When swimming, the body is directly immersed in water, which not only has great resistance, but also has very good thermal conductivity and fast heat dissipation, so it consumes more heat. Like a boiled egg, the cooling rate in air is far less than that in cold water. Experiments show that the heat consumed by a person swimming in a standard swimming pool for 20 minutes is equivalent to swimming on land at the same speed 1 hour, and staying in water with 100 minutes is as high as 100 kcal, which is equivalent to being in air with the same temperature. In addition, swimming diet can avoid sports injuries of lower limbs and waist.
When you exercise on land to lose weight, your body (especially lower limbs and waist) will bear great gravity load because of the heavier weight of obese people, which will reduce your exercise ability and make you tired easily, thus greatly reducing your interest in losing weight and damaging the joints and bones of lower limbs. When swimming in water, a considerable part of obese people's weight is borne by the buoyancy of water, which makes their lower limbs and waist much easier and greatly reduces the risk of joint and bone injury. It can be seen that water sports make many people who want to lose weight get twice the result with half the effort. Therefore, swimming is one of the most effective aerobic exercises to keep healthy.
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Matters needing attention
1. You must swim under the guidance of your parents (guardians). Swimming alone is the most prone to problems. If your companion is not a parent (adult), it is difficult to guarantee that you can get proper help when you are in danger. (taboo for children)
People who are sick should not go swimming. Patients with chronic diseases such as otitis media, heart disease, dermatosis, liver and kidney diseases, hypertension, epilepsy and pinkeye, as well as those with colds, fever, mental fatigue and physical weakness, should not go swimming, because these patients are not only prone to aggravate their illness, but also prone to cramps, accidental coma and life-threatening. Patients with infectious diseases are easy to infect others. In addition, female students are not allowed to swim during menstruation.
3. After taking part in strong physical labor or strenuous exercise, you can't jump into the water to swim immediately, especially when you are sweating or fever. Otherwise, it is easy to cause cramps and colds.
4, cold, illness, physical discomfort or weakness, after meals, fasting, drinking alcohol is not suitable for swimming.
5. Polluted (poor water quality) rivers, reservoirs, places with rapids, the intersection of two rivers and lakes with gaps are not suitable for swimming. Generally speaking, all rivers and lakes with unknown water conditions are not suitable for swimming. Bad weather such as thunderstorm, strong wind and sudden change of weather is not suitable for swimming.
6. It is best to experience the water temperature before entering the water. If the water temperature is too cold or too hot, try not to rush into the water. The temperature of the pool water has an influence on blood circulation, heart, blood pressure, respiration, metabolism, human skin and muscles.
7. Before launching, do warm-up activities on the shore, warm up for 10 to 15 minutes, and exercise joints and muscles in all parts. Otherwise, it is easy to cause muscle injury or other accidents if you suddenly engage in more intense activities. Lift your legs, squat, and stand up.
8. Don't dive, lest the abdomen and testicles be directly hit by water.
9. When swimming, you need to pay attention to protect your eyes, prevent sunburn, and pay attention to the low tide time.
10, after swimming, rinse the whole body with clear water to avoid infectious diseases.
1 1. After swimming, you can recover your physical strength by supplementing sports drinks, relaxing training, breathing adjustment, hypnotic suggestion, psychological adjustment, massage recovery, water roaming and other means.
12, the potential dangers are leg cramps, dizziness, headache, nausea, vomiting, chest tightness, earache, tinnitus, abdominal pain, abdominal distension, itchy eyes and so on.
13, the common diseases are conjunctivitis, otitis media, sinusitis, pharyngolaryngitis, contact dermatitis, allergic dermatitis and aspiration pneumonia.
14, avoid swimming in the sun for a long time.
Prolonged exposure can lead to sunburn or acute dermatitis, also known as sunburn. In order to prevent sunburn, it is best to use an umbrella to shade the sun after landing, or rest in a cool place, or use a bath towel to protect the skin, or apply sunscreen to exposed parts of the body.
15, avoid swimming without warm-up activities.
The water temperature is usually lower than the body temperature. Therefore, warm-up activities must be done before entering the water, otherwise it will easily lead to physical discomfort.
16, avoid eating immediately after swimming.
It is advisable to rest for a while before eating after swimming, otherwise it will suddenly increase the burden on the gastrointestinal tract, which will easily lead to gastrointestinal diseases after a long time.
17, avoid swimming for too long.
Skin generally has three reaction periods to cold stimulation. The first stage: after entering the water, stimulated by cold, the skin blood vessels contract and the skin color is pale. The second stage: after staying in the water for a certain period of time, the blood flow on the body surface expands, the skin turns from pale to reddish, and the skin turns from cold to warm. The third stage: the stay time is too long, the heat dissipation of body temperature is greater than fever, and the skin has goose bumps and chills. This is a taboo period for summer outing, so leave the water in time. Generally, the swimming time should not exceed 1.5~2 hours.
18, avoid swimming before and after meals.
Swimming on an empty stomach will affect appetite and digestive function, and there will be accidents such as dizziness and fatigue during swimming. Swimming with a full stomach will also affect the digestive function, and it will also cause stomach cramps and even vomiting and abdominal pain.
19, avoid swimming in unfamiliar waters.
When swimming in natural waters, don't jump into the water. Under complicated circumstances, it is not advisable to swim around the water surface and underwater to avoid accidents.
20. Avoid swimming on an empty stomach
Many people who like swimming have a feeling that after swimming ashore, they will feel hungry and weak. This is because swimming is a heavy physical exercise, with a large amount of muscle activity in the limbs, which will consume a lot of energy and calories. If we go swimming on an empty stomach, it will cause hypoglycemia, especially for diabetics, and the risk of hypoglycemia coma is greater. If swimmers are hungry, their blood sugar is too low and they consume a lot of energy, they are particularly prone to muscle trembling, dizziness, collapse, coma and even direct drowning. Therefore, swimmers should properly supplement some fruits, milk, candy and other foods before swimming, and then swim in the water.
2 1, avoid swimming during physiological period.
Girls who come to menstruation must avoid swimming in the water at this time, because during menstruation, germs can easily enter the uterus, fallopian tubes and other places through water, causing infection, leading to irregular menstruation, excessive menstruation or prolonged menstruation.
References:
Baidu encyclopedia-swimming