How to stop shivering

People usually shiver to warm up when they are cold. However, there are other causes of shivering, some of which may signify an underlying health problem.

When people are cold, the muscles in their body will contract and relax rapidly to generate heat. This causes part or all of the body to shiver or shake. People can still shiver on a warm day if there is a cool breeze or they are sitting in the shade.

Shivering is an involuntary movement of the body, which means that it is uncontrolled. Hiccups and sneezing are other examples of involuntary movements.

Read on to learn about eight causes of shivering and when it is necessary to see a doctor.

What causes shivering?

Shivering occurs most commonly when a person is cold. It is usually temporary and should stop once the individual warms up.

However, shivering can also be a symptom of physical or mental illness.

Below are eight potential causes of shivering:

1. Fever

Other than being cold, the most common cause of shivering is fever, which doctors define as a body temperature higher than 100°F.

Fever usually occurs as a result of infection, but inflammation or an allergic reaction can also increase body temperature. Some people with a fever may also have signs of flu, but others will have no additional symptoms.

Drinking plenty of fluids and taking nonsteroidal anti-inflammatory drugs (NSAIDs) can help to reduce a temperature.

If a person has other symptoms, particularly a stiff neck, rapid heartbeat, or shallow breathing, they should seek medical advice within 24 hours. If they have no other symptoms, they will only need to visit a doctor if the fever lasts for more than 3 days.

2. Psychogenic movement disorders

For some people, stress or mental health factors can cause shivering and other involuntary movements. This usually occurs due to a psychogenic movement disorder, which can affect any part of the body.

A doctor who specializes in medical conditions affecting the brain, called a neurologist, will usually diagnose psychogenic movement disorders. They may look for the following characteristics when making a diagnosis:

movements happening suddenly, without warning

memories of a traumatic event triggering movements

movements stopping if a person is distracted

underlying mental health issues, such as depression

There is often no underlying brain or nerve damage. Instead, shivering is the body's response to stress.

Doctors will often treat psychogenic movement disorders with a combination of mental health therapy and physical therapy.

3. Postanesthetic shivering

Shivering can occur when a person regains consciousness after a general anesthetic.

A person's temperature may drop during a surgical procedure, which can cause them to shiver when they wake up after the operation is over.

Anesthetics can also affect the body's ability to regulate temperature, which can make it difficult for the body to warm up quickly after an operation.

Doctors will usually check a person's temperature and provide them with blankets or heaters if necessary.

Source: Medical News Today

Vitamin D and brain health: New mechanism may explain link

New research finds that vitamin D deficiency affects a type of brain "scaffolding" that supports the neurons. This finding could lead to new therapies for the neurological symptoms of mental health conditions such as schizophrenia.

Vitamin D, which people sometimes refer to as the "sunshine vitamin," is necessary for maintaining healthy bones. It also benefits the immune and cardiovascular systems, as well as endocrine function.

For instance, research has suggested that insufficient vitamin D may compromise the immune system, raise the risk of hypertension, and negatively affect insulin secretion in people with type 2 diabetes.

Newer studies have focused on the potential link between vitamin D and brain health. For example, a recent study that Medical News Todayreported on reinforced the notion that there may be an association between vitamin D deficiency and a higher risk of schizophrenia.

Other studies have shown that depriving middle-aged rodents of vitamin D led them to develop brain damage and perform less well on cognitive tests. Researchers have also found that people who survive sudden cardiac arrest are less likely to recover brain function if they have low levels of vitamin D.

A new study delves deeper into this link between vitamin D and brain function to find a potential reason why the nutrient may be key to memory function.

Thomas Burne, an associate professor at the University of Queensland Brain Institute in St. Lucia, Australia, led the new research. Burne and his colleagues published their findings in the journal Trends in Neurosciences.

Reduction in the brain's 'scaffolding'

Burne explains the motivation for the study, saying, "Over a billion people worldwide are affected by vitamin D deficiency, and there is a well-established link between vitamin D deficiency and impaired cognition."

"Unfortunately, exactly how vitamin D influences brain structure and function is not well-understood, so it has remained unclear why deficiency causes problems."

To determine the underlying mechanism, Burne and colleagues deprived healthy adult mice of dietary vitamin D for 20 weeks, after which they used tests to compare them with a group of control mice.

Cognitive tests revealed that the mice that lacked vitamin D were less able to learn new things and remember compared with the mice in the control group.

Scans of the rodents' brains showed a reduction in the so-called perineuronal nets in the hippocampus — the brain area that is key for memory formation.

The perineuronal nets act like "scaffolding" in the brain. "These nets form a strong, supportive mesh around certain neurons, and in doing so, they stabilize the contacts these cells make with other neurons," Burne explains.

The researcher goes on to report that, "There was also a stark reduction in both the number and strength of connections between neurons in [the hippocampus]."

Although the study did not firmly establish this mechanism, the researchers think that vitamin D deficiency makes perineuronal nets more vulnerable to the degrading action of enzymes.

"As neurons in the hippocampus lose their supportive perineuronal nets, they have trouble maintaining connections, and this ultimately leads to a loss of cognitive function," Burne says.

The author also thinks that impaired brain function in the hippocampus may contribute to some of the symptoms of schizophrenia, such as memory loss and cognitive distortions.

"The next step is to test this new hypothesis on the link between vitamin D deficiency, perineuronal nets, and cognition," Burne says. The researcher is hopeful about the therapeutic implications of his team's findings.

"We are also particularly excited to have discovered these nets can change in adult mice. I'm hoping that because they're dynamic, there is a chance that we can rebuild them, and that could set the stage for new treatments." Thomas Burne.

Source: Medical News Today

Nature vs. nurture: Do genes influence our morals?

To what extent do environment and education shape our moral compass, and how responsible is the genetic cocktail we inherit from our parents? Recent research aims to get to the heart of the matter.

The well-known "nature versus nurture" debate goes back hundreds of years, and it is still of interest today.

It asks whether certain behaviors are rooted in our natural inclinations, or whether our social environment shapes them.

Recently, the release of the documentary Three Identical Strangers reignited some discussions into the importance of environmental factors and education versus that of heritable traits.

The documentary presents the case of a contentious "twin study" (or in this case "triplet study") conducted in the 1960s. It involved separating identical triplets during infancy and adopting them out to different families as "only children" to assess how the siblings would evolve throughout their lives.

A new study by Pennsylvania State University in State College, the University of Oregon in Eugene, and Yale University School of Medicine in New Haven, CT, followed sets of siblings in an effort to better understand whether our moral compass is solely down to our upbringing, or whether our genetic inheritance also has a say in the matter.

First study author Amanda Ramos, from Penn State University, refers to a person's moral qualities as their "virtuous character" and explains that both nurture and nature could work together to shape them.

"A lot of studies have shown a link between parenting and these virtuous traits, but they haven't looked at the genetic component," says Ramos.

However, she adds, "I thought that was a missed opportunity because parents also share their genes with their children, and what we think is parents influencing and teaching their children these characteristics may actually be due, at least in part, to genetics."

So, Ramos and team conducted a study investigating the extent to which "virtuous character" is a heritable trait. The researchers report their findings in the journal Behavior Genetics.

The impact of heritable traits

The scientists worked with 720 pairs of siblings with different degrees of relatedness. They ranged from identical twins who grew up together in the same environment to half-siblings and step-siblings with no common genetic material but who grew up under the same roof.

"If identical twins are more similar than fraternal twins, for example, it's assumed there's a genetic influence," says Ramos. She adds, "Including multiple degrees of relatedness can give you more power to disentangle the genetic influences from the shared environment."

The scientists assessed the relevant data — such as parental practices and the children's apparent sense of responsibility — in two rounds: first, during the siblings' adolescent periods, and then again when they were young adults.

Ramos and team found that nurture, in the form of positive parenting — that is, reinforcing and rewarding good behavior — did correlate with a stronger sense of responsibility in the children. However, they point out that this association was notably more visible in siblings who not only grew up in the same environment, but who were also related by blood.

"Essentially," continues Ramos, "we found that both genetics and parenting have an effect on these characteristics."

"The way children act or behave is due, in part, to genetic similarity and parents respond to those child behaviors," she adds, explaining, "Then, those behaviors are having an influence on the children's social responsibility and conscientiousness."

Source: Medical News Today

Growing up in a green area may help support mental health

New research from Aarhus University in Denmark suggests that people who have grown up in close contact with nature are much less likely to develop mental health problems in adulthood than peers who had less access to green space as children.

According to recent studies, mental health problems have been on the rise in the United States, with particular increases in cases of anxiety and depression.

The reasons behind this worrying trend are as numerous as they are complex, ranging from the evermore stressful demands of modern-day life, such as being constantly "on call" through email, phone, and social media, to environmental factors, such as pollution.

Researchers from around the world have been trying to disentangle each of these risk factors, so as to get a better idea of what changes are necessary to prevent mental health problems from developing into an increasingly serious, society-wide issue.

Now, a new study from postdoctoral researcher Kristine Engemann and colleagues from Aarhus University in Denmark has found a link between growing up in a natural environment and enjoying better mental health in adulthood.

Green spaces may safeguard our minds

In their research — the findings of which appear in PNAS — they used satellite data from 1985 to 2013 to identify the green spaces in close proximity to the childhood homes of more than 900,000 Danes.

They then correlated these data with this population's risk of developing one out of 16 different mental health conditions throughout adulthood.

The researchers found that people who grow up surrounded by green areas have an up to 55 percent lower risk of developing mental health problems as adults than others.

These results remained in place even after the team adjusted for potentially modifying factors, including a person's socioeconomic status, their family history of mental health problems, and migration from rural to urban areas.

"Our data is unique," notes Engemann. "We have had the opportunity to use a massive amount of data from Danish registers of, among other things, residential location and disease diagnoses and compare it with satellite images, revealing the extent of green space surrounding each individual when growing up," she explains.

The Danish study also reveals that the longer someone spent surrounded by nature during their childhood — from early infancy until the age of 10 years old — the more likely they are to experience good mental health later in life.

"With our dataset, we show that the risk of developing a mental disorder decreases incrementally the longer you have been surrounded by green space from birth and up to the age of 10. Green space throughout childhood is therefore extremely important."

Source: Medical News Today

How can estrogen help control type 2 diabetes?

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ew research finds that estrogen improves insulin sensitivity and details the mechanism behind this effect. The findings have a "profound impact on our understanding of obesity and diabetes, as well as potential dietary interventions," say the researchers.

The female sex hormone may have significant metabolic benefits.

About 84 million people in the United States are living with prediabetes, a condition in which blood sugar levels are very high but not high enough to warrant a diagnosis of type 2 diabetes.

Usually, prediabetes occurs in people with insulin resistance — a condition in which the cells in some vital organs do not respond well to insulin and therefore do not absorb enough glucose from the blood.

But what if there was a hormone that could lower insulin resistance and the production of glucose?

Researchers believe that estrogen has the potential to do so, and consequently, to reduce the prevalence of type 2 diabetes.

Currently, over 100 million people in the U.S. are living with diabetes or prediabetes, and estimates show that over 30 million adults have type 2 diabetes.

Shaodong Guo, Ph.D., an associate professor in the Department of Nutrition and Food Science at Texas A&M University in College Station, led the new research. The study appears in Diabetes, the journal of the American Diabetes Association.

Why study the metabolic effect of estrogen?

Guo explains the motivation for the study, saying that previous observational research has uncovered a link between a lower incidence of type 2 diabetes and premenopausal women.

Furthermore, clinical and animal studies found a strong link between estrogen deficiency and metabolic disorders.

"Premenopausal women exhibit enhanced insulin sensitivity and reduced incidence of type 2 diabetes, compared with age-equivalent men," Guo says. "But this advantage disappears after menopause with disrupted glucose homeostasis, in part owing to a reduction in circulating estrogen."

However, researchers have not yet been able to elucidate the mechanisms responsible for these connections.

Also, blindly using estrogen as a potential treatment for type 2 diabetes and other prediabetes metabolic dysfunctions could have serious side effects. For example, stroke, breast cancer, blood clots, and heart attack are some of the health risks associated with estrogen therapy.

"This is why it is so important to understand the tissue-specific action of estrogen and its molecular mechanism in metabolic regulation," Guo explains. "Once that mechanism is understood, it will aid in the development of targeted estrogen mimics that can provide the therapeutic benefits without unwanted side effects."

Foxo1 mediates estrogen's metabolic effects

In the new study, the researchers "wanted to understand the mechanism by which estrogen regulates gluconeogenesis by means of interaction with hepatic Foxo1," the lead investigator continues, referring to a gene also called forkhead box O1.

Gluconeogenesis describes the synthesis process through which glucose is generated.

The Foxo1 gene encodes a transcription factor, or a type of protein that helps activate or deactivate other genes.

Diet tips to improve insulin resistance

We take a look at some dietary changes that may improve insulin sensitivity.

Foxo1 "is the main target of insulin signaling and regulates metabolic homeostasis in response to oxidative stress," the U.S. National Library of Medicine report.

As Guo explains, "Foxo1 has an important role in the regulation of glucose production through insulin signaling. It is an important component of insulin-signaling cascades regulating cellular growth, differentiation, and metabolism."

To investigate the gene's role and how it interacts with estrogen, the researchers studied male mice, female mice whose ovaries had been removed, and both male and female mice whose Foxo1 genes had been knocked out in the liver.

The researchers used a subcutaneous implant that released estrogen in the mice. This implant "improved insulin sensitivity and suppressed gluconeogenesis" in the male mice as well as in the ovariectomized female mice.

However, the implant did not affect the rodents whose liver-specific Foxo1 genes had been knocked out. "This suggests Foxo1 is required for estrogen to be effective in suppressing gluconeogenesis," Guo explains.

The researcher reports, "We further demonstrated that estrogen suppresses hepatic glucose production through activation of estrogen receptor signaling, which can be independent of insulin receptor substrates Irs1 and Irs2."

"This reveals an important mechanism for estrogen in the regulation of glucose homeostasis," Guo says. The beneficial effects of estrogen on glucose homeostasis may be controlled by gluconeogenesis — which is, in turn, mediated by liver-specific Foxo1 — not by promoting the uptake of glucose in the muscles.

Therapeutic and dietary implications

Guo explains the therapeutic implications of the findings. "The identification of tissue-specific actions of estrogen and direct targets of estrogen receptors will facilitate the development of novel selective ligands that prevent type 2 diabetes, cardiovascular disease, and obesity without promoting abnormal sex characteristics or breast cancer."

Finally, the researcher also comments on the dietary implications of the study. Certain foods, such as soybeans, tofu, and miso soup contain phytoestrogens, which may have the same beneficial effects on metabolic health.

The study "provides a fundamental understanding that dietary intervention can play a crucial role in controlling obesity, diabetes, and associated chronic diseases," says Guo.

"[W]e investigated the role of estrogen in control of glucose homeostasis, which has profound impact on our understanding of obesity and diabetes as well as potential dietary interventions."

Source: MedicalNewsToday