Page 92 - Journal of Special Operations Medicine - Fall 2014

decrements in athletic performance as well as increased Timing provides more examples for meals and snacks
risk of other health problems, such as heat injury. 59,61 Ad- (http://hprc-online.org/nutrition/files/HPRCAthletes
equate hydration and sweating are crucial to your body’s GuideNutrientTIming052714.pdf).
ability to dissipate excess heat. Intense exercise can pro-
duce sweating rates of up to 1.0 to 2.4L/hr, so a 170lb 7. Consume a snack containing CHO and some protein
59
individual could lose 2% of his weight in less than 1 hour. within 45 to 60 minutes after strenuous exercise lasting
However, maintaining hydration status during strenuous 90 minutes or longer, and be sure to rehydrate.
missions is not always possible because maximal sweat
rates can easily exceed maximal fluid absorption rates. The Our seventh commandment is based on accumulating
goal of replacing fluids during exercise is to limit dehydra- scientific evidence relating to accelerating recovery af-
tion to less than 2% of weight, not to maintain hydration ter training. Rapid replenishment of muscle and liver
status—rehydration will take place after completing the glycogen and providing amino acids to the muscles for
activity or mission. The current recommendation is to repair are part of the recovery process. Both endurance
61
ingest no more than 1.5 quarts per hour, to ensure rapid and resistance exercise can deplete glycogen stores and,
gastric emptying and optimal fluid absorption. 62,63 exercise stimulates the breakdown of muscle proteins.
Thus, what and when foods are eaten following physical
The beverage of choice during extended missions or exertion become very important for optimal recovery.
training is one that provides carbohydrates (CHO) and
electrolytes. The CHO serve to maintain blood glucose Consuming a healthy meal or snack containing CHO
and the electrolytes—sodium and potassium—are to and some protein is the best choice after training or
replace sweat losses and encourage thirst. Current rec- competing. This timing appears critical for providing
ommendations are to ingest a beverage containing 6% nutrients to the muscles and enhancing recovery in prep-
to 8% CHO. Certainly, the amount of the fluid replace- aration for the next workout. 64−68 This dietary practice—
ment beverage will depend on the duration (longer than post workout refueling—may also reduce injuries. For
69
1 hour), intensity, and environmental conditions of the long-duration missions or endurance events, some form
activity; SOF personnel should learn to evaluate their of CHO should also be consumed right after exercise.
own hydration needs by assessing urine frequency and An Athlete’s Guide to Nutrient Timing provides spe-
volume and measuring changes in body weight under cific examples of amounts of CHO and protein for the
various conditions to minimize the consequences of de- pre- and post-fueling (http://hprc-online.org/total-force
hydration. For more information about fueling before, -fitness/files/hprc-athletes-guide-to-nutrient-timing
during, and after training, see HPRC’s An Athlete’s Guide -PDF). Ingesting some protein with the CHO during
to Nutrient Timing (http://hprc-online.org/nutrition/files recovery is recommended to enhance protein synthesis.
/HPRCAthletesGuideNutrientTIming052714.pdf). The amount of protein depends on the amount of CHO,
but a good rule of thumb is that usually no more than
CHO intake before, during, and after extended exercise 25g of protein should be consumed at one time. The
and strenuous missions is essential for optimal physical most important point is to eat a healthy snack right after
performance. All SOF personnel should be educated on a training session, focusing on CHO-rich foods.
this point and encouraged to consume healthy, CHO-
rich foods, such as fresh fruits and vegetables, whole Importantly, rehydrate after any vigorous activity. To
grains, and beans, between missions and to use CHO rehydrate appropriately, 16 to 24 oz (450–675mL) of
supplements as needed during prolonged missions. If the fluid should be consumed for every pound (0.5kg) of
training involves low to moderate intensity, only 2 to 3g body weight lost—this means you need to measure your
of CHO/lb of body weight each day may be required, weight before and after vigorous activity to estimate
but more is needed when exercise intensity is higher. In sweat losses. 59
this case, between 3 and 5g of CHO/lb of body weight
should be consumed daily—or about 400g. Stated dif- 8. Eat fresh fruits, fresh vegetables, and high-fiber foods
ferently, during high levels of aerobic activity, approxi- daily.
mately 55% to 70% of the total energy each day should
come from CHO. Other “short-burst” athletes (e.g., Commandment eight has changed somewhat to meet
weightlifters) may find that consuming 50% of the total the current recommendations and evidence: it states that
energy from CHO is adequate. As shown in Table 2, you should eat fresh fruits and fresh vegetables every
approximately 400g of CHO is equivalent to one apple, day—preferably five servings of each. A large body of
one banana, an 8 oz cup of fruit yogurt, ½ cup raisins, evidence supports this recommendation both for perfor-
a bagel, an ear of corn, and 2 cups of spaghetti. Of mance and long-term health. Diets high in fresh fruits
course, other foods can be selected, but it is not diffi- and vegetables are recommended because such diets have
cult to achieve the goal of 400g, especially when spaced been linked to a reduced risk of coronary heart disease,
throughout the day. An Athlete’s Guide to Nutrient diabetes, and many types of cancer. 70−72 Unfortunately,

84 Journal of Special Operations Medicine Volume 14, Edition 3/Fall 2014