Background Interoception refers to the body’s physiological responses that occur in response to emotions. This phenomenon influences decision-making, an important cognitive ability that affects the maintenance of an exercise routine. However, it is controversial whether interoception is a reliable measure of an individual’s traits or their response to emotion. Given this evidence, we hypothesized that performing an exercise with positive feelings could improve interoception and that the rational decision-making capabilities acquired by improved interoception would, in turn, help in maintaining an exercise routine. Persistent aerobic exercise is essential for improving cognitive and musculoskeletal function in the long term. Therefore, we aimed to investigate changes in interoception during moderate-intensity aerobic exercise at a level that might potentially improve cognitive function. Methods We devided 48 healthy university students into an exercise group (n = 37) and a control group (n = 11). The control group did not perform any exercises, while the exercise group performed bench step exercises at an intensity of 50% of heart rate reserve for 30 min a day, three times a week, for three months. We assessed their cognitive function by measuring their auditory information/working memory processing speed using a paced auditory serial addition task (PASAT) and evaluated their interoceptive accuracy (IA) using a heartbeat tracking task at baseline and 1, 2, and 3 months after the start of the exercise intervention. Results There was a significant positive correlation between IA and PASAT scores at baseline. However, exercise did not lead to a significant increase in PASAT scores of the exercise group as compared with the control group. IA scores increased at 2 and 3 months after the start of exercise only in the exercise group. Conclusions This preliminary study showed an improvement in interoception after persistent moderate-intensity aerobic exercise. We believe that exercise-induced improvement of interoception may facilitate exercise maintenance through improved cognitive function. Statistical analysis did not explain the non-uniformity of sample sizes, therefore, future studies should have larger sample sizes with equal subjects in each group to allow for better comparability and generalizability. Trial registration: UMIN, UMIN000042891. 04/01/2021, retrospectively registered.

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Recently we recorded readiness potentials for self-paced movements of various body parts in the posterior parietal cortex (PPC) as well as in the motor cortex. To study involvement of the PPC in muscle force control, we analyzed readiness potentials recorded by electrodes implanted in many cortical areas in two monkeys performing self-paced hand movements to lift a lever either with or without additional load. Readiness potentials in the PPC increased in amplitude as required muscle force in hand movements increased as well as in the premotor, motor and somatosensory cortices. Further, we investigated in which body part the PPC activates muscles and how easily. Electromyograms induced in muscles in various body parts after cortical stimulation in three monkeys were analyzed. Stimulation of areas 5 and 7 produced a somatotopic pattern in muscle activities, as in the motor cortex. Stimulus intensity in area 5 for inducing muscle activity was slightly higher than that in the motor cortex, while much higher stimulus intensity was required in area 7. Taken together, preparative muscle force control was found in the PPC, which could activate muscles in various body parts, similar to the motor cortex but with a higher threshold. These suggest that the PPC plays important roles in motor functions.