Long rides and long car rides can make a person sleepy. While driving, this is one of the most common causes of accidents involving one in five accidents due to drowsiness or tiredness behind the wheels.
Lead author, PhD researcher Neng Zhang, in virtual simulator.
A team of researchers has found that the vibrations emitted by the car can be the cause of drowsiness. They found that only about 15 minutes of these vibrations are enough to let a person sleep in a car. The study appeared in the latest issue of the journal ergonomics,
Researchers at RMIT University in Australia have warned motorists, together with road safety experts and car manufacturers, that this is an important element to consider when making and driving cars. Stephen Robinson, one of the study authors, said that when a person is tired, it takes little to stop them.
The study, he explained, has found that the soft vibrations of car seats are able to engulf the brains and bodies of these over-tired individuals and make them drowsy. He said that these vibrations are "stationary" and "low frequency" experienced while driving trucks and cars. He said that people who are rested and healthy can also feel sleepy when exposed to these vibrations.
For this study, the team experimentally placed 15 volunteers on a virtual simulator capable of vibrating at different frequencies. Then the participants were tested once without vibration and then again with low-frequency 4-7 Hz oscillations. Over a one-hour session, the participants' heart rate variations (HRV) were measured. These variations are signs of drowsiness. When the brain gets tired, the heart rate changes.
The results showed that the participants felt drowsiness within 15 minutes and after 30 minutes most participants felt "significantly" drowsy. Drowsiness continued until the end of the test.
The research team explained that the brain is usually synchronized with the vibrations and enters early stages of sleep. This leads to drowsiness. They explain that this study needs to be done in a larger group of individuals in order to be meaningful and to be applicable in everyday scenarios. Nevertheless, the results are remarkable and should be considered for further investigation.
The team says they plan to test different frequencies in larger groups of participants to see if their hypothesis is true. Robinson says that some vibrations can keep people awake instead of lulling them to sleep.