Thursday, November 18, 2010
Resistance exercise such as weight training affects blood vessels differently than aerobic exercise and offers other cardiovascular benefits, finds a new study.
Researchers at the Appalachian State University in Boone, N.C., compared blood vessel (vascular) responses to two types of moderate-intensity workouts: three sets of 10 repetitions of eight resistance exercises and 30 minutes of aerobic cycling.
There were significant differences in the vascular responses to the two types of exercises. Resistance exercise produced greater increases in blood flow to the limbs, while aerobic exercise reduced arterial stiffness, but without an increase in blood flow.
"Resistance exercise may offer greater benefits from the increases in blood flow to active muscles and could be implemented as a companion to an aerobic training program," wrote study leader Scott R. Collier, of Appalachian State University, and colleagues in a press release.
"The present study indicates that an acute bout of resistance exercise shows many favorable cardiovascular benefits and should therefore be considered as part of a daily exercise training program," the researchers concluded.
Source: November issue of Journal of Strength and Conditioning Research.
Wednesday, November 17, 2010
Recently, researchers in Finland made the discovery that there are those who just do not become fitter or stronger, no matter what exercise they undertake. To reach this conclusion, the researchers enrolled 175 sedentary adults in a 21-week exercise program. Some lifted weights twice a week. Others jogged or walked. Some did both. Before and after the program, the volunteers’ fitness and muscular strength were assessed.
At the end of the 21 weeks,some improved their strength enormously, some not at all. Others became aerobically fitter but not stronger, while still others showed no improvements in either area. Only a fortunate few became both fitter and more buff. As the researchers from the University of Jyvaskyla wrote with some understatement, “large individual differences” exist “in the responses to both endurance and strength training.”
Hidden away in the results of almost any study of exercise programs is the fact that some people do not respond at all, while others respond at an unusually high rate. Averaged, the results may suggest that a certain exercise program reliably will produce certain results — that jogging, say, three times a week for a month will improve VO2max (maximal oxygen capacity) or reduce blood pressure; and for almost any given group of exercisers, those results are likely to hold true. But for outliers, the impacts can be quite different. Their VO2max won’t budge, or it will fall, or it will soar.
The implications of such wide variety in response are huge. In looking at the population as a whole, writes Dr. Jamie Timmons, Ph.D., a professor of systems biology at the Royal Veterinary College in London, in a review article published last month in The Journal of Applied Physiology, the findings suggest that “there will be millions of humans that cannot improve their aerobic capacity or their insulin sensitivity, nor reduce their blood pressure” through standard exercise.
But what is it about one person’s body that allows it to react so vigorously to exercise, while for others the reaction is puny at best? One answer, to no one’s surprise, would seem to be genetics.
In other words, this issue is as intricate as the body itself. There is a collection of compelling data that indicate that about half of our aerobic capacity “is genetic,” Dr. Timmons wrote in an e-mail. “The rest may be diet,” or it could be a result of epigenetics, a complicated process in which the environment (including where you live and what you eat) affects how and when genes are activated. “Or it could be other factors,” he said. Although fewer studies have examined why people respond so variously to strength training, “we have no reason to doubt,” he said, that genetics play a similar role.
But none of this means that if you once took up jogging or weight lifting and didn’t respond, you should take to the couch. It may be that a different exercise regimen would prompt beneficial reactions from your particular genome and physiology, Dr. Timmons said. (Although scientists still have a long way to go before they can say, definitively, who needs what exercise, based on genetic and other differences.) In the meantime, Dr. Timmons stressed, even low responders should continue to sweat. Just as scientists don’t yet understand the complicated underpinnings of the body’s response to exercise, they also don’t necessarily understand the full range of exercise’s impacts. Even if you do not increase your VO2max, Dr. Timmons said, you are likely to be deriving other benefits, both big and small, from working out. Exercise does still remain, “on average,” he said, “one of the best ‘health’ treatments we have.”
Source: NY Times, 11/17/2010
Tuesday, November 16, 2010
Slimming patches stick on the skin like a Band-Aid. Marketers say the patches reduce cravings and speed metabolism, helping you to lose weight. Some doctors say there's no proof the patches work, and in recent years the Federal Trade Commission has charged certain companies with false advertising.
Slimming patches are being widely advertised on the Web and in some stores. The ingredients are typically a mixture of plants and natural ingredients, such as hoodia gordonii, a seaweed called fucus vesiculosus and guarana, a stimulant. The Slim Weight Patch, sold by Roduve Healthcare Solutions BV of Rotterdam, the Netherlands, contains a blend of ground seaweed, guarana and nine other ingredients the company's website says will "control your hunger cravings and speed up your metabolism."
Some obesity experts are skeptical of the patches. "There is no evidence that it works. I think you are wasting your money," says Xavier Pi-Sunyer, director of the New York Obesity Nutrition Research Center at St. Luke's-Roosevelt Hospital Center in New York.
Typically the patches are applied once a day, anywhere on the body that is clean, dry and hairless. Companies who sell the patches say the active ingredients are absorbed through the skin. Costs vary, but typically range from $15 to $40 for a month's supply.
The patches being marketed haven't generally been tested in rigorous clinical trials. "There is weak evidence that it affects the thyroid [which helps regulate metabolism] but evidence is lacking for its use in weight loss," says Catherine Ulbricht, co-founder of Natural Standard and senior attending pharmacist at Massachusetts General Hospital in Boston.
Another issue is that even if the ingredients themselves do affect appetite and weight, there is no proof they are getting into the body via the patches, without well-designed clinical trials. "Just because a drug is effective when swallowed doesn't mean the drug is going to be effective when put on the skin," says Mark R. Prausnitz, director of the Center for Drug Design, Development and Delivery at Georgia Institute of Technology in Atlanta. To pass effectively through the skin, he adds, a substance must have a low molecular weight (which means it is very small) and must be oily. And once an ingredient is in the body, it may have a different effect when eaten compared with skin absorption, scientists say.
Source: Wall Street Journal 11/16
Looks like you might be able to save your money by passing this patch up and instead spend it on a gym membership.
Friday, November 12, 2010
Most of us are pretty conscientious about preparing for an upcoming competition, special athletic event or particularly grueling training session. We build our stamina. We hydrate. We take on extra fuel. We get a little extra rest.
But how much attention do you pay to the hours and days after you finish that century ride, alumni soccer game or 20-mile training run? Do you collapse on the couch, spent, and indulge in a double cheeseburger with fries to celebrate your achievement and the extra calories you burned?
Experts and top athletes know that the energy and focus you put into your recovery will go a long way toward determining not only how you feel for the next few days, but how well you perform the next time. (Assuming there is a next time.) And that effort helps prevent injury.
"If you don't recover, you wind up getting into overuse syndromes" and suffering injuries such as stress fractures, says Karen Merrill, a master trainer for the American Council on Exercise, who recommends at least 10 minutes of stretching after a good workout.
While this knowledge has slowly seeped down to the rest of us - Gatorade now markets "before," "during" and "after" sports drinks - it's not as ingrained as pre-event regimens. And how to go about it is somewhat more confusing.
I learned this the hard way (seems like the only way for me) after I ran my first marathon in 2005. My wife and I scheduled a walking tour of New Orleans for the next morning. In theory I was doing the right thing: keeping those legs moving, gently, is the best way to recover from 26.2 miles of pounding. But I didn't know anything about post-race care and soon was having trouble walking down stairs on stiff quads and swollen feet. (I also ate a great post-race bacon cheeseburger. Which I don't regret.)
Here are a few things you might consider after your next tough outing.
You're exhausted, you're proud, you've earned a few hours with your feet up and the ballgame on. Don't do it. At least not right away. That burning in your legs while you were working so hard came from lactate, a byproduct of exercise. You want to keep your blood circulating well so your body can get rid of it as efficiently as possible, and you want to keep those tired muscles limber.
Distance runners, from high school on up, take cool-down runs right after competition. You should do something, too. Take a walk, do some yoga, slowly pedal an exercise bike. And by all means, stretch as much as you can as part of the cool-down.
Under no circumstances "should anyone just stop," says Lynn Millar, a professor of physical therapy at Andrews University in Berrien Springs, Mich. Although conventional wisdom calls for stretching muscles while they're warm, Millar has found that some people need an additional, gentle stretching session later.
"It may be more important to do some of that stretching three hours later," she says. "That may help better at preventing that tightness or lack of range of motion."
In a small 2008 study of women rock climbers, French and Belgian researchers found that active recovery - in this case, pedaling a stationary bike - removed lactate more quickly than other methods and led to better performance when the women went back onto the climbing wall 20 minutes later.
Nothing feels better on sore muscles after a tough workout than a hot shower or, if you have access to one, a steaming whirlpool. Haven't we seen pro athletes doing this for years? Unfortunately, it may be the wrong way to go. It seems wherever you go now, someone is touting the benefits of an ice bath or, more technically, cold-water immersion.
It seems intuitive that cold would reduce the inflammation in overworked legs. Distance runners swear by the practice; they've been standing in buckets of icy water after races and workouts for years. An ice bath "constricts blood vessels and decreases metabolic activity, which reduces swelling and tissue breakdown," top ultra-marathoner Nikki Kimball wrote in Runner's World in 2008. (For ultra-wusses like me, Kimball notes that she wears a down jacket, a hat and neoprene booties and drinks hot tea during her 20 minutes in a 50- to 59-degree tub.)
This idea is not universally accepted, however. Kenneth L. Knight, a professor of athletic training at Brigham Young University who has spent his career studying cryotherapy for athletes, says there is no research to support or refute the effect of ice baths on inflammation, even if so many say it feels so good.
"There's no evidence that it's not good, but there's no evidence to support it, either," Knight says. "It's just out there."
In that 2008 study of rock climbers, cold-water immersion was the other method that researchers found helped maintain performance. (Passive recovery and electric stimulation were the ones that didn't pan out as well.)
I don't have the space here to help you navigate the river of commercial post-workout beverages or foods that make similar claims about aiding recovery. I did check into one of the latest fads, chocolate milk, because so many people seem to be drinking it after workouts. Turns out it makes sense.
Nancy Clark, a registered dietitian and author of "Nancy Clark's Sports Nutrition Guidebook," says chocolate milk provides fluid, carbohydrates (sugar) to replenish your body's supply, protein to promote muscle healing and the sodium that you've sweated away. Plus, it gives you that sated feeling that other products may not. A small University of Connecticut study found that fat-free chocolate milk seems to protect muscles better than a carbohydrate recovery drink.
For noncompetitive athletes, Clark says, there are myriad ways to take in the same essentials in the 24 to 48 hours after a workout, from protein shakes to the small, low-fat meals you should be eating anyway.
In most instances, "the body will take care of it on its own" by signaling what it needs, she says. "Your job is to make sure there's food around."
Source: Washington Post; Lenny Bernstein Tuesday, November 9, 2010
Obesity often follows the young into adulthood
People who were obese between the ages of 12 and 21 are seven times more likely than normal-weight or overweight peers to develop severe obesity by the time they reach their late 20s to early 30s, a study finds.
Some adolescent memories — prom dates, fashion choices, Facebook postings — tend to fade and, mercifully, disappear in the transition to adulthood. But a study released Tuesday finds that one increasingly common source of teen angst — obesity — has a cruel knack for following adolescents into their adult years, then tightening its grip.
The result not only confers profound health risks for teens whose excess weight follows them and accelerates into adulthood, it also spells a looming public health disaster in a country where almost 1 in 5 adolescents is obese, experts say.
By the time they reach their late 20s to early 30s, people who were obese between 12 and 21 are more than seven times more likely than normal-weight or overweight peers to develop severe obesity — defined as having a body mass index, or BMI, of 40 or more — according to the study published in the Journal of the American Medical Assn.
For women and for ethnic minorities, the likelihood of proceeding from adolescent obesity to adult severe obesity is particularly pronounced. Among women, 51.3% of those who had been obese when they were younger became severely obese adults (for men, the figure was 37.1%). Among African American women, 52.4% who had been obese in earlier years went on to become severely obese.
By comparison, 7.9% of all participants in the study, and less than 5% of those whose weight was in the normal range, became severely obese in adulthood.
The authors, epidemiologists based in North Carolina, estimated from their findings that 1 million Americans who were between the ages of 12 and 21 in 1996, when the study began, became severely obese adults. As they did so, they took on the increased risk of developing obesity-related conditions such as cardiovascular disease, Type 2 diabetes, certain cancers and musculoskeletal pain.
The report comes against the backdrop of evidence that the ranks of the severely obese — typically, those who carry at least 80 to 100 pounds of excess body weight — are rising faster in the U.S. population than those classified as moderately obese. Given the scarcity of solutions — drugs and diet-and-exercise interventions have proved less safe and effective than experts had hoped — the authors note that "prevention is critical."
For those already obese, the authors said, it is important to identify those at greatest risk of becoming severely obese and focusing weight-loss programs on them.
The investigation tracked 8,834 participants ages 12-21 at the study's start for 13 years. Because of the long follow-up, the study provides a clearer picture than most of obesity's progression in individuals of different genders, ages and ethnicities, said lead author Penny Gordon-Larsen, an epidemiologist with the Carolina Population Center at the University of North Carolina.
In particular, the findings underline that for children who struggle with their weight, the transition to adulthood can be a particularly perilous crossing, Gordon-Larsen said.
Obese teens increasingly are steered toward riskier measures to avert future health problems, including bariatric surgery — a weight-loss intervention that grew sevenfold among teens between 2005 and 2007, according to a recent report. The authors of the JAMA study suggested such surgery may be justified because it "is the only treatment to have long-term success," albeit with "major potential complications."
Pediatric endocrinologist David S. Ludwig, director of Children's Hospital Boston's Optimal Weight for Life program, said the JAMA study emphasized the "critical importance" of treating childhood obesity early, before poor lifestyle habits can become deeply ingrained. Early obesity also "may produce changes in metabolism, hormones or the brain that oppose weight loss," Ludwig added.
At the same time, some experts in weight management across the lifespan said the study's usefulness was limited by its reliance on the BMI as the primary measure of an individual's healthful weight.
"I'm not a big fan of BMI, especially for kids," said Dr. David Heber, director of UCLA's Risk Factor Obesity Program. A rough measure of fat based on an individual's height and weight, the BMI can be useful for detecting population trends, but is often not the best measure of an individual adolescent's fitness or prospects of developing obesity-related health conditions, he said.
Instead, Heber prefers to measure an adolescent's fat and lean-muscle mass and calculate their relative proportions. "They'll tell you what your target weight should be," he said.
Source:Melissa Healy, Los Angeles Times, November 9, 2010
Tuesday, November 9, 2010
Overweight children may be more stressed than those of normal weight, a report suggests today. Among 1,136 kids and teens ages 8-17 surveyed online in August, those of above-normal weight reported more health problems in the previous month.
Such problems, experts say, signal stress. Among them:
•Sleep problems, 48% (compared with 33% of normal-weight kids).
•Headaches, 43% (vs. 28%).
•Anger and fighting, 22% (vs. 13%).
"There are some good data out there that show connections between stress and being overweight," says Kathryn Henderson, a clinical psychologist at the non-profit Rudd Center for Food Policy & Obesity at Yale University, which helped develop the weight-related survey section.
Compared with normal-weight kids, overweight children were more likely to report eating when stressed (27% vs. 14%) or taking a nap (26% vs. 15%). Kids and teens of normal weight who are stressed report more healthy activities, such as playing sports (21%, vs. 13% for overweight kids).
Henderson says all kids are fairly likely to cope by doing sedentary behaviors, "and in particular screen time. It might just be the go-to activity."
Calorie burning activity appears to be good for everybody, every day.
Overweight children show more signs of stress
By Sharon Jayson, USA TODAY Publication: Date: Nov 8, 2010
Monday, November 8, 2010
Organically grown produce may offer no nutritional benefits over traditional growth methods, according to a new study.
Published in the Journal of Agricultural and Food Chemistry, the study reports new evidence that organically grown onions, carrots, and potatoes generally do not have higher levels of polyphenol antioxidants than vegetables grown with traditional fertilizers and pesticides.
“On the basis of the present study carried out under well controlled conditions, it cannot be concluded that organically grown onions, carrots, and potatoes generally have higher contents of health-promoting secondary metabolites in comparison with the conventionally cultivated ones,” stated the researchers, led by Pia Knuthsen from the National Food Institute at Technical University of Denmark.
The new study adds further confusion to the ongoing debate on whether organically grown fruit and vegetables are any more nutritious than their traditionally cultivated counterparts.
Organic vs Conventional: Controversial
The fundamental differences between organic and conventional agricultural systems are in fertilization strategy and soil fertility management, which in theory affect the nutrient composition in plants and provide healthier better tasting produce. However, previous studies on the nutrient content of organically and conventionally grown plants have generated contradicting results.
In 2009 an FSA review on the nutritional content of organic and conventional produce sparked controversy after it concluded that there are no differences. The research conducted at the London School of Hygiene and Tropical Medicine concluded that “there is no evidence to support the selection of organically produced foodstuffs to increase the intake of specific nutrients or nutritionally relevant substances.”
However, several smaller studies have since reported higher levels of certain nutrients in organically grown produce, including strawberries . In addition, a French review completely contradicted the findings of the FSA concluding that “organic plant products contain more dry matter and minerals – such as iron and magnesium – and more antioxidant polyphenols like phenols and salicylic acid.”
Knuthsen and colleagues pointed out that there are many reasons to pay a premium for organic food products, including improved animal welfare, environmental protection and better taste and freshness. However, they noted that the health benefits of organic food consumption are still controversial and not considered scientifically well-documented.
“The objective of our study was to compare the content of selected flavonoids and phenolic acids in organically and conventionally grown onions, potatoes, and carrots and to evaluate if the ability of the crops to synthesize selected secondary metabolites is systematically affected by growth systems across different growth years as well as geographic locations [and soil types],” stated the authors.
The researchers reported that onions and carrots, showed no statistically significant differences between growth systems for any of the analyzed polyphenols over a two year growing period.
Organically grown potatoes fertilized with cover crops, were however observed to have a higher content of one polyphenol – chlorogenic acid (5-CQA) – compared to the conventional growth system.
The researchers concluded that, based on the results of their study, it cannot be concluded that organically grown onions, carrots, and potatoes have higher contents of polyphenols and related secondary metabolites, in comparison with conventionally cultivated ones.
“The ability of crops to synthesize selected secondary metabolites was not systematically affected by the growth system across different growth years and geographical locations,” they stated.
However, some commentators have previously pointed out that nutrition is not the main reason that many people opt for organics, stating that the avoidance of pesticides and consumer preference for produce grown using land-conscious practices account for much of the sector.
Source: Journal of Agricultural and Food Chemistry
Volume 58, Issue 19, Pages 10323–10329, doi: 10.1021/jf101091c
“Effects of Organic and Conventional Growth Systems on the Content of Flavonoids in Onions and Phenolic Acids in Carrots and Potatoes”
Authors: M. Søltoft, J. Nielsen, K. Holst Laursen, S. Husted, U. Halekoh, P. Knuthsen
Wednesday, November 3, 2010
San Francisco's board of supervisors has voted, by a veto-proof margin, to ban most of McDonald's Happy Meals as they are now served in the restaurants.
The measure will make San Francisco the first major city in the country to forbid restaurants from offering a free toy with meals that contain more than set levels of calories, sugar and fat.
The ordinance would also require restaurants to provide fruits and vegetables with all meals for children that come with toys.
"We're part of a movement that is moving forward an agenda of food justice," said Supervisor Eric Mar, who sponsored the measure. "From San Francisco to New York City, the epidemic of childhood obesity in this country is making our kids sick, particularly kids from low income neighborhoods, at an alarming rate. It's a survival issue and a day-to-day issue."
Just after the vote, McDonald's spokeswoman Danya Proud said, "We are extremely disappointed with today's decision. It's not what our customers want, nor is it something they asked for."
The ban, already enacted in a similar measure by Santa Clara County, was opposed by San Francisco Mayor Gavin Newsom, who was vying to be lieutenant governor in Tuesday's election. But because the measure was passed by eight votes — one more than needed to override a veto — his opposition doesn't matter unless one of the supervisors changes his or her mind after the promised veto.
Under the ordinance, scheduled to take effect in December 2011, restaurants may include a toy with a meal if the food and drink combined contain fewer than 600 calories, and if less than 35% of the calories come from fat.
Over the last few weeks, the proposed ban caused a stir online and on cable television, with supporters arguing that it would help protect children from obesity, and opponents seeing it as the latest example of the nanny state gone wild.
Supervisor Bevan Dufty, whose swing vote provided the veto-proof majority, said critics should not dismiss the legislation as a nutty effort by San Franciscans. "I do believe the industry is going to take note of this. I don't care how much they say, 'It's San Francisco, they're wacked out there.' "
Proud, the McDonald's spokeswoman, said the city was out of step with the mainstream on the issue.
"Public opinion continues to be overwhelmingly against this misguided legislation," she said. "Parents tell us it's their right and responsibility — not the government's — to make their own decisions and to choose what's right for their children."
McDonald's is not the only fast-food chain to offer toys with children's meals, but because it is so prominent the company has become a key face of opposition to the ban.
Daniel Conway, spokesman for the California Restaurant Assn., bemoaned the ordinance's passage and contrasted it with San Franciscans' exuberant feelings after the Giants won the world series on Monday night.
"One day you're world champions, and the next day, no toys for you," Conway said.
He said the industry could respond in a number of ways to the ordinance. Some might continue to include toys but charge separately for them. Others might reformulate their meals so that they comply with the law. Restaurants might also simply stop offering children's meals altogether, he said.
Proud said the company does offer more healthful menu options, including apple slices that can be ordered with kids' meals instead of French fries.
The vote was held the same day that McDonald's reintroduced nationwide its McRib sandwich, a pressed pork patty that gets half its calories from fat and has a cult-like legion of fans.
Mar said it would lead the fast-food giant and other restaurants to provide more healthful food for kids. The ban, he said, was crucial to the fight against childhood obesity and the illnesses that go along with it, including diabetes and the risk of heart problems and stroke. The cost of fighting those diseases, he said, will be in the billions.
"It's astronomical how much it's going to cost if we don't address it," Mar said. "It's incredible the crisis that's going to hit us."
Copyright © 2010, Los Angeles Times