A large study has found that heart rate variability (HRV), which can be an indicator of stress, is associated with tinnitus.
The link was uncovered during analysis of data from more than 72,000 people in the large Apple Hearing Study who answered questions about tinnitus and wore an Apple Watch.
“We believe this is the largest study to date to show that HRV, as a potential physiological indicator of stress, is associated with tinnitus,” the researchers from Apple and the University of Michigan wrote.
“We encourage people who have tinnitus to monitor and protect their ears from noise exposure and to consider interventions that could help reduce both tinnitus and stress.”
The main study is a collaboration between the University of Michigan in the US and Apple. They are studying 160,000 adults aiming to understand how sound exposure affects hearing health.
In 2024, the study found that about 15% of participants experienced tinnitus daily.
After noise trauma, stress was the second most common factor that users attributed as being the cause of their tinnitus.
The researchers analysed data from 72, 229 of the participants who answered questions about tinnitus and wore an Apple Watch between September 2020 and March 2025.
“We wanted to see if an individual’s tinnitus severity (self-reported interference with hearing, loudness, duration, frequency) was associated with lower heart rate variability which can be an objective indicator of whether an individual is under stress,” they reported on the University of Michigan School of Public Health website.
“While HRV is also influenced by fitness level, sleep and other factors that may limit its interpretation at the individual level, on the population level HRV data can provide valuable insights into how stress may be related to tinnitus.”
They used HRV data gathered on an Apple Watch from 30 days before a participant did the tinnitus survey until 30 days after.
The data was automatically collected over a one-minute period about six times daily and summarised as the standard deviation between normal to normal heartbeats. (SDNN).
They said lower variability in the time between a person’s heartbeats (lower HRV) generally indicated less healthy interactions between the nervous system and heart.
They used data during waking hours that were averaged over a minimum seven days.
After grouping subjects according to age, they compared participants’ average log-transformed SDNN between different tinnitus severity groups determined from survey responses.
“On average we found that HRV was generally lower when participants reported that tinnitus interfered more with hearing, sounded louder, lasted longer, or occurred more frequently,” the researchers said.
The association between higher measures of tinnitus severity and lower HRV remained consistent after accounting for factors such as age, sex and body mass index.
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