A Physiologist Explains How to Keep Your Body Feeling Warm in Cold Weather


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JohnEric Smith wrote . . . . . . . . .

Whether waiting for a bus, playing outside or walking the dog – during the colder winter season, everyone is looking for ways to stay warm. Luckily, the process your body uses to break down foods serves as an internal heater.

But when the weather is cold, some defensive strategies are also necessary to prevent your body from losing its heat to the surrounding environment. As the temperature difference between your warm body and its frigid surroundings increases, heat is lost more quickly. It becomes more of a challenge to maintain a normal body temperature.

And two people with the same exact body temperature in the same exact environment may have very different perceptions. One may feel frozen while the other is completely comfortable.

But beyond the subjective experience of coldness, researchers do know that natural physiological responses to cold as well as behavioral adaptations – like bundling up! – can help keep your body around 98.6 degrees Fahrenheit and make sure you feel warm.

What your body does

Your blood courses through your body carrying nutrients, oxygen and other biological important substances. And this delivery system also brings heat produced in the muscles to the skin, where it’s released.

When you enter a cold environment, your body redistributes blood to the torso, protecting and maintaining the warmth of the vital organs there. At the same time, your body constricts blood flow to the skin. Narrowing the roads to the skin means less heat can make the journey, and so less is lost to the environment. And minimizing how much blood goes to the skin – which is in closest proximity to the cold – means you can hold onto more of your internal heat longer.

Another defensive strategy the body uses to stay warm is cranking up muscle activity. This in turn increases your metabolism and creates more heat. Think of a brisk winter walk when the mercury has really plunged – your teeth may chatter and your arms and legs may shake uncontrollably in shivers. This seemingly nonproductive use of the muscles is actually an effort to increase body temperature by breaking down more nutrients to stoke your internal furnace.

Differences in body size, body fatness and metabolic activity influence how different individuals experience cold. Smaller people with lower levels of body fat lose more heat to the environment than larger people with more body fat. A bigger individual may have increased muscle mass, which is a producer of heat, or elevated body fatness, which functions as an insulator to reduce heat loss. These differences are not easy to change.

Things you can do

In order to maintain a feeling of warmth, you can manipulate your clothing, your activity and your food.

The most common thing people do to stay warm is wear a coat, hat and gloves. Obviously increasing clothing thickness or piling on the layers helps. Winter clothes serve not to warm you up, but more as a means to keep the heat you are producing from dispersing to the surrounding environment.

Contrary to popular belief, the head is not a greater source of heat loss than any other adequately covered body part. If you were to wear a warm hat and no coat, your torso would contribute the most to heat loss, thanks to how your body redistributes its blood in cold conditions. If you can keep your torso warm, you’ll maintain blood flow to your limbs and can often keep the arms, legs, hands and feet warm.

Secondly, being physically active causes your muscles to contract, breaking down more nutrients, which generates additional heat. This additional heat production can help maintain body temperature and the feeling of warmth. Maybe you’ve noticed this in your own life if you’ve run in place for a bit or done a quick set of jumping jacks when you’re out in the cold.

Unfortunately, physical activity or layers of clothing can tip the balance past what you need to offset heat losses. In that case, you’ll experience an increase in body temperature – and your body will start sweating in an effort to cool down. This is a bad outcome, because the evaporation of sweat will lead to greater rates of heat loss.

Finally, eating increases the body’s production of heat. The process of breaking down food is going to slightly increase body temperature. Sometimes campers will have a snack before bed in an effort to stay warmer through the night. While the metabolic impact of a small snack may not be huge, the tipping point between heat balance and heat loss is pretty small.

You may also notice the urge to urinate – what physicians call cold diuresis. It’s a side effect of constricting blood vessels and the resulting increase in blood pressure as the same amount of blood has a smaller space available to travel through your body.

And if you’re the type who tends to feel cold and leave your coat on even inside, you might want to rethink the habit. Your skin will be flush with blood as your body tries to dissipate excess heat inside. Worst of all, you may start to sweat. Once you head back out the door, you might feel even colder initially than you would have as the cold air saps the heat from your skin and your sweat evaporates. To stay comfortable, your best bet is dressing appropriately, whether inside or outdoors this winter.

Source: The Conversation

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The Key to Our Humanity Isn’t Genetic, It’s Microbial

Ian Myles wrote . . . . . . . . .

What if the key to perfecting the human species were actually … yogurt?

The fantasy of trying to perfect humanity through genetics was recently reignited by the announcement of the Chinese scientist claiming to have made the first “CRISPR babies,” which were named for the technique used to edit the DNA of the embryos. While major ethical and regulatory concerns are present, fears that CRISPR will lead us into the dystopian world depicted in the movie “Gattaca” are unfounded. In fact, if the movie were remade today it would likely be a story about the government mandating probiotics and healthy eating.

Eugenics is the belief that humanity can be perfected through genetic manipulation. Past eugenic policies placed restrictions on marriage and immigration, justified slavery and forced sterilizations, and ultimately culminated in the Holocaust. I am a physician-scientist specializing in allergies who became interested in eugenics not in relation to skin color, but skin rashes. Most prominent researchers who study a a skin rash called eczema were convinced that the vast majority of the disease is determined by fixed genetic sequences. Many still are. However, just like the studies of intelligence and criminal behavior that came before it, research into the genetics of eczema has fallen well short of what the 15th-century techniques had predicted.

To be fair, the public’s fascination with this subject is understandable. Commercial breaks are filled with pseudoscientific claims that your DNA can reveal, for example, that you are 12.4 percent Italian, 3.1 percent Neanderthal, and 1/512th Native American. Spoiler alert: It can’t. Prominent magazines, podcasts and newspapers have pushed the debunked claim that intelligence is genetically encoded. In reality, genetic studies that were supposed to explain at least 80 percent of being a genius have explained only 5 percent. This means your genes, at best, have less impact on your IQ score than a good night’s sleep. However, modern misunderstanding of how complex traits are passed down isn’t just burdening society with hucksters and racists. Ignorance is causing us to overlook opportunities for improving health and treating disease.

Where did ideas like a ‘gene for IQ’ come from?

Most of the ideas of “genes for” complex traits come from twin studies that assumed that identical twins and fraternal twins would differ only by the amount of shared DNA. What twin researchers either didn’t realize, or willfully ignored, is that the influence of the environment is also stronger for identical twins. Because identical twins are more likely to be dressed alike and confused for one another, they form more of a shared identity.

Thus, identical twins are more likely to share the same hobbies, eat the same foods, and run in the same social circles than fraternal twins. Modern research shows these differences are more psychology than biology. Furthermore, since identical twins share the same embryonic sac in the womb, their environmental exposures are also more biologically similar than fraternal twins. As such, researchers claiming that twin study data is indicative of genetics are, at best, ill-informed.

What is the modern understanding of heritable traits?

It may seem counterintuitive, but just because one change can worsen a gene’s function, that doesn’t mean that a different change can enhance it. When scientists say a gene “contributes to intelligence” they are referring to situations in which mutations in the gene cause a loss of intelligence or delay in cognitive development. They are not implying that a special version of the gene can guarantee a college degree.

Enhancing the functions of genes is most often accomplished via epigenetic modifications – chemical tags that are attached to the DNA but do not alter the genetic code. If genes are words, sentences and paragraphs, then epigenetics is the cadence, emphasis and diction. This is akin to having Hamlet performed by Gilbert Gottfried versus Benedict Cumberbatch. While epigenetic changes can be passed on from parents to children, they can also be altered by stress, diet, environment and behavior. Therefore, I believe that environmental modification, not CRISPR, would be needed to enhance the vast majority of genetic functions.

Another way to inherit traits

A more recently appreciated influencer of heritable traits is the microbiome, the term for all of the microorganisms (bacteria, fungi and viruses) that peacefully co-exist with humans.

From a genetic standpoint, your human genes are probably outnumbered over 100 to 1 by microbial genes. Modern research suggests that the microbiome may be directly involved in diseases ranging from autism to obesity. The microbial influence can be passed from mother to child during and possibly before birth, but remains partially sensitive to diet and environment into adulthood.

The microbiome can even influence your epigenetics. Researchers are just beginning to tap into the potential of microbial treatments for diseases. Similar to our lab’s experimental treatment for eczema, live bacterial therapies for food allergies, depression and anxiety, heart disease and select cancers are in development. As scientists clarify which strains of microbes are most helpful, these treatments are expected to become even more powerful.

Think of it this way: The current and former U.S. presidents share 99.9 percent of their genetic sequence, despite being slightly more than 0.1 percent different. As such, modern scientists do not hide from eugenics-based ideas because they are controversial; they dismiss them because both “Gattaca” and The Bell Curve are to genetics what Flat Earthers are to astrophysics.

While properly conducted gene therapy does offer real hope for curing rare genetic diseases, its limitations stop well short of sci-fi. As just one example, feeding mice one specific type of bacteria significantly enhanced their memory, whereas genomics has failed to find any genes that could do the same. Ancestry charlatans and neo-eugenicists may deny the fact that people are more a product of their experiences than their genetic heritage, but perhaps their mothers just didn’t breastfeed them long enough.

Source : The Conversation


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Healthy Lifestyle Lowers Odds of Breast Cancer’s Return

There’s more evidence that when a survivor of early stage breast cancer takes up healthy eating and regular exercise, the odds of the disease returning go down.

The key is sticking with such programs, said study lead author Dr. Wolfgang Janni.

Healthier lifestyles “might improve the prognosis of breast cancer patients if adherence is high,” said Janni, who directs obstetrics and gynecology at the University of Ulm in Germany. His team developed and implemented a new program to help keep those lifestyle changes on track.

The findings were presented at the annual San Antonio Breast Cancer Symposium.

In the study, Janni’s team tracked outcomes for nearly 2,300 early stage breast cancer patients who’d been treated with chemotherapy. Half of these cancer survivors were randomly assigned to two years of ongoing telephone-based, personalized healthy living advice. The other half (the “control” group) received standard, general advice on a healthy lifestyle.

Those in the personalized lifestyle intervention group were coached in areas such as improving their diet, reducing fat intake, and increasing physical activity.

After two years, people in the intervention group saw an average weight loss of 2.2 pounds, while those in the control group experienced an average weight gain of 2.1 pounds, the findings showed.

But the real difference was in cancer outcomes, Janni’s team said. The rate of disease-free survival among the nearly 1,500 patients who completed the lifestyle intervention was 35 percent higher than that of those who didn’t complete the program. And it was 50 percent higher than women who didn’t get the intervention at all.

The findings shouldn’t come as a big surprise, Janni said.

Prior research “has shown that obesity and low physical activity are associated with higher risks of developing breast cancer, as well as an increased risk of recurrence and reduced survival,” he noted in a meeting news release.

One U.S. expert agreed.

Many women who’ve survived breast cancer may feel helpless, but “it is great to be able to tell patients that, yes, there is something they can do to help prevent a recurrence,” said Dr. Alice Police. She is regional director of breast surgery at the Northwell Health Cancer Institute, in Sleepy Hollow, N.Y.

She said sometimes women need a little nudge, though, to stay healthy.

“This is a very specific and focused look at the issues and includes information on exactly how a program of diet and lifestyle changes should look and function,” Police said, “and that makes it very important.”

Dr. Lauren Cassell is chief of breast surgery at Lenox Hill Hospital in New York City. Looking over the new study, she agreed that the new program appears to have merit.

“By providing the patient with a systematic telephone lifestyle intervention program — which was not difficult to develop and implement — they were able to increase patient compliance and as a result improve outcomes,” Cassell said.

“I believe patients want to help themselves,” Cassell said. “Sometimes they just need a little extra support.”

Source: HealthDay

Why I Won’t Stop Slurping My Soup Noodles

Luisa Tam wrote . . . . . . . . .

Whenever I travel to Europe, the same dilemma always crosses my mind, which is: to slurp or not to slurp when I eat in the company of Westerners or anyone unfamiliar with Asian cultural norms.

When travelling abroad, it is reasonable to assume the need to respect and follow certain universally accepted table manners, like not talking with your mouth full or chewing loudly, and rightly so because these habits are rather unsavoury in most countries.

However, certain rules must be enforced. Given that table manners differ from culture to culture, it is necessary to follow a reasonable level of dining etiquette to avoid giving offence or committing any undue faux pas.

For example, eating with your left hand is taboo in India. The culture rarely uses cutlery, so the right hand is reserved for eating while the other one is strictly for doing your business in the toilet. In Chinese culture, it is ominous to put the chopsticks upright in a bowl of rice because it resembles incense sticks being burned in memory of the dead.

Having stayed in France for the past several weeks, I have been aware of my table manners, but I decided to slip back to more familiar ways once I felt settled. I made myself a bowl of noodles and ate it in the traditional Chinese way, which meant I slurped through it unashamedly till my bowl was completely empty. I felt great afterwards, or, dare I say, liberated. All this was done in the presence of my French host, but only after I sounded the slurp alert to forewarn him.

Every culture has its own rules at the dining table and what is considered acceptable in one culture might be perceived as disrespectful in another.

When planning and serving a great Chinese meal, the chef often goes to great lengths to ensure the dishes are colourful, aromatic and tasty. This means the diner often feels obliged to make an audible effort to show how much they have enjoyed their meal.

I do agree that chewing like a cow is without doubt the most unpalatable dining behaviour, no matter how delicious the food is. But there is one habit which I would be reluctant to break; slurping soup and noodles, which to most Chinese people is the definitive expression of culinary enjoyment.

Soup noodles can only be fully enjoyed when eaten with loud slurping sound effects, and the louder it is the stronger the recognition. It can be likened to what almost every driving enthusiast would swear by, which is that driving a sports car is most fun when shifting a manual transmission. Many would agree that without it, the excitement and authenticity of racing simply isn’t there.

I am not saying we should shove all “Asianness” down the throats of others who have opposing views of cultural conduct. But we should try to make people understand that while some of these traditions might appear odd, or even annoying at times, they are unique and have their distinct values. And people sometimes do it out of habit and without any intention to offend others.

In this globalised era, different cultures are constantly overlapping and interacting with one another. We work, live, study and even marry people from diverse ethnic backgrounds. There is no denying how significant it is for us to understand each other better in order to bridge diverse differences and coexist in harmony.

There is absolutely no need to feel embarrassed and hide or abandon your cultural behaviour, provided they are harmless and not unethical. Neither should you feel the pressure to assimilate and bury your heritage. We should be proud of our ancestry but remain respectful and accommodating to others, which means not looking down on their customs.

We have to increase cultural awareness and sensitivity. Many of us already know this principle intuitively; the best cultural practice is to make sure we manoeuvre delicately and respectfully in dealing with other cultures, for fewer misunderstandings.

We need to be more aware of our individual behaviours, be mindful of cultural differences, show respect, communicate openly and explain our reasons (like my slurp alert). It is essential to find common ground so that we can allow each other to accept differences in a mutually comfortable manner and make room for cultural diversity to flourish.

Source : SCMP

Healthy lifestyle Is Crucial for Heart Health of Middle-aged Women

A healthy lifestyle during the transition to menopause may offset the acceleration of atherosclerosis, the slow narrowing of the arteries that increases with age, according to new research in the Journal of the American Heart Association, the Open Access Journal of the American Heart Association/American Stroke Association.

Women participating in the Study of Women’s Health Across the Nation (SWAN), ages 42-52 at enrollment, were evaluated using a 10-year “Healthy Lifestyle Score,” developed for this study. Each woman had annual medical exams and completed questionnaires about their physical activity, eating habits and tobacco use. In addition, participants had at least one coronary artery ultrasound, which is a non-invasive test that provides images of the inside of an artery leading to the heart.

Compared to women with the lowest ”Healthy Lifestyle Score,” those with the highest scores had significantly wider arteries, less arterial thickening and buildup of fatty plaque. The risk factor most associated with unhealthy arteries was smoking tobacco.

“Midlife is a crucial window for women to take their cardiovascular wellness to heart and set a course for healthy aging. The metabolic changes that often occur with menopause, especially increases in cholesterol levels and blood pressure, can significantly increase the risk of heart attacks, strokes and cognitive impairment later in life, said Ana Baylin, M.D., Dr.P.H., an associate professor of nutritional health sciences and epidemiology at the University of Michigan School of Public Health, in Ann Arbor, Michigan.

“The good news is that middle-aged women can take their wellbeing into their own hands and make healthy lifestyle changes, such as avoiding tobacco smoke, eating a healthier diet and getting more physical activity to reduce their cardiovascular risk,” Baylin said.

The study also notes that only 1.7 percent of the study population adhered to the three components of the “Healthy Lifestyle Score” throughout the study.

”The low prevalence of a healthy lifestyle in this group of midlife women highlights the potential for lifestyle interventions aimed at this vulnerable population,” added co-author Dongqing Wang, a Ph.D. candidate at the University of Michigan. “Our prospective analysis clearly suggests that women approaching menopause can significantly lower this risk if they adopt healthier behaviors, even if cardiovascular issues have never been on their radar.”

Source: American Heart Association


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