes.

According to research from the University of California, eggs release a hormone that attracts sperm, which responds within 1 second. Then, the sperm overcomes various obstacles in the cervix and fallopian tubes in a short period of time, ultimately meeting the egg and creating life in just half an hour.

Nail growth is 2-4 millimeters per month.

A study conducted by scholars at the University of North Carolina in 2009 found that nails grow at a rate of 3.55 millimeters per month. The study also found that the middle finger has the fastest nail growth rate, while the pinky finger has the slowest. This may be because the middle finger is used more frequently, resulting in better blood circulation.

Water enters the bloodstream after 1 hour of drinking.

Dr. Reece, a urologist at the Royal Hampshire Hospital in the UK, believes that after absorption in the intestines, liquids enter the bloodstream within an average of 1 hour, and then they are filtered by the kidneys, entering the bladder and forming urine. Based on the bladder's capacity to hold about 300 milliliters of fluid, most people need to urinate every 3-4 hours.

Brain maturity takes 25 years.

Professor Price, a developmental neurobiologist at the University of Edinburgh, says, "The brain is like a telephone system, where the main lines are already connected, but finer lines require careful installation and debugging, and the first 3-4 years of life are a critical period for this adjustment." By adolescence, except for the prefrontal cortex, the brain is already well-developed. The prefrontal cortex is a critical area associated with thoughts and impulse control, and it doesn't fully develop until around 25 years of age. This may explain the unpredictability and tendency for risk-taking in adolescents' behavior.

Lung development takes 18-22 years.

If you find that your singing ability isn't as good as before, don't blame yourself for a decline in skills. It's actually a natural body response. The lungs reach their peak function at the age of 20 and then start to decline. Pregnant women who want their children to have good vocal cords and a healthy body should avoid smoking, as it can lead to future lung infections or asthma.

Puberty lasts for 3-8 years.

Adolescents entering puberty experience significant physical changes associated with gender characteristics. Girls may start puberty between the ages of 9-12, lasting for about 3-5 years. Boys, on the other hand, enter puberty between the ages of 10-13, with a longer duration than girls, typically lasting for 5-8 years.

Menopause lasts 2-10 years.

Women generally enter menopause between the ages of 40 and 55, with 51 being the average age of menopause. This special period usually lasts for 2-10 years.