Nutrient Needs during Deployment and Shift Work

by NSCA's Essentials of Tactical Strength and Conditioning
Kinetic Select August 2021

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This excerpt explains the importance of optimal nutritional strategies in conjunction with good sleep hygiene and how that can help mitigate damaging effects of deployment and shift work on performance.

The following is an exclusive excerpt from the book NSCA's Essentials of Tactical Strength and Conditioning, published by Human Kinetics. All text and images provided by Human Kinetics.

Deployment and shift work are realities for the tactical athlete and can negatively affect sleep, physical performance, cognition, and immune function (42). Besides practicing good sleep, nutritional strategies may help reset the circadian rhythm (28). Some research has shown consuming a high-glycemic meal within 4 hours of bedtime may improve sleep-onset latency compared with a low-glycemic meal (28). Timing is critical; a high-glycemic meal 1 hour before bed has been shown to disturb sleep (56). Consuming a high-protein diet, avoiding a high fat intake, and taking in around 1 g of tryptophan (the amount found in 10 oz or 284 g of turkey) may also improve sleep onset and quality (28). Melatonin may serve as an alternative to pharmaceutical interventions to promote sleep (17). Employing optimal nutritional strategies in conjunction with good sleep hygiene can mitigate the deleterious effects of deployment and shift work on performance.

Operating on a Caloric Deficit for Prolonged Periods

Nindl and associates have documented the negative consequences of operating in a prolonged caloric deficit (53). At the U.S. Army Ranger School, soldiers experiencing 1,000 kcal deficits per day for eight weeks lost 13% body mass, with 6% being fat-free mass (4). The soldiers also experienced a drop in physical performance, with a 16% decrease in jump height, 21% decrease in explosive power, and 20% loss in maximal lift strength (53). Similarly, Sharp and colleagues (69) reported a 3.5% decrease loss in fat-free mass, 4.5% loss in V.O2max, and 4.9% loss in explosive power but no significant change in vertical jump and lifting strength after a nine-month Afghanistan deployment (58). Such data are not available for tactical athletes within the civilian sector, but similar consequences might be expected.

One of the proven strategies to counter energy restriction and mitigate the associated lean mass losses and performance decrements during prolonged tactical operations is to increase protein intake. The Center Alliance for Dietary Supplement Research (CADSR) and the U.S. Army Medical Research and Materiel Command (USAMRMC) consensus statement recommends a protein intake of 1.5 to 2.0 g/kg body weight (0.7-0.9 g/lb) per day for periods of substantial exertion with inadequate caloric intake (57).

Coping with Unpredictable Access to Food and Water

Due to operational demands and unpredictable missions, tactical athletes need to be prepared to maintain their fueling at any given moment. One simple way to meet nutritional needs is to carry a protein-rich bar (19) or other whole foods such as nut butters or boiled eggs as a snack. Being prepared is critical. One study of 387 Marines found that a snack bar consisting of 8 g carbohydrate, 10 g protein, and 3 g fat led to fewer medical visits and heat exhaustion cases compared with controls receiving either no snack bar or a snack bar with identical carbohydrate and fat grams without protein (22). Having a nutritionally balanced snack available at all times can mitigate the consequences of missing a meal (59).

Although fat intake is usually not a concern because most tactical situations requiring restriction are not long enough to warrant concerns about a deficiency, the type of fat consumed is important. In particular, linoleic acid and omega-3 fatty acids are beneficial (27). Omega-3 fatty acids, specifically, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are of interest to the tactical athlete because their availability may be limited in tactical situations and prepared snacks (62). Several medical and nutrition experts recommend supplementation as the most efficient means of increasing EPA and DHA in the tactical athlete (21). Although no recommendations are yet available for the tactical athlete, ways to increase EPA and DHA in the diet of the warfighter are being explored (50). Industry and the military are looking for ways to increase the availability of foods high in omega-3 fatty acids by enhancing the omega-3 content of various foods, including chicken, baked goods, milk, and eggs.

Hydration is also a concern during unexpected and unplanned missions because of the negative effects even mild dehydration can have on cognitive function, mood, and marksmanship (24, 76). Given that 1 quart (1 L) of water weighs 2 pounds (1 kg), the total weight of the load to be carried by tactical athletes may limit the amount of water carried. Nolte and colleagues (54) recommended a minimum volume of 300 ml (10 fl oz) per hour for soldiers undergoing a 16 km (10 mi) rucksack march when the temperature was only 24.6 °C (76.3 °F) (68). Fluid intakes for wildland firefighters are somewhat higher during work in hot environments (up to 39 °C [102 °F]) and will likely range from 300 to 1,000 ml (10-34 fl oz) per hour depending on the ambient temperature (40, 61). See the previous box on mission hydration for guidance. Planning for extra water via air drops or using known safe water sources in the area with the appropriate prophylactics such as iodine tablets are other ways to circumvent carrying the extra weight.

Key Point

Establish a nutrition and hydration plan before the mission and an alternative plan in case the mission goes long so the tactical athlete remains fueled regardless of the situation.

NSCA's Essentials of Tactical Strength and Conditioning is the ideal preparatory guide for those seeking Tactical Strength and Conditioning Facilitator® (TSAC-F®) certification, and a reference for fitness trainers who work with tactical populations such as military, law enforcement, and fire and rescue personnel. The book is available in bookstores everywhere, as well as online at the NSCA Store.

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