Recent research published in journals Royal Society Open Science It suggests that a common method used to measure how sensitive people are to internal signals may not actually be linked to mental health conditions such as anxiety and depression. The findings challenge previous assumptions and provide evidence that a widely used heart rate measurement task may not be an effective tool for psychological research. The researchers recommend that future studies rely on other methods of measuring internal consciousness.
Interoception is the nervous system’s ability to perceive and process information from within the body. This complex bodily function includes everyday sensations such as your heart racing, feeling full, and changes in your breathing patterns. Scientists use a variety of tests to measure how accurately a person can sense these internal physical signals.
“How the brain interacts with the rest of the body has been a popular scientific question for quite some time,” says Niall W. Duncan, an associate professor at Taipei Medical University’s Institute for Mind, Brain, and Consciousness. “In particular, people interested in mental health conditions have focused on how signals from the body influence our conscious experience.”
Duncan explained that one common approach to studying this internal consciousness is to have participants count their own heartbeats.
“One common approach to studying how well people can sense what’s going on inside their bodies is to use a task (inconceivably called a heart rate counting task) that asks people to count their own heart rate,” Duncan said.
During this particular task, a person sits quietly and counts his or her heart rate over a short period of time without taking the pulse with their hands. Your score for this test is based on how well your mentally measured heart rate matches your recorded heart rate. For years, scientists have used this counting task to investigate the relationship between internal consciousness and certain psychological traits.
Some studies have linked reduced heart rate perception to clinical symptoms such as depression and severe anxiety. Another condition commonly studied in this context is alexithymia. Alexithymia refers to a psychological phenomenon in which a person has significant difficulty identifying, understanding, and explaining his or her own inner feelings.
Recent reviews of the psychological literature have yielded highly conflicting results regarding these associations with mental health. Some analyzes found strong associations between heart rate tracking and mental health, while other reviews found no association at all. These mixed results suggest that there may be a fundamental problem with the way data is currently collected or interpreted by experts.
“However, there has been a lot of discussion recently about the validity of this mission,” Duncan noted. “Are we really measuring what people say they’re measuring, which is how well an individual can perceive signals from within their body?”
Some experts argue that the task of measuring heart rate has major flaws as a measurement tool. The researchers believe that participants simply inferred their heart rate based on how fast they thought their heart normally beat, rather than actually physically feeling their heart beating in their chest. Additionally, humans’ innate ability to estimate time can skew heart rate measurement scores. If you know your heart beats about once per second, you can get a perfect score just by counting the seconds in your head.
The specific instructions given to participants can also have a significant impact on their performance on the test. For example, when participants are asked to only count heartbeats that they are sure they are feeling, accuracy scores tend to drop by half. Given these methodological concerns, the authors aimed to test the validity of the heart rate measurement task.
“I’m interested in how science is done and the more general question of improving our methods, so this challenge and its use in the study of mental health-related psychological constructs presented an interesting example,” Duncan said.
“First, we were interested in knowing whether the associations between the tasks and these psychological constructs were likely to be real, based on the totality of available evidence,” he continued. “Many discussions about the role of body awareness in mental health cite this supposed association, so it’s important to know its certainty.”
Duncan noted that some older studies already suggest there is no real effect. The research team wanted to build on existing knowledge by examining more recent data.
“From a metascience perspective, that would be interesting, because people’s continued use of this task despite evidence of its invalidity raises interesting questions about how change happens (or doesn’t happen) in some areas of modern science,” Duncan added.
To investigate these discrepancies, the researchers conducted two separate studies. The first study was a behavioral study with exactly 79 human participants. The sample included 45 women and 34 men, and the average age of the participants was approximately 27 years. All participants were completely healthy and had no documented neurological, psychiatric, or cardiac disease.
Participants completed three established psychological questionnaires at the beginning of the experiment. They administered the Beck Depression Inventory-II to measure underlying depressive symptoms. They completed the trait scale of the State-Trait Anxiety Inventory to assess baseline levels of daily anxiety. Finally, they completed the Toronto Alexithymia Scale to measure their ability to recognize and explain complex emotions.
The researchers also measured each participant’s height and weight to calculate their BMI. Your weight can affect your perception of your heartbeat because thicker layers of body tissue make it harder to sense subtle internal movements. Next, participants completed an actual heart rate measurement task. They sat comfortably with their feet flat on the floor and their hands in their laps.
They were connected to a three-lead electrocardiogram, a medical device that records the heart’s electrical signals using sensors placed on the left and right forearms and left ankle. The researchers gave them very strict instructions to only report the heartbeats they really felt, not guesses. Participants completed seven blocks of tasks. Each block contained three separate counting intervals lasting 25, 35, or 45 s. Trials were presented in random order, with a short 5-s pause between each trial.
Researchers compared participant-reported counts to actual electrocardiogram recordings to determine exact accuracy scores. The results showed no significant association between heart rate measurement scores and any of the three psychological questionnaires. Although 12 participants were classified as overweight, BMI did not affect task performance. Even when the researchers excluded participants who showed mild symptoms of anxiety or depression from the statistical analysis, the results did not change at all.
After the behavioral study, the researchers conducted a comprehensive meta-analysis. Meta-analysis is a statistical method that combines the mathematical results of many independent studies to examine broad overall trends. The researchers collected data from 78 different experiments across 70 published academic papers. They specifically looked for previous studies that used tasks that measured heart rate alongside the exact same three psychological questionnaires used in behavioral studies.
A meta-analysis revealed no association between heart rate measurement ability and symptoms of depression or alexithymia. Researchers found a very weak positive correlation between heart rate measurement accuracy and trait anxiety. However, this weak link seemed to be significantly moderated by the type of instructions given to participants.
Studies using the original, less stringent work instructions showed a modest correlation. Studies using modern, strict instructions showed no correlation at all. This provides evidence that results can be artificially altered by the wording of task instructions.
The meta-analysis also highlighted significant systemic issues within the existing psychological literature. The researchers found no evidence of publication bias, which occurs when journals ignore failed experiments and publish only positive or exciting results. However, they found that the included studies consistently had very low statistical power. This means that the sample sizes used in previous studies are too small to reliably detect true psychological effects.
The median statistical power of the evaluated studies was only about 6–7%. None of the 78 experiments had sufficient statistical power to accurately identify the small effect size found in the final meta-analysis. Readers should be careful not to misinterpret these particular findings as absolute proof that internal consciousness has nothing to do with mental health. This study only suggests that the task of measuring heart rate is an inefficient way to measure that complex connectivity.
“Regarding the heart rate counting task and its association with the psychological concepts we incorporated, our study shows very strong evidence that how people perform on that task is not related in any meaningful way to their reported symptoms like anxiety and depression,” Duncan told PsyPost.
“This doesn’t mean that feelings of anxiety and depression aren’t related to how people sense input from within the body, just that this particular task isn’t useful for studying that,” he continued. “Establishing that fact helps foster the development of new and better methods. It’s already happening, and that in turn means we can improve our theories.”
There are some limitations to consider. The meta-analysis was not preregistered. Preregistration is a common scientific procedure that usually helps researchers prevent accidentally changing their analysis plan after viewing the raw data.
Additionally, the researchers only examined three specific psychological questionnaires to maintain data consistency. This result may not apply to other tools used by doctors to measure anxiety, depression, or alexithymia.
Finally, the researchers noted large differences between participants in the meta-analysis. Differences in the proportion of men and women, differences in clinical diagnosis, and differences in testing duration may have clouded the combined data. Future research should focus on developing better methods and rigorous testing to measure awareness within the body. Scientists might study different types of heart tests that completely eliminate the requirement for mental arithmetic or time estimation.
They were also able to fully examine other body signals. For example, researchers can measure how aware people are of their own breathing rhythms or monitor changes in stomach and gastric activity. Finding more reliable measurement tools will help scientists better understand how our physical sensations directly interact with our ongoing mental well-being.
“I think our work is a good illustration of how the scientific process works,” Duncan said. “People will make some discoveries first, and over time other people will test the idea in different ways and produce more evidence.”
“Eventually, we will be able to get to a point where we can put all the evidence together and make more robust claims about the world,” he concluded.
The study, “Testing the correlation between heart rate measurement tasks and anxiety, depression, and alexithymia scales: behavioral studies and meta-analysis,” was authored by Evgeny A. Parfenov, Elizaveta Baranova, and Niall W. Duncan.
