Moderate aerobic exercise enhances the brain’s “eighth sense”

A new study published in Psychology of Sport and Exercise shows that regular aerobic exercise not only improves mood but also strengthens people’s ability to sense what’s happening inside their bodies—a skill known as interoception. In a 12-week intervention, young adults who previously led sedentary lifestyles showed increased accuracy in perceiving their own heartbeats, greater confidence in those perceptions, and reduced symptoms of depression and anxiety.

Exercise is widely recognized for its ability to enhance emotional well-being, and it’s often recommended as a strategy to reduce symptoms of anxiety and depression. But while many studies focus on external improvements like energy levels or fitness, fewer have explored how exercise might influence internal awareness.

Interoception—the sense of internal bodily signals like heartbeat or breathing—is sometimes referred to as the “eighth sense.” In addition to the traditional five senses, scientists often include proprioception (body position) and vestibular sensation (balance) as sixth and seventh.

Interoception rounds out this expanded list as the sense responsible for detecting the physiological condition of the body—things like hunger, thirst, heart rate, breathing, or the need to use the bathroom. It helps people stay in tune with what’s happening inside them, which can shape emotional experiences, guide decisions, and support self-regulation. Impaired interoception has been linked to several psychological conditions, including anxiety, depression, and eating disorders.

The researchers wanted to investigate whether regular aerobic exercise could strengthen this internal sense—and whether those changes might be accompanied by improvements in mental health.

“Regular physical exercise is known to benefit mental health, but the underlying physiological mechanisms remain unclear. We were particularly interested in whether exercise improves cardioception—our ability to perceive our own heartbeats,” said study author Tomasz S. Ligeza, a postdoctoral researcher affiliated with the Institute of Psychology at Jagiellonian University in Kraków.

“Since aerobic (cardio) training directly engages the cardiovascular system, we hypothesized that it could also enhance ‘cardio awareness.’ Moreover, most prior research on the exercise–mental health relationship has focused on clinical or older populations, so we wanted to examine whether these effects also apply to healthy but physically inactive young adults—a population that has grown recently.”

The study involved 62 young adults between the ages of 18 and 32 who were not physically active at the start of the research. Participants were randomly assigned to either an exercise group or a control group that continued their usual habits. The exercise group completed a supervised 12-week cycling program on stationary bikes. The first six weeks involved moderate, continuous cycling; the following six weeks used a more demanding interval approach with alternating high and low intensities.

Participants’ interoceptive accuracy (IAcc) was measured using the heartbeat counting task, in which they tried to count their own heartbeats without physically checking their pulse. After each trial, they rated their confidence in their performance, giving researchers a measure of interoceptive confidence (ICon). Depression and anxiety symptoms were assessed using standardized self-report questionnaires, along with a scale measuring general self-efficacy—a person’s belief in their ability to succeed at tasks and handle challenges.

These assessments took place at three points: before the program began, after six weeks, and after the full 12 weeks. Throughout the intervention, the exercise group completed three training sessions per week, and both groups wore activity trackers to monitor adherence.

The exercise group showed clear improvements in interoception and emotional well-being after just six weeks. Participants became better at detecting their heartbeats (higher IAcc) and reported feeling more confident in their ability to do so (higher ICon). These improvements held steady through the remainder of the study but did not increase further after the shift to more intense training. By contrast, the control group showed no change in interoceptive accuracy at any point in the study.

Mood-related outcomes followed a similar pattern. The exercise group reported reduced symptoms of depression and anxiety after six weeks, and those improvements were maintained—but not amplified—after completing the second half of the program. Their scores on the self-efficacy scale also increased, indicating a stronger belief in their own capabilities. The control group, on the other hand, showed no meaningful changes in mood or self-efficacy during the 12-week period.

“Our 12-week program had two phases: the first with moderate-intensity exercise, the second with higher intensity,” Ligeza said. “We expected greater improvements after the second phase, but that wasn’t the case. It’s possible we reached a ceiling effect—meaning that in healthy young adults, further increases in intensity (or a longer program) might not bring additional benefits for mood or cardioception.”

These findings suggest that moderate aerobic exercise is enough to produce meaningful psychological and physiological changes, and that higher-intensity workouts do not necessarily add further benefits—at least in terms of internal bodily awareness or mood in young adults.

“Exercise improves both mental health and aspects of body awareness—and the good news is, you don’t need much,” Ligeza told PsyPost. “Just three sessions per week of moderate-intensity activity like cycling, for 30 to 60 minutes, can be enough. So if someone is physically inactive and unsure whether it’s worth starting, this study should serve as a friendly scientific nudge to get moving.”

But why does interoception matter? Previous research indicates that interoception plays an important role in emotional life. The ability to perceive internal states like heart rate or breathing contributes to how people experience and regulate emotions. Better interoceptive accuracy has been linked to improved emotional insight, decision-making, and mental health. Conversely, disrupted interoception has been associated with conditions like depression, anxiety, eating disorders, and chronic pain.

The study has some limitations. The control group was entirely passive, meaning participants did not engage in any structured activity during the study. While this design allowed researchers to compare natural lifestyle conditions, it also meant that differences between groups may reflect not just exercise but other factors, such as time spent in a structured routine.

Another limitation is that the study was not designed to determine whether improved interoception caused the improvements in mood—or whether both were separate effects of the exercise program. Although the similar patterns across measures suggest a possible link, the researchers were not able to test this directly. Future studies could help clarify whether better interoception leads to better emotional regulation, or whether the relationship works in the other direction—or both.

Looking forward, “we aim to better understand the psychophysiological mechanisms through which physical activity influences mental functioning,” Ligeza explained. “Another goal is to explore more personalized exercise prescriptions, so that individuals can maximize the mental and physiological benefits of training.”

The study, “Long-term aerobic exercise enhances interoception and reduces symptoms of depression and anxiety in physically inactive young adults: A randomized controlled trial,” was authored by Michał Remiszewski, Gabriela Rajtar, Zuzanna Komarek, Tomasz Pałka, Marcin Maciejczyk, and Tomasz S. Ligeza.