Aim 2: Interoceptive accuracy will be assessed via the "Schandry test" and interoceptive awareness will be assessed via the "Multidimensional Assessment of Interoceptive Awareness" (MAIA) questionnaire. During the Schandry test the participants will be instructed to subjectively count their heart rate without any aid or tools. The heart rate will be objectively measured at the same time via ECG. A high congruence of the objective and subjective results indicate a high interoception ability, and is assumed to be correlated with high fear of physical activity. Additionally, we expect positive correlations between the MAIA and FActS scores.