Why is the heart volume larger in water than on land?

When people get up from lying flat to standing still, due to the effect of gravity on the blood column, about 600 ml of blood accumulates in the veins of the legs, so the heart volume decreases. At this time, the organism has to increase the heart rate to maintain the blood output of the heart per minute. This is why people have faster heart rate and smaller heart volume when standing than when lying flat. On the contrary, when people change from standing to lying flat, the hydrostatic pressure in the body decreases and the blood moves from all parts of the body to the chest. So the heart volume increases and the heart rate slows down.

When swimming, because the hydrostatic pressure in the body is offset by the buoyancy of water, it will feel like weightlessness. The pressure of water will press 700 ml of blood in the superficial veins to the chest, so the central venous pressure will be significantly increased. Results the blood in the heart increased, the heart volume increased to about 840 ml, and the cardiac frequency slowed down accordingly. Therefore, patients with heart disease should be cautious when swimming.

Can swimming catch sexually transmitted diseases?

can’t. Dr. Chen Jianhao, who is always engaged in the front-line prevention and treatment of sexually transmitted diseases in Sun Yat Sen Memorial Hospital of Sun Yat sen University, said that there is no evidence that swimming will infect sexually transmitted diseases under normal circumstances. The vast majority of STD pathogens will die naturally in a few hours in vitro. Swimming pool water is usually disinfected by chlorination. The high concentration of chlorine will accelerate the death of pathogens.

However, Dr. Chen Jianhao reminded that if you go to the hot spring or the hot spring swimming pool, you need to be alert to the possibility of the spread of condyloma acuminatum. Condyloma acuminatum is caused by human papillomavirus (HPV) infection, about 30% of patients are indirectly transmitted by non sexual means. HPV virus has a certain transmission power in a warm and humid environment. If the skin is damaged or just goes into the water with patients with condyloma acuminatum, there is a risk of infection. Some hotel swimming pools and hot springs will provide slippers and bath towels. If the disinfection is not qualified, it can also create conditions for the transmission of virus and fungi. Because Therefore, if the skin is scratched, damaged or allergic, it is best not to swim in the water. Try not to use a public bath towel to wipe your body, especially not to wipe your private parts.

Female swimming is easy to get vaginitis?

In fact, this is mostly caused by “meditation”. Especially in summer, the swimming pool is wet and warm, which just provides a perfect breeding environment for bacteria. However, female friends do not need to worry too much. When swimming, the body is in a state of motion, and the possibility of bacteria invading the vagina is actually very small. In fact, most patients with vaginitis in the swimming pool like to sit still by the swimming pool in wet bathing suits after swimming. Bacteria often find them at this time.

Professor Zhang Xiaowei, chief gynecologist of the First Affiliated Hospital of Guangzhou Medical University, reminded that to prevent swimming pool vaginitis, we should first choose a regular swimming pool, take a shower immediately after swimming, dry our body, and change into clean clothes, which can effectively prevent swimming pool vaginitis. If you feel vaginal itching and pain after swimming, see a doctor in time.

Swimming helps “sex”

British sports medicine experts have found that swimming can help enhance men’s sexual ability and make it easier for women to have an orgasm. The survey shows that swimming can effectively prolong men’s erection time. Even when some male swimmers are 60-80 years old, their sexual life is still as active as men around the age of 30. The benefits of swimming to sex are more obvious in women. Women who often swim are more likely to reach orgasm in their sexual life. Breaststroke and butterfly are considered to be the most suitable sexual sports for women. Breaststroke, in particular, exercises women’s leg muscles, pelvic floor muscles and abdominal muscles in the opening and closing of two legs. These groups of muscles are the most important muscles used by women in sexual life. People who often swim can get good exercise in pelvic floor muscles, abdominal wall and thigh muscles, relax at the beginning of sexual life and prolong men’s erection time; In the second half of sexual life, you can help yourself reach orgasm through appropriate and powerful contraction.

However, Xiaobian should remind that swimming belongs to swimming. Even if swimming can enhance men’s sexual ability and help women achieve orgasm, don’t have sex in the water! A study at the University of Alberta found that underwater piston movement can easily push urine into the vagina, and it is not good for urine to enter the genitals. Even if no one pees in water, human sweat also contains urea. If you are in a swimming pool where chlorine is used as a disinfectant, you can’t have sex in it. Because the Royal College of Obstetrics and Gynecology found that the vagina contains beneficial bacteria, which can protect the vagina. Destroying these bacteria may cause infections, such as bacterial vaginitis. Chlorine and other detergents in the swimming pool can damage vaginal bacteria. If you slap in the pool, these substances may enter and cause damage, causing various infections.

Although water is wet, its lubrication effect is very bad. In addition, water will wash away the natural lubricant secreted by the body, making sex life difficult in water. You can hardly push smoothly in the water. If you have to insist, you may get hurt by friction. Underwater sex does not prevent sexually transmitted infections or pregnancy. You can use condoms, but due to lack of lubrication, condoms are likely to break or slip out without your awareness.

Beware of sepsis

Once a lady took her daughter to a public swimming pool. When she came home, she found that her daughter’s lower body was red and swollen, like being bitten by insects. She went to the hospital and diagnosed that her daughter had high fever, skin infection and sepsis, which were all infections suffered during swimming. Some children have skin redness, rash, pruritus, peeling and other phenomena after swimming, and suffer from dermatitis. Some children have diarrhea after swimming. Many parents think they have caught a cold. Sometimes it is the gastrointestinal reaction caused by the stimulation of low water temperature, and some are acute enteritis caused by unclean water quality. In addition, urinary tract infection is also one of the diseases easily infected by swimming. The probability of transmitting conjunctivitis in the pool is also relatively high. As long as one person in the pool suffers from conjunctivitis, the chance of cross infection will be greatly increased. Some children have water in their ears and choking in their airway when swimming. If the pool water is not clean, it may lead to diseases such as sinusitis, otitis media and external auditory canal inflammation.