INDECISIVE lovers are often advised to listen to their hearts. Now it seems that people who want to relax should do the same. Those who listen to music based on their own heart rates stay cooler and calmer under pressure.
The findings come from the lab of Kiyoko Yokoyama, an IT engineering expert at Nagoya City University, Japan. Yokoyama wanted to know what effect heart-related vibes have on the heart’s owner.
His heart music takes its cues from portable heart monitors worn by volunteers. Software analyses the heart trace from the monitors and measures the time between peaks, the “R-R interval”. This gives the instantaneous heart rate – the frequency of consecutive heartbeats – rather than a rate averaged over a minute like standard pulse measurements.
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An algorithm written by Yokoyama converts the heart rate into pitch data that can be understood by a Musical Instrument Digital Interface (MIDI) system. For example, an instantaneous heart rate of 60 beats per minute produces middle C, or “doh”. If the rate increases to 69, it produces an A or “lah”. The length of each note, whether a minim, a crotchet or a quaver, is also derived from the R-R interval. The shorter the interval, the shorter the note that is played.
The music also becomes louder or softer according to how much the heart rate fluctuates. The more variability there is in the heart rate, the louder the music becomes.
The result is that a fast, irregular heart rate produces loud, fast and higher-pitched notes. Quieter, long notes that are lower in tone reflect a slower, less varied heart rate. Yokoyama says the music can reveal a lot about a person. A higher heart rate is a good indication that someone is feeling stressed. Little variability in the heart rate reflects high concentration, he says.
Twenty-two volunteers were asked to sit at a desk and carry out a series of increasingly hard calculations. Half were played music from their heart traces and the rest worked in silence. After 3 minutes, they filled in a questionnaire designed to measure how much pressure they had felt during the test, how tense they were at the end of the test and if they felt fatigued.
Yokoyama says that the heart music does make a difference because those who listened to the music fared better – they were more relaxed and less fatigued than those who didn’t. “These people seem to keep themselves relaxed unconsciously by hearing music reflecting their heart function,” he says. Yokoyama wants to develop the system to help workers who suffer from fatigue.