13.3: Psychological Moderators of Perceived Effort and Exertion

While the experience of effort and exertion depends on task intensity, and is strongly associated with physiological measures (e.g., ventilation rate, oxygen uptake; Chen et al. 2002), there is also a significant contribution of psychological factors. Indeed, psychological factors are estimated to account for approximately two thirds of the variance in RPE among individuals working at the same relative intensity (Noble & Robertson, 1996). RPE can also be altered by experimentally manipulating psychological factors such as self-efficacy (Hutchinson et al., 2008), attentional focus (Tenenbaum & Connolly, 2008), and expected duration of exercise (Baden et al., 2004).

13.3.1. Dispositional Moderators

Dispositional factors operate at the trait level, not the state level. A number of dispositional factors have been examined in relation to RPE, perhaps the most common being personality variables. Findings are mixed, but largely it does not appear that ratings of effort or exertion are influenced by personality type. Studies examining a variety of personality factors such as extraversion and neuroticism (Garcin et al., 2006), Type-A personality (Dishman et al., 2001), and behavioral activation/inhibition systems (Malik et al., 2020) have all reported no significant relationship with RPE. Preference for and tolerance of exercise intensity are interrelated heritable traits (Ekkekakis et al., 2006) that have been shown to influence how people feel during exercise (Box & Petruzzello, 2020; Jones et al., 2018), however there is no evidence yet that these traits might also influence perceptions of effort and exertion (Bradley et al., 2019; Vandoni et al., 2016).

Individual differences in chronotype, or natural circadian patterns, have been found to influence ratings of perceived exertion (Vitale & Weydahl, 2017). Prior research has identified a significant interaction between chronotype and time of day for RPE, wherein higher RPE was observed during evening training for “morning-types” while “evening-types”showed higher RPE values when training in the morning (Vitale et al.,2017).

Recent scientific breakthroughs related to the genome have enabled scientists to study the heritability of subjective responses to exercise. Using identical and nonidentical twin pairs and their singleton siblings, Schutte et al. reported that genetic factors explained 29% and 35% of the individual differences in RPE during cycle ergometer and treadmill tests, respectively (Schutte et al., 2017).A future challenge to researchers is to identify the specific genes underlying the heritability of the perceptual response to exercise, to test their predictive value for the adoption and maintenance of exercise behavior, and their usefulness in personalizing exercise interventions (Schutte et al., 2017). A promising finding by Bryan and colleagues indicated that variants in the brain-derived neurotrophic factor (BDNF) gene moderate the effect of exercise on RPE. These researchers found that individuals with a specific BDNF genotype reported higher RPE in response to moderate-intensity exercise than participants with a different variation (Bryan et al., 2007).

13.3.2. Social-Contextual Factors

Social-contextual factors operate at the state level, not the trait level. They can be external (e.g.,the social context of exercise) or internal (e.g., situational motivation), real or imagined, and conscious or nonconscious.

13.3.2.1. Environmental Influences

Both physical and social aspects of the exercise environment can affect RPE. Exercise in an outdoor exercise setting is associated with lower RPE, relative to indoor exercise (Focht, 2009; Krinski et al., 2017). This effect is likely due to increased environmental distractions outdoors resulting in a more externally oriented attentional focus (Gladwell et al., 2013). Findings on the presence of others in the exercise environment are mixed and are often difficult to separate from performance enhancing effects. Characteristics of the observer can also cause differential effects, for example among male runners, the introduction of a female observer caused a significant decrease in RPE, whereas the introduction of a male observer caused a significant increase in RPE compared to the control trial (Winchester et al., 2012).

The presence of mirrors in the exercise environment can create or exacerbate self-presentation concerns, which may influence RPE. The effect of mirrors has not been assessed on RPE directly, however sedentary women report greater levels of physical exhaustion after exercising in a mirrored (vs. non-mirrored) environment (Martin Ginis et al., 2003). This effect appears to be exacerbated when in presence of co-exercisers (Martin Ginis et al., 2007).

13.3.2.2. Performance Expectations

An individual’s prediction of the expected level of effort or exertion associated with a future bout of exercise is known as predicted RPE. A mismatch occurs when predicted RPE is greater than actual experienced RPE which can lead to negative attitudes regarding exercise initiation and maintenance (Haile et al., 2015). Expectations of exercise duration and anticipation of an exercise end-point can also influence RPE. Specifically, participants have reported a significant increase in RPE consequent to misinformation about the expected exercise duration compared to when they were honestly informed of the correct duration of the run (Baden et al., 2014). Participants with experimentally induced positive expectations about exercise reported significantly lower perceived exertion than participants in a “no expectation” control condition (Mothes et al., 2017). This effect was moderated by physical self-concept, wherein those with a higher physical self-concept appeared to benefit more (in terms of decreased RPE) from positive outcome expectations.

The role of placebos and expectancy has been documented in many fields of research, including exercise science. McClung & Collins (2007) were able to evaluate the relative contributions of expectancy belief and actual pharmacological impact of a performance enhancing substance (sodium bicarbonate) using a balanced placebo design. Endurance athletes completing 1000m time trials reported lower RPEs only when they believed themselves to be running “under the influence” of the drug, regardless of whether they received the actual intervention or the placebo. This demonstrates that expectancy effects alone can influence perceptions of exertion. In a similar study, Azevedo and colleagues reported that when runners believed they received an ergogenic substance their RPE decreased, but when they were told they had received an anti-ergogenic substance their RPE increased, regardless of the actual intervention, which was a caffeine supplement in both sessions (Azevedoet al., 2019).

13.3.3. Self-Efficacy

Social-cognitive theory (Bandura, 1986) posits that the relationship between self-efficacy and subjective psychological responses is reciprocal (for more discussion on self-efficacy, see Chapter 27 [Hepler et al., 2021]). Prior research has confirmed this in the case of RPE, where individuals high in self-efficacy reported lower perceived exertion during activity than those with low self-efficacy, and lower perceptions of exertion, in turn, predicted higher post-exercise efficacy (Pender et al., 2002; Robbins et al. 2004). In experimental research designs, self-efficacy for a specific task can be manipulated using false performance feedback. In such experiments, increased self-efficacy led to lower perceptions of effort and exertion (Hutchinson et al., 2008; McAuley et al., 1999). Interestingly the relationship between RPE and daily physical activity has been found to be mediated by self-efficacy for exercise(Pender et al., 2002).