30-Minute Exercise More Effective Against Obesity Than Intense 1-Hour Workout

Health officials fighting the “battle of the bulge” against obesity just got some good news. According to new research, 30 minutes of light, daily exercise can help someone shed more pounds than an hour of intensive training.

Additionally, those who committed to 30 minutes of daily exercise reported having higher levels of energy and more motivation to take the small steps necessary to lose the weight. The researchers at the University of Copenhagen who conducted the study say this could go a long way in battling the extremely harmful side effects of obesity.

Their study is now published in the Scandinavian Journal of Public Health.

“Obesity is a complex social problem requiring a multidisciplinary approach,” said Professor Bente Stallknecht from the Department of Biomedical Sciences at the Faculty of Health and Medical Sciences, University of Copenhagen in a statement.

“In a new scientific article we combine data from biomedical studies of the subjects’ bodies with ethnological data on their experiences during the 13-week trial period.”

Following this trial the test subjects were given qualitative interviews to understand on a deeper level how this exercise regimen affected their lives. Professor Stallknecht and PhD student Anne Sofie Gram recruited over 60 slightly overweight but otherwise healthy men to take part in this study. Some of these men were asked to simply exercise for a full 30 minutes every day. A second group of men were asked to undertake a one-hour, strenuous training regime every day.

Following the three month study, the men who exercised for just 30 minutes a day lost, on average, 7.94 pounds. By contrast, those men who exercised twice as long and twice as hard lost an average of 5.95 pounds at the end of the experiment.

The hard data shows a preference towards what the researchers call “light weight” 30-minute exercises. Yet they weren’t only interested in solid figures and also wanted to understand how this kind of exercise program affected the men on different levels, including culturally, emotionally and psychologically.

“The qualitative data offer a possible explanation for the surprising biological data,” says Astrid Jespersen, an ethnologist and associate professor at the University of Copenhagen.

“The subjects in the test group that exercised the least talk about increased energy levels and a higher motivation for exercising and pursuing a healthy everyday life. They take the stairs, take the dog for an extra walk or cycle to work. In contrast, the men who exercised for one hour a day, after training, felt exhausted, demotivated and less open to making a healthy change. We are thus seeing that a moderate amount of exercise will significantly impact the subjects’ daily practices.”

Jespersen’s desire to understand the multi-faceted effects of obesity don’t stop at simple exercise. The professor also says the issue of obesity must be tackled at many points by creating a holistic approach to the problem.

This isn’t the first time research has shown that even the littlest steps can go a long way in fighting obesity and staying healthy. An April report by the American Heart Association (AHA) showed that a brisk walk was just as effective as running.

Source: Michael Harper for redOrbit.com - Your Universe Online

Low-Fat Livers Linked to ‘Healthy’ Obesity

People who are obese usually have high blood pressure, high cholesterol and diabetes, but some obese individuals don’t suffer from these conditions. The key to understanding this phenomenon may lie in the liver, according to a new study published by the University of Helsinki.

The Finnish researchers studied pairs of twins who were genetically identical and usually raised in similar environments. But, on average, one twin of each pair weighed 17 kilograms more than their sibling. The obese twins who had much fattier livers than their thin siblings showed other signs of ill-health, such as high cholesterol, insulin resistance, high blood pressure and inflammation. But those whose liver fat was similar to that of their thin twin lacked these symptoms. The unhealthy obese twins also had fewer but larger fat cells than their thin twins, unlike the healthy pairs.

It remains unclear why fat accumulates in the livers of some and not others, but previous studies suggest that organelles called mitochondria need to be present for new fat cells to grow. Anti-inflammatory drugs might boost the activity of mitochondria to promote the growth of healthier fat while also reducing the risk of developing diabetes.

Biological link between diabetes and heart disease found

Researchers from the UC Davis Health System have discovered a biological link between diabetes and heart disease, which may explain why diabetes sufferers have an increased risk for heart disease. This is according to a study published in the journal Nature.

The researchers found that when blood sugars are abnormally high (hyperglycemia), this activates a biological pathway that causes irregular heartbeats - a condition called cardiac arrhythmia - that is linked to heart failure and sudden cardiac death.

According to the World Heart Federation, people who suffer from diabetes are two to four times more likely to develop cardiovascular disease, compared with people who do not have diabetes.

The American Heart Association says that around 65% of diabetes sufferers die from heart disease or stroke, emphasizing the need for new research looking at links between the conditions.

For this study, UC Davis researchers, alongside collaborators at the Johns Hopkins University School of Medicine, conducted a series of experiments to determine any biological reasons as to why diabetes sufferers are at higher risk of cardiovascular disease.

O-GlcNAc-modified CaMKII a trigger of arrhythmias

The experiments involved detailed molecular analysis in rat and human proteins and tissues, calcium imaging in isolated rat cardiac myocytes (cells found in muscle tissues) that were exposed to high glucose, as well looking at whole heart arrhythmias with optical mapping within isolated hearts and live diabetic rates.

Their findings showed that moderate to high blood glucose levels, similar to those found in diabetics, triggered a sugar molecule called O-GlcNAc (O-linked N-acetylglucosamine) in heart muscle cells to bind to a specific site on a protein called CaMKII (calcium/calmodulin-dependent protein kinase II).

According to the researchers, CaMKII plays an important part in regulating normal calcium levels, electrical activity and the pumping action of the heart.

But they found its interaction with O-GlcNAc caused CaMKII to overactivate, causing pathological changes in the calcium signaling system it controls. This action triggered fully active arrhythmias within minutes.

However, the researchers say the arrhythmias were prevented by inhibiting CaMKII and its binding to O-GlcNAc.

An additional experiment, which involved analyzing the hearts and brains of deceased humans who had diabetes, revealed high levels of O-GlcNAc-modified CaMKII. The highest levels were found in patients who suffered from both heart failure and diabetes.

"Since O-GlcNAc is directly made from glucose and serves as a major nutrient sensor in regulating most cellular processes, it is perhaps not surprising that attachment of this sugar to proteins is emerging as a major molecular mechanism of glucose toxicity in diabetes," says Gerald Hart, DeLamar professor and director of biological chemistry at Johns Hopkins University School of Medicine, and study author.

"However, this represents the most clear-cut mechanistic study to date of how high glucose can directly affect the function of a critical regulatory protein."

Findings will 'undoubtedly' lead to new treatments

Prof. Hart notes that these findings will undoubtedly lead to development of treatments for diabetic cardiovascular disease and potential therapeutics for glucose toxicity in other tissues affected by diabetes, such as the nervous system, the kidney and the retina.

Donald Bers, chair of the Department of Pharmacology at UC Davis and senior study author, says:

"The novel molecular understanding we have uncovered paves the way for new therapeutic strategies that protect the heart health of patients with diabetes.
While scientists have known for a while that CaMKII plays a critical role in normal cardiac function, ours is the first study to identify O-GlcNAc as a direct activator of CaMKII with hyperglycemia."

The study authors say that further studies are needed, particularly to identify whether the fusion of O-GlcNAc to CaMKII plays a part in disorders of the peripheral nervous system, a condition that is also common in diabetics.

Medical News Today recently reported on a study detailing the discovery of a particular gene variant in type 2 diabetics that is linked to higher risk of heart disease.

Written by Honor Whiteman

Copyright: Medical News Today

Sleep 'regenerates brain support cells'

It goes without saying that we all need a good night's sleep to feel re-energized for the day ahead. But now, researchers have found that sleep also helps to boost reproduction of the cells involved in brain repair.

Scientists from the University of Wisconsin, Madison, have discovered that sleep increases the reproduction of cells that form myelin - the insulating material found on nerve cell projections in the brain and spinal cord.

Previous studies over the years have shown that numerous genes are switched on as we sleep and switched off during wakefulness. But according to the researchers, how sleep can affect certain types of cells was unknown.

They point to oligodendrocytes. These cells are responsible for making myelin within a healthy brain and in response to injury. The researchers add that myelin is responsible for allowing electrical impulses to move from cell to cell, "similar to insulation around an electrical wire."

They conducted a study in mice, analyzing gene activity of oligodendrocytes in the cerebral cortex of mice that slept, and then comparing these with the gene activity of mice that stayed awake.

Myelinated fibers in mouse cerebral cortex (myelin appears black in the left image, and green after segmentation in the right image) electron microscopy image.
Image credit: SBF-SEM; courtesy of Chiara Cirelli

Results showed that in the mice that slept, genes were turned on that triggered the formation of myelin. But in the mice that stayed awake, this triggered the genes involved in cell death and cellular stress response.

Additionally, further analysis showed that cells that become oligodendrocytes, called oligodendrocyte precursor cells (OPCS), double in reproduction during sleep. This reproduction is heightened during rapid eye movement (REM), which is linked to dreaming.

Chiara Cirelli, of the Center for Sleep and Consciousness at the University of Wisconsin, says:

"For a long time, sleep researchers focused on how the activity of nerve cells differs when animals are awake versus when they are asleep.
Now it is clear that the way other supporting cells in the nervous system operate also changes significantly depending on whether the animal is asleep or awake."

Dr. Cirelli notes that these findings may suggest that extreme or chronic lack of sleep could trigger some symptoms associated with multiple sclerosis (MS), a progressive brain disease associated with myelin damage. However, she adds that further studies are needed to determine whether this link exists.

Other studies have shown how sleep benefits brain function. Recent research from Brown University suggests that sleep helps our brains to better learn specific motor tasks, such as typing or playing the piano.

A 2012 study from the University of California, Los Angeles suggests that when asleep or under anesthetic, the brain acts as if it is trying to access memories.

Written by Honor Whiteman

Copyright: Medical News Today

Fighting fears possible during sleep

For many patients with phobias, typical treatment involves gradual exposure to the feared object or situation. But researchers have now found that emotional memory can be manipulated during sleep, paving the way to new phobia treatments as we dream.

The researchers, from Northwestern University, published the results of their study in the journal Nature Neuroscience.

They note that previous projects have demonstrated spatial learning and motor sequence learning can be strengthened during sleep, but until now, emotional memory has never been manipulated during slumber.

In the study, the researchers gave 15 healthy volunteers mild electric shocks while two different faces were presented to them. The volunteers also smelled different odorants - such as clove, new sneaker or mint - while looking at each face and being shocked.

This linked the face and the smells with fear for the volunteers, say the researchers.

As the subjects were sleeping, one of the odorants was released, but this time the faces and shocks were absent. The researchers released the odorant during slow wave sleep, which is when they say "memory consolidation" occurs.

Katherine Hauner, from the Northwestern University Feinberg School of Medicine, says:

"While this particular odorant was being presented during sleep, it was reactivating the memory of that face over and over again, which is similar to the process of fear extinction during exposure therapy."

After the subjects awoke, they were then shown both faces. However, when presented with the face linked to the odor they smelled during sleep, their fear levels were lower than when the saw the other face.

Measuring fear in sleep

The research team notes that fear was measured in two ways:

1. Through amounts of sweat in the skin (similar to a lie detector test)
2. Through functional magnetic resonance imaging (fMRI).

The results from the fMRI revealed that there were changes in regions linked with memory, such as the hippocampus, as well as changes in emotion regions, such as the amygdala.

These changes, say the team, show a "decrease in reactivity" linked to the face associated with the odor the volunteers smelled during sleep.

Hauner says:

"It's a novel finding. We showed a small but significant decrease in fear. If it can be extended to pre-existing fear, the bigger picture is that, perhaps, the treatment of phobias can be enhanced during sleep."

The benefit of fighting fears during sleep, notes the team, is that fear extinction can be carried out without having to endure re-exposure to the feared object or situation.

Medical News Today recently reported that researchers found sleep helps boost reproduction of the cells involved in brain repair.

Written by Marie Ellis

Copyright: Medical News Today

Sleeping too much or too little linked to chronic diseases

A new study finds that too much sleep, as well as too little sleep, is linked to leading chronic diseases, such as diabetes, coronary heart disease, obesity and anxiety in those aged 45 and over.

The study defines too much sleep as 10 hours or more, and too little as 6 hours or less.

Researchers from the Centers for Disease Control and Prevention (CDC) report their findings in the October issue of the journal SLEEP.

Study co-author Dr. Janet B. Croft, a senior chronic disease epidemiologist in the Division of Population Health at the CDC, says:

"Some of the relationships between unhealthy sleep durations and chronic diseases were partially explained by frequent mental distress and obesity."

She says this suggests doctors looking after patients with chronic diseases should think about keeping a check on their mental health and body weight, as well as their sleep quality.

For their study, the researchers examined data on over 54,000 people aged 45 and over living in 14 states of the US.

The data showed 31% of the participants were "short sleepers" who slept an average of 6 hours or less in a 24-hour period, over 65% were "optimal sleepers" who slept 6 to 9 hours on average, and 4% were "long sleepers" who slept an average of 10 hours or more.

When they analyzed the relationships between sleep and health, the team found that compared with optimal sleepers, short sleepers tended to suffer more from coronary heart disease, stroke and diabetes, as well as obesity and frequent mental distress.

They found the same was true of long sleepers, except in their case, links with coronary heart disease, stroke and diabetes were even stronger.

Dr. M. Safwan Badr, president of the American Academy of Sleep Medicine (AASM), says:

"Sleeping longer doesn't necessarily mean you're sleeping well."

He says people should understand that sleep affects health: a healthy, balanced lifestyle is not just about following a good diet and staying fit, but also getting the right quantity and quality of sleep.

The AASM advises patients suffering from chronic conditions - like diabetes, anxiety, heart disease and obesity - to have their sleep patterns evaluated by a doctor who specializes in sleep medicine.

Dr Badr says:

"It's critical that adults aim for 7 to 9 hours of sleep each night to receive the health benefits of sleep, but this is especially true for those battling a chronic condition."

He says people with chronic diseases often suffer from common sleep conditions like apnea and insomnia, which affects their ability to get a good night's sleep. If you wake up exhausted, then you need to get help to identify the problem:

"If you are diagnosed with a sleep illness, treating it could significantly improve disease symptoms and your quality of life."

The researchers call for further studies to look at how mental health and keeping to a normal weight may interact with sleep duration to prevent chronic diseases.

Another study published recently found yoga helped menopausal women with insomnia.

Written by Catharine Paddock PhD

Copyright: Medical News Today

Low testosterone in men linked to CVD risk

Men with low testosterone levels may be at higher risk of cardiovascular disease, according to a study review published in the Journal of Clinical Endocrinology and Metabolism.

Testosterone is a male sex hormone, important for maintaining sperm production, sex drive and bone health. Low testosterone levels have been found to cause increases in body fat, as well as loss of muscle bulk and body hair.

But now, researchers from Ghent University Hospital in Belgium have found that low testosterone levels may also be linked to a higher risk of developing or dying from cardiovascular disease.

To arrive at their findings, the research team examined previous studies that analyzed cardiovascular disease and testosterone levels between 1970 and 2013.

The review of the studies revealed modest evidence that low testosterone levels are linked to an increased risk of cardiovascular disease.

However, the researchers note there was little evidence of a link between low testosterone and artherosclerosis - the hardening and narrowing of the arteries that can lead to heart attacks and strokes, and there was no evidence of a specific link between heart attacks and testosterone levels.

Johannes Ruige, of Ghent University Hospital and lead study author, explains:

"When we reviewed the existing research into testosterone and cardiovascular disease, a growing body of evidence suggested a modest connection between the two.
A specific pathogenesis did not come forward, but perhaps less frequently investigated events may play a role, such as thrombosis, where a blood clot develops in the circulatory system or arrhythmia, where there is a problem with the heart beat or rate."

Additionally, the researchers found that although the number of older and middle-aged men are prescribed testosterone replacement therapy to treat low testosterone levels, the procedure appeared to have no positive effect on cardiovascular health.

Many of the reviewed studies did not provide information regarding causality of either condition, the researchers say, but the review did include 19 observational studies that provided information on whether one condition causes another.

Because this review has not ruled out potential causes of low testosterone levels and cardiovascular disease completely, the researchers say further research is needed to confirm the link between both conditions.

"Based on current findings, we cannot rule out that low testosterone and heart disease both result from poor overall health," says Ruige.

"Gaps still remain in our understanding of low testosterone and cardiovascular disease. Ultimately, the goal is to more accurately assess the impact testosterone substitution therapy may have on the heart health of men who qualify for the treatment."

Earlier this year, Medical News Today reported on a study that suggested Parkinson's disease in men may be linked to a sudden decline in testosterone.

Written by Honor Whiteman

Copyright: Medical News Today

Exercise 'as effective as drugs' for common diseases

Scientists claim that exercise may be just as effective as drugs for treating common conditions, such as coronary heart disease and stroke.

It has long been established that regular exercise is beneficial for health in general, but researchers now think exercise is "potentially as effective" as drug intervention, and they suggest it "should be considered as a viable alternative to, or alongside, drug therapy."

Physical activity has well-documented health benefits, yet in England, roughly one-third of adults meet the recommended levels of physical activity. And a recent survey revealed that the same is true in the US.

By contrast, prescription drug rates continue to skyrocket, sharply rising to an average of 17.7 prescriptions for every person in England in 2010, compared with 11.2 in 2000.

However, there is very little evidence on how exercise compares with drugs in reducing the risk of death for common diseases, researchers say.

While pharmaceutical companies spend millions researching and developing new drugs, they seldom test the drugs' efficacy against exercise alone. The report published on bmj.com today suggests pharmaceutical companies should include exercise intervention as an active comparator arm in drug trials.

Huseyin Naci, a researcher from the London School of Economics, is hopeful that this will change. He says:

"I think there will likely be a culture shift in the coming years with exercise interventions gaining more interest. If such a shift occurs, patients and physicians may demand such evidence about the comparative life saving benefits of exercise and drugs.

Preventing diabetes and heart disease

Researchers at the London School of Economics, Harvard Pilgrim Health Care Institute at Harvard Medical School and Stanford University School of Medicine compared the effectiveness of exercise versus drugs on mortality across four conditions (secondary prevention of coronary heart disease, rehabilitation of stroke, treatment of heart failure and prevention of diabetes).

Secondary prevention refers to treating patients with existing disease before it causes significant illness.

They analyzed the results of 305 randomized controlled trials involving 339,274 individuals and found no statistically detectable differences between exercise and drug interventions for secondary prevention of heart disease and prevention of diabetes.

Among stroke patients, exercise was more effective than drug treatment, while for heart failure, diuretic drugs were more effective than exercise and all other types of drug treatment.

'Blind spots'

The authors point out that the amount of trial evidence on the mortality benefits of exercise is considerably smaller than that on drugs, and this may have had an impact on their results.

They argue that this "blind spot" in available scientific evidence "prevents prescribers and their patients from understanding the clinical circumstances where drugs might provide only modest improvement but exercise could yield more profound or sustainable gains in health."

Despite this uncertainty, they say that, based on the available data, physical activity is potentially as effective as many drug interventions, and they call for more trials to address the disparity between exercise and drug-based treatment evidence.

And while it is tempting to believe popping a pill will cure all ills, simple lifestyle changes have already proved effective in the treatment of arthritis of the knee, depression, and high blood pressure.

"In cases where drug options provide only modest benefit, patients deserve to understand the relative impact that physical activity might have on their condition," they conclude.

Written by Belinda Weber

Copyright: Medical News Today