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Interoceptive differences in elite sprint and long-distance runners: A multidimensional investigation [1]
['Tom Seabury', 'Swansea University', 'Wales', 'United Kingdom', 'David Benton', 'Hayley A. Young']
Date: 2023-03
Interoception, the process of detecting and interpreting bodily sensations, may facilitate self-regulation and thereby play a crucial role in achieving elite performance in competitive sports. However, there is a lack of research conducted in world-class athletes. In the present research, two studies examined self-reported (interoceptive sensibility) and behavioural (interoceptive accuracy) interoception in elite (top 100 ranking) sprint and long-distance runners, and non-athletes. Study 1 used the Multidimensional Assessment of Interoceptive Awareness Questionnaire. Sprinters reported having better regulation of attention to internal sensations, greater emotional awareness, better self-regulation, and reported a greater propensity to listen to their body for insight, than distance runners. Compared to non-athletes, sprinters and distance runners had more bodily trust, attention regulation, and self-regualtion. Additionally, elite athletes reported lower emotional awareness, self-regulation, and body listening. Study 2 examined cardioception using two tasks: The Heartbeat Counting Task, and The Heartbeat Detection Task. Elite and non-elite runners performed the tasks under two conditions; in silence, and whilst listening to pre-recorded crowd noise that simulated the live sounds of spectators during a sporting event. Sprinters and distance runners were able to maintain heartbeat detection accuracy when distracted, whereas non-athletes could not. Across both tasks, compared to non-athletes, sprinters and distance runners were more confident than non-athletes in their interoceptive percept. Additionally, elite athletes compared to non-elite athletes were less accurate when counting their heartbeat and were characterised by a higher interoceptive prediction error. Athletic populations have altered interoceptive abilities.
Introduction
Interoception describes the detection and perception of stimuli originating from within the body [1]. To perform well, elite track athletes must monitor and utilise internal afferent sensations, such as those related to effort and fatigue. For example, early research found that elite long-distance runners reported regulating their pace by "reading their bodies", as well as attending closely to bodily input such as "respiration" and "sensations in their feet and legs" [2]. Conversely, less elite runners reported predominantly directing their attention away from the body [2]. Unfortunately, most of the early research connecting interoception and sports performance was based solely on the athlete’s qualitative reports. However, in recent years the definition of interoception has expanded considerably. Despite once being considered a unitary concept, interoception is now understood to comprise multiple dimensions including both self-reported and behavioural components [3]. Therefore, more research is needed to determine which aspects of interoception are associated with achieving world-class performance.
Recently, several interoceptive taxonomies were proposed [1, 3–7]. Table 1 describes the interoceptive indices most commonly used in empirical research and those which were used here [1, 3–8]. Evidence indicates that some interoceptive components (i.e., accuracy, awareness, and sensibility) are empirically dissociable [3, 9, 10] and may differentially associate with behaviour [10, 11]. Consequently, when considering the role of interoception in elite sports performance, it is important that these dimensions are studied separately.
Despite the paucity of research examining interoception in athletes, several recent theoretical reviews have been published that have emphasised the role of interoception in physical activity [17–20]. For example, Tucker [21] proposed a model whereby the regulation of exercise work rate during self-paced exercise is achieved by combining interoceptive feedback (e.g., body temperature, metabolite concentrations, arterial saturation levels, increased ventilatory rates and increased heart rates which generates conscious feelings of exertion) and existing expectations about the optimal rate of exertion required for the exercise (e.g., based on expected duration/ distance, motivations / goals which produces anticipated feelings of exertion against which the experienced exertion is compared). This idea has similarities to recent applications of prediction processing to interoception which imply that subjective feeling states are determined by predictions about the interoceptive state of the body [22, 23]. These models provide the theoretical foundations for the proposed influence of interoception on self-regulation during exercise. However, hitherto empirical verification of these models has been limited.
Nonetheless, there is some experimental evidence that better interoception might facilitate self-regulation during exercise [24–26]. For example, Herbert, Ulbrich [25] conducted one of the first studies on heartbeat perception accuracy and exercise performance. Using a bike ergometer, participants were instructed to set their own pace for fifteen minutes. Those who were more accurate at counting their heartbeat had lower cardiac output and lower heart rate during the exercise. In addition, they cycled a shorter distance in the time limit. Herbert, Ulbrich [25] interpreted these findings as suggesting that poor heartbeat perceivers may be less efficient at regulating their pace during physical effort. This interpretation is consistent with more recent evidence indicating that better heartbeat perceivers were better able to replicate their physical effort, albeit only at lower training intensities [27]. If better interoception does facilitate self-regulation during exercise, this would have clear implications for long-distance athletes where optimal ‘pacing’ is crucial to achieving high level performance. Nonetheless, an alternative explanation for Herbert, Ulbrich [25] findings is that those with better interoception had more difficulties performing physical activity at the limit of their physical abilities. For example, those with higher metacognitive awareness of their interoceptive accuracy reported more fatigue during a knee extension endurance task after having been pre-fatigued [26]. Therefore, it is also plausible that athletes who are particularly sensitive to internal sensation may struggle to push beyond their physiological boundaries as required in elite athletes. In addition, this could be particularly important in sprint athletes who are required to train at high intensities. Supporting this suggestion, interventions that reduce interoceptive attention may lower the rate of perceived excursion associated with physical exertion [28].
Interestingly, the results of one study could help clarify these alternative interpretations [11]. It was reported that the association between the ability to perceive one’s heartbeat and the behavioural regulation of exercise performance might depend on one’s subjective response to the perturbation of internal signals [11]. Those who were more accurate at perceiving their heartbeat decreased their power output during a 30-second Wingate sprint task, but only if they reported high levels of subjective anxiety sensitivity [11]. These findings illustrated how individual dispositional tendencies may alter inferences made about interoceptive perturbations, thereby dictating whether better interoceptive abilities facilitate or debilitate physical performance. In addition, they further highlight the importance of understanding the possible inter-relationships between key interoceptive concepts, regarding physical activity.
Although the supposed links between interoception and physical activity are not new, limited research has compared athletes and non-athletes. Faull, Cox [29] compared the ventilatory awareness of endurance athletes (defined as training five or more times per week in cycling, rowing, or distance running) and non-athletes. Participants completed a hypercapnic ventilatory response test during which they self-reported their breathlessness anxiety and intensity. The hypercapnic ventilatory response did not differ between athletes and non-athletes indicating that central chemoreceptor sensitivity was similar in both populations. However, the correlation between perturbated ventilation rate and breathlessness intensity and anxiety was significant only in the athlete group. This suggested that athletes were more aware of changes in their ventilation rate. Whilst this increased awareness could benefit self-regulation during physical exertion, the emotional component of breathlessness anxiety could also be a limiting factor. It is important to note that the domain generality of interoceptive signals is currently debated [30], and these effects may be limited to ventilatory interoception. In addition, it is unclear whether these effects vary according to the athlete’s sport.
Hitherto, studies comparing interoception across different sports are rare and have resulted in inconsistent findings. For example, Jones and Hollandsworth [31] compared the performance of those who were sedentary, intermediate tennis (which requires short burst of anaerobic activity over a prolonged period of time) players, and distance runners (mostly aerobic) on a heartbeat detection task, both before and after exercise that raised resting heartrate by 75%. Male runners were more accurate at rest, and exercise increased the performance of other groups to a similar level. Notably, the increased interoceptive performance observed after exercise suggested that an increased salience of cardiac afferents during and after acute physical activity could enhance interoceptive abilities. Taken together with the previously mentioned studies, this indicates a potential reciprocal association between physical activity and interoceptive processes [17]. Specifically, physical activity increases the salience of interoceptive afferents thereby enhancing the development of accurate internal interoceptive models. These models then contribute to the maintenance of allostasis during subsequent physical exertion (Fig 1).
PPT PowerPoint slide
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TIFF original image Download: Fig 1. Positive feedback loop between physical activity and interoception. Note. This model shows the reciprocal association between acute and chronic physical activity and interoceptive processes. Physical activity increasing the salience of interoceptive signals enhancing interoceptive accuracy and attention. Accurate internal models facilitate allostasis and minimise prediction error during subsequent exertion.
https://doi.org/10.1371/journal.pone.0278067.g001
Interestingly, Hirao, Vogt [32] hypothesised that long-distance runners would have better interoception than sprinters. Interoceptive accuracy (using the heartbeat counting task), and sensibility (using the Multidimensional Assessment of Interoceptive Awareness questionnaire (MAIA) [14]), were examined in university-level athletes who competed in either event. Contrary to their hypothesis, Hirao, Vogt [32] found that sprinters scored significantly higher in subjective attention regulation (belief in their ‘ability to sustain and control attention to body sensations’) than their endurance counterparts. No differences were found in interoceptive accuracy.
There are several possible explanations for these inconsistent results. Firstly, a limitation of Hirao, Vogt [32] was that they used the heartbeat counting paradigm to measure interoceptive accuracy. This is a concern because there are often methodological differences in how the heartbeat counting task is conducted which might explain mixed results from recent meta-analysis [33, 34]. The heartbeat counting paradigm is also potentially biased by non-interoceptive factors, such as previous knowledge of resting heartrate [35]. This might be a particularly relevant consideration when testing athletes, given that athletes are often exposed to technology such as heart rate monitors and smartwatches. In this context, heartbeat detection tasks, which are not influenced by explicit knowledge of heartrate [35], might offer a more rigorous assessment of interoceptive accuracy.
Secondly, Jones and Hollandsworth [31] combined interoceptive certainty (i.e., confidence ratings) and heartbeat detection performance into a single ‘accuracy’ score. It is now recognised that these represent empirically dissociable interoceptive dimensions [3]. Finally, prior research has not considered that effects could vary according to the athlete’s level of expertise. Indeed, answering this question will be essential if interventions targeting interoception are to be recommended for enhancing sports performance.
In summary, there is good theoretical and some empirical evidence that interoception (accuracy and/ or awareness) might be related to self-regulation during exercise [17–20, 25–27]. In addition, athletes may have better interoceptive abilities than non-athletes [29, 31]. However, conclusions are so far limited due to studies taking a unidimensional approach [25], methodological inconsistencies [31, 32]’, and the recruitment of college-level, rather than elite athletes [29, 31, 32]. The present studies aimed to address some of these concerns by taking a multidimensional approach to understanding interoception in world-class (ranked in the top 100) sprint and long-distance athletes, and non-athletes. These populations were chosen to extend the work by Hirao, Vogt [32]. Two questions were addressed: (1) whether sprinters, distance runners and non-athletes differ in their interoceptive abilities, and (2) whether elite athletes differ from non-elite athletes in their interoceptive abilities. In a large online sample, study one considered whether elite and non-elite athletes could be differentiated according to their self-reported interoceptive attentional and regulatory styles. Study two used both a counting task and a ‘gold standard’ Heartbeat Detection Task to examine differences in interoceptive accuracy, confidence, and metacognitive awareness. Although previous research has considered interoception in either the respiratory or the cardiac domain, here we focused on cardioception for consistency with the study by Hirao, Vogt [32]. In both studies we had three hypotheses: (1) that athletes would show better interoceptive abilities than non-athletes (directional); (2) that elite athletes would differ from novices in their interoception (non-directional); and (3) that interoception would vary based on the athletes’ sport (non-directional).
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