Researchers analyzed audio recordings of participants speaking each evening after work over the period of a week, and found that having a tough day in the office changes our voices.
The researchers asked participants to report the stressors they experienced that day and their perceived stress levels.
When they analyzed the audio recordings using computer programs, they noticed some characteristic changes on the days when people reported more stressors.
They found that participants spoke more quickly and more intensely when they had more stress that day, regardless of how stressed they actually were.
The researchers now hope their findings can be used to help people keep track of their daily stress levels so they can better manage them.
They suggested that the audio recordings be an objective measure that does not depend on a person's observation of how stressful they might be.
Study author Dr Markus Langer, from the University of Saarland in Germany, said stress activates the sympathetic nervous system, which leads to the production of hormones such as cortisol and adrenaline.
This can lead to bronchiectasis - the opening of the airways - and a higher breathing rate, which can increase the intensity or volume of the voice and the rate of speech.
The research team has now suggested that audio recording technology could be used to help people monitor stress.
Due to the proliferation of wearable technologies and microphone sensors in smartphones and smart speakers, it will be possible to collect audio data over an extended period of time, providing insight into human stress levels, according to the research paper.
Given that stress is a global cause of health problems, it may help to monitor the daily impact of stress and facilitate early detection of stress, which may contribute to improved well-being.
111 people between the ages of 19 and 59 completed audio diaries over seven days, from Sunday to Sunday, during the study, which was published in Psychological Science.
Participants worked in a range of professions including medicine, healthcare, consulting, engineering and management.
They used their smartphones to send voice messages in which they answered a set of four questions about their day, asked by a chatbot.
They also completed a set of daily self-report measures of daily work stress and perceived stress level.
Since long-term stresses, such as debt and health problems, may also contribute to changes in voice features, the researchers also asked people to record them on the first Sunday of the assignment so they could factor them into their analysis.