Music on the move? Earmuff phones are best

Music on the move? Earmuff phones are best
Okay, here is the lowdown on whether listening to portable music is bad for the ears. First, there’s general agreement that prolonged exposure to sound levels of 85 decibels or more can be damaging over the long term. Second, digital players that now store hundreds of hours of music and play up to 20 hours on a charge encourage users to listen longer than they did a decade ago with players that held a single CD (74 minutes) or tape (90 minutes). A 2006 study of five digital music players by researchers at Children’s Hospital Boston and the University of Colorado found that they were all remarkably similar in sound output at comparable volume levels — maxing out at 100 decibels or more. A hundred decibels is the noise you’ll perceive standing next to a passing subway train.
Another study, this one involving 100 doctoral students at Harvard, found that most listened to music at the same volume level when there was little outside noise. But many cranked up the volume to dangerous levels when ambient noise increased. This was particularly true of males and earbud users. Yet another study, by Australia’s Hearing Cooperative Research Centre, showed that a third of teens routinely listen to music at 85 decibels or more. The bottom line: Even though they’re bulkier and not as cool looking as earbuds, earmuff-style phones block more outside noise, so listeners aren’t as likely to crank up the volume to harmful levels. Custom in-ear models designed to reduce outside noise also may help.

Warm milk will help you go to sleep at night
According to age-old wisdom, milk is chock full of tryptophan, the sleep-inducing amino acid that is also well known for its presence in another food thought to have sedative effects, turkey. But whether milk can induce sleep is debatable, and studies suggest that if it does, the effect has little to do with tryptophan. To have any soporific effect, tryptophan has to cross the blood-brain barrier. And in the presence of other amino acids, it ends up fighting—largely unsuccessfully—to move across. One study by researchers at the Massachusetts Institute of Technology demonstrated this in 2003. The study, which was published in The American Journal of Clinical Nutrition, showed that eating protein-rich foods—like milk—decreased the ability of tryptophan to enter the brain. The trick, the study showed, is to eat foods high in carbohydrates, which stimulate the release of insulin. Insulin, in turn, makes it easier for tryptophan to enter the brain.

Dogs, even on a leash, give birds a fright
Australian researchers have found that walking leashed dogs along woodland paths leads to a significant reduction in the number and diversity of birds in the area, at least over the short term. Peter B. Banks and Jessica V. Bryant of the University of New South Wales surveyed birds along woodland trails near Sydney shortly after dogs were walked on them or after people walked alone. All kinds of dogs were involved, big and small, purebred and mutt. As a control, they also surveyed birds on trails that no one, human or canine, had recently walked on. Banks said the study was an outgrowth of his interest in predator-prey interactions. “Here you have a predator that is being walked through the bush quite regularly,” he said.
The researchers chose trails in places where dogs were banned and in other areas where dog walking was common, expecting different results in each. “We thought that where there was regular dog walking birds would get used to it,” Banks said. “Well, they didn’t.” Regardless of the type of area, dog walking led to a 35 percent reduction in the number of bird species and a 41 percent reduction in overall bird numbers, compared with the control. The study, published in Biology Letters, provides support for park managers and others on the same side of what can be a heated debate over dogs in natural areas.