Train with Wayne

Wednesday, November 21, 2018

Different types of physical activity offer varying protection against heart disease

While it is well known that physical activity is important for heart health, neither research nor recommendations consistently differentiate between the benefits of different types of physical activity. New research, presented at the ACC Latin America Conference 2018 in Lima, Peru, found that while all physical activity is beneficial, static activities -- such as strength training -- were more strongly associated with reducing heart disease risks than dynamic activities like walking and cycling.

"Both strength training and aerobic activity appeared to be heart healthy, even in small amounts, at the population level," said Maia P. Smith, PhD, MS, statistical epidemiologist and assistant professor in the Department of Public Health and Preventive Medicine at St. George's University in St. George's, Grenada. "Clinicians should counsel patients to exercise regardless -- both activity types were beneficial. However, static activity appeared more beneficial than dynamic, and patients who did both types of physical activity fared better than patients who simply increased the level of one type of activity."

Researchers analyzed cardiovascular risk factors, such as high blood pressure, overweight, diabetes and high cholesterol, as a function of self-reported static and/or dynamic activity (strength training or walking/biking) in 4,086 American adults using data from the 2005-2006 National Health and Nutrition Examination Survey. The researchers then adjusted for age, ethnicity, gender and smoking and stratified by age: 21 to 44 years old or over 45 years old.

In total, 36 percent of younger and 25 percent of older adults engaged in static activity, and 28 percent of younger and 21 percent of older adults engaged in dynamic activity. Researchers found engaging in either type of activity was associated with 30 to 70 percent lower rates of cardiovascular disease risk factors, but associations were strongest for static activity and in youth.

"One interesting takeaway was that both static and dynamic activity were almost as popular in older people as younger," Smith said. "I believe this gives clinicians the opportunity to counsel their older patients that they will fit into the gym or the road race just fine. The important thing is to make sure they are engaging in physical activity."

Smith said future research and data collection should use definitions of physical activity that separate static from dynamic activity to further investigate independent effects.

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Materials provided by American College of Cardiology. Note: Content may be edited for style and length.

Cite This Page:

American College of Cardiology. "Different types of physical activity offer varying protection against heart disease: Static activity, such as strength training, appears more beneficial." ScienceDaily. ScienceDaily, 16 November 2018. .

Antioxidants may prevent cognitive impairment in diabetes

Cognitive difficulties in patients with diabetes, caused by repeated episodes of low blood sugar, could be reduced with antioxidants, according to a new study presented at the Society for Endocrinology annual conference in Glasgow. The study findings suggest that stimulating antioxidant defences in mice reduces cognitive impairments caused by low blood sugar, which could help to improve the quality of life for diabetic patients.

Long-term decline in cognitive function, with everyday learning and memory tasks becoming harder and taking longer to complete, is a common consequence for patients who frequently experience low blood sugar levels when using insulin to manage their diabetes. Previous studies in mice have shown that reoccurring episodes of low blood sugar leads an accumulation of cell damaging free radicals in the brain. Whether this build-up of free radical stress directly effects cognitive function, and if the body's own antioxidative systems, which can remove free radicals, can be harnessed to counteract these changes and improve quality of life is not known.

In this study, Dr Alison McNeilly and colleagues at the University of Dundee used insulin to induce repeated bouts of low blood sugar in a mouse model of type-1 diabetes. In the experiment, one group of mice were also dosed with the vegetable derived antioxidant sulforaphane (SFN). Mice treated with SFN showed increased expression of antioxidant markers, decreased free radical cell damage and had significantly improved cognitive ability in memory tasks.

Dr McNeilly commented, "Low blood sugar is an almost unavoidable consequence of insulin therapy. This work demonstrates that by improving the body's own antioxidant defence system we can reverse some of the side effects associated with diabetes, such as poor cognitive function."

Dr McNeilly and her colleagues now intend to find out if boosting the body's antioxidative system can minimise cognitive decline associated with low blood sugar in humans, by using drugs based on the chemical structure of SFN.

Dr McNeilly said, "The concentration of SFN used in this study would not be attainable in a normal diet rich in vegetables. However, there are numerous highly potent compounds in clinical trials which may prevent cognitive impairments caused by free radicals to help diabetes patients."

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Materials provided by Society for Endocrinology. Note: Content may be edited for style and length.

Being fair: The benefits of early childhood education

Children from low-income families who got intensive education early in life treat others with high levels of fairness in midlife, more than 40 years later, even when being fair comes at a high personal cost, according to a new study published today in Nature Communications.

The 78 people in the study were followed as part of the Abecedarian Project, begun in the 1970s and to this day one of the longest running randomized controlled studies of the effects of early childhood education in low-income and high-risk families.

Participants played games designed to measure their adherence to social norms and their social decision-making processes. In one game, a player was asked to split a sum of money -- $20 -with another participant. The participant could either accept the amount proposed, or reject it, in which case neither received any money. When faced with unequal offers, participants had to make trade-offs between self-interest and the enforcement of social norms of equality.

This is where the value of early childhood education became apparent. Players who, in the 1970s, had been given intensive educational training including cognitive and social stimulation when they were young children, strongly rejected unequal division of money among players when they were in midlife, even if it meant they would miss out on hefty financial gains themselves.

"When someone rejects an offer, they are sending a very strong signal to the other player about the decision regarding how the money should be divided," said Université de Montréal assistant psychology professor Sébastien Hétu, a first-author of the study. "People who received educational training through the Abecedarian Project were inclined to accept generally equal offers, but would reject disadvantageous and advantageous offers. In effect, they punished transgressions that they judged to be outside of the social norm of equality."

Originally developed and led by Craig Ramey, a professor and distinguished research scholar at the Virginia Tech Carilion Research Institute, the Abecedarian Project investigates the impacts of intensive early childhood educational interventions on language and learning in disadvantaged children. The new research involves an international group of scientists led by Virginia Tech neuroscientist Read Montague, in whose laboratory Hétu was a postdoctoral associate before coming to Montreal.?

Using computational modeling, the study's researchers also discovered differences in social decision-making strategies between participants. For example, in another game, players who had received educational interventions early in life planned further into the future than people who didn't.

"The participants who received early educational interventions were very sensitive to inequality, whether it was to their advantage or their disadvantage," said Yi Luo, first author of the study and a postdoctoral associate in Montague's lab. "Our results also suggest that they placed more value on the long-term benefits of promoting social norms as opposed to short-term benefits for personal gain."

She concluded: "Our research shows that investment in early childhood education, especially in the education of highly vulnerable children from low-income families, can produce long-term effects in decision-making even decades after the educational experience."

Story Source:

Materials provided by University of Montreal. Note: Content may be edited for style and length.

Journal Reference:

Yi Luo, Sébastien Hétu, Terry Lohrenz, Andreas Hula, Peter Dayan, Sharon Landesman Ramey, Libbie Sonnier-Netto, Jonathan Lisinski, Stephen LaConte, Tobias Nolte, Peter Fonagy, Elham Rahmani, P. Read Montague, Craig Ramey. Early childhood investment impacts social decision-making four decades later. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-018-07138-

Sunday, November 18, 2018

Why It's Harder to Lose Weight as You Age

DOES YOUR FAVORITE PAIR of jeans fit more snugly around the waist with each birthday? Is your favorite dress a little tighter with each passing year?

Research suggests that many people gain weight as they advance in age from young adulthood into middle age. Between ages 29 and 39, women typically gain about 7 pounds, and men put on an additional 15 pounds, according to the U.S. Department of Health and Human Services. Conversely, losing weight in your 30s and 40s is more difficult than when you're a young adult. (Men and women tend to put on little or no weight after age 40 and lose weight in their 70s, according to HHS.) For a variety of reasons, it's tougher for men and women to drop pounds as they transition from young adulthood into middle age than it is to shed weight during young adulthood, experts say. The factors behind middle-age weight gain are biological and related to lifestyle.

Beginning in your 30s, you lose muscle mass every decade, research suggests. That muscle mass is replaced with fat. This happens even if you exercise regularly, whether it's working out at the gym, running, swimming or playing in a pickup basketball, softball or volleyball game. Since muscles use more calories than fat, less muscle mass and more fat slow your metabolism, which means you need fewer calories, says Kimberly Gomer, a registered dietitian and director of nutrition at the Pritikin Longevity Center + Spa in Miami. "As we age, unless we work at it, we lose muscle mass," Gomer says. "Fat needs very few calories to exist."

Women and men face other biological challenges to losing weight in their middle-age years. Because of changing hormones and a loss of estrogen, women typically gain 15 pounds around the time of menopause, says Dr. Kathryn Boling, a primary care physician with Mercy Medical Center in Baltimore. She's also board-certified in obesity medicine. Women going through menopause tend to gain weight around their tummy, Boling says. Men going through middle age face a different issue: the loss of testosterone, which can cause the diminution of muscle mass, Boling says.

[See: 10 Unusual Weight-Loss Tips That Actually Work.]

In addition to biological issues, changes in lifestyle can be a factor that causes some people to put on pounds in their 30s and 40s. Many people become parents during that phase of their life, and they're less physically active because of family responsibilities. Career demands can also cause many people to become more sedentary than they were when they were young adults, says Jessalynn Adam, a primary care sports medicine physician with Orthopedics and Joint Replacement at Mercy Medical Center in Baltimore. "Your schedule isn't your own at that point," Adam says. Gomer agrees. "Many of us are very active when we're younger, running around carefree with few responsibilities," she says. "In grade school, high school and college, we participate in sports, walk more and run more. As we age – maybe get a desk job, have a family – our free time/leisure time gets decreased."

…

Exercising less can lead some people to bad eating habits, Gomer says. Physical activity releases endorphins, neurotransmitters in the brain that block pain and can help you feel calmer and happier. Eating foods that are salty, fatty and sugary can have a similar effect. Consuming such foods leads the brain to produce surges of dopamine, a brain chemical that's released when we experience pleasure. Some people who miss the feelings of well-being associated with exercising may turn to unhealthy foods as a substitute.

While you can't do anything to slow the passage of time, there are steps you can take to lose weight as you age. Experts recommend these strategies:

In Your 30s, 40s and 50s

Learn to cook and plan your meals. Have you ever picked up a quick dinner of burgers and fries from the nearest fast-food outlet because you had to work late to meet a deadline? Fast food is typically highly processed and poor in nutrients. It's also often high in calories, sugar, sodium and unwanted additives, Adam says. Consequently, eating meals from fast-food outlets won't help your efforts to shed pounds. If you learn to cook and to plan your meals out a few days in advance, you can avoid impromptu stops at greasy burger joints, Adam says. She suggests taking a cooking class to learn how to prepare healthy meals that focus on fresh vegetables and healthy sources of protein. Learn how to make enough food for more than one day at a time; you can refrigerate the food so you'll have healthy meals prepared, and no need to make a spur of the moment fast-food run.

Do weight-bearing exercises. Lifting weights helps you maintain muscle mass, which becomes increasingly important as you move from young adulthood into middle age, Boling says. Maintaining your muscle mass helps you burn more calories. "If you have less muscle mass, you burn fewer calories," she says. Maintaining your muscle mass also helps cut down the chances of sustaining injuries. She recommends doing exercise with free weights and resistance machines.

Make physical activity a family affair. Having a spouse and children doesn't have to interrupt your exercise regimen, Adam says. For instance, if you're part of a pickup hoops game, shoot baskets with your significant other or child before or after the contest. You can ride bikes with your partner or with your kids. Look for opportunities to make exercise a family activity. For example, some triathlons also have a "fun run" for kids. Introducing your kids to exercise could also encourage them to adopt their own workout regimens that they'll continue into adulthood. In the long run, this can lead to lower obesity rates, Adam says.

Can Exercising Too Much Affect Your Mental Health?

LET’S BE PERFECTLY clear from the start: Exercise is one of the best ways to boost your mental health. Countless studies have proved this beyond any reasonable doubt. Case closed.

However, a recent study revealed that, for some people, there can be too much of a good thing. Researchers from Yale University looked at data sourced from 1.2 million people in the U.S. to try to find out how much and which types of exercise are best for mental health. In the process, they found something a bit surprising.

The study, published in The Lancet, concludes that physical exercise was “significantly and meaningfully” associated with improved mental health, but that, “More exercise was not always better.”

[See: 9 Offbeat Physical Activity Hacks for People Who Really Hate to Exercise.]

Those who exercised for 30 to 60 minutes three to five times per week saw the most benefit, the researchers found. People who were physically active for more than 90 minutes every day also saw their mental health improve, though less so. But subjects who exercised for more than 90 minutes a day or more than 23 times a month actually had worse mental health than those who did not exercise at all.

This finding was “a little bit surprising,” says the study’s lead author, Dr. Adam Chekroud, an adjunct assistant professor of psychiatry at Yale. Previous studies have typically compared how different intensities of exercise affect mental health, but none have looked closely at different volumes of exercise, he says.

The Exercise Sweet Spot

Chekroud stresses that people should not read this the wrong way. “The take-home is, we showed that no exercise is worse than exercise, and that those who exercise too much had the worst mental health. There is a sweet spot, for sure,” he says.

He admits it’s hard to know if excessive exercise leads to mental illness, or the other way around. People who exercise so frequently or so long may be doing so because they are exhibiting obsessive or other poor psychological and emotional behaviors, including body dysmorphia or eating and weight disorders. On the other hand, overexercising to this degree can cause physical and emotional stress, fatigue and inflammation, all of which can have a deleterious impact on mental health. This chicken-or-egg question still needs to be resolved, he says.

For most of us, this issue is not really a problem. “Overexercising is rare, it is not common,” says Dr. Ronald L. Kamm, a psychiatrist who subspecializes in sports psychiatry. Those who are at risk, he says, include people with bipolar disorder, which can include mania. Also at risk are those with addictive personalities because “They overdo exercise, like with any addiction, and neglect other things in their life,” Kamm says. Then there is what he calls secondary exercise addiction, in which exercise is part of an eating disorder. “You see that in athletes more than in those with anorexia nervosa, athletes who compulsively exercise to the point of muscle damage and destruction to lose weight and control body fat,” he says. This is most common in sports that value aesthetics like skating or gymnastics or have weight limits like boxing, wrestling or crew. “Some call it athletica nervosa,” Kamm says.

Sometimes, the sport drives the disorder. Athletes in team sports may overtrain if they are trying to make a team or keep up with others on the team. “Doing that can bring on depression, fatigue and physiological problems like sleep disruption,” says Kamm, director of Sport Psychiatry Associates in Oakhurst, New Jersey, and past president of the International Society for Sport Psychiatry. “Parents and coaches need to sit these athletes down and say, 'Take some time off.' Usually, the depression and fatigue go away.”

However, Kamm believes that, for the most part, mental illness drives overexercising, not the other way around, and it needs to be treated as such. “Those with anorexia nervosa must be prevented from overexercising,” he says. “Many times, people don’t see it. They are athletes, so of course they are training very seriously, and it isn’t realized that they are compulsively exercising to control body weight. You treat the mental illness with intensive inpatient care, so they can control exercising.”

[See: The Many Ways Exercise Fights Depression.]

Exercise as Effective as Zoloft

Both Chekroud and Kamm continue to point out that exercise is, by and large, a good thing. “It is highly unlikely anyone reading this is exercising too much,” Chekroud says. Some people have taken his research and inferred they don’t need to exercise; “That is definitely not what we are messaging,” he says.

The bigger message from his study is that, on average, those who exercised had 1.5 fewer days of poor mental health per month than those who did no exercise at all. The difference was even greater in people with a previous diagnosis of depression: Those who exercised had 3.75 fewer bad days per month than nonexercisers. Overall, exercise was equated with a 43.2 percent reduction in instances of poor mental health, greater than the association between mental health and other modifiable factors.

That jibes with a landmark 1999 study out of Duke University that showed how a brisk 30-minute walk or jog three times a week was as effective as the antidepressant Zoloft in treating major depression. “That has become the gold standard,” Kamm says. He believes that 30 to 45 minutes of exercise per session is plenty. “I don’t see the benefit of going over 45 minutes,” he says. Exercising more than that starts to put unnecessary strain on the body. “You can run into physical problems, like damaging knees and ankles,” he says, and the risk increases as you get older.

A new approach to detecting cancer earlier from blood tests

Cancer scientists led by principal investigator Dr. Daniel De Carvalho at Princess Margaret Cancer Centre have combined "liquid biopsy," epigenetic alterations and machine learning to develop a blood test to detect and classify cancer at its earliest stages.

The findings, published online today in Nature, describe not only a way to detect cancer, but hold promise of being able to find it earlier when it is more easily treated and long before symptoms ever appear, says Dr. De Carvalho, Senior Scientist at the cancer centre, University Health Network.

"We are very excited at this stage," says Dr. De Carvalho. "A major problem in cancer is how to detect it early. It has been a 'needle in the haystack' problem of how to find that one-in-a-billion cancer-specific mutation in the blood, especially at earlier stages, where the amount of tumour DNA in the blood is minimal."

By profiling epigenetic alterations instead of mutations, the team was able to identify thousands of modifications unique to each cancer type. Then, using a big data approach, they applied machine learning to create classifiers able to identify the presence of cancer-derived DNA within blood samples and to determine what cancer type. This basically turns the 'one needle in the haystack' problem into a more solvable 'thousands of needles in the haystack', where the computer just needs to find a few needles to define which haystack has needles.

The scientists tracked the cancer origin and type by comparing 300 patient tumour samples from seven disease sites (lung, pancreatic, colorectal, breast, leukemia, bladder and kidney) and samples from healthy donors with the analysis of cell-free DNA circulating in the blood plasma. In every sample, the "floating" plasma DNA matched the tumour DNA. The team has since expanded the research and has now profiled and successfully matched more than 700 tumour and blood samples from more cancer types.

Beyond the lab, next steps to further validate this approach include analysing data from large population health research studies already under way in several countries, where blood samples were collected months to years before cancer diagnosis. Then the approach will need to be ultimately validated in prospective studies for cancer screening.

Dr. De Carvalho is a trained immunologist (University of Sao Paulo, Brazil) with postdoctoral training in cancer epigenomics (University of Southern California, USA) whose research focuses on cancer epigenetics. He holds the Canada Research Chair in Cancer Epigenetics and Epigenetic Therapy and is an Associate Professor in Cancer Epigenetics, Department of Medical Biophysics, University of Toronto.

The research was supported by University of Toronto's McLaughlin Centre, Canadian Institutes of Health Research, Canadian Cancer Society, Ontario Institute for Cancer Research through the Province of Ontario, and The Princess Margaret Cancer Foundation.

Story Source:

Materials provided by University Health Network. Note: Content may be edited for style and length.

Journal Reference:

Shu Yi Shen, Rajat Singhania, Gordon Fehringer, Ankur Chakravarthy, Michael H. A. Roehrl, Dianne Chadwick, Philip C. Zuzarte, Ayelet Borgida, Ting Ting Wang, Tiantian Li, Olena Kis, Zhen Zhao, Anna Spreafico, Tiago da Silva Medina, Yadon Wang, David Roulois, Ilias Ettayebi, Zhuo Chen, Signy Chow, Tracy Murphy, Andrea Arruda, Grainne M. O’Kane, Jessica Liu, Mark Mansour, John D. McPherson, Catherine O’Brien, Natasha Leighl, Philippe L. Bedard, Neil Fleshner, Geoffrey Liu, Mark D. Minden, Steven Gallinger, Anna Goldenberg, Trevor J. Pugh, Michael M. Hoffman, Scott V. Bratman, Rayjean J. Hung, Daniel D. De Carvalho. Sensitive tumour detection and classification using plasma cell-free DNA methylomes. Nature, 2018; DOI: 10.1038/s41586-018-0703-0

Study of two tribes sheds light on role of Western-influenced diet in blood pressure

A South American tribe living in near-total isolation with no Western dietary influences showed no increase in average blood pressure from age one to age 60, according to a study led by researchers at Johns Hopkins Bloomberg School of Public Health. In comparison, a nearby tribe whose diet includes some processed foods and salt did show higher blood pressure into late middle age.

In the U.S. and most other countries, blood pressure rises with age, beginning early in life. Results of this study support the idea that the tendency in Westernized societies for blood pressure to rise with age is not a natural part of aging but could result from a cumulative effect of exposure to Western diet and lifestyle.

The findings appear November 14 in the journal JAMA Cardiology.

"The idea that rising blood pressure is a result of aging is a widely held belief in cardiology, but our findings add to evidence that rising blood pressure may be an avoidable consequence of Western diet and lifestyle rather than aging itself," says Noel Mueller, PhD, MPH, assistant professor of epidemiology at the Bloomberg School and member of the Welch Center for Prevention, Epidemiology and Clinical Research.

For their study, the researchers took blood pressure measurements from 72 Yanomami aged one to 60, and found no trend towards higher or lower readings as the participants aged. The researchers also measured blood pressure in 83 members of the nearby Yekwana tribe, which is more exposed to Western influences including dietary -- and here they found a clear trend towards higher pressure with advancing age.

The Yanomami live as hunter-gatherers and gardeners in a remote rainforest region of northern Brazil and southern Venezuela. Their diet is low in fat and salt and high in fruits and fiber. Studies of adult Yanomami since the 1980s have shown that atherosclerosis and obesity are virtually unknown among them, and that they have extraordinarily low blood pressure on average, with no apparent increase as they age.

The new study reveals that this age-stability of blood pressure among the Yanomami starts in early childhood. It is the first to compare the Yanomami to a geographically co-located population -- the Yekwana -- that has had a different exposure to Western diet and other Western lifestyle influences.

The researchers, examining members of Yanomami villages in southern Venezuela, found that their blood pressure measurements averaged 95 (mm Hg) systolic over 63 diastolic. (In U.S. adults, the average systolic is 122 and diastolic 71.) This low figure among the Yanomami is consistent with prior studies in Yanomami adults, but the researchers measured roughly the same blood pressure among Yanomami children as well. In fact, the data suggest that blood pressure in this population remains close to the same low level from age one at least through age 60, with no trend towards an increase or decrease.

In contrast to the Yanomami, the Yekwana have been exposed to some aspects of Western lifestyle and diet, including processed foods, through interaction and trade with the industrialized world. While blood pressure readings at the youngest ages were virtually the same as those for their Yanomami peers, there was a statistically clear trend towards rising levels with advancing age -- roughly 0.25 mm Hg per year -- such that the Yekwana had levels averaging 5.8 mm Hg higher by age 10, and 15.9 mm Hg higher by age 50.

"This age-related rise in blood pressure begins in early childhood -- which suggests that early childhood may be a 'window of opportunity' for lifestyle interventions to prevent later rises in blood pressure," Mueller says.

To put these findings in context, in the U.S. systolic blood pressure rises by about 1.5 mm Hg and 1.9 mm Hg per year among boys and girls, respectively, and 0.6 mm Hg per year among adults.

Mueller and his colleagues plan to follow up with a study of the gut bacteria of the Yanomami and Yekwana to determine if the gut microbiome account for the two tribes' differences in blood pressure with advancing age.

Funding was provided by the National Heart, Lung and Blood Institute (K01HL141589), the Alfred P. Sloan Foundation, the C&D Fund and the Emch Fund for Microbial Diversity.

Story Source:

Materials provided by Johns Hopkins University Bloomberg School of Public Health. Note: Content may be edited for style and length.

Journal Reference:

Noel T. Mueller, Oscar Noya-Alarcon, Monica Contreras, Lawrence J. Appel, Maria Gloria Dominguez-Bello. Association of Age With Blood Pressure Across the Lifespan in Isolated Yanomami and Yekwana Villages. JAMA Cardiology, 2018; DOI: 10.1001/jamacardio.2018.3676