The impact of nutritional intervention on affective states has largely been ignored in the exercise-affect literature. For decades the impact of such interventions on perceptions of exertion has been well documented. However, Hardy and Rejeski (1989) assert that `what' a person feels, as measured by the rating of perceived exertion (RPE) scale, may be very different from `how' they feel, and that on its own the RPE provides limited information about the subjective experiences of individuals during exercise. This thesis describes a series of studies that assess the influence of various fluid ingestion regimes on both `how' and `what' a person feels. Seven studies were undertaken, incorporating a variety of exercise modes, including prolonged running (Study 1,3 & 7), prolonged cycling (Study 2& 4) and prolonged intermittent, high intensity exercise (Study 5,6 & 7). The relationship between fluid ingestion during exercise and affective states during and following exercise proved to be a complex one. The initial investigation (Study 1) showed that the ingestion of water during prolonged running resulted in an overall improvement in valence during the recovery period. A significant increase in activation was also noted in the water trial only, from pre to post exercise. Furthermore, subjective ratings of energy post-exercise were higher in the water trial, compared to the no water trial. In study 2 the beneficial effects observed in study 1 were not so apparent. In this instance the only significant change of interest was in energetic arousal, which was found to be higher 5 min post exercise in the water trial compared to the no water trial. When the ingestion of a CHO solution during exercise was compared to a placebo or flavoured water solution (Studies 3-7) the findings also varied. However, the observation of an enhanced affective profile following CHO ingestion in Study 4 and Study 5 highlights the importance of considering nutritional status and intervention when investigating the exercise-affect relationship. These studies have highlighted some important aspects in our understanding of the exercise-affect relationship alone. Firstly, a robust finding across all the studies was the observation of an almost uniformly positive shift in valence from the final within-exercise assessment to the post exercise assessments. Thus emphasising the dynamic nature of affect and the importance of repeated within exercise assessments. Secondly, moderate intensity exercise of a fixed duration was marked by highly variable inter-individual differences in the response of participants to the valence and activation dimensions. However, exercise to fatigue elicited a homogenous valence response as participants came closer to reaching their exercise capacity.