42 Nutritional Assessment of Athletes, Second Edition
that hyperhydration improves performance per se, hyperhydration prior to some distance events performed in hot, humid environments may minimize performance decrements. Therefore, the American College of Sports Medicine recommends that hyperhydration be used before exercise or performance in heat environments.61 Cold water or a glucose–electrolyte solution can assist athletes in hyperhydrating.116
Euhydration is defined as the rate of fluid intake that is adequate to replace fluid losses. It is important for athletes to be euhydrated or, in certain circumstances, hyperhydrated prior to exercise or an event. Being properly hydrated helps in mini- mizing fluid loss and performance, and may prevent heat-related illness.116
Rehydration results when an individual consumes fluids in an effort to replen- ish fluid lost during an event that has caused the body to be in a dehydrated state.
Rehydrating can also reduce the rise in body temperature and minimize the stress on the cardiovascular system during longer periods of endurance exercise.116
It is critical for athletes to rehydrate following exercise training or competition to ensure proper performance during the next day’s training or event. As mentioned in Section 1.3, rehydration is needed and can be simple using the correct tech- niques. Being aware of the amount of time available for rehydration is imperative.
It is important to weigh prior to exercise and then immediately after. By comparing these numbers, rehydration can be determined. For each kilogram lost, a person should consume 1.5 liters of fluid if needing to rehydrate in a short period of time, approximately 12 hours.123 Plain water with food that contains sodium to assist in the replacement of electrolytes will be able to adequately rehydrate an athlete who has an extended amount of time for rehydration.
paying particular attention to misreporting, snacking, and openness in reporting. A successful dietary assessment depends on the expertise of the registered dietitian, who needs to be aware of the client’s perceptions toward food as well as toward the professional. Special issues that sports dietitians need to be familiar with regarding tAble 1.6
supplements: their safety and effectiveness
supplement safety (at recommended doses) effectiveness Androstenedione Safety concerns about chronic use Not effective Branched chain amino
acids
Possibly safe Not effective to delay fatigue; some studies found related immune system support
Caffeine Possibly safe; known to have adverse effects that could affect performance
Effective as a stimulant to the central nervous system
Carnitine Possibly safe Results from studies are mixed in
terms of effectiveness Chromium picolinate Safety concerns with chronic use Not shown to be effective for
increasing muscle mass as well as decreasing fat mass
Conjugated linoleic acid Possibly safe Results from studies are mixed in terms of effectiveness
Creatine Possibly safe Effective in increasing lean body mass
in weightlifters and high-intensity, short-duration performance Dehydroepiandrosterone
(DHEA)
Safety concerns with chronic use and acute high doses
Not effective Glucosamine/chondroitin
sulfate
Possibly safe Effective in some individuals
Glutamine Possibly safe Results from studies are mixed in
terms of effectiveness Beta-hydroxy-beta-
methylbutyrate (HMB)
Possibly safe Results from studies are mixed in terms of effectiveness
Medium-chain triglycerides Safety concerns with acute and chronic use
Not effective Multivitamin and mineral
supplements
Safety concerns with doses, in conjunction with the diet, that would exceed the upper intake level (UL)
Effective with nutrient deficiencies;
daily multivitamin use is recommended by some to prevent chronic disease
Protein Possibly safe for individuals without known or unknown kidney or liver disease
No difference in comparison to food protein
Pyruvate Possibly safe Not effective
Ribose Possibly safe Not effective
Source: Modified from Dunford, M., Sports Nutrition: A Practice Manual for Professionals, American Dietetic Association, Chicago, 2006, p. 131.
44 Nutritional Assessment of Athletes, Second Edition
nutritional assessment of the athletic population include periodization, fluid intake, supplements, and traveling. In order to effectively translate dietary assessment into analysis, sports dietitians should evaluate the population they are working with, as well as the cost and quality of the extremely wide availability of software and data- bases in the market. They should also be aware of several factors such as ethnic foods, fluid replacement beverages, and supplements that may not be included in databases. Therefore, a very detailed dietary assessment needs to be performed in order to conduct the necessary research that would in turn translate into a more accu- rate dietary analysis and future recommendations.
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