Do you know why outdoor activity protects children from myopia?

Prof. Know Why answers for your general knowledge and awareness on: Do you know why outdoor activity protects children from myopia?

We all know that the more children are allowed to play outdoor sports, the better it is for their health in the growing days. But a recent study found that time spent outdoors even protects children against myopia.

The study has suggested that time spent in the open appears to protect children from near-sightedness, adding a new factor for a common condition that has long been blamed on extensive reading or genes.

Researchers at the University of Sydney, Australia, believe the intensity of outdoor light may be an important, but till now unrecognized, factor that influences the development of myopia, which usually begins during school years.

“Increasing outdoor activity may be a way to counter factors that might be contributing to myopia,” said Kathryn Rose, an ophthalmologist who led the study that involved more than 4,000 schoolchildren in Australia. It was published last week in the journal Ophthalmology.

The researchers found that 12-year-olds with the highest outdoor activity had the lowest rates of myopia, independent of the amount of reading or other near work they did. Myopia was most common in children with low levels of outdoor activity and high near work.

Long hours of indoor playtime or sports had no effect on myopia levels. “It appears to be the effect of intense light,” Rose said.

Myopic eyes are mildly elongated, front to back. The scientists believe that in response to light, the retina releases a chemical called dopamine and prevents eye elongation. The pupils also constrict in intense light, increasing the distance at which objects can be seen.

Near-sightedness has long been attributed to genetics. Children with parents who have myopia are at risk. “But we still can’t say whether it’s the effect of genes or whether the parents create an environment that promotes myopia,” Rose said.

“What has held out over the years is that children with strong scholastic achievements tend to have myopia. Our new study shows that children who do a lot of schoolwork and spend time outdoors appear protected.”

Independent studies in the US and Singapore appear to support these findings, she said.

The researchers have recommended more studies to try and establish the connection more firmly, and explore the mechanism of how exposure to daylight by means of outdoor activity, can prevent myopia.

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Do you know why delayed fatherhood can cause miscarriage?

Prof. Know Why answers for your general knowledge and awareness on: Do you know why delayed fatherhood can cause miscarriage?

Couples who want to start a family, better plan it early in your life because the more you delay, the stronger becomes the risk of a miscarriage, say the scientists. And this applies to both men and women. Contrary to the older belief that men remain fertile even at old age, this new research points out that delayed fatherhood can also cause miscarriage like late motherhood.

Delayed fatherhood for men is a cause of concern for a healthy pregnancy and the baby as well, doctors warn, after a recent research found that male fertility begins to decline when they reach their mid-30s. Doctors said men who wait until their 40s before starting a family face a greater chance of their partner having a miscarriage, because of the poorer quality of their sperm.

The researchers studied the records of more than 12,000 couples treated for infertility at the fertility clinic, Eylau Centre for Assisted Reproduction in Paris between January 2002 and December 2006; and separated out the influence of male and female ages on the couples' chances of having a baby. They found that women whose partners were 35 or older had more miscarriages than those who were with younger men, regardless of their own age. The men's ages also affected pregnancy rates, which were lower in the over-40s.

The study looked at pregnancies and miscarriages recorded for couples having IUI treatment at the clinic. It found the risk of miscarriage was on average 16.7% when men were aged 30-34. That rate rose to 19.5% when men were 35-39 and 33% in men aged 40 or over.

The findings are a concern, researchers say, because of the trend for men to delay fatherhood. Stéphanie Belloc, lead author of the study, said that until now, gynecologists only focused on maternal age, and the message was to get pregnant before the age of 35 or 38 because afterwards it would be difficult. But now the gynecologists must also focus on paternal age and give this information to the couple.

Yves Ménézo, an embryologist at the Eylau Centre for Assisted Reproduction, said older men become less fertile because genetic defects build up in their sperm. In younger men, the damage is minor and can be repaired inside the fertilized egg. But in older men the amount of DNA damage can overwhelm the body's natural repair mechanisms. "We think there's a critical threshold of DNA damage and above that, the damage can no longer be repaired. When that happens, genetic mistakes get through to the embryo and you get an increase in miscarriages," Ménézo said.

Jacques de Mouzon, a co-author at the French National Institute for Medical Research, said: "People say men are fertile into old age, 90 even. That may be true sometimes, but the product is different and there are more semen abnormalities as age advances. There is a decrease [in male fertility] and an increase in the spontaneous abortion rate after the age of 40 and especially after 45. It is necessary for men to try to have children before the ages of 40 to 45."

Previous research has pointed to a slight increase in birth defects in babies born to older men. A 2005 study of 70,000 couples by epidemiologist Jorn Olsen at the University of California, Los Angeles, found a fourfold rise in Down's syndrome among babies born to men aged 50 and older. They were also more likely to have limb deformities.

Dr Allan Pacey, a fertility expert at Sheffield University and secretary of the British Fertility Society, said: "There is growing evidence from a number of studies to show that men are not totally immune from reproductive ageing. "Previous studies of couples trying to conceive naturally or undergoing IVF have shown that men over the age of about 40 are less fertile than younger men. Moreover, if they do achieve a pregnancy their partners are more likely to miscarry. This study reinforces the message that men aren't excused from reproductive ageing."

Normally, men don't typically worry about reproductive ageing, but perhaps they should if the study is to be believed, as now, delayed fatherhood is also being linked to miscarriages, and birth deformities.

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Do you know why children are at risk from passive smoking?

Prof. Know Why answers for your general knowledge and awareness on why children are at risk from passive smoking:

Babies, infants and children on the whole don’t smoke or so do we think! But, the reality says something different. In fact, infants and children belonging to smoker parents are forced to smoke because of ignorance by the latter – yes, I’m talking about passive smoking! But do you know about the consequences?

Well, children who are exposed to secondhand tobacco smoke that is passive smoking, early in life are at greater risk of being hospitalized for infections than those brought up in a smoke-free environment, researchers from Hong Kong reported, recently.

The risk of being hospitalized was greatest among babies 6 months old and younger, but the increased risk persisted up until the children were 8 years old, Dr. M. K. Kwok of the University of Hong Kong and colleagues found in their research. Children who were premature or had low birth weight were particularly vulnerable.

The findings suggest that passive smoking exposure may not only be harmful to children's respiratory tracts, but to their immune systems as well, the researchers Kwok and colleagues noted in their report in the journal Tobacco Control.

Even if smoking is banned in public places, babies and children may still be exposed to passive smoking at home. So, the risks remain.

While the danger that passive smoking poses, to children's developing respiratory systems is well understood, less is known about its effects on overall infection risks. To investigate, the researchers looked at a group of 7,402 children born in 1997 who were followed up until age 8. At the study's outset, nearly 42% were exposed to passive smoking at home.

Children who had been within 3 meters (or about 9.8 feet) of a person smoking cigarettes at any point during their first 18 months of life were 14% more likely to be hospitalized for any type of infection by 8 years of age, the researchers found.

The greatest difference was seen among infants, with 1 in 3 exposed babies being hospitalized for an infection by the time they were one year old. Exposure during the first 3 months of life had the strongest effect.

Premature and low birth weight infants seemed to be more vulnerable to the effects of passive smoking and they were twice as likely to be hospitalized for an infection by age 8 than unexposed children.

The researchers concluded that passive smoking exposure in early infancy, instigates all infectious illnesses and not just respiratory and related infections. And again, this may even have a larger and more long-lasting impact in developmentally more vulnerable subgroups, such as premature or low birth weight infants.

So, if you fall among the ignorant smoker parent’s group, just do bother to keep your children away from passive smoking, at least from now on – that is of course, if you care! Gift your children a smoke-free home and not hospital!

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Do you know why women may have diminished libido?

Prof. Know Why answers for your general knowledge and awareness on why women may have diminished libido:

Are you having problems in your sex life? Is your woman having diminished libido? Well, she may be suffering from pelvic floor disorder, which may impact women's sex life!

Incontinence and other disorders of the pelvic organs can take a toll on a woman's sex life, a new study suggests.

Researchers found that among 300 women aged 40 and above, those with symptoms of a pelvic floor disorder were more likely to have a diminished libido, pain during sex, or problems reaching orgasm.

Pelvic floor disorders refer to problems with a woman's pelvic organs - the uterus, bladder and rectum; and the muscles and connective tissue that support them. Among the most common of these are urinary incontinence and pelvic organ prolapse, where weakened muscles and supporting tissue allow one or more pelvic organs to drop down and protrude into the vagina.

Some symptoms of prolapse include pressure in the vagina, pain in the lower abdomen or lower back, and chronic constipation.

It has been estimated that one-third of U.S. women have at least one type of pelvic floor disorder, but studies have come to conflicting conclusions as to whether the conditions hinder women's sex lives.

The new findings, reported in the journal Obstetrics & Gynecology, suggest that many women with these disorders, do in fact, have problems with sexual function.

However, the risk of sexual dysfunction was not elevated among women who had mild prolapse that was not causing symptoms, said lead researcher Dr. Victoria Handa, an associate professor of gynecology and obstetrics at Johns Hopkins University in Baltimore. This is important, she explained, because it indicates that women who have sexual complaints but no other potential symptoms of pelvic organ prolapse do not need to be evaluated for the disorder.

The findings are based on 301 patients recruited from gynecology offices affiliated with Johns Hopkins. Eighty women were seeking care for a pelvic floor disorder, including bladder control problems and pelvic organ prolapse. The rest of the women had other conditions or were getting a routine checkup. All of the women completed questionnaires on their overall health, pelvic symptoms and sexual function.

Overall, the researchers found, women with pelvic floor disorders were more likely to have symptoms of a diminished libido, pain during sex and infrequent orgasms - regardless of age and whether they had gone through menopause.

According to the findings of an earlier study by Dr. Handa and her colleagues, women's diminished libido and sexual function are often improved after having surgery to correct significant prolapse.

So, women with pelvic floor disorders should talk it out with their doctors about any sexual difficulties they have. That may only help, improve their diminished libido.

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Do you know why erectile dysfunction is an early sign of heart disease?

Prof. Know Why answers for your general knowledge and awareness on why erectile dysfunction is an early sign of heart disease:

Erectile dysfunction and heart disease may seem to be two different problems, but recent findings from two studies of men with diabetes add to the evidence that erectile dysfunction can be a powerful early warning sign for serious heart disease.

A Hong Kong study of 2,306 men with diabetes but no signs of heart disease found that those with erectile dysfunction at the start were 58 percent more likely to have a heart attack or other major cardiac problems over the next four years than those with adequate sexual function.

And, Italian physicians who followed 291 men who had diabetes and early coronary heart disease for four years, reported similar numbers - those with erectile dysfunction were twice as likely as men without the problem to have major adverse events, including strokes.

There's a physical connection between male sexual failure and heart disease, involving the effect of diabetes on the nervous system and the blood vessels, said Dr. E. Scott Monrad, director of the Cardiac Catheterization Lab at Montefiore Medical Center in New York City. "Neuropathy would interfere with the neurogenic responses feeding into proper erection," Monrad said. "And obstruction of blood flow into the arteries reduces the pressure needed to achieve erection."

It has been known that erectile dysfunction shares many risk factors with coronary heart disease, such as high blood pressure, smoking and diabetes, according to Dr. Robert A. Kloner, a professor of medicine at the University of Southern California. "What is new here is that erectile dysfunction remained a significant risk factor for developing heart disease after controlling for other cardiovascular risk factors," Kloner said in a statement.

"These reports add two things to what we already know," said Dr. R. Parker Ward, an associate professor of medicine at the University of Chicago, who led an earlier study linking erectile dysfunction with heart disease. "One is that they indicate the importance of erectile dysfunction in diabetic patients in terms of predicting future cardiovascular events. These studies suggest that the additional presence of erectile dysfunction places them at incrementally higher risk. Secondly, they show that even when considered in combination with traditional risk factors, erectile dysfunction offers incremental information about the risk of future cardiovascular events."

The researches indicate that acknowledgment of erectile dysfunction can prompt doctors to suggest more aggressive treatment at an early stage for risk factors such as high blood pressure and cholesterol that may lead to heart diseases.

So, if you are having erectile dysfunction, talk it out with your physicians, since this may prove to be a very sensitive marker for cardiovascular risk. Remember, an early and more sensitive measure may save you from future heart risks.

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Do you know why exercise may protect girls from future breast cancer?

Prof. Know Why answers for your general knowledge and awareness on why exercise may protect girls from future breast cancer:

We are all aware of the fact that exercise is good for health. And middle-aged women have long been advised to get active to lower their risk of breast cancer after menopause. But, starting young, pays off, too. A new research shows, exercise during the teen years — starting as young as age 12 — can help protect girls from breast cancer when they're grown.

Dr. Graham Colditz of Washington University School of Medicine in St. Louis, the study's lead author, points out that the benefit of sustained physical activity from adolescence through the adult years, gets the maximum benefit.

Researchers tracked nearly 65,000 nurses, ages ranging from 24 to 42 who enrolled in a major health study. They answered detailed questionnaires about their physical activity dating back to age 12. Within six years of enrolling, 550 were diagnosed with breast cancer before menopause. A quarter of all breast cancer is diagnosed at these younger ages, when it's typically more aggressive.

Women who were physically active as teens and young adults were 23 percent less likely to develop premenopausal breast cancer than women who grew up sedentary, researchers reported in the Journal of the National Cancer Institute.

The biggest impact was regular exercise from ages 12 to 22.

The women at lowest risk of breast cancer, reported doing 3 hours and 15 minutes of running or other vigorous activity a week — or, for the less athletic, 13 hours a week of walking. Typically, the teens reported more strenuous exercise while during adulthood, walking was most common.

But, why exercise may protect girls from future breast cancer? How exactly, would it help? A big point of exercise in middle age and beyond is to keep off the pounds. After menopause, fat tissue is a chief source of estrogen.

In youth, however, the theory is that physical activity itself lowers estrogen levels. Studies of teen athletes show that very intense exercise can delay onset of menstrual cycles and cause irregular periods.

While the study examined only premenopausal breast cancer, "it's certainly likely and possible" that the protection from youthful exercise will last long enough to affect more common postmenopausal breast cancer, too, Colditz added.

Dr. Alpa Patel, a cancer prevention specialist at the American Cancer Society, who praised the new research, said that though the moderate exercise reported in this study of breast cancer was nowhere near enough for those big changes, but it probably was enough to cause slight yet still helpful hormone changes.

Dr. Patel believes that even if someone was a bookworm as a teen, it's not too late, because other researches on the middle-age benefits of exercise show, mom should join her daughters for that bike ride or game of tennis or at least a daily walk around the block.

There are quite a few breast cancer risks that a woman can't change, like:

• How early she starts menstruating
• How late menopause hits
• Family history of the disease

But, physical activity and body weight are such factors that women can control. Women who engage in physical activity not only during adolescence but also during adulthood, lower their risks of breast cancer, said Dr. Patel.

So, what are you still waiting for? If your young daughter is a bookworm or simply a TV buff, just simply get her off the couch.

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Do you know why women can’t be medically fit when fat?

Prof. Know Why answers for your general knowledge and awareness:

The popular belief that supports the 'fit but fat' theory, has recently got a setback. New research challenges the notion that you can be fat and medically fit at the same time, finding that being active can lower but not eliminate medical risks like heart attacks and other complications, faced by heavy women.

Previous research has gone back and forth on whether exercise or weight has a greater influence on heart disease risks.

The new study involving nearly 39,000 women helps sort out the combined effects of physical activity and body mass on women's chances of developing heart disease.

The study by Harvard-affiliated researchers appeared in the Archives of Internal Medicine.

Participants were women aged 54 on average who filled out a questionnaire at the study's start, detailing their height, weight and amount of weekly physical activity in the past year, including walking, jogging, bicycling and swimming. They were then tracked for about 11 years. Overall 948 women developed heart disease.

In the study, women were considered active if they followed recommended guidelines and got at least 30 minutes of moderate activity most days of the week, including brisk walking or jogging. Women who got less exercise than that were considered inactive.

Weight was evaluated by body mass index: A BMI between 25 and 29 is considered overweight, while obese is 30 and higher.

It was found that compared with normal-weight active women, the risk for developing heart disease was 54 percent higher in overweight active women and 87 percent higher in obese active women. By contrast, it was 88 percent higher in overweight inactive women; and 2.5 times greater in obese inactive women.

Women over 50, who eventually develop heart attacks or other cardiovascular problems, excess weight can raise those odds in many ways, by increasing blood pressure and risks for diabetes, and by worsening cholesterol. But exercise counteracts all three to some extent – it was observed.

"It is reassuring to see that physical activity really does make an impact," said lead author Dr. Amy Weinstein of Boston's Beth Israel Deaconess Medical Center. However, she added, "If you're overweight or obese, you can't really get back to that lower risk entirely with just physical activity alone."

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Do you know why masturbation reduces the risk of cancer?

Prof. Know Why answers for your general knowledge and awareness:

People have always linked masturbation with adult topics of discussions as because the first thought that comes with the word masturbation, is sex and lust. The society is normally hesitant and feels awkward to discuss on the subject of masturbation, openly and freely. Well, that is fine! But do the elders know the benefit of masturbation? I bet, not! A recent research-study has discovered an amazing fact about masturbation that may change the outlook of the society on the whole.

Researchers have found out that men who masturbate regularly are at a reduced risk of developing prostate cancer.

Yes, you read it right! In the study, Australian researchers concluded that frequent masturbation may help men cut their risk of contracting prostate cancer. It is believed that carcinogens may build up in the prostate if men do not ejaculate regularly, reported BBC News.

The researchers surveyed more than 1,000 men who had developed prostate cancer, and 1,250 men who had not. They found that men who had ejaculated the most between the ages of 20 and 50 were the least likely to get cancer. Men who ejaculated more than five times each week were a third less likely to develop prostate cancer.

Sexual intercourse may not have the same effect because of the higher risk of contracting a sexually transmitted disease, which could in turn raise the risk of cancer. "Had we been able to remove ejaculations associated with sexual intercourse, there should have been an even stronger protective effect of ejaculations", Graham Giles of the Cancer Council Victoria, who led the researchers, said in the article.

The prostate produces a fluid that is incorporated into ejaculation, which activates sperm and prevents them from sticking together. Studies on animals have shown that carcinogens like 3-methylchloranthrene can be harbored in the prostate. Frequent ejaculation encourages the cancer-inducing fluids to flush out.

So, do I still need to say, “Carry on men” or you have already got the message?

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Do you know why men should chuck smoking and drinking for offspring?

Prof. Know Why answers for your general knowledge and awareness:

We all learned people know that too much of smoking or drinking is injurious to our health as science has long been clear that smoking or heavy alcohol consumption causes cancer. But, a new study has found that babies could inherit genetic damage from a father who puffs or drinks heavily.

A team of international researchers has found that smoking or drinking alcohol can cause chemical changes in the semen in men and the alterations could be potentially inherited by their offspring and their future generations.

The researchers came to the conclusion after they analyzed the effects of smoking and heavy drinking — both toxic in nature — on a group of mice. They gave pregnant female mice daily injections of pesticide vinclozolin during the period when the sex of embryos is determined. Male offspring had abnormalities, including prostate and sperm development problems, and genetic changes that the researchers found were passed on through four generations when the males were mated with healthy females.

The researchers have also identified specific genes involved in the production of sperm that were permanently altered by the exposure to the pesticide. "In addition to the spermatogenic and prostate abnormalities, trans-generational effects on numerous disease states were observed including tumour development and kidney disease”, said Matthew Anway of the University of Idaho.

Anway said the doses used, far exceeded the levels that humans could expect to be exposed to, but the study was designed to demonstrate how toxins lead to inheritable abnormalities.

"Studies have shown significant associations between male toxic exposures and increased rates of infertility, miscarriage, stillbirth and childhood health problems to open our eyes and look at the evidence" and "when you harm the male reproductive system you can see multi-generational harm transmitted through the male gamete (sperm). This research has human implications as it suggests an avenue of harm and a model of trans-generational effects”, said co-researcher Dr Cynthia Daniels of the Rutgers University.

Before it becomes too late, one thought-provoking question to the men of these bad habits, who are yet father a child - you might justify the privilege of living your own life on your preferred terms, but do you sincerely have the right to snatch away a desired healthy life from your offspring?

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Do you know why it does not pain cutting our nails?

Prof. Know Why answers:

In medical dictionary, nail is defined as “the horny epidermal derivative covering the dorsal aspect of the terminal phalanx of each finger and toe”. Well, in common man’s language, by fingernails and toenails, we understand hard scaley transparent structures that grow at the tip of our fingers and toes. Nails are part of our body. But the amazing thing is that it does not hurt when we cut them short, although it does not happen with other body parts (except hair).

A nail consists of:

• Eponychium or cuticle - the fold of skin at the proximal end of the nail.
• Paronychium - the fold of skin on the sides of the nail.
• Hyponychium - the attachment between the skin of the finger or toe and the distal end of the nail.
• Nail plate - the hard and translucent portion composed of keratin.
• Nail bed - the adherent connective tissue that underlies the nail.
• Lunula - the crescent shaped whitish area of the nail bed.
• Nail fold - a fold of hard skin overlapping the base and sides of a fingernail or toenail.

But, why it does not pain, cutting our nails? In common usage the word nail usually refers to the nail plate only. Nails are made of a tough protein called keratin and are produced from living skin cells in the fingers and toes. But they do not have nerve endings and pain receptors like the rest of our body. So the pain sensation does not reach our brain and we do not feel pain when they are cut.

But we do feel pain when a nail is plucked, because there are sensory nerves underlying the nail bed and pressure on it is transmitted to these nerves, which results in the sensation of pain. So as long as a nail is attached to the nail bed, harming or cutting it, creates pain. Actually it is the nail bed that causes the pain and not the nail. Thus, when we cut the tip of a nail, where it is detached from the nail bed, we are not hurt.

Usually, nails grow at an average rate of 0.03 centimeters a day (3 cm every 100 days). Fingernails require 3 to 6 months to re-grow completely. Toenails require 12 to 18 months. Precise growth rate of an individual is dependent on age, season, exercise level, and hereditary factors.

And, contrary to popular belief, nails do not continue to grow after death. Actually, the skin shrinks - giving the illusion that the nails grow.

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Do you know why body temperature rises high during fever?

Prof. Know Why answers:

A healthy person's normal body temperature usually fluctuates between 97°F (36.1°C) and 100°F (37.8°C), with the average being 98.6°F (37°C). When our body temperature rises above 98.6°F, we call it fever. But why does the body temperature rise during fever?

Our normal body temperature is maintained by a regulatory center called the “anterior hypothalamus”, located deep within the brain. This region functions like a thermostat, registering body temperature. The nervous system constantly relays information about the body's temperature to the thermostat, which in turn activates different physical responses designed to cool or warm the body, depending on the circumstances in order to maintain the body temperature at a normal set point.

Fevers are primarily caused by viral or bacterial infections. So, when an infection occurs, fever-inducing agents called pyrogens are released in the bloodstream, either by the body's immune system or by the invading cells themselves. These pyrogens trigger the resetting of the thermostat at a higher level and we thus register a higher body temperature during fever.

To reach a higher temperature from the normal body temperature, the body moves blood to the warmer interior, increasing the metabolic rate, and inducing shivering. The "chills" that often accompany a fever are caused by these movements of blood to the body's core, leaving the surface and extremities cold. Once the higher temperature is achieved, the shivering and chills stop. Again, when the infection is overcome or drugs such as aspirin or acetaminophen are taken, the thermostat resets to normal (i.e. 98.6°F) and the body's cooling mechanisms send the blood back to the surface and sweating occurs.

We often panic when we have high temperature or fever. But on the contrary, fever is an important component of our immune system. Actually, the immune system chemicals that react with the fever-inducing agent and trigger the resetting of the thermostat, increase the production of cells that fight off the invading bacteria or viruses. Higher temperatures also inhibit the growth of some bacteria, accelerating the chemical reactions that help the body cells to repair themselves. In addition, the increased heart rate that may accompany the changes in blood circulation, also speeds up the arrival of white blood cells to the site of infection to fight with the invaders.

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Do you know why mosquito bites itch?

Prof. Know Why answers:

Mosquitoes are the familiar flying insects belonging to the family of Culicidae. There are about 2,500 known species of mosquitoes in the whole world. Mosquitoes are particularly dangerous insects since they are known to transmit such serious diseases as yellow fever, malaria, filariasis dengue and Japanese B encephalitis.

Mosquitoes generally bite at any time, but prefer the evening. And, do you know that only the female mosquitoes bite? Yes! The male mosquitoes, and sometimes the female mosquitoes, feed on nectar and other plant juices. But in most species the female mosquitoes require a blood meal to acquire protein, needed to produce eggs. Female mosquitoes lay multiple batches of eggs during their lifespan, and a new blood meal is needed to produce every batch. Different mosquito species prefer different host species. Some mosquitoes seek blood meals from birds, while other mosquitoes love mammals. And some are generalists.

But why do mosquito bites itch? The female mosquito inserts her needle-like proboscis (a slender, tubular, feeding and sucking organ) into the victim's skin, to draw blood. She sucks until her abdomen is full. But doing that is not easy as blood clots very quickly (on contact with air) to have a drink. So, the mosquito injects her saliva, containing digestive enzymes and anticoagulants that stop the blood from clotting. Our body sees that as an enemy and produces and sends chemical called histamines to the injected area, to ward off infection. And, it’s the reaction between histamines and the saliva of the mosquito that causes the itching, swelling and redness.

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Do you know why pregnant women should not drink?

Prof. Know Why answers:

Women who are pregnant or trying for a baby should stop drinking alcohol altogether or at least restrict to moderate drinking – the doctors advice. Because by exceeding the recommended limit they often put their babies at risk. But do women ever pay any serious attention on this cliché warning, ever? If not, all you women better know the consequences now, than be sorry, later!

Although, moderate drinking like up to two units once or twice a week is permissible, total abstinence is always desirable – as the doctors say. Heavy drinking can cause Foetal Alcohol Syndrome, an incurable condition resulting in retardation, poor memory and in the worst cases, facial abnormalities. Surveys say, about one in 1,000 babies are born with the syndrome each year, worldwide.

But a milder condition, Foetal Alcohol Spectrum Disorder, is more common, affecting more than 6,000 children each year in Britain alone, and is a leading cause of learning difficulties.

Because many women do not realize that they are pregnant for the first few months, the advice is extended to those trying to conceive as well. And if a pregnant woman chooses to carry on drinking, she should not get drunk and keep to the recommended limit of one to two units once or twice a week in order to minimize risks to the baby.

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Do you know why dark chocolates are beneficial?

Prof. Know Why answers:

Chocolates are always yummy, delicious and irresistible, especially with girls and kids. And now, they also seem to be beneficial for your health because a daily dose of yummy dark chocolate may help patients suffering from the chronic fatigue syndrome (CFS).

Serotonin (a brain chemical related to CFS) is believed to play an important role in the regulation of anger, aggression, body temperature, mood, sleep, vomiting, appetite and fatigue. According to scientists from Hull York Medical School, dark chocolates have been found to lower levels of serotonin. The research team said that patients with CFS, found that their symptoms were reduced when they consumed dark chocolate, much more so when they consumed milk chocolate that had brown dye added to it. The researchers noted that patients taking dark chocolate reported significantly less fatigue when they started eating the sweet. They also reported more fatigue when they stopped eating it. The scientists, however, stressed that the quantity of dark chocolate consumed should be moderate.

Endocrinologists say, dark chocolate is high in polyphenols, which have been associated with health benefits, like reduction in blood pressure. Also, high polyphenols appear to improve levels of serotonin in the brain , which has been linked with CFS.

According to doctors and nutritionists, cocoa is rich in antioxidant properties and so consuming dark chocolate can over stimulate the nervous system, helping reducing fatigue.

So cheer up all you girls and chocolate lovers – now you have reasons to gorge on your favorite dark chocolates.

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Do you know why siestas are good?

Prof. Know Why answers:

Usually it is said by doctors that six to eight hours of sleep at night is ideal for most people, though what is more important is the quality of sleep. But recent studies say that, also 40 winks, better known as catnap or siesta in the middle of the day is good to health and can protect you from a heart attack.

A recent large UK study of around 23,000 people in Greece reported that those who catnapped for at least 30 minutes in the afternoon, three times or more a week had a 37 percent lower risk of death due to heart attacks compared to those who did not.

People who occasionally took a siesta had a 12 percent lower risk. In the study, a siesta was defined as “typically short naps or rest periods of no more than an hour that are taken in the afternoon”. Cardiologists say siestas help people relax, reduce their stress levels and benefit heart function by lowering blood pressure. Blood pressure and heart rate decrease while sleeping. Lowered blood pressure reduces strain on the heart and decreases the risk of a fatal heart attack.

While earlier studies on siestas have linked it to a slight increase in heart attack risk, newer and more controlled studies have shown that afternoon naps or siestas reduce the risk of fatal heart attacks. Taking a long afternoon nap, however, can lead to heightened heart risk by making people inactive and overweight, - warn cardiologists. Care should also be taken that, siestas do not lead to reduced overall physical activities.

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Do you know why we have heartburn?

Prof. Know Why answers:

Before you start thinking something else, let me clarify what is heartburn! Heartburn has nothing to do with ‘heart’. Also known as pyrosis, heartburn is a form of indigestion. It is a painful burning sensation in the esophagus below the breastbone, caused by regurgitation of gastric acid.

Now let’s see how we have heartburn! Heartburn happens when acid from your stomach gets forced upwards into the oesophagus (gullet). This is called acid reflux. The stomach wall is coated with a layer of mucus that protects it from digestive acid. The oesophagus does not have this protection, so any acid that leaks up, irritates and damages its lining. This causes the burning pain associated with heartburn.

But why do we have heartburn? Heartburn is becoming the single most important factor behind the rise in gastroesophageal reflux disease (GERD) that nowadays largely affects the urban population, mostly due to their long working hours, erratic lifestyle, bad posture (the way you sit and stand) and bad eating habits.

Foods that may cause heartburn are:

• Alcohol (especially red wine) and Tobacco (in any form).
• Caffeinated and carbonated beverages like Coffee, tea, cola and soda.
• Chocolates and ice creams.
• Citrus fruits and juices; tomatoes and sauces.
• Spicy foods; fatty foods; dry foods like peanuts.
• Red pepper; peppermint and spearmint.

Remedies: Drink lots of water and maintain a proper diet. If heartburn occurs when lying down, raising the head with pillows or sitting up frequently may provide some relief. Doctors treat heartburn with antacids or H2-receptor antagonists and proton pump inhibitors (in that order).

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