Out on a limb: Arm-swinging riddle is answered

Tue Jul 28, 7:49 pm ET
PARIS (AFP) – Biomedical researchers on Wednesday said they could explain why we swing our arms when we walk, a practice that has long piqued scientific curiosity.
Swinging one's arms comes at a cost. We need muscles to do it, and we need to provide energy in the form of food for those muscles. So what's the advantage?
Little or none, some experts have said, contending that arm-swinging, like our appendix, is an evolutionary relic from when we used to go about on all fours.
But a trio of specialists from the United States and the Netherlands have put the question to rigorous tests.
They built a mechanical model to get an idea of the dynamics of arm-swinging and then recruited 10 volunteers, who were asked to walk with a normal swing, an opposite-to-normal swing, with their arms folded or held by their sides.
The metabolic cost of this activity was derived from oxygen consumption and carbon dioxide (CO2) production as the human guinea pigs breathed in and out.
Arm-swinging turned out to be a plus, rather than a negative, the investigators found.
For one thing, it is surprisingly, er, "'armless" in energy costs, requiring little torque, or rotational twist, from the shoulder muscles.
Holding one's arms as one walks requires 12 percent more metabolic energy, compared with swinging them.
The arms' pendulum swing also helps dampen the bobbly up-and-down motion of walking, which is itself an energy drain for the muscles of the lower legs.
If you hold your arms while walking, this movement, called vertical ground reaction moment, rises by a whopping 63 percent.
Should you prefer to walk with an opposite-to-normal swing -- meaning that your right arm moves in sync with your right leg and your left arm is matched to the motion of your left leg -- the energy cost of using your shoulder muscles will fall.
The downside, though, is that opposite-to-normal swing forces up the metabolic rate by a quarter.
The study, headed by Steven Collins at the University of Michigan at Ann Arbor, says we should give the thumb's-up to arm swinging.
"Rather than a facultative relic of the locomotion needs of our quadrupedal ancestors, arm swinging is an integral part of the energy economy of human gait," says the paper.
It appears in Proceedings of the Royal Society B, the biological research journal of the Royal Society, Britain's de-facto academy of sciences.

Study: Tanning beds definitely cause cancer

By MARIA CHENG, AP Medical Writer Maria Cheng, Ap Medical Writer – 2 hrs 49 mins ago
LONDON – International cancer experts have moved tanning beds and ultraviolet radiation into the top cancer risk category deeming both to be definite causes of cancer.
For years, scientists have described tanning beds and ultraviolet radiation as "probable carcinogens."
A new analysis of about 20 studies concludes the risk of skin cancer jumps by 75 percent when people start using tanning beds before age 30.
Experts also found that all types of ultraviolet radiation caused worrying mutations in mice, proof the radiation is carcinogenic. Previously, only one type of ultraviolet radiation was thought to be lethal.
The new classification means tanning beds and ultraviolet radiation are definite causes of cancer, alongside tobacco, the hepatitis B virus and chimney sweeping, among others.
The research was published online in the medical journal Lancet Oncology on Wednesday by experts at the International Agency for Research on Cancer in Lyon, the cancer arm of the World Health Organization.
"People need to be reminded of the risks of sunbeds," said Vincent Cogliano, one of the cancer researchers. "We hope the prevailing culture will change so teens don't think they need to use sunbeds to get a tan."
Cogliano said the classification means experts are confident that tanning beds cause cancer, but he noted they may not be as potent as other carcinogens like tobacco or arsenic.
Most lights used in tanning beds give off mainly ultraviolet radiation, which cause skin and eye cancer. As use of tanning beds has increased among people under 30, doctors have seen a parallel rise in the numbers of young people with skin cancer, though most types of skin cancer are benign.
According to the studies reviewed by Cogliano and colleagues, using tanning beds caused about a 20 percent increased relative risk of developing melanoma, the deadliest kind of skin cancer.
Cogliano said it was impossible to know how many benign skin cancers might be caused by tanning beds, because of complicating factors like exposure to regular sunlight. He and colleagues examined data from more than 7,000 melanoma cases and found a strong association between tanning bed use and the disease. He compared the link to that found between tobacco and lung cancer.
In Britain, melanoma is now the leading cancer diagnosed in women in their 20s. Normally, skin cancer rates are highest in people over 75. According to a British study from 2003, about 100 people every year die of melanoma attributable to tanning beds.
Previous studies found younger people who regularly use tanning beds are eight times more likely to get melanoma than people who have never used them. In the past, WHO warned people younger than 18 to stay away from tanning beds.
The American Cancer Society advises people to try bronzing or self-tanning creams instead of tanning beds.

Organic food is no healthier, study finds

LONDON (Reuters) – Organic food has no nutritional or health benefits over ordinary food, according to a major study published Wednesday.
Researchers from the London School of Hygiene & Tropical Medicine said consumers were paying higher prices for organic food because of its perceived health benefits, creating a global organic market worth an estimated $48 billion in 2007.
A systematic review of 162 scientific papers published in the scientific literature over the last 50 years, however, found there was no significant difference.
"A small number of differences in nutrient content were found to exist between organically and conventionally produced foodstuffs, but these are unlikely to be of any public health relevance," said Alan Dangour, one of the report's authors.
"Our review indicates that there is currently no evidence to support the selection of organically over conventionally produced foods on the basis of nutritional superiority."
The results of research, which was commissioned by the British government's Food Standards Agency, were published in the American Journal of Clinical Nutrition.
Sales of organic food have fallen in some markets, including Britain, as recession has led consumers to cut back on purchases.
The Soil Association said in April that growth in sales of organic products in Britain slowed to just 1.7 percent in 2008, well below the average annual growth rate of 26 percent over the last decade, following a plunge in demand at the end of the year.
(Reporting by Ben Hirschler; editing by Simon Jessop)

Delta enhancing frequent-flier program

By HARRY R. WEBER, AP Airlines Writer Harry R. Weber, Ap Airlines Writer – Tue Jul 28, 3:39 pm ET
ATLANTA – Delta Air Lines Inc. is taking a page from the cell phone industry and will be allowing elite frequent fliers to roll over miles earned above their qualification status in a given year so they have an easier time maintaining that status or improving to a higher one the next year.
The world's biggest airline operator planned to announce Tuesday enhancements to its SkyMiles Medallion program that will go into effect over the next nine months.
The changes come at a time of weak demand in the airline industry amid the recession. Business travel, in particular, has been in a slump, and giving extra advantages to elite frequent fliers could be one way to lure in more business travelers.
Atlanta-based Delta has three elite frequent flier statuses — silver, gold and platinum — and will be adding a fourth, diamond. Customers reach those levels by flying a lot — you reach the lowest level after flying 30 segments in a year — and in return they get extra benefits like priority boarding, waived checked bag fees and free upgrades.
Now, Delta says it will allow customers to retain any Medallion qualification miles earned above a Medallion threshold at the end of the year, supplementing the ability to earn status the following year. For example, should a member accrue 40,000 Medallion qualification miles in one calendar year, the 15,000 Medallion qualification miles that exceed the 25,000 threshold for silver status will be rolled over to the following year.
Delta said there is no limit to the number of miles rolled over, and the benefit takes effect immediately.
The rollover idea is similar to one offered for several years to some AT&T cell phone customers, who can roll over unused minutes in certain plans to the following month.
Among other changes coming from Delta:
_The new diamond level for flyers who earn 125,000 MQMs or fly 140 segments per calendar year will include a complimentary Delta Sky Club membership, among other benefits.
_Diamond, platinum and gold Medallion members will have ticketing fees waived for all bookings, whether completed by phone, online or in person.

Modern Insanity: What Really Makes Us Crazy

Robin NixonSpecial to LiveScienceLiveScience.com robin Nixonspecial To Livesciencelivescience.com – Wed Jul 29, 8:33 am ET

Last month, researchers found that schizophrenics were more likely to have been subjected to influenza in the womb than healthy individuals. Other common experiences can also drive away our wits, long after we are out of diapers.
In fact, the typical American lifestyle teems with risk factors for mental illness, says Stephen Ilardi, a psychologist at the University of Kansas and author of "The Depression Cure: The 6-Step Program to Beat Depression without Drugs" (DeCapo Press, 2009). But we can protect ourselves by adopting the habits of our distant ancestors, he said.
"In modern life, our environment is continually activating the brain's stress response," Ilardi said, bombarded as we are by email, tragic news and interpersonal demands. Certain circuits in the brain react to stress as if it is an infection, triggering social withdrawal, inflammation and potentially leading to brain damage in areas such as the hippocampus, the frontal cortex and the basal ganglia, Ilardi said.
In many mental disorders, "inflammation is a big culprit," Ilardi said.
In short bouts, inflammation is the body's way of protecting itself. But if prolonged, it can take a tremendous toll. Like heart disease and insulin resistance, mental illnesses such as schizophrenia, depression, autism, anxiety and bipolar disorder have all been linked to inflammation. And the prevalence of many of these illnesses has increased in lockstep with modernization, Ilardi said.
The relative sanity of our distant ancestors should not imply they led stress-free lives. Hunting dangerous game does not exactly instill Zen-like breaths. But "our remote ancestors had many factors woven into the fabric of their lives that turned off the brain's stress response," - habits that in most developed countries have fallen out of fashion, Ilardi said.
For example, if met with an impediment on a path to some succulent boar, hunter-gatherers may have vented their frustration by, say, heaving a boulder out of the way. Physical exertion holds up a potent stop sign to the stress-inflammation circuitry, Ilardi said. But today, an urban dweller stuck in traffic can do little but stew.
Many mental illnesses are recognized as a problem with brain chemistry, and therefore treated chemically with medication. But behavior also alters brain chemistry. Several primitive habits, researchers have found, may check the stress response and prevent it from making our brains sick. A program developed by Ilardi and colleagues - that helps individuals adopt the habits of cool, collected cavemen - is proving more effective in treating mental illnesses than conventional medication.
For primal protection from modern insanity, try to:
Balance your Omegas
The ideal balance between Omega 6 and Omega 3 fats is one-to-one. In the typical American diet, the ratio is closer to 16-to-one, largely due to the modern tendency of feeding livestock grains instead of grass. Compounds derived from Omega 6 fats encourage inflammation, cross the blood-brain barrier and can trigger depressive responses, Ilardi said. Omega 3 fats, found in salmon, walnuts and flaxseeds, are anti-inflammatory and can help break the stress-inflammation cycle.
Get more Zzzzs
A century ago, Americans were averaging nine hours of sleep every night. These days, according to the National Sleep Foundation, many people get less than seven, a trend that has been linked to an overall decline in mental health. Strive to get 8 to10 hours of sleep each night to help your brain and body fully recuperate.
Seek social support
While our distant ancestors likely enjoyed being the best at something, say the best gooseberry spotter among their community of 50 to 100 individuals, in "today's global village of 6.5 billion people, nobody is the best at anything," Ilardi said. Finding a niche in a subset community may dissuade this inevitable ego knocker as well as provide other mental health goodies, such as halting rumination.
Interrupt circle-think
Focusing on a problem or discomfort can be adaptive; it helps us find solutions. But when we become fixated, the repetitive stress can erode our ability to rebound. Rumination, Ilardi says, is particularly common when we're alone, a state familiar to many inhabitants of developed countries. In contrast, our ancient ancestors rarely went solo. Having company or partaking in engaging activities can stop ruminative thoughts in their tracks.
Walk it off
We evolved as recreational athletes. Our ancestors not only spent much of the day engaged in moderate aerobic activity but also undertook regular weight-bearing chores, such as digging ditches and building huts. Studies have shown, just 90 minutes of exercise a week can be as effective as psych-medicines such as Zoloft.
Take time to bask
Everyone knows sunlight feels good. But it may also stave off illness. Sunlight - in modest quantities - triggers the production of an endogenous form of Vitamin D that, like Omega 3 fats, is anti-inflammatory and can help deter a runaway stress response.
Develop a world view
While research on the relationship between religion and mental health is inconclusive, individuals who have a global framework - a way of understanding the world, whether it be religious, philosophical or scientific - may have an increased ability to withstand blows to their mental health, Ilardi said.
What's Behind Human Insanity?
Humans: The Strangest Species
5 Keys to Happiness
Original Story: Modern Insanity: What Really Makes Us CrazyLiveScience.com chronicles the daily advances and innovations made in science and technology. We take on the misconceptions that often pop up around scientific discoveries and deliver short, provocative explanations with a certain wit and style. Check out our science videos, Trivia & Quizzes and Top 10s. Join our community to debate hot-button issues like stem cells, climate change and evolution. You can also sign up for free newsletters, register for RSS feeds and get cool gadgets at the LiveScience Store.

Lawmakers propose ban on texting while driving

By KEN THOMAS, Associated Press Writer Ken Thomas, Associated Press Writer – 28 mins ago
WASHINGTON – A group of Democrats want states to ban texting while driving or face cuts in highway funds, citing the need to reduce driver distraction and potential highway deaths and injuries.
"When drivers have their eyes on their cell phones instead of the road, the results can be dangerous and even deadly," said Sen. Charles Schumer, D-N.Y., who unveiled the legislation Wednesday with Democrats Robert Menendez of New Jersey, Mary Landrieu of Louisiana and Kay Hagan of North Carolina.
Fourteen states and the District of Columbia have passed laws making texting while driving illegal.
Some critics have questioned whether the laws could be enforced, whether there is enough data to warrant such bans, or if reckless driving statutes already cover texting behind the wheel.
The Governors Highway Safety Association, which represents state highway safety agencies, said it does not doubt the dangers of texting and driving but does not support a ban because it would be difficult to enforce.
"Highway safety laws are only effective if they can be enforced and if the public believes they will be ticketed for not complying. To date, that has not been the case with many cell phone restrictions," said Vernon Betkey, the highway safety association's chairman.
The proposal follows a series of studies showing the dangers of operating handheld electronic devices while driving.
In a study released earlier this week, the Virginia Tech Transportation Institute found that when drivers of heavy trucks texted, their collision risk was 23 times greater than when not texting. Dialing a cell phone and using or reaching for an electronic device increased risk of collision about six times in cars and trucks.
The Virginia Tech researchers said the risks of texting generally applied to all drivers, not just truckers.
The lawmakers also cited a separate report by Car and Driver magazine that found that texting and driving is more dangerous than drunken driving.
Texting has grown from nearly 10 billion messages a month in December 2005 to more than 110 billion in December 2008, according to CTIA, the cellular phone industry's trade group.
The legislation would require states to ban texting or e-mailing while operating a moving vehicle or lose 25 percent of their annual federal highway funding. It would be patterned after the way Congress required states to adopt a national drunken driving ban.
The transportation secretary would be required to issue guidelines within six months of the measure becoming law, and states then would have two years to approve the bans on texting and driving.
States could recover highway funds by passing the legislation following the two-year period.
The bill would target the activity in a moving vehicle and not prohibit a driver from texting or e-mailing in a stopped car.

After stunning loss, Phelps rebounds with record

By PAUL NEWBERRY, AP National Writer Paul Newberry, Ap National Writer – 27 mins ago
ROME – Now that's more like it. Michael Phelps bounced back from a stunning loss with something more familiar — another world record Wednesday.
One night after he was soundly beaten by Germany's Paul Biedermann, Phelps set a world record in the 200-meter butterfly with a time of 1 minute, 51.51 seconds — more than a half-second ahead of his previous mark, 1:52.03.
Phelps whipped around quickly to see his time and held up his right index finger when the "WR" was posted. And just like Beijing, he has taken down another of Mark Spitz's standards, this time with the 34th world record of his career — one more than Spitz had during his brilliant run in the pool.
"I wanted to step on it in the first 100 to get out there in the clean water, and that's pretty much what happened," Phelps said. "It was a lot more pain last night than tonight."
There couldn't have been a more appropriate place for Phelps to add another record to his resume. Shortly after he climbed from the pool, Italy's Federica Pellegrini sent the home crowd into a frenzy when she set the 20th world mark of the four-day-old meet in the 200 freestyle.
Before the night was done, South Africa's Cameron van der Burgh broke the mark he set in the semifinals to win the 50 breaststroke and China's Zhang Lin took down Grant Hackett's four-year-old 800 free by more than six seconds, with Tunisia's Ous Mellouli also going under the old mark but only getting silver. Both are non-Olympic events.
Earlier, Germany's Daniela Samulski and Russia's Anastasia Zueva got things rolling by setting records in consecutive semifinal heats of the 50 backstroke, another event not on the Olympic program. And let's not forget American Mary Descenza, who took more than three seconds off her personal best to swim the fastest women's 200 butterfly ever — in the preliminaries, no less.
For those who've lost count, that's 22 records in Rome, hardly living up to it label as the Eternal City. Nothing is sacred in these high-tech bodysuits, which have already helped surpass the 15 records set at the last worlds in Melbourne two years ago, with four days still to go.
Phelps couldn't wait to get on the podium to collect his first individual title at the Foro Italico. While his name was being announced in English and Italian, he stood impatiently with his right foot already on the stand.
Finally, he hopped up to the highest rung, thrust both arms in the air with a defiant look that melted into a crooked smile. He was back on top.
The scene was much different than a night earlier, when Biedermann blew away Phelps in the 200 free, winning by more than a full body length and snatching away one of the American's five individual world records.
The loss — Phelps' first in an individual race at the Olympics or world championships since 2005 — was followed by coach Bob Bowman's angry tirade against the sport's governing body, which allowed polyurethane suits to be used at these championships.
FINA plans to ban all bodysuits sometime early in 2010, but Bowman said Phelps might take his goggles and go home until the rule goes into effect, believing Biedermann's Arena suit gave him a huge edge over Phelps' once-revolutionary Speedo LZR Racer because it's more buoyant.
Phelps stuck with Speedo for the fly, though he did change out of a model that stretches up to his shoulders, going with one that stretched only from waist to ankles.
"It didn't feel right in warmup," Phelps said. "I changed out of it and put this on. This is what I've always worn in this race."
"He actually warmed up with the full body and he just said it felt too tight and he took it off," Bowman said. "Then I noticed he hadn't shaved his chest, but I'm like, 'Just don't worry about it.'"
No worries, indeed. No one was even close.
"I said to Bob beforehand, 'I'm going to go for the 150 and whatever happens, happens. I'm going to try to hang on the last 50,'" Phelps said. "I was able to."
Bowman knew Phelps had it when he made the last turn ahead of everyone else, no matter how hard he went out.
"He swam a really fast first 150 and he paid for it a little on the last lap," the coach said. "I'm sure he'll be tired, but I knew nobody was getting by him. That's how he is."
Actually, Bowman was confident from the moment he saw Phelps at lunch. Instead of fretting over the loss to Biedermann, he had that look the coach likes to see — and there weren't any concerns about someone having a technological edge.
"I just felt like he was really relaxed tonight," Bowman said. "I saw him at lunchtime and he was in really good spirits. You can always tell when something like this is kind of going to happen. He was definitely there tonight."