.]]
Drinking is the act of consuming
water or a
beverage through the mouth. Water is required for many of life’s physiological processes. Both excessive and inadequate water intake are associated with health problems.
Physiology
A daily intake of 3-6 liters of water is required for the normal physiological functioning of the
human body, depending on ambient weather conditions and diet (especially salt and sugar intake). The absolute minimum over the long term is about 1.6 liters (600 ml for urine, 200 ml for fecal losses, and 800 ml for losses via the skin and lungs). This includes water contained in food (i.e., it is not essential to actually drink 1-2 liters of water a day for survival, though it is often recommended for good health).
The sensation caused by dehydration of the body is called
thirst. The sensation of thirst is a dry feeling in the back of the throat and an intense desire to drink fluids. Thirst is regulated by the
hypothalamus in response to subtle changes in the body's
electrolyte levels, and also as a result of changes in the volume of blood circulating.
Role in disease
patient is drinking oral rehydration solution in order to counteract his cholera-induced dehydration]]
Polydipsia is the medical term for the desire to consume large quantities of water and may be a sign of various diseases (
Diabetes Mellitus,
Diabetes insipidus, and some psychiatric conditions).
Much of the world's disease is caused by the lack of clean
drinking water. Lack of water in diet will eventually cause death by
hypernatremia and
dehydration, particularly when
sweating consumes much of the body water. Unclean and unsanitary water can contain many
bacteria and parasites that would otherwise be absent in clean water. Studies show that in some developing countries more than half of the population does not have access to safe drinking water.
It is also possible to
overhydrate, which sometimes happens with athletes who consume too much water, thereby diluting the concentration of salts in the body. Overconsumption of water can be a sign of
disease and/or mental health problems(e.g. damage to the hypothalamus), as stated above.
Fluid restriction
Fluid restriction or
water restriction is where a person intentionally abstains from drinking water (or other beverage for hydration), either partially or completely.
Partial fluid restriction can be used in
medicine, but have the disadvantages of being difficult to maintain, and it is often ineffective. Drugs causing increased diuresis (
diuretics) is generally an alternative, and have less risk of causing decreased
glomerular filtration rate through the kidneys and resultant decreased
kidney function. Fluid restriction is occasionally a practice in
management of heart failure. However, according to a
review in 2009, there is apparently no evidence of benefit of fluid restriction in patients with clinically stable heart failure otherwise receiving optimal pharmacological treatment. Rather, diuretics are preferred in heart failure, mainly
ACE inhibitors, with substantial evidence of improving survival and quality of life in heart failure patients. Theoretically, fluid restriction could also correct the
electrolyte imbalance in
hyponatremia, but again, diuretics, mainly
vasopressin receptor antagonists, show better efficiency.
Fluid restriction can also be part of religious practice, such as being part of the fasting from dawn till dusk in the
Ramadan period for Muslims. During the daylight hours of Ramadan fasting, practising Muslims are
dehydrating, but it is not clear whether this is chronic during the month of Ramadan. No detrimental effects on health have as yet been directly attributed to negative water balance at the levels that may be produced during Ramadan.
Alcoholic beverages
“Drinking” is often used as a
synonym for the consumption of
alcoholic beverages. Additionally, “having a thirst” or “being thirsty” can
metonymically express a desire to drink
alcohol.
See also
References