Consequences of not drinking enough water

Water is virtually everywhere, from soil moisture and ice caps, to the cells inside our own bodies. Depending on factors like location, fat index, age, and sex, the average human is between 55-60% water. At birth, human babies are even wetter. Being 75% water, they are swimmingly similar to fish. But their water composition drops to 65% by their first birthday. 

So what role does water play in our bodies, and how much do we actually need to drink to stay healthy?

The H20 in our bodies works to cushion and lubricate joints, regulate temperature, and to nourish the brain and spinal cord. Water isn't only in our blood. An adult's brain and heart are almost three quarters water. That's roughly equivalent to the amount of moisture in a banana. Lungs are more similar to an apple at 83%. And even seemingly dry human bones are 31% water. If we are essentially made of water, and surrounded by water, 

why do we still need to drink so much?

Well, each day we lose two to three liters through our sweat, urine, and bowel movements, and even just from breathing.  While these functions are essential to our survival, we need to compensate for the fluid loss. Maintaining a balanced water level is essential to avoid dehydration or over-hydration, both of which can have devastating effects on overall health.

At first detection of low water levels, sensory receptors in the brain's hypothalamus signal the release of antidiuretic hormone. When it reached the kidneys, it creates aquaporins, special channels that enable blood to absorb and retain more water, leading to concentrated, dark urine. Increased dehydration can cause notable drops in energy, mood, skin moisture, and blood pressure, as well as signs of cognitive impairment.

A dehydrated brain works harder to accomplish the same amount as a normal brain, and it even temporarily shrinks because of its lack of water. Over-hydration, or hyponatremia, is usually caused by overconsumption of water in a short amount of time.

Athletes are often the victims of over-hydration because of complications in regulating water levels in extreme physical conditions. Whereas, 

• the dehydrated brain speed up the production of antidiuretic hormone, 
• the over-hydrated brain slows, or even stops, releasing it into the blood. 

Sodium electrolytes in the body become diluted, causing cells to swell.

In severe cases, the kidneys can't keep up with the resulting volumes of dilute urine. Water intoxication then occurs, possibly causing headache,  vomiting, and, in rare instances, seizures or death. But that's a pretty extreme situation. 

On a normal, day-to-day basis, maintaining a well-hydrated system is easy to manage for those of us fortunate enough to have access to clean drinking water.

For a long time, conventional wisdom said that we should drink eight glasses a day. That estimate has since been fine-tuned. Now, the consensus is that the amount of water we need to imbibe depends largely on our weight and environment.

The recommended daily intake varies from between 2.5-3.7 liters of water for men, and about 2-2.7 liters for women, a range that is pushed up or down if we are healthy, active, old, or overheating. While water is the healthiest hydrator, other beverages, even those with caffeine like coffee or tea, replenish fluids as well. And water within food makes up about a fifth of our daily H20 intake. 

Fruits and vegetables like strawberries, cucumbers, and even broccoli are over 90% water, and can supplement liquid intake while providing valuable nutrients and fiber. Drinking well might also have various long-term benefits. 

Studies have shown that optimal hydration can lower the chance of stroke, help manage diabetes, and potentially reduce the risk of certain types of cancer. No matter what, getting the right amount of liquid makes a world of difference in how you'll feel, think, and function day to day.

STAY HYDRATED...!!

Why blood types are important?| ABO blood group

It's often said that despite humanity's many conflicts, 

we all bleed the same blood. 

It's a nice thought but not quite accurate. 

In fact, our blood comes in a few different varieties. Our red blood cells contain a protein called hemoglobin that binds to oxygen, allowing the cells to transport it throughout the body. But they also have another kind of complex protein on the outside of the cell membrane. These proteins, known as antigens, communicate with white blood cells, immune cells that protect against infection.

Antigens serve as identifying markers, allowing the immune system to recognize your body's own cells without attacking them as foreign bodies. The two main kinds of antigens, A and B, determine your blood type. 

But how do we get four blood types from only two antigens? 

Well, the antigens are coded for by three different alleles, varieties of a particular gene. While the A and B alleles code for A and B antigens, the O allele codes for neither, and because we inherit one copy of each gene from each parent, every individual has two alleles determining blood type. When these happen to be different, one overrides the other depending on their relative dominance. 

For blood types, the A and B alleles are both dominant, while O is recessive. So, A and A gives you type A blood, while B and B gives you type B. If you inherit one of each, the resulting codominance will produce both A and B antigens, which is type AB. The O allele is recessive, so either of the others will override it when they're paired, resulting in either type A or type B. But if you happen to inherit two Os, instructions will be expressed that make blood cells without the A or the B antigen. 

            

Why do blood types matter?

For blood transfusions, 

finding the correct one is a matter of life and death. If someone with type A blood is given type B blood, or vice versa, their antibodies will reject the foreign antigens and attack them, potentially causing the transfused blood to clot. But because people with type AB blood produce both A and B antigens,  they don't make antibodies against them, so they will recognize either as safe, making them universal recipients. On the other hand, people with blood type O do not produce either antigen, which makes them universal donors, but will cause their immune system to make antibodies that reject any other blood type.

Rh Factor:

Unfortunately, matching donors and recipients is a bit more complicated 

due to additional antigen systems, particular the Rh factor, named after the Rhesus monkeys in which it was first isolated. 

Rh+ or Rh- refers to the presence or absence of the D antigen of the Rh blood group system. And in addition to impeding some blood transfusions, it can cause severe complications in pregnancy. If an Rh- mother is carrying an Rh+ child, her body will produce Rh antibodies that may cross the placenta and attack the fetus, a condition known as hemolytic disease of the newborn. Some cultures believe blood type to be associated with personality, though this is not supported by science. And though the proportions of different blood types vary between human populations, scientists aren't sure why they evolved; perhaps as protection against blood born diseases, or due to random genetic drift.

Finally, different species have different sets of antigens. 

In fact, the four main blood types shared by us apes 

seem paltry in comparison to the thirteen types found in dogs.

 

What causes some people to be left-handed?

Evolution spent nearly 400 million years crafting these works of art, two of the most important pieces of the human evolutionary puzzle. Yet 99% of us end up being good with one hand and not the other, for common tasks like writing, high-fiving, and the all-important one-handed texting. Even life itself seems to have chosen sides: our amino acids are said to be “left-handed”, our DNA turns in a right-handed helix..!

If you know an older left-handed person, chances are they had to learn to write or eat with their right hand. And in many parts of the world, it's still common practice to force children to use their "proper" hand.

 

Even the word for right also means correct or good, not just in English, but many other languages, too. But, 

If being left-handed is so wrong, then why does it happen in the first place?

Today, about 1/10 of the world's population are left-handed. 

Archeological evidence shows that it's been that way for as long as 500,000 years, with about 10% of human remains showing the associated differences in arm length and bone density, and some ancient tools and artifacts showing evidence of left-hand use. And despite what many may think, handedness is not a choice. It can be predicted even before birth based on the fetus' position in the womb.

So, if handedness is inborn, does that mean it's genetic?

Well, yes and no...! Identical twins, who have the same genes, can have different dominant hands.

In fact, this happens as often as it does with any other sibling pair. But the chances of being right or left-handed are determined by the handedness of your parents in surprisingly consistent ratios. 

• If your father was left-handed but your mother was right-handed, you have a 17% chance of being born left-handed, 
• If your father was right-handed but your mother was left-handed, you have a 22% chance of being born left-handed, 
• if both father and mother are lefties,  the chances of left handed child are 25%,
• while two righties will have a left-handed child only 10% of the time. 

Handedness seems to be determined by a roll of the dice, but the odds are set by your genes. All of this implies there's a reason that evolution has produced this small proportion of lefties, and maintained it over the course of millennia. And while there have been several theories attempting to explain why handedness exists in the first place, or why most people are right-handed, a recent mathematical model suggests that the actual ratio reflects a balance between competitive and cooperative pressures on human evolution. The benefits of being left-handed are clearest in activities involving an opponent, like combat or competitive sports. For example, about 50% of top hitters in baseball have been left-handed. 

But Why it is so?

Think of it as a surprise advantage. Because lefties are a minority to begin with, both right-handed and left-handed competitors will spend most of their time encountering and practicing against righties. So when the two face each other, the left-hander will be better prepared against this right-handed opponent, while the righty will be thrown off. This fighting hypothesis, where an imbalance in the population results in an advantage for left-handed fighters or athletes, is an example of negative frequency-dependent selection.

But according to the principles of evolution, groups that have a relative advantage tend to grow until that advantage disappears. 

If people were only fighting and competing throughout human evolution, natural selection would lead to more lefties being the ones that made it until there were so many of them, that it was no longer a rare asset. So in a purely competitive world, 50% of the population would be left-handed. 

But human evolution has been shaped by cooperation, as well as competition. And cooperative pressure pushes handedness distribution in the opposite direction. 

In golf, where performance doesn't depend on the opponent, only 4% of top players are left-handed, an example of the wider phenomenon of tool sharing. Just as young potential golfers can more easily find a set of right-handed clubs, many of the important instruments that have shaped society were designed for the right-handed majority. Because lefties are worse at using these tools, and suffer from higher accident rates, they would be less successful in a purely cooperative world, eventually disappearing from the population. 

So by correctly predicting the distribution of left-handed people in the general population, as well as matching data from various sports, the model indicates that the persistence of lefties as a small but stable minority reflects an equilibrium that comes from competitive and cooperative effects playing out simultaneously over time. And the most intriguing thing is what the numbers can tell us about various populations. 

From the skewed distribution of pawedness in cooperative animals, to the slightly larger percentage of lefties in competitive hunter-gatherer societies, we may even find that the answers to some puzzles of early human evolution are already in our hands.