How everyday stress changes our voice – stress is reflected in subtle changes in pitch, volume and tempo

Higher, faster, louder: when we are stressed it also affects our voice and the way we speak, the study shows. As a result, stressed people subconsciously speak higher, faster and a little louder than usual; the differences are so subtle that our ears often do not notice them, but can be detected by acoustic analysis. Also interesting: These changes occur even when we are not subjectively feeling particularly stressed.

Time pressure, conflicts, problems: More and more people are exposed to increased stress at work and in the family. The extent to which we suffer from these stresses varies – not everyone experiences stress the same way. Nevertheless, research shows that long-term stress is harmful to health and the psyche. The consequences include sleep disturbances, depression and burnout, effects on the immune system, cardiovascular disease and even cancer.

Problem: It is difficult to objectively determine a person’s level of stress. Typically, the stress hormone cortisol is measured, which requires a blood or saliva sample to be analyzed and is therefore time consuming.

Voice as an indicator of stress?

But there’s a simpler way: A person’s daily stress is also reflected in their voice and manner of speaking, as Markus Langer from Saarland University and his team found out. The impetus for her research came from earlier studies that had already shown voice changes in extremely stressful situations. “There were ratings of the pilots’ votes just before the plane crash. Their voices showed signs of stress, which is perhaps not surprising, ”explains Langer.

To find out if normal daily stress also causes these changes, the team asked 111 recruited test persons to report their daily work and possible stress factors daily for a week. Participants were also asked about their subjective stress level. Each test person also sent a voice message in the evening, which the researchers then subjected to acoustic analysis. For this purpose, the physical parameters were averaged over the course of a week, and then it was measured to what extent and in what form individual daily measurements deviated from them.

Louder, faster and higher

Outcome: If test subjects had a stressful day full of meetings, conflicts, or difficult tasks, their voices showed subtle but significant changes from the way they spoke on less stressful days. “On the one hand, the intensity of the voice increased, which meant that people spoke a little louder,” reports Langer. “Also, the voice was taller and they spoke faster than usual.”

However, the extent of these stress-related changes is small: if, for example, the tester spoke an average of 60 decibels, the volume only increased by one unit to 61 decibels with increased stress. “These little changes are often not noticeable to human ears, but the differences can be measured significantly on a computer,” explains Langer.

Objective indicator of stress

Also important: This vocal stress response occurs even when the person does not have a subjective feeling of stress. Even when the subjects stated that they did not feel more stressed than usual, their voices showed a tiring day with high levels of stress. “This is an important discovery because if you ask people if they are stressed, many say,” Oh no, it’s okay “even if it’s time to make a difference, says Langer.

According to the researchers, voice analysis could therefore help in a relatively simple way to determine the objective level of stress of a person. A few simple voice recordings via a mobile phone or computer can provide sufficient data to measure the stress level using, for example, automatic assessment software. “Voice could then serve as an easy-to-measure early warning sign of stress-related health consequences,” explains Langer and his team. (Psychological Sciences, 2022; doi: 10.1177 / 09567976211068110)

Source: University of Saarland

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