Nutrition Considerations for Open-Water Swimming

Abstract

Open-water swimming (OWS) is a rapidly developing discipline. Events of 5-25 km are featured at FINA World Championships, and the international circuit includes races of 5-88 km. The Olympic OWS event, introduced in 2008, is contested over 10 km. Differing venues present changing environmental conditions, including water and ambient temperatures, humidity, solar radiation, and unpredictable tides. Furthermore, the duration of most OWS events (1-6 hr) creates unique physiological challenges to thermoregulation, hydration status, and muscle fuel stores. Current nutrition recommendations for open-water training and competition are either an extension of recommendations from pool swimming or are extrapolated from other athletic populations with similar physiological requirements. Competition nutrition should focus on optimizing prerace hydration and glycogen stores. Although swimmers should rely on self-supplied fuel and fluid sources for shorter events, for races of 10 km or greater, fluid and fuel replacement can occur from feeding pontoons when tactically appropriate. Over the longer races, feeding pontoons should be used to achieve desirable targets of up to 90 g/ hr of carbohydrates from multitransportable sources. Exposure to variable water and ambient temperatures will play a significant role in determining race nutrition strategies. For example, in extreme environments, thermoregulation may be assisted by manipulating the temperature of the ingested fluids. Swimmers are encouraged to work with nutrition experts to develop effective and efficient strategies that enhance performance through appropriate in-competition nutrition.

Nutrition Considerations in Special Environments for Aquatic Sports

“…First, optimal prerace fueling (glycogen stores) and in-race carbohydrate and fluid intake appear to combat shivering thermogenesis and the preferential glycogen utilization when cold (for a review, see Haman, 2006). Thus, optimizing in-race OWS fueling should be a priority (Shaw et al, 2014). A plethora of studies have also demonstrated positive effects of cold water or slushy consumption on lowering core body temperature, improving performance in the heat, or both (for a review, see Burdon et al, 2010).…”

“…Probably the most important intervention to prevent, or attenuate, OWS hypothermic responses appears to be an athlete's inherent body fat, which can be chronically manipulated by a combination of energy intake and expenditure in a race-targeted periodized fashion. Indeed, depending on the aquatic event, compared with weight-supported terrestrial sports, extra body fat is of less consequence to overall swimming performance and may be of value in cold-water OWS conditions for both buoyancy and protection against hypothermia (Brannigan et al, 2009;Gullstrand, 2000;Macaluso et al, 2013;Shaw et al, 2014). Nevertheless, it is important to recognize that a higher fat physique may limit an athlete's ability to dissipate heat, and place the athlete at higher risk for heat stress or heat stroke, in warm-water conditions (Macaluso et al, 2013).…”

“…The official rules of the international governing body for swimming, the Fédération Internationale de Natation (FINA), state that during competition temperatures must be between 25 and 28 °C for pool water and 16 and 31 °C for open-water swimming (OWS) for the 10-km Olympic marathon and the 5-, 10-, or 25-km races at the FINA World Championships (Shaw et al, 2014). In training, elite aquatic athletes can cover between 10 and 100 km/ week -1 (10 and 35 hr/week -1 ) in pool and OWS in which temperatures are not necessarily regulated.…”

Nutrition for Recovery in Aquatic Sports

“…Reviews of the goals and practice of the training and competition programs of each of the aquatic sports have been provided elsewhere in this issue (Benardot et al, 2014;Cox et al, 2014;Robertson et al, 2014;Shaw et al, 2014aShaw et al, , 2014b. Each has identified specific physiological and nutritional challenges that arise from specific features of workouts or competitive events, as well as nutritional issues that accrue across the microcycles and macrocycles of the periodized sporting calendar.…”

“…Many of the workouts undertaken by aquatic athletes, particularly those involving prolonged or high-intensity swimming as commonly undertaken in the preparation for pool and open-water racing, would be expected to cause substantial depletion of muscle glycogen stores (Shaw et al, 2014a(Shaw et al, , 2014b. After high-intensity exercise that results in high muscle and blood concentrations of lactate, some recovery of glycogen stores in the absence of additional carbohydrate feeding is possible, but sustained muscle glycogen synthesis after exercise is dependent on provision of a dietary source of carbohydrate (Burke et al, 2004).…”