Efficacy of Eat-on-Move Ration for Sustaining Physical Activity, Reaction Time, and Mood

• Autores: Scott J. Montain, Carol J. Baker-Fulco, Philip J. Niro, Andrew R. Reinert, John S. Cuddy, Brent C. Ruby
• Localización: Medicine & Science in Sports & exercise: Official Journal of the American College of Sports Medicine, ISSN 0195-9131, Vol. 40, Nº. 11, 2008, págs. 1970-1976
• Idioma: inglés
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• Resumen

  • Repeated carbohydrate feedings and caffeine have been shown to increase self-paced physical activity. Whether a field ration pack that promotes snacking of these items would enhance physical activity remains unclear.

    Purpose: Evaluate the effectiveness of a ration pack consisting of eat-on-move items to promote snacking, as well as caffeine items, as a nutritional strategy to improve performance.

    Methods: Twenty-eight wildland firefighters consumed both an eat-on-move ration (first strike ration (FSR): 13.2 MJ, 420 g CHO, 665 mg caffeine daily) and entree-based ration (meals, ready-to-eat (MRE): 11.9 MJ, 373 g CHO, 100 mg caffeine daily) for 2 d separated by 1 d. Diet order was counterbalanced. Outcome measurements included self-paced physical activity determined by actimetry, reaction time, number of eating occasions using dietary recall, and dietary intake from food wrapper collection.

    Results: Total eating episodes were higher with FSR compared with MRE (P = 0.013; mean +/- SD: 8.2 +/- 1.3 vs 7.6 +/- 1.1 episodes[middle dot]2 d-1), as were 2-d energy intake (22.0 +/- 2.4 vs 18.4 +/- 2.5 MJ; P < 0.01), carbohydrate intake (698 +/- 76 vs 546 +/- 82 mg; P < 0.01), self-reported caffeine intake (347 +/- 262 vs 55 +/- 65 mg; P < 0.01), and average end-shift salivary caffeine (1.6 +/- 1.9 vs 0.7 +/- 1.0 [mu]g[middle dot]mL-1; P < 0.01). Total activity counts were higher (P = 0.046) when consuming FSR (507,833 +/- 129,130 counts per shift) compared with MRE (443,095 +/- 142,208 counts per shift). This was accomplished by spending a greater percentage of work shift with activity counts >1000 counts[middle dot]min-1 (21 +/- 8% vs 18 +/- 6%; P = 0.01) and less percent of work shift <50 counts[middle dot]min-1 (33 +/- 10% vs 38 +/- 10%; P = 0.01).

    Conclusions: Delivery of energy and caffeine in a manner that promotes snacking behavior is advantageous for increasing self-selected physical activity during arduous labor