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Older adults: Build muscle and you’ll live longer: UCLA research
Stone Hearth News
New UCLA research suggests that the more muscle mass older Americans have, the less likely they are to die prematurely. The findings add to the growing evidence that overall body composition — and not the widely used body mass index, or BMI — is a better predictor of all-cause mortality.
The study, published in the American Journal of Medicine, is the culmination of previous UCLA research led by Dr. Preethi Srikanthan, an assistant clinical professor in the endocrinology division at the David Geffen School of Medicine at UCLA, that found that building muscle mass is important in decreasing metabolic risk.
"As there is no gold-standard measure of body composition, several studies have addressed this question using different measurement techniques and have obtained different results," Srikanthan said. "So many studies on the mortality impact of obesity focus on BMI. Our study indicates that clinicians need to be focusing on ways to improve body composition, rather than on BMI alone, when counseling older adults on preventative health behaviors."
The researchers analyzed data collected by the National Health and Nutrition Examination Survey (NHANES) III, conducted between 1988 and 1994. They focused on a group of 3,659 individuals that included men who were 55 or older and women who were 65 or older at the time of the survey. The authors then determined how many of those individuals had died from natural causes based on a follow-up survey done in 2004.
The body composition of the study subjects was measured using bioelectrical impedance, which involves running an electrical current through the body. Muscle allows the current to pass more easily than fat does, due to muscle's water content. In this way, the researchers could determine a muscle mass index — the amount of muscle relative to height — similar to a body mass index. They looked at how this muscle mass index was related to the risk of death.
They found that all-cause mortality was significantly lower in the fourth quartile of muscle mass index compared with the first quartile.
"In other words, the greater your muscle mass, the lower your risk of death," said Dr. Arun Karlamangla, an associate professor in the geriatrics division at the Geffen School and the study’s co-author. "Thus, rather than worrying about weight or body mass index, we should be trying to maximize and maintain muscle mass."
This study does have some limitations. For instance, one cannot definitively establish a cause-and-effect relationship between muscle mass and survival using a cohort study such as NHANES III. "But we can say that muscle mass seems to be an important predictor of risk of death," Srikanthan said. In addition, bioelectrical impedance is not the most advanced measurement technique, though the NHANES III measurements were conducted in a very rigorous fashion "and practically, this is the best situation possible in a study of this size," she noted.
"Despite these limitations, this study establishes the independent survival prediction ability of muscle mass as measured by bioelectrical impedance in older adults, using data from a large, nationally representative cohort," Srikanthan and Karlamangla write, adding that BMI’s association with mortality in older adults has proven inconsistent. "We conclude that measurement of muscle mass relative to body height should be added to the toolbox of clinicians caring for older adults. Future research should determine the type and duration of exercise interventions that improve muscle mass and potentially increase survival in (healthy), older adults."
CDC: Doctors Increasingly Prescribe Exercise
WebMD (Feb. 9, 2012) A new report from the CDC shows that more patients are getting prescriptions for exercise from their doctors.
In 2010, 1 in 3 adults who saw a doctor or other health care professional was advised to increase their physical activity as a means of maintaining or improving their health. That?s a significant increase over 2000, when less than a quarter of consultations included such advice.
Trends over the past 10 years suggest that the medical community is increasing its efforts to recommend participation in exercise and other physical activity that research has shown to be associated with substantial health benefits,? states the report, from the CDC?s National Center for Health Statistics.
It's an important development, the report indicates, because patients listen to their doctors. According to a 2008 study, overweight patients were nearly five times more likely to exercise if their doctors counseled them to do so. They were even more likely to keep active if their doctor followed up with them after the initial prescription.
Exercise lowers the risk of many chronic diseases, including heart disease , type 2 diabetes , and depression . Yet, according to government estimates, only 3 in 10 U.S. adults get the recommended amount of exercise each week.
According to the report, doctors and other health professionals most frequently prescribed exercise to their overweight and obese patients. Nearly half of obese patients received such advice in 2010, compared to less than a quarter of healthy-weight adults.
Although Hispanic patients showed the largest increase in exercise recommendations, increases were seen across all races and ethnic groups, the report states.
Almost 30% of adults aged 85 and older received exercise advice in 2010, a nearly two-fold increase over the 10 years covered by the report. However, the largest number of adults receiving prescriptions for physical activity were those aged 45 to 74. Adults younger than 25 received the fewest.
The same upward trend can be seen among patients with chronic diseases, particularly those with type 2 diabetes, half of whom received exercise counseling from their doctors. In 2010, a significantly greater number of patients with heart disease and stroke risk, high blood pressure , and cancer received exercise advice compared to 2000.
Despite the rise in the number of patients being advised to get and stay active, the authors of the report acknowledge that there is a long way to go before such advice reaches a sufficient number of people.
"The prevalence of receiving this advice remains well below one-half of U.S. adults and varies substantially across population subgroups," the authors write.
Routine Head Hits in School Sports May Cause Brain Injury
ScienceDaily (Nov. 14, 2011) The brain scans of high school football and hockey players showed subtle injury -- even if they did not suffer a concussion -- after taking routine hits to the head during the normal course of play, according to a University of Rochester Medical Center study.
The research, reported online in the journal Magnetic Resonance Imaging, is preliminary, involving a small sample of athletes, but nonetheless raises powerful questions about the consequences of the mildest head injury among youths with developing brains, said lead author Jeffrey Bazarian, M.D., M.P.H., associate professor of Emergency Medicine at URMC with a special interest in sports concussions.
Bazarian and colleagues used a cutting edge statistical approach to analyze before-and-after images of the players' brains from diffusion tensor imaging (DTI). A DTI scan is similar to an MRI but it does not relay pictures, rather it captures and relays quantitative data that must be decoded and interpreted.
Collaborators and co-authors Tong Zhu, Ph.D., and Jianhui Zhong, Ph.D., uniquely applied a novel (wild bootstrap) statistical method to the DTI imaging study and detected the small but noteworthy changes in the white matter of the teenagers.
"Although this was a very small study, if confirmed it could have broad implications for youth sports," Bazarian said. "The challenge is to determine whether a critical number of head hits exists above which this type of brain injury appears, and then to get players and coaches to agree to limit play when an athlete approached that number."
Nine athletes and six people in a control group from Rochester, N.Y., volunteered to take part in the research during the 2006-2007 sports season. Among the nine athletes, only one was diagnosed with a sports-related concussion that season, but six others sustained many sub-concussive blows and showed abnormalities on their post-season DTI scans that were closer to the concussed brain than to the normal brains in the control group.
The imaging changes also strongly correlated with the number of head hits (self-reported in a diary), the symptoms experienced, and independent of cognitive test results, Bazarian said.
The URMC study is unique because it was able to compare brain scans from the same player, pre-season and post-season. Most other studies compare the injured brain of one person to the normal brain of another person from a control group. However, that becomes a problem when searching for very subtle changes, Bazarian said, because so much natural variation exists in every individual's brain.
Indeed, among athletes there is no easy, objective way to diagnose concussions. High schools, colleges, and professional programs routinely administer pre-season, computer-based cognitive tests. Yet some athletes have become adept at tricking the test, Bazarian said. They intentionally do poorly on the baseline so that a mild concussion will not show up if re-tested later.
The DTI scan provides detailed information of axonal injury at the cellular level, by measuring the motion of water in the brain. Axons, which are like cables woven throughout brain tissue, swell up when injury occurs. As the swelling impacts the movement of water, scientists can measure changes in flow and volume and thus make an educated guess at the extent of axonal injury.
Measurements in the study at hand showed many changes in the brain of the player with the diagnosed concussion; however an intermediate level of changes also occurred among the players who reported anywhere from 26 to 399 total sub-concussive blows. The fewest changes occurred in the control group, as expected.
A key objective of the study was to determine if this statistical approach worked, and the preliminary results showed that white matter changes among the intermediate group were three times higher than the controls.
Efforts to further understand the significance of study results are already underway. Bazarian and collaborators at the Rochester Center for Brain Imaging, the URMC Department of Emergency Medicine, Department of Athletics and Recreation, and the Department of Imaging Sciences, are working on an NFL-funded study of UR football players this fall. Ten players agreed to wear helmets with special sensors that objectively detect the number of head hits they sustain, the velocity and angle. Each player is also receiving a pre-season and 2 post-season DTI scans, and the data downloaded from the helmet sensors will be correlated with information from the images.
"Our studies are taking important steps toward personalized medicine for traumatic brain injury," Bazarian said. "In the future we'd like to be able to have a baseline image of a brain and clearly know the significance of changes that occur later."
Funding was provided by the National Institutes of Health and the UR Health Sciences Center for Computational Innovation.
The story above is reprinted from materials provided by University of Rochester Medical Center.
Note: Materials may be edited for content and length. For further information, please contact the source cited above.
Inactivity Causes Excess Body Fat — Or Is the Reverse True?
From The Sports Medicine Bulletin
By Kathleen F. Janz, Ed.D., FACSM, and Soyang Kwon, Ph.D.
Given the health consequences for individuals and the economic burden of health care for society, the lack of physical activity and increased prevalence of obesity are major areas of interest for researchers, health practitioners and the public. There is substantial evidence that both the lack of physical activity and the rise in obesity contribute to poor health, independently of and synergistically with each other.
Physiologically, it makes sense that the lack of physical activity contributes to adiposity accumulation. Many epidemiologic studies have also shown the effect of inactivity on obesity phenotype. However, the role of adiposity on physical activity participation (reverse causation hypothesis) has been investigated less often. Understanding the potential effects of adiposity levels on physical activity has significant implications for designing physical activity intervention programs, even those not specifically aimed at preventing or reducing obesity. The reverse causation hypothesis implies a positive feedback loop, where becoming obese leads to physical inactivity which leads to becoming more obese – a pattern that may continue throughout life. The consequences of this loop could be particularly devastating for children due to the strong tracking of adiposity and the critical formation of attitudes, values and motor skills that takes place during childhood.
How can adiposity level negatively influence physical activity behaviors in children – especially given that the general population, including most children, is aware of the detrimental health consequences of obesity as well as the weight loss potential afforded by physical activity? (One might assume that being obese would be an excellent motivator for high levels of physical activity.) The reality is that obesity and physical activity behaviors exist in a complex bio-behavioral context. There is accumulating support for obesity-induced biomechanical and physiological changes and psycho-societal influences of obesity, which in turn, could act to suppress physical activity behaviors. For example, there is some evidence that obesity leads to musculoskeletal changes, decreased mobility, modification of gait patterns, changes in energy expenditure and, perhaps most importantly, decreased affect during moderate-intensity movement. That is, exercise doesn't feel the same if you are obese. Obesity has also been shown to decrease physical activity self-efficacy. In addition, obese children are more likely to be bullied and perceived as less athletic.
New Evidence on Skeletal Muscle Properties Encourages Exercise for Rheumatoid Arthritis Patients
From the ACSM Sports Medicine Bulletin
By Verena Matschke, M.D.
For patients with rheumatoid arthritis (RA), activities of daily living often are a struggle. They experience pain and swelling of the joints, fatigue and loss of muscle strength – all of which are characteristic for this common chronic joint disease caused by autoimmune inflammation of the joint lining. Improved clinical management of this disease has been achieved by the development of powerful disease-modifying antirheumatic drugs, which reduce progression of joint damage and deformity and enable many patients to maintain an active life in the community. But even patients with stable disease and minimal joint symptoms suffer limitations of physical function, often leading to work disability.
Recent studies have confirmed that significant muscle loss (termed rheumatoid cachexia) occurs in most patients with RA, often at an early stage of disease, and this contributes significantly to reduced strength and function. Major factors in this process include the catabolic effect of pro-inflammatory cytokines such as TNF and down regulation of factors anabolic for muscle, such as insulin-like growth factor I. We and others have demonstrated that intense exercise training can restore muscle mass and physical function without exacerbating disease activity. Thus, encouragement to exercise has increasingly become part of routine rheumatology care, and a growing number of patients – especially those with milder, well-controlled disease – attend public gyms.
Our recent research into the physiological and biomechanical properties of muscle in RA, published in the Dec. 2010 issue of Medicine & Science in Sports & Exercise, has shown that skeletal muscle parameters of patients with stable disease display similar characteristics to those of healthy people. Using methods that are routinely applied in exercise science, such as ultrasound and EMG, we demonstrated that though skeletal muscle mass tends to be reduced in patients with RA, muscle contractile properties, voluntary activation capacity, concentric force and power are not compromised. As a consequence, the force produced per unit muscle (i.e. muscle quality) is preserved, even in cachectic patients. The findings are consistent with, and provide an explanation for, the normal responses to resistance training (i.e. muscle hypertrophy and increased strength) observed in RA patients. These are important results for rheumatology health professionals and sports scientists involved in designing exercise training for RA patients, as they demonstrate that patients with RA are not resistant to the anabolic effects of exercise as previously thought. Rather, rheumatoid muscle should adapt to exercise training in a similar way as healthy muscle.
This is also encouraging news to impart to the people living with RA. Patients not only experience physical barriers to exercise such as pain and fatigue, but they often fear a lack of effect of exercise or even worry about a negative effect. Knowing about muscle characteristics and the benefits of exercise can help improve their perception of exercise training and motivate them to persist with this essential part of rehabilitation in RA, which is likely to lead to meaningful improvements in physical function and mortality for patients.
Why Skipping Exercise Can Be Deadly
Recent studies show how neglecting your weight and fitness has serious consequences for your health.
Rebecca Ruiz, Forbes
One day in the summer of 2001, Dan Radin decided to run to the end of his block. For many, that short distance might be conquered in a minute or two. But Radin, a 21-year-old who weighed nearly 275 pounds at the time, barely made it--and hobbled back to his doorstep. Yet, he refused to quit and increased his distance daily; it was three months before he ran a mile, but the challenge changed his life.
Now, Radin, a marketing copywriter in Los Angeles, exercises for an hour most days of the week. He is a lean, muscular 170 pounds. At an annual checkup, his physician remarked that his low blood pressure and cholesterol were likely an improvement from even before he gained excess weight in the late 1990s.
"Losing a lot of weight and changing your body has a profound impact," Radin says.
More than he may expect, it turns out. According to a study of more than 4,300 people published this summer in the journal of the American College of Sports Medicine, the least-fit individuals had a three-fold increased all-cause mortality risk and a nearly four-fold increased cardiovascular mortality risk when compared to the most fit. In other words, improving your fitness level can better your chances for a longer life.
That study is just one in a recent spate of research in children and adults that draws connections between physical inactivity or obesity and poor health outcomes. It's no secret that exercise is critical to excellent health, but many of us let the week slip by with nothing more than a brisk walk to the parking lot. Yet, neglecting one's weight and fitness is a certain path to increased risk for life-shortening ailments and conditions.
Exercise as Medicine
While physical activity is just one component of developing fitness--the others include overall health and genetic predisposition--exercise is essential.
The ideal amount, says Jonathan Myers, Ph.D., a co-author of the ACSM study and a health research scientist at the VA Palo Alto Health Care System in northern California, is a half-hour of moderate-intense activity five days of the week. Even better is an hour of exercise most days of the week.
When Myers and his co-authors separated their 4,300 participants into different fitness quintiles and studied them for nearly 20 years, the ones that performed the best reached that five-hour-a-week threshold. Those with the poorest fitness had a three-fold increase in overall mortality risk; 170 participants in this category died of all causes while only 55 in the highest quintile died.
"We've been chasing this for the last 20 years or so," Myers says of the results, "and we've seen it over and over again." Fifty years of epidemiological studies, he says, have demonstrated that people who are more fit or are more physically active have lower mortality rates.
A study published last week in the British Medical Journal found a similar correlation between weight gain and maintaining optimal health into old age. Of the 17,000 women who participated in the 20-year observational study, those who were overweight at age 18 and gained more than 22 pounds by 50 had the worst odds for optimal health. For every 11 pounds gained during that time, the chances for "healthy survival" decreased by 5%.
But it's never too late to start exercising. Myers' research shows that there are tremendous benefits to be had for the worst-off individuals who can change their ways. When the co-authors compared the least-fit group to the next least-fit group, they noticed a striking difference: The two-fold increase in mortality risk was predominantly due to variations in physical activity, not other risk factors like hypertension and diabetes.
"We don't know yet why exercise has such protective benefits," says Myers, "but your fitness level can outperform the traditional risk factors"--such as smoking and high blood pressure--"in predicting mortality."
The Kids Aren't Alright
Though fitness often becomes a major concern in adulthood, when aging and the onset of chronic disease makes exercise imperative, there's increasing evidence that physical activity in childhood has significant long-term implications for health.
Kathleen F. Janz, a professor in the departments of Health and Sport Studies and Epidemiology at the University of Iowa, found in a recent study that children who lead less active lives are more likely to be overweight years later.
Janz studied 333 5 year olds over eight years by monitoring their physical activity with a device known as an accelerometer and measuring the subjects' fat mass with body imaging. The protective benefit of physical activity, according to Janz and her co-authors, continued through childhood; the most active children at age five had significantly lower fat mass at eight and 11 compared with those in the lowest quartile.
"It's not unusual that there are windows of opportunity for critical periods where it's most important to do it right," says Janz. Childhood is one of them, she adds.
It's not just fatness that matters, either. A recent study in Circulation found that some Type 2 diabetic and obese teenagers have a thicker carotid artery, an association that had only been seen previously in adults and one that may put them at greater risk for stroke and heart attacks later in life.
Yet, like Jonathan Myers at the Palo Alto Health Care System in northern California, Janz says the protective benefits of exercise are immediate, regardless of how long it's been since the last workout. Certainly, Dan Radin considers himself an example of what can be accomplished with enough determination and direction.
"I hadn't grown up playing sports," he says. "Exercising was something I had to figure out."
But he's far beyond using the corner block as a benchmark or gateway to a longer, healthier life; his next target is a triathlon.
Being Big Around the Middle Poses Big Risks
By Alice Park
Being overweight is one thing, but where your body fat is stored may make more of a difference to your health. Researchers in Germany report that even among people who are normal weight, having excess fat around the abdomen - being apple-shaped, that is - can increase the risk of premature death.
Dr. Tobias Pischon, an epidemiologist and physician at the German Institute of Human Nutrition in Potsdam, analyzed data collected in a large European database of subjects. Among 359,000 subjects who were followed for nearly 10 years, those with the largest waist measurements, 40.4 inches or greater for men and 35.0 inches or more for women, were twice as likely to die prematurely than those with smaller waists, less than 33.8 inches for men and 27.6 inches for women. By the end of the study, 4,232 of the largest waisted people had died of various causes, from heart disease to cancer and other ailments, while 2,155 of the smallest waisted people had died in the same period. Most surprising was that the association applied even to men and women who were not overweight: People with bigger waists had a greater risk of early death.
Current obesity guidelines rely on the body mass index (BMI), a ratio of height and weight. The problem, as many experts have noted, is that the weight component does not distinguish between fat and muscle mass not does it account for how fat distributed. Recent research suggest that the fat that accumulates around the midsection - and deep in the body around the organs - is more likely to contribute to conditions such as heart disease and diabetes, since it is more metabolically active. Known as visceral fat, these adipose cells tend to secrete hormones and cytokines that can throw the body's energy and biochemical balance off kilter; subcutaneous fat, on the other hand, which rests just under the skin in other parts of the body, is more inert, serving mostly as an energy sink.
Pischon's study highlights the growing importance of measuring the amount of the more active visceral fat, and as the results suggest, waist circumference can be an effective marker and a god predictor of how dangerous that fat can be. "What this study shows is that it is not sufficient to simply rely on BMI," says Psichon. "Waist circumference can even be related to higher mortality in normal weight individuals."
But the difficulty with waist circumference is that so far, the data do not point to a threshold at which health risks shoot up. That means that unlike BMI, which gives people a "normal" or healthy range to adhere to, there is no ideal waist measurement. The study found that waist circumference and risk of death increased linearly, meaning that at any given weight, those with greater waist measurements were at greater risk of dying than those with smaller waists. Pischon's team calculated that for every 5 cm ( about 2 inches) increase in girth, the risk of dying increased by 17% for men and by 13% in women.
There is no goal waist circumference, and that is the difficult thing," acknowledges Pischon. "All we can say is that it's good to have a low waist circumference."
Much still needs to be worked out about how waist circumference is contributing to the greater risk of death - in addition to simply adding visceral fat, says Dr. Francisco Lopez-Jiminez, director of clinical practice and preventive cardiology at the Mayo Clinic, greater waist circumference generally also indicates a greater burden of fat overall, which is a big contributor to heart disease and other metabolic conditions that can lead to early death. "The take-home message from this study is that clinicians need to start measuring waist circumference more and more," he says. "It is rarely measured in clinical practice."
Highlight on Health
How much exercise is enough?
Physical activity and gain in life expectancy — quantified
Harvard Gazette (Nov. 6, 2012) — We all know that exercise is good for you, but how good? While previous studies have shown the link between physical activity and a lower risk of premature mortality, the number of years of life expectancy gained among persons with different activity levels has been unclear — until now.
In a new study from Harvard-affiliated Brigham and Women’s Hospital (BWH), in collaboration with the National Cancer Institute, researchers have quantified how many years of life are gained by being physically active at different levels, among all individuals as well as among various groups having different body mass indexes (BMI).
The study was published in PLOS Medicine on Nov. 6.
“We found that adding low amounts of physical activity to one’s daily routine, such as 75 minutes of brisk walking per week, was associated with increased longevity: a gain of 1.8 years of life expectancy after age 40, compared with doing no such activity,” explained Harvard Medical School Professor of Medicine I-Min Lee, an associate epidemiologist in the Department of Preventive Medicine at BWH and senior author on this study. “Physical activity above this minimal level was associated with additional gains in longevity. For example, walking briskly for at least 450 minutes a week was associated with a gain of 4.5 years. Further, physical activity was associated with greater longevity among persons in all BMI groups: those normal weight, overweight, and obese.”
Researchers from Brigham and Women’s Hospital have quantified how many years of life are gained, by being physically active at different levels, among all individuals as well as among various groups with different body mass index (BMI). Courtesy of BWH
In pooled data from six prospective cohort studies, the researchers examined associations of leisure-time physical activity of a moderate to vigorous intensity with mortality. They analyzed data from more than 650,000 subjects and followed subjects for an average of 10 years, analyzing more than 82,000 deaths. The large sample size allowed them to estimate years of life gained after the age of 40 among persons with different levels of physical activity and BMI.
The findings show that physical activity was associated with longer life expectancies across a range of activity levels and BMI groups. Participation in a low level of leisure time physical activity of moderate to vigorous intensity, comparable to up to 75 minutes of brisk walking per week, was associated with a 19 percent reduced risk of mortality compared with no such activity.
Assuming a causal relationship, which is not specifically demonstrated in this research, this level of activity would confer a 1.8-year gain in life expectancy after age 40, compared with no activity. For those who did the equivalent to 150–299 minutes of brisk walking per week — the basic amount of physical activity currently recommended by the federal government — the gain in life expectancy was 3.4 years.
These benefits were seen in both men and women, and among white and black participants. Importantly, they were also observed among persons who were normal weight, overweight, and obese. Participants faring best were those who were both normal weight and active: among normal weight people who were active at the level recommended by the federal government, researchers observed a gain in life expectancy of 7.2 years, compared with those with a BMI of 35 or more who did no leisure time physical activity (a 5-foot, 5-inch-tall person with BMI of 35 weighs 210 pounds).
“Our findings reinforce prevailing public health messages promoting both a physically active lifestyle and a normal body weight,” explained Steven C. Moore, research fellow at the National Cancer Institute and lead author of this study. These findings may also help convince currently inactive persons that even being modestly active is ‘‘worth it’’ for greater longevity, even if it may not result in weight control.