Maintain your mind, maintain your focus: Effects of focused attention and intensity in experienced runners

The intensity that people choose for their endurance activities has a major influence on their affective experience. Furthermore, the direction of attention (e.g., internal or external) during endurance activities may significantly influence performance and personal perceptions. Therefore, in the current study, we focus on the interaction between intensity and attentional focus. We aim to address the question of whether adopting an internal (IAF; breathing) or an external attentional focus (EAF; environment), compared to a control condition, leads in differences in speed, heart rate, and affect during running at different intensities in experienced runners. Data from 59 participants were analyzed (M_age: 26.95 (SD = 4.78) years; 34 male; 25 female). Participants ran 9 × 3 min in an outdoor park with three intensity conditions (light, somewhat hard, hard) and three attention conditions (internal, external, control). Intensity, but not attentional focus, impacted affective responses. Results revealed a significant interaction between attentional focus and intensity on heart rate (p < 0.001, ω²p = 0.199): during the somewhat hard intensity, the control focus condition was significantly lower compared the internal and external attentional focus conditions. Additionally, we used exploratory multilevel models (MLM). In the best-fitting MLM of heart rate, 45% of the variance is attributed to differences between athletes, and thus 55% of the variance within athletes. Furthermore, the model indicated that athletes running at a somewhat hard intensity and maintaining an EAF (b = 7.69) or IAF (b = 6.36) had an increase in heart rate compared to the control condition. We speculate that simultaneously monitoring effort and following an attentional instruction was such a difficult task that led to a favorable effect for the control condition. In practice, this could mean that the implementation of an unfamiliar focus of attention, for example, initially requires additional energy expenditure.