Just when you thought you had your workout routine down pat--from the right shoes to the right music--comes this unnerving caveat: Using headset stereos while exercising may be hazardous to your hearing.
So says Richard Navarro, a speech pathologist and audiologist at the University of Nevada-Reno who recently evaluated the decibel levels of 51 tape players. When the stereos were played at one-third volume, Navarro found the average level to be 85--a potentially dangerous one, according to hearing experts. At two-thirds volume, the level averaged 96 and, at full volume, 108.
Navarro speculates that listening to loud music while working out compounds the risk of hearing loss because exercise increases blood flow to the extremities, decreases oxygen around the ear and increases the flow of adrenalin, making the ear more vulnerable.
Manufacturers of headset stereos share Navarro's concerns, according to Bob Miller, vice president of merchandising at Radio Shack in Ft. Worth, Tex., which sells stereo headsets. "It's probably a very good study," said Miller, who noted many companies are trying to educate the public about the possible dangers of playing stereo headsets too loudly.
Levels in excess of 85 to 90 decibels can produce temporary hearing impairment, said a spokeswoman for the American Academy of Otolaryngology--Head and Neck Surgery in Washington D.C., an organization of ear, nose and throat specialists. "Headphone radios often produce sound in excess of 100 decibels, which causes reversible damage to the inner ear," said the spokeswoman, noting that repeated, long-term exposure to high-decibel levels can lead to irreversible damage.
Many personal tape players and radios are not safe, contends Navarro, and buying more expensive models may not negate the danger. In his university-funded study, the cheaper models tended to be safer because they emitted fewer decibels when tuned to the same volume, he said.
Research audiologist Steve Otto of the House Ear Institute in Los Angeles said Navarro's measurements sound feasible and are similar to those of his 1985 study of tiny stereos.
But Larry Royster, a professor of mechanical engineering at North Carolina State University, questioned Navarro's findings and methodology. In his evaluation of personal stereos, Royster found the average decibel output was 64 at 25% volume and 81 at 50% volume. "Ninety percent of people using personal stereos play them at 83 decibels or lower, and 83 is clearly acceptable," Royster said.
How can you determine the safety of your personal stereo? Here's the experts' advice:
--Carefully review accompanying brochures. Most manufacturers include safety information provided by the Electronic Industries Assn., a Washington-based consumer electronics group. Among the warnings, according to an association spokeswoman: "Do not play your headset at high volume. Hearing experts advise against continuous extended play. If you experience a ringing in your ears, reduce volume or discontinue use."
--Contact the manufacturer for more information about a model's decibel range. Otto of the House Ear Institute said many audiologists have meters which can measure decibels.
--"Don't turn up the music so much that your heartbeat increases in response to the music," Navarro suggested. "When you can just hear the music comfortably, leave it at that level," advised Victor Garwood, a USC professor emeritus of communication arts and sciences and otolaryngology.
--Finally, don't listen more than four hours a day at one-third volume, more than an hour at half volume and never above half volume, Navarro advised. And be prepared to modulate music when the volume is not entirely under your control. "Some of my graduate students now wear earplugs at aerobics class," Navarro noted.
Preventing the itchy, agonizing rash caused by poison oak and ivy may soon be easier, thanks to a chemically treated clay that acts as a kind of Scotchguard for the skin.
Called organoclay, the compound is currently used as a suspension aid in aerosol deodorants and anti-perspirants, said Dr. William L. Epstein, a UC San Francisco professor of dermatology who compared organoclay with three other preparations commonly used to prevent reactions to poison oak and ivy.
In a study of 28 subjects, the protection provided by organoclay was "spectacular," preventing breakouts more than 95% of the time, three times that of the other preparations, Epstein said. He speculates the chemicals in organoclay may bind better to urushiol--the main allergen in poison oak and ivy, thus reducing the amount absorbed. His study, recently reported in the Archives of Dermatology, was funded by the U.S. Forest Service and the clay's manufacturer.
Though not yet approved by the Food and Drug Administration for prevention of poison oak and ivy dermatitis, Epstein estimates organoclay may be available within a year. "It's not a cure-all," he said, noting it is not meant for those with severe allergies. "But it will help people sensitive to garden-variety poison oak and ivy."
Meanwhile, old standbys--such as calamine lotion and antihistamines--can offer some relief, said Dr. Gail Anderson, director of the department of emergency medicine at Los Angeles County/USC Medical Center. Taking a cold shower immediately after exposure may or may not work, he added.