Sleep is not merely rest, but far from it there are process improvements in all organs of the body. When the repair process is underway, should give the body a chance to 'breathe' with the release of underwear.Not just resting the muscles, during sleep the body undergoes repair and detoxification (remove toxins). Sleep also gives an opportunity for the immune system to produce hormones immunity (immune system).
Therefore, you should use a loose-fitting clothing or remove clothing in your sleep, so it can accelerate and streamline the performance of the body in the repair process.
For women, a bra should not use while sleeping. Scientists from Sydney Singer and Soma Grismaijer his wife in 1991, once wrote in his book 'Dressed To Kill: The Link Between Breast Cancer and Bras', which contains about women who want to avoid breast cancer should wear a bra in the shortest time possible and preferably less than 12 hours per day.
"The best time to rest his breast without a bra is during sleep. Do not sleep with a bra," said Sydney Singer, as quoted by chetday, Wednesday (03/09/2011).
According to the Sydney Singer, use a bra for too long can increase the temperature of breast tissue and women who wear bras had higher levels of the hormone prolactin (hormone that functions to stimulate the milk glands) is higher. Both of these can affect the formation of breast cancer.
In addition, too often uses bra bra is too tight or use dangerous to health because it can also restrict the flow of lymph in the breast. Normally, lymph fluid wash waste material and other toxins, and also remove him from the breast.
As for men, you should use a loose underwear or pull the pants in his sleep. This is to give opportunity for the testes (testicles) to reduce its temperature to keep sperm quality remains good.
Male reproductive organs outside the body, so influenced by the situation around and used clothing. If he uses tight pants or underwear for too long, it will make the temperature around the appliance into increased reproduction and will certainly affect sperm production.
Testis can not function properly unless the temperature is colder than other body parts. If the testicular temperature is raised to 98 degrees F (36.67 degrees C), it will stop producing sperm.
When production is interrupted, then the negative impact could be many months. Can lower sperm count, sperm mortality and affect the morphology of the sperm itself.
In addition, sleep without wearing underwear allows air evenly distributed, so that body heat can be properly distributed.
This will launch the body's circulatory system. It is estimated that sleep with wearing underwear can restrict air flow in the skin and interfere with the evaporation of perspiration, especially in intimate parts of both women and men.
source: http://health.detik.com/read/2011/03/09/181836/1588199/766/tidur-tanpa-pakaian-dalam-lebih-sehat