As the body gets heated, the blood vessels in the skin open up. The oxygen content of superficial capillaries increases. Sweating starts. It is most profuse on the forehead. The blood volume and the cardiac output increases. For the first thirty minutes after the abrupt exposure to heat the blood volume increases due to influx of extra vascular fluid (fluid from tissue and muscles, surrounding the blood vessels). The blood gets diluted with more plasma. After half an hour the dilution is 5%. If the body continues to get heated for 1-4 hours this dilution may increase up to 13%. Not only this , the red cells circulating in the blood also increase. Later, there is formation of fresh plasma which further increased the blood volume.
As the blood volume increases the respiration slow down. When the body is heated the sleep contracts pushing more red cells into circulation. Thirst increases with a rise in temperature. Increases thirst is indication of dehydration of the body. It is always wiser to drink a glass or two before entering a heating chamber. The sweat glands keep on secreting regardless of the body hydration. The thirst mechanism proves inadequate. There is a decrease in the blood volume resulting in haemo-concentration. In men exposed to heat there is an average reduction of body weight by 3%. The plasma reduces 6.5%. The total circulating cells and protein in total blood remain the same.
When the atmosphere heats up suddenly, one feels lazy. This is due to inadequate blood volume, an increased body temperature and raised blood pressure. In a few days the body adapts itself to hot climate, and then you feel more comfortable and efficient in the same climate. This state of feeling better comes due to an increased blood volume, lowering of increased blood pressure and increased capacity of the body to sweat thus lowering the body temperature.
Sweating is an efficient mechanism to lower body temperature. This can be proved by the fact that a person can survive for 15 minutes even at a temperature of 1300C/(2660F). The rate of sweating is related to skin temperature, the sweating starts 5-40 minutes after being exposed to high temperature. Sweating first starts on the dorsum of the foot, then the calf, thigh, trunk, upper extremity and face. Sweating depends on the temperature, the degree of thermal acclimatization, metabolic rate, salt intake and sweat gland fatigue.
On exposure to extreme condition the sweat rate may be even 3 litres per hour for a short period. A person can sweat upto 14 litres a day. An increased water intake does not alter much the rate of sweating. If we take extra salt than what we excrete out in our sweat may reduce the rate of sweating. The ability to sweat more increases with acclimatization. The sweating rate is not uniform it is cyclic having a high and low peak. The highest sweating occurs in the neck, back, forehead and forearm.
If a person is immersed in hot water upto the neck, the sweating is at the peak in the first hour then it starts declining. It always occurs in fresh water. If salt is added there is less decline and it may reach to no decline in a 15% sodium chloride solution. Sweat also helps in the excretion and secretion from the body. This is also one of the most important channel for removing waste from body. 99% of sweat consists of water. The most important content of sweat is sodium chloride (common salt.) High sweat rate may result in as much as 20 gms. Salt loss in one day. This can lead in deficiency of salt in the body leading to heat cramps.
The Finnish sauna is believed to stimulate the adrenal cortex. This helps to decrease eosinophy II in the blood and increase excretion of 17-ketosteroids. This is why the sauna helps in cases of eosinophyllia. The peak value of 0.65 mgm/hrs of blood reached within 4 hours after a steam bath and 24 hours later it was 0.55 mgm/hrs. On third day it was 0.45 mgm/hrs almost reaching 0.42 mgm/hrs level which was prior to steam bath. This is why it is advocated to take steam or sauna not more than twice a week. The ideal is once a week. Due to the increased level of 17 – ketosteroids in the blood, the leucocytes count is slightly increased and the eosinophyll count reduced which came to almost the same level next day.
Sweat also contains urea and ammonia but their level in the sweat is higher than in the serum. Amino acid level in the sweat is lower than in the serum. By the end of the day you may feel a slimy substance deposited on the skin, you feel sticky. This substance is called sebum and it contains lactic acid, amino acid, urea, uric acid, ammonia and triglyceride fatty acids. These serve a double purpose as excretion of waste from the body and as a fungistatic, resisting the fungal infection on our skin.
It is not true to say that the skin can only excrete and that it cannot absorb. By warming the skin its permeability increases. It is found that the water penetrates the skin at a rate of 1.5mg/cm2/hour. If we add some extracts in bathing water they enter the skin and reach the blood. This is why spring water also helps in certain diseases. In an experiment, tritium oxide was addedAs the body gets heated, the blood vessels in the skin open up. The oxygen content of superficial capillaries increases. Sweating starts. It is most profuse on the forehead. The blood volume and the cardiac output increases. For the first thirty minutes after the abrupt exposure to heat the blood volume increases due to influx of extra vascular fluid (fluid from tissue and muscles, surrounding the blood vessels). The blood gets diluted with more plasma. After half an hour the dilution is 5%. If the body continues to get heated for 1-4 hours this dilution may increase up to 13%. Not only this , the red cells circulating in the blood also increase. Later, there is formation of fresh plasma which further increased the blood volume.
As the blood volume increases the respiration slow down. When the body is heated the sleep contracts pushing more red cells into circulation. Thirst increases with a rise in temperature. Increases thirst is indication of dehydration of the body. It is always wiser to drink a glass or two before entering a heating chamber. The sweat glands keep on secreting regardless of the body hydration. The thirst mechanism proves inadequate. There is a decrease in the blood volume resulting in haemo-concentration. In men exposed to heat there is an average reduction of body weight by 3%. The plasma reduces 6.5%. The total circulating cells and protein in total blood remain the same.
When the atmosphere heats up suddenly, one feels lazy. This is due to inadequate blood volume, an increased body temperature and raised blood pressure. In a few days the body adapts itself to hot climate, and then you feel more comfortable and efficient in the same climate. This state of feeling better comes due to an increased blood volume, lowering of increased blood pressure and increased capacity of the body to sweat thus lowering the body temperature.
Sweating is an efficient mechanism to lower body temperature. This can be proved by the fact that a person can survive for 15 minutes even at a temperature of 1300C/(2660F). The rate of sweating is related to skin temperature, the sweating starts 5-40 minutes after being exposed to high temperature. Sweating first starts on the dorsum of the foot, then the calf, thigh, trunk, upper extremity and face. Sweating depends on the temperature, the degree of thermal acclimatization, metabolic rate, salt intake and sweat gland fatigue.
On exposure to extreme condition the sweat rate may be even 3 litres per hour for a short period. A person can sweat upto 14 litres a day. An increased water intake does not alter much the rate of sweating. If we take extra salt than what we excrete out in our sweat may reduce the rate of sweating. The ability to sweat more increases with acclimatization. The sweating rate is not uniform it is cyclic having a high and low peak. The highest sweating occurs in the neck, back, forehead and forearm.
If a person is immersed in hot water upto the neck, the sweating is at the peak in the first hour then it starts declining. It always occurs in fresh water. If salt is added there is less decline and it may reach to no decline in a 15% sodium chloride solution. Sweat also helps in the excretion and secretion from the body. This is also one of the most important channel for removing waste from body. 99% of sweat consists of water. The most important content of sweat is sodium chloride (common salt.) High sweat rate may result in as much as 20 gms. Salt loss in one day. This can lead in deficiency of salt in the body leading to heat cramps.
The Finnish sauna is believed to stimulate the adrenal cortex. This helps to decrease eosinophy II in the blood and increase excretion of 17-ketosteroids. This is why the sauna helps in cases of eosinophyllia. The peak value of 0.65 mgm/hrs of blood reached within 4 hours after a steam bath and 24 hours later it was 0.55 mgm/hrs. On third day it was 0.45 mgm/hrs almost reaching 0.42 mgm/hrs level which was prior to steam bath. This is why it is advocated to take steam or sauna not more than twice a week. The ideal is once a week. Due to the increased level of 17 – ketosteroids in the blood, the leucocytes count is slightly increased and the eosinophyll count reduced which came to almost the same level next day.
Sweat also contains urea and ammonia but their level in the sweat is higher than in the serum. Amino acid level in the sweat is lower than in the serum. By the end of the day you may feel a slimy substance deposited on the skin, you feel sticky. This substance is called sebum and it contains lactic acid, amino acid, urea, uric acid, ammonia and triglyceride fatty acids. These serve a double purpose as excretion of waste from the body and as a fungistatic, resisting the fungal infection on our skin.
It is not true to say that the skin can only excrete and that it cannot absorb. By warming the skin its permeability increases. It is found that the water penetrates the skin at a rate of 1.5mg/cm2/hour. If we add some extracts in bathing water they enter the skin and reach the blood. This is why spring water also helps in certain diseases. In an experiment, tritium oxide was added to water in the bathing tub. In ten minutes it appeared in the urine. When water was warm this process wad enhanced and in an hour it reached the maximum concentration in the urine.
When a person is exposed to a temperature of 550 – 600C (131-1400F) for 15-30 minutes in a sauna, sweating is profuse and the weight loss is about 1/2 kg. On repeated exposure to heat, pigmentation can be developed due to melanin-producing cells. These are stimulated by pituitary glands which are responsible for secreting the melanocyte stimulating hormone. This is one of the main reasons why the sauna and steam bath help in cases of leucoderma in darkening the skin.\ to water in the bathing tub. In ten minutes it appeared in the urine. When water was warm this process wad enhanced and in an hour it reached the maximum concentration in the urine.
When a person is exposed to a temperature of 550 – 600C (131-1400F) for 15-30 minutes in a sauna, sweating is profuse and the weight loss is about 1/2 kg. On repeated exposure to heat, pigmentation can be developed due to melanin-producing cells. These are stimulated by pituitary glands which are responsible for secreting the melanocyte stimulating hormone. This is one of the main reasons why the sauna and steam bath help in cases of leucoderma in darkening the skin.