Everyday Noise Levels May Affect the Heart

Even not-so-loud sounds seemed to raise people's heart rate in small study

By Amy Norton

HealthDay Reporter

THURSDAY, May 9 (HealthDay News) -- Even the minor noise that fills everyday life, from the ring of a cell phone to the conversation that follows, may have short-term effects on heart function, a small new study suggests.

In the study of 110 adults equipped with portable heart monitors, researchers found that people's heart rate tended to climb as their noise exposure increased -- even when the noise remained below 65 decibels. That's about as loud as a normal conversation or laughter.

There was also a negative impact on people's heart rate "variability" -- a measure of the heart's adaptation to what is going on around you. Greater variability in the interval between heartbeats is better. When people are relaxed, the space between heartbeats is usually a bit longer as they exhale, and shorter as they inhale.

When people are stressed, however, some of that natural variation is lost. And studies have linked lesser heart rate variability to an increased risk of heart attack.

So does all of this mean you need to wear earplugs to protect your heart? Probably not, experts say.

For any one person, the effects of everyday noise on heart function may be small, said Charlotta Eriksson, a researcher at the Karolinska Institute, in Stockholm, Sweden. Eriksson was not involved in the study.

But since we are all exposed to noise, even a minor effect on heart health could be important on the broad "population level," said Eriksson, who has studied the effects of loud traffic -- from roads or airports -- on people's blood pressure and heart function.

Research has consistently found links between loud workplaces and an increased risk of heart disease, said Dr. Wenqi Gan, a researcher at North Shore-LIJ Health System's Feinstein Institute for Medical Research, in Manhasset, N.Y.

The evidence is more mixed when it comes to "community noise," like traffic sounds, said Gan, whose own research has found a connection.

He said the mixed results may be because it's difficult to weed out the effects of community noise on individuals. You might live in a noisy section of a big city, but have good, sound-muffling windows, for example.

"And some people are more sensitive to noise than others," Gan said. If noise affects the heart by stressing people out, he said, then your personal sensitivity to it would be important.

The new findings, reported in the May issue of the journal Environmental Health Perspectives, are based on 110 adults who wore portable devices that measured their heart activity and noise exposure during their normal daily routines.

What was "interesting," Eriksson said, is that lower-level noise seemed to curb activity in the parasympathetic nervous system -- the branch of the nervous system that acts as a "brake," lowering heart rate and relaxing the blood vessels, for example.

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High-Frequency Noise Boosts Math Skills in Study

But the treatment isn't ready for prime time yet, expert says

By Randy Dotinga

HealthDay Reporter

THURSDAY, May 16 (HealthDay News) -- Could you someday zap your way to a smarter brain? Preliminary new research suggests that it's a possibility: Scientists report that they were able to improve the math-calculation skills of college students by buzzing their brains with doses of random high-frequency noise.

But don't go searching for a brain zapper at Walmart just yet. It's not clear why "transcranial random noise stimulation" might boost thinking skills, and the necessary equipment isn't sitting on the shelves at your local hardware store. The treatment is considered to be harmless but has only been studied for a few years, and the study findings aren't definitive.

For now, though, the results of the new study are promising, said author Roi Cohen Kadosh, a cognitive neuroscientist at the University of Oxford, in England. "We can enhance one of the most complicated high-level cognitive [mental] functions and improve brain response after just five days of training, with a long-lasting effect six months later."

Scientists have only been studying transcranial random noise stimulation for about five years, Cohen Kadosh said. Researchers use the technique to stimulate the brain's cortex by putting electrodes on the scalp and delivering random bits of electrical noise. "It is non-invasive, painless -- the level of current is generated by home batteries, and is very low -- and relatively cheap," he said.

Transcranial random noise stimulation is considered to be harmless, and several studies haven't mentioned any adverse effects in those who have been zapped. Researchers are interested in one possible positive effect, though: changes in how the brain processes things.

"The brain is working on electricity, and in some cases poor behavior and cognitive [thinking] abilities appear when there's less activation of regions that are otherwise active," Cohen Kadosh said. "We thought that if we can make it easier for neurons to fire, it will allow an improved performance."

In the study, appearing May 16 in the journal Current Biology, researchers recruited 51 Oxford students and gave them five days of training and testing as they performed arithmetic tasks. The tasks tested their ability to remember math facts (like 4 x 8 = 32) and make calculations (like 32 - 17 + 5 = 20), Cohen Kadosh said.

Some of the participants received transcranial random noise stimulation when they performed the math tasks. Those participants were two to five times better at learning things, he said. And, six months after the stimulation, they were 28 percent better at making calculations than the other participants.

Scientists aren't sure why the stimulation treatment may boost learning and thinking, but Cohen Kadosh said it may have something to do with activating neurons in the brain.

Why might brain-zapping be a good thing? "We all want to improve our learning and to make it faster if possible, and we also want to help those who have problems in learning" due to disease, developmental problems or aging, he said. Also, "around 20 percent of the population finds math challenging."

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No Noise At Selfridges

In need of a stress-free 2013? Get yourself down to Selfridges between 11 January and the end of February to experience No Noise, an initiative centred around the legendary Silence Room, first created by store founder Harry Gordon in 1909.

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