Implementing intentions to drink a carbohydrate-electrolyte solution during exercise

Abstract

In this study, we examined the effectiveness of a theory-based psychological implementation intention strategy on the volume and frequency of intake of a carbohydrate-electrolyte solution by participants engaged in submaximal exercise. Thirty-five participants were randomly assigned to an implementation intention or control condition. Participants assigned to the implementation intention condition were required to write down when and where they would carry out their intention to drink a sports drink in the upcoming exercise trial. Participants completed self-report measures of intentions, the psychological antecedents of intentions, and past behaviour for sports drink use and physical activity before and after receiving the experimental manipulation. Participants then engaged in a one-hour submaximal exercise trial on a cycle ergometer and had free access to a carbohydrate-electrolyte solution throughout. The frequency and volume of sports drink consumed by participants over the course of the trial was recorded. Participants also provided pre- and post-trial urine samples, which were tested for osmolality. Experimental participants imbibed a significantly greater volume of sports drink and had significantly higher urine osmolality than controls. The intervention had no effects on psychological variables. Results support the use of implementation intentions to effectively promote sports drink intake among sports participants.

Keywords:

• Motivation
• volitional strategy
• Action Phase Model
• if–then plans
• sports drink

Acknowledgements

This research was supported by a grant awarded to the first author from the University of Essex Research Promotion Fund. We thank Prof. Sheina Orbell of the School of Psychology, University of Essex for her advice on the development of the intervention and study design and Dr. Niels Vollaard of the Exercise Biology Research Group, Heriot Watt University for his assistance with physiological measures and the exercise protocol.