The health benefits of drinking water include boosted energy levels, normal body temperature, metabolism, and easy breathing. It also helps in preventing digestive issues like constipation, headaches, and osteoporosis. It plays an important role in kidney function and skin care.
According to the United States Geological Survey, water covers over 70% of the Earth’s surface, the vast majority of which (greater than 95%) is in the oceans. All living forms require water for their metabolic activities. It plays a vital role in our body and it is impossible to imagine the existence of an individual without it. 
Water is an essential component of our body and plays a vital role in maintaining nearly all major organ systems of the body. The human body contains up to 60 percent water by weight. It is an integral part in the formation of saliva and mucus. According to science, the brain and heart are composed of 73 percent water; the lungs- 83 percent; skin- 64 percent; muscles and kidneys- 79 percent, and bones- 31 percent water.
Health Benefits of Drinking Water
Water has one of the most important roles to play in maintaining a healthy body and some of its benefits include:
Dehydration may cause fatigue, reduced motivation, and mood swings. Several studies have been conducted on the role of water and hydration in physical performance, particularly in athletes and in the military. 
One such comprehensive research by the University of North Carolina has shown the effect of dehydration on physical performance. It states that under mild dehydration levels, people engaged in vigorous physical activity experience a dip in performance levels related to reduced endurance, increased fatigue, and increased perceived effort. 
Cheuvront SN et al. from the US Army Research Institute of Environmental Medicine found that if the individual does not compensate for the fluid loss during high-intensity activities such as marathon running, it reduces endurance levels. 
Therefore, consuming ample amounts of water is very important to improve energy levels while exercising.
Brain Function and Headaches
When you are properly hydrated, it becomes easy for you to indulge in complex tasks.
A fluid balance helps in improving the mood, boosting memory, reducing the frequency of headaches, and improving brain function. If the body experiences fluid loss, it may lead to anxiety and excessive fatigue. 
A study conducted in the Netherlands on eighteen volunteers who suffered from regular headaches (all a migraine) showed a reduction in the total number of hours of headaches and also its intensity after drinking 1.5 liters of water per day for a period of 12 weeks.  
|Serving Size :|
|Calcium, Ca [mg]||10|
|Magnesium, Mg [mg]||2|
|Sodium, Na [mg]||2|
|Copper, Cu [mg]||0.01|
|Sources include : USDA |
Water carries oxygen, nutrients, and hormones to the body parts and also provides a medium for the removal of toxins, dead cells, and waste material via the kidneys. 
It helps you flush out the waste in the form of urine, sweating, and feces.
Unlike aerated beverages like soda and coke, water contains zero calories. It can make you feel full before meals so that you do not overeat. 
It also promotes metabolism and thereby aids in weight loss. 
Studies conducted in Germany by researchers led by Michael Boschmann showed that drinking 500 ml of water increased the metabolic rate by 30 percent. In fact, these metabolic rate increases were seen within 10 minutes of drinking the water and it reached a maximum after 30-40 minutes. 
A number of skin problems can be prevented by drinking adequate amounts of water. According to research, the skin may be more affected by frostbite and blisters if water levels are low in the body. 
The Department of Dermatology at The University of Franche-Comté, France conducted a study on 80 individuals, men and women, to assess the effect of natural mineral water intake on the skin. Results showed that there was an improvement in hydration, softness as well as the smoothness of the skin. 
Water is one of the major components that promote the smooth functioning of our digestive tract.
It helps in maintaining regular bowel movements and in preventing any difficulty in passing stool. Studies show that water can have positive effects on constipation. 
Water also helps to keep the liver healthy. 
Water can help you with hangovers in two ways.
Replacing alcoholic beverages with unsweetened soda water and lemon during parties may help you consume less alcohol and prevent the chance of hangovers at all.
On the other hand, if you have a feeling of dry mouth, thirst, fatigue, and headache caused by a heavy night of drinking, hydrating yourself can help. 
Water is an efficient solvent. This property helps prevent salts and minerals from accumulating to form stones, as salt reaching the kidney gets diluted and eliminated in the urine. 
According to the International Kidney Stone Institute, consuming 2 liters or 10 glasses of water through food and beverages each day can help prevent the formation of kidney stones. 
Much of the human body is made up of water and it is responsible for the regulation of body temperature. 
We perspire when it’s hot to lower our body temperature via evaporation. This temperature regulation property has been attributed to it as well. Particularly during exercise, the body’s water loss (via sweat) often exceeds water intake. This makes hydration even more important during and after physical exertion.
According to the research, your bones may become weak if you regularly consume low mineral water. Moreover, it is also important for the lubrication of your joints. 
Tap water contains a decent amount of minerals that are beneficial to your body. Do remember to filter it for preventing contamination. 
There is also evidence that acid-base imbalance may play a role in the formation of osteoporosis. While more research in this area is needed, studies show that individuals drinking adequate amounts of water may have a reduced risk of osteoporosis.  
Oxygen & Breathing
Water makes for 90 percent of human blood. As blood carries oxygen around the body, keeping your body hydrated is important.
The weight of the body is supported by the spinal cord. Water acts as a shock absorber for not only the spinal cord but also the brain, helping to protect this delicate system. 
Drinking water may help in increasing your blood pressure if you are suffering from hypotension. 
However, many studies show zero or no relation between water and metabolic/heart disease. If you are suffering from any such condition, do ask for a tip on your fluid intake from your doctor.
Dehydration has been shown to increase blood viscosity. Water helps maintain proper viscosity or thickness and stickiness of blood.
Some research shows that maintaining adequate hydration may be beneficial in lowering the risk of disorders including coronary heart disease and stroke.  
Pregnant Women & Nursing Mothers
A pregnant woman carries a new life in her womb that develops from her body’s resources.
During pregnancy, a woman’s blood volume increases, increasing her water needs. Other factors including amniotic fluid and fetal circulation need also increase a pregnant woman’s hydration needs. 
Also, during infancy, the baby requires more water. This is replenished by breastmilk or formula, but vomiting, diarrhea, or hot climate may lead to dehydration in your little one. So, it makes it important for breastfeeding mothers to keep themselves hydrated. 
Are you drinking enough water?
According to research, the average consumption of 8 glasses of water (sometimes, even more) is recommended every day; however, there have been NIH studies that say fluid intake depends on other variable factors such as weather conditions and activity levels. 
A 2010 research report by Meinders AJ et al. recommends that men should have a total daily fluid intake of 3,000 ml (12 cups) and women should have 2,200 ml (about 9 cups). It also adds that higher fluid intake has not shown any convincing health benefits, except in potentially preventing recurrent kidney stones. Although you don’t necessarily have to drink it directly, 20% of our H20 intake can be fulfilled by our food intake through a proper diet rich in fruits and vegetables. 
Word of Caution
Though water is safe and in fact necessary for life, it is possible to get too much of a good thing.
Drinking excessive amounts of water can cause hyponatremia or low sodium in the blood. Sodium is an electrolyte, and very important in fluid balance. This condition, usually caused by other medical issues or medications, is serious and can be life-threatening. Other than people with certain medical conditions including heart or kidney problems, severe vomiting or diarrhea, or those experiencing hormonal changes, those most at risk for developing this condition are endurance athletes. People lose both water and electrolytes through sweat; if you replace just the water and not the electrolytes they are losing during the activity, you can end up with hyponatremia. 
If you have a medical condition that increases your risk of hyponatremia, or take diuretic medications, speak with your doctor about your fluid needs.
Overall, water makes for an integral part of our lives. So, carry a bottle along and keep sipping it!