Usuarios estratégicos

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Previous research has explored the effects of pre-exercise nutrition on physical performance, creating a set of guidelines for athletes and the active population to follow. For example, it is recommended that CHO is consumed 2-3 h prior to exercise to improve endurance capacity (American Dietetic Association, 2009). However, achieving optimal physical performance is often not the sole motivation for exercise. Performance is a multi-dimensional paradigm, which also encompasses aspects of cognition and mood. An acute bout of sub-maximal exercise has been shown to improve some facets of cognitive performance, such as RT (Etnier et al., 1997) and decision making (Adam, Teeken, Ypelaar, Verstappen & Paas, 1997; McMorris & Graydon, 1996), as well as mood (Scully, Kremer, Meade, Graham & Dudgeon, 1998), an effect often thought to be caused by increased arousal during the recovery period (Lambourne & Tomporowski, 2010). Many members of the general population exercise regularly for these additional health benefits. It has been found that consuming CHO during exercise can enhance these cognitive (Ali & Williams, 2009; Collardeau et al., 2001) and mood (Lieberman et al., 2002) effects demonstrating an

interaction between nutritional state and exercise.

The timing of exercise likely influences pre-exercise nutritional intake. When exercise is undertaken in the morning, it is perhaps more common to remain fasted due to lack of time. Some individuals may choose to exercise in a fasted state due to the associated increase in fat oxidation (Backhouse et al., 2007; Gonzalez et al., 2013), as weight loss is also a common goal of exercise. Exercise can transiently suppress hunger (Broom et al., 2007; King et al., 2010; Martins et al., 2007) and an increase in EI post-exercise appears to be only partial in relation to energy expended during exercise (King et al., 2010; Martins et al., 2007; Stensel, 2010), advocating this practice for weight loss. However, if breakfast is omitted prior to exercise, research which states that breakfast consumption is important for health and wellbeing is contradicted (Barton et al., 2005; Pereira et al., 2011; Smith, 1998). In a recent survey (N=699), nearly half of the active individuals asked agreed that they had more energy on days when they ate breakfast and that they felt they must eat breakfast before they engaged in exercise (Reeves et al., 2013). The positive health benefits of consuming breakfast include mood enhancement (Kral et al., 2012) and improvement in some aspects of cognitive performance, in particular, memory (for review see Hoyland, Dye & Lawton, 2009). Consuming breakfast can also reduce overall appetite and EI for the rest of the day, an observation supported by previous trials (Astbury et al., 2011; Farshchi et al., 2005; Hubert et al.,

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1998). Although the acute mood-enhancing effects of breakfast do tend to diminish after a few hours (Smith et al., 1999), consuming a mid-morning snack has been shown to improve declining mood following a large breakfast (Benton et al., 2001). Even if guidelines for exercise recovery are followed and energy is replaced immediately following exercise (for example, by consuming chocolate milk; Karp et al., 2006; Thomas, Morris & Stevenson, 2009), omitting breakfast and inducing a further energy deficit through exercise following an overnight fast may detrimentally affect cognition, mood and appetite later in the day.

Exercising in a post-prandial state has been shown to reduce appetite (Cheng et al., 2009; Deighton et al., 2012; Martins et al., 2007). However, breakfast omission was not compared directly with breakfast consumption in these trials. Paul et al. (1996) previously reported no difference in post-recovery EI following consumption or omission of a cereal breakfast prior to cycling, despite increases in hunger reported when breakfast was omitted. However, this study did not compare the effects of exercise to those of resting following the same nutritional interventions. In addition, an alternative mode of exercise, such as running, may produce different results to those reported previously (Stensel, 2010). Many earlier studies have not assessed the satiety response to food within 1 h post-exercise (Martins et al., 2007; Paul et al., 1996); beyond this time point, the effects of exercise on appetite may have disappeared (King et al., 1994).

Trials which have investigated the effect of consuming or omitting breakfast prior to exercise on cognitive performance have produced diverse results (Hill et al., 2011; Paul et al., 1996; Vermorel et al., 2003). Vermorel et al. (2003) suggested that when adolescents have a

morning physical education lesson they require a substantial breakfast for cognitive benefits later in the day. There was no difference identified in the mood state of swimmers who either consumed or omitted CHO before a morning training session (Hill et al., 2011) although Paul et al. (1996) reported an increase in mental fatigue during the recovery period following a 90 min cycle if breakfast was omitted rather than consumed beforehand, but found no effect on cognition. It has been suggested that further research on nutritional status and appetite regulation is required in active individuals (La Bounty, Campbell & Wilson, 2011) and that studies examining the potential interactive effects of both meal consumption and exercise (Cheng et al., 2009) and studies

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importance of comparing the interaction between meal omission or consumption and exercise or rest within subjects rather than making assumptions based on results from different studies, has also been highlighted (Hubert et al., 1998). Therefore the purpose of this study was to assess the effect of breakfast consumption and breakfast omission prior to rest or exercise, followed by a post- exercise chocolate milk drink on appetite, cognitive performance and mood responses. It was hypothesized that consuming breakfast prior to exercise may elicit the most beneficial effects with regards to appetite control, cognitive performance and mood following a morning run.