Stress could cause cancer claim scientists

Scientists have discovered that everyday emotional stress is a trigger for the growth of tumours

They discovered that any sort of trauma, emotional or physical, can act as a "pathway" between cancerous mutations bringing them together in a potentially deadly mix.

The findings, published in Nature, seemed to show for the first time that the conditions for developing the disease can be affected by your emotional environment including every day work and family stress.

Professor Tian Xu, a geneticist at Yale University who led the study, said: "A lot of different conditions can trigger stress signaling - physical stress, emotional stress, infections, inflammation – all these things.

"Reducing stress or avoiding stress conditions is always good advice."

Until now, scientists believed more than one cancer-causing mutation needed to take place in a single cell in order for tumours to grow.

But Prof Xu and colleagues at Yale University, working with fruit flies, showed mutations can promote cancer even when they are located in different cells. This is because stress opens up "pathways" between them.

He said: "The bad news is that it is much easier for a tissue to accumulate mutations in different cells than in the same cell."

Exercise associated with preventing, improving mild cognitive impairment

Moderate physical activity performed in midlife or later appears to be associated with a reduced risk of mild cognitive impairment, whereas a six-month high-intensity aerobic exercise program may improve cognitive function in individuals who already have the condition, according to two reports in the January issue of Archives of Neurology, one of the JAMA/Archives journals.

Mild cognitive impairment is an intermediate state between the normal thinking, learning and memory changes that occur with age and dementia, according to background information in one of the articles. Each year, 10 percent to 15 percent of individuals with mild cognitive impairment will develop dementia, as compared with 1 percent to 2 percent of the general population. Previous studies in animals and humans have suggested that exercise may improve cognitive function.

In one article, Laura D. Baker, Ph.D., of the University of Washington School of Medicine and Veterans Affairs Puget Sound Health Care System, Seattle, and colleagues report the results of a randomized, controlled clinical trial involving 33 adults with mild cognitive impairment (17 women, average age 70). A group of 23 were randomly assigned to an aerobic exercise group and exercised at high intensity levels under the supervision of a trainer for 45 to 60 minutes per day, four days per week. The control group of 10 individuals performed supervised stretching exercises according to the same schedule but kept their heart rate low. Fitness testing, body fat analysis, blood tests of metabolic markers and cognitive functions were assessed before, during and after the six-month trial.

A total of 29 participants completed the study. Overall, the patients in the high-intensity aerobic exercise group experienced improved cognitive function compared with those in the control group. These effects were more pronounced in women than in men, despite similar increases in fitness. The sex differences may be related to the metabolic effects of exercise, as changes to the body's use and production of insulin, glucose and the stress hormone cortisol differed in men and women.

"Aerobic exercise is a cost-effective practice that is associated with numerous physical benefits. The results of this study suggest that exercise also provides a cognitive benefit for some adults with mild cognitive impairment," the authors conclude. "Six months of a behavioral intervention involving regular intervals of increased heart rate was sufficient to improve cognitive performance for an at-risk group without the cost and adverse effects associated with most pharmaceutical therapies."

In another report, Yonas E. Geda, M.D., M.Sc., and colleagues at Mayo Clinic, Rochester, Minn., studied 1,324 individuals without dementia who were part of the Mayo Clinic Study of Aging. Participants completed a physical exercise questionnaire between 2006 and 2008. They were then assessed by an expert consensus panel, who classified each as having normal cognition or mild cognitive impairment.

A total of 198 participants (median or midpoint age, 83 years) were determined to have mild cognitive impairment and 1,126 (median age 80) had normal cognition. Those who reported performing moderate exercise—such as brisk walking, aerobics, yoga, strength training or swimming—during midlife or late life were less likely to have mild cognitive impairment. Midlife moderate exercise was associated with 39 percent reduction in the odds of developing the condition, and moderate exercise in late life was associated with a 32 percent reduction. The findings were consistent among men and women.

Light exercise (such as bowling, slow dancing or golfing with a cart) or vigorous exercise (including jogging, skiing and racquetball) were not independently associated with reduced risk for mild cognitive impairment.

Physical exercise may protect against mild cognitive impairment via the production of nerve-protecting compounds, greater blood flow to the brain, improved development and survival of neurons and the decreased risk of heart and blood vessel diseases, the authors note. "A second possibility is that physical exercise may be a marker for a healthy lifestyle," they write. "A subject who engages in regular physical exercise may also show the same type of discipline in dietary habits, accident prevention, adherence to preventive intervention, compliance with medical care and similar health-promoting behaviors."

Future study is needed to confirm whether exercise is associated with the decreased risk of mild cognitive impairment and provide additional information on cause and effect relationships, they conclude.

3 Ways to Help Teenagers Get More, Better Sleep

If your teenagers are cranky, distracted, and disorganized, it may well be because they're not getting enough sleep during the week. And sleeping in on weekends doesn't solve the problem.

The latest contribution to the growing pile of evidence showing that teenagers are being seriously shortchanged found that just 10 percent of adolescents are getting the optimal 10 hours of shut-eye a night. (Given that the high school bus rumbles through my neighborhood at 6:45 am, I'm not surprised.)

Who's least likely to get enough sleep? The survey of students across the nation, published in this month's Journal of Adolescent Health, found that those most likely to miss out on sleep are female, black, and/or in the higher grade levels. That last one's not surprising, considering how the homework piles up in junior and senior years of high school.

I asked Danice Eaton, an epidemiologist with the Centers for Disease Control and Prevention who conducted the study, how parents can help teens get the most possible sleep, despite the demands of school and work. Her advice:

Teenagers should stick to a consistent bedtime, preferably before 10 p.m.
Keep sleep and wake times as consistent as possible from day to day. Research shows that maintaining a more regular sleep schedule makes it easier to fall asleep.
Don't sleep in. Strive to wake up no more than two to three hours later on weekends to keep biological clocks on cycle.
Kids have a lot of demands on their time," Eaton said. "But sleep is important. If they are chronically shortchanging their sleep, it does have negative medical and mental health outcomes."
How much sleep do your teenagers get? And are you able to pry them out of bed on weekend mornings?

Yoga reduces cytokine levels known to promote inflammation

COLUMBUS, Ohio – Regularly practicing yoga exercises may lower a number of compounds in the blood and reduce the level of inflammation that normally rises because of both normal aging and stress, a new study has shown.

The study, done by Ohio State University researchers and just reported in the journal Psychosomatic Medicine, showed that women who routinely practiced yoga had lower amounts of the cytokine interleukin-6 (IL-6) in their blood.

The women also showed smaller increases in IL-6 after stressful experiences than did women who were the same age and weight but who were not yoga practitioners.

IL-6 is an important part of the body's inflammatory response and has been implicated in heart disease, stroke, type-2 diabetes, arthritis and a host of other age-related debilitating diseases. Reducing inflammation may provide substantial short- and long-term health benefits, the researchers suggest.

"In addition to having lower levels of inflammation before they were stressed, we also saw lower inflammatory responses to stress among the expert yoga practitioners in the study," explained Janice Kiecolt-Glaser, professor of psychiatry and psychology and lead author of the study.

"Hopefully, this means that people can eventually learn to respond less strongly to stressors in their everyday lives by using yoga and other stress-reducing modalities."

For the study, the researchers assembled a group of 50 women, age 41 on average. They were divided into two groups – "novices," who had either taken yoga classes or who practiced at home with yoga videos for no more than 6 to 12 sessions, and "experts," who had practiced yoga one of two times weekly for at least two years and at least twice weekly for the last year.

Each of the women was asked to attend three sessions in the university's Clinical Research Center at two-week intervals. Each session began with participants filling out questionnaires and completing several psychological tests to gauge mood and anxiety levels.

Each woman also was fitted with a catheter in one arm through which blood samples could be taken several times during the research tasks for later evaluation.

Participants then performed several tasks during each visit designed to increase their stress levels including immersing their foot into extremely cold water for a minute, after which they were asked to solve a series of successively more difficult mathematics problems without paper or pencil.

Following these "stressors," participants would either participate in a yoga session, walk on treadmill set at a slow pace (.5 miles per hour) designed to mirror the metabolic demands of the yoga session or watch neutral, rather boring videos. The treadmill and video tasks were designed as contrast conditions to the yoga session.

Once the blood samples were analyzed after the study, researchers saw that the women labeled as "novices" had levels of the pro-inflammatory cytokine IL-6 that were 41 percent higher than those in the study's "experts."

"In essence, the experts walked into the study with lower levels of inflammation than the novices, and the experts were also better able to limit their stress responses than were the novices," Kiecolt-Glaser explained.

The researchers did not find the differences they had expected between the novices and experts in their physiological responses to the yoga session.

Co-author Lisa Christian, an assistant professor of psychology, psychiatry and obstetrics and gynecology, suggested one possible reason:

"The yoga poses we used were chosen from those thought to be restorative or relaxing. We had to limit the movements to those novices could perform as well as experts.

"Part of the problem with sorting out exactly what makes yoga effective in reducing stress is that if you try to break it down into its components, like the movements or the breathing, it's hard to say what particular thing is causing the effect," said Christian, herself a yoga instructor. "That research simply hasn't been done yet."

Ron Glaser, a co-author and a professor of molecular virology, immunology and medical genetics, said that the study has some fairly clear implications for health.

"We know that inflammation plays a major role in many diseases. Yoga appears to be a simple and enjoyable way to add an intervention that might reduce risks for developing heart disease, diabetes and other age-related diseases" he said.

"This is an easy thing people can do to help reduce their risks of illness."

Bill Malarkey, an professor of internal medicine and co-author on the study, pointed to the inflexibility that routinely comes with aging.

"Muscles shorten and tighten over time, mainly because of inactivity," he said. "The stretching and exercise that comes with yoga actually increases a person's flexibility and that, in turn, allows relaxation which can lower stress."

Malarkey sees the people's adoption of yoga or other regular exercise as one of the key solutions to our current health care crisis. "People need to be educated about this. They need to be taking responsibility for their health and how they live. Doing yoga and similar activities can make a difference."

As a clinician, he says, "Much of my time is being spent simply trying to get people to slow down."

The researchers' next step is a clinical trial to see if yoga can improve the health and reduce inflammation that has been linked to debilitating fatigue among breast cancer survivors. They're seeking 200 women to volunteer for the study that's funded by the National Cancer Institute.

Study: Running Shoes Could Cause Joint Strain

Running shoes, decked out with the latest cushioning, motion control and arch support technologies, may not be as beneficial to your feet and joints as you might think.

A new study finds that running shoes, at least the kind currently on the market, may actually put more of a strain on your joints than if you were to run barefoot or even to walk in high-heeled shoes, and the increased pressure could lead to knee, hip and ankle damage. The scientists don’t recommend ditching your high-tech sneaks, however, as going barefoot on man-made surfaces could also prove harmful,

While exercise is no doubt beneficial for overall health, running and walking put stresses on your joints that may predispose you to getting osteoarthritis in those areas, said Dr. D. Casey Kerrigan, who conducted the study while at the University of Virginia, where she was a professor of physical medicine and rehabilitation. Osteoarthritis is the breakdown of cartilage in your joints, which can lead to bone rubbing on bone, causing pain, Kerrigan explained. Walkers and runners should try to minimize forces on their joints to prevent this damage, she said.

In pervious work, Kerrigan and colleagues had shown that women's high-heeled shoes cause an increase in pressure on the knee joint, specifically in areas where osteoarthritis typically develops, compared with walking barefoot. Since cushioning in running shoes can also create a slightly elevated heel, Kerrigan decided to investigate whether or not these shoes also increase these potentially damaging forces.

Running on a "bathroom scale"

The study enrolled 37 women and 31 men who ran recreationally, at least 15 miles (24 km) per week. The subjects were then studied in a "gait laboratory," running either barefoot or with a typical running shoe. The subjects had markers on their knees, hips and ankle joints, and as they ran, cameras picked up these markers, allowing the researchers to see how the joints moved.

The subjects ran on a treadmill that contained a forceplate, a device Kerrigan describes as a "glorified bathroom scale." With each step, the forceplate provided measurements of the magnitude of their bodyweight forces on the joints, and the direction of those forces.

They specifically looked at torque, twisting force, which in this case mainly came from the participants’ bodyweight, For example, if you stand on one leg, your bodyweight would put more pressure on the inside part of your knee than on the outside part, causing a torque at the knee, Kerrigan explained.

The researchers found an increase in this torque for the knees, hips and ankles when the participants were wearing running shoes as compared with when they were running barefoot.

Specifically, they saw a 38 percent increase in torque in areas of the knee where osteoarthritis develops, Kerrigan said. Such a large increase was surprising, she said, because it was greater than the increase in knee torque she had observed for women wearing high heels, which was only 20 percent to 26 percent.

Kerrigan noted the study only provides an estimate of the joint forces, and not the exact forces, because the methods used do not directly measure the forces inside the knee and other joints. However, there are other studies to support that these types of estimates do match up fairly well with the actual forces inside the joints.

Is barefoot better?

Should you ditch your running shoes altogether? While the results might seem to suggest that you should go barefoot — a way of running that has recently become popular thanks to the best-selling book "Born to Run," by Christopher McDougall, in which the author argues that barefoot running is better for you — Kerrigan says that’s not the case.

"I'm concerned, I don't think this study should promote running barefoot," she said. "I think people should run in what they feel most comfortable running in ... and whether that's in a pair of running shoes or in a minimum kind of running shoe, that's just fine."

The problem with running sans shoes is that most of the man-made surfaces we run on are not "compliant" — they don't give, or compress, at the right time to absorb the peak forces on your joints, Kerrigan said.

"We've evolved to run on compliant surfaces, not on asphalt or concrete," she said. "You run on something hard, your body has to work that much harder to help absorb those forces, and that can lead to stresses and strain, wear and tear, really throughout the whole body."

Also, while certain aspects of shoes, such as arch support, may not be the best for your knee joints, they do protect the foot itself, and may help prevent other injuries, such as shin splints, Kerrigan said.

Kerrigan does have what she believes is a better running shoe system in mind that she thinks would help to minimize the harmful joint torques. She is currently developing her patented shoe design through JKM Technologies, LLC, a manufacturing and information technology service company of which Kerrigan is chairman.