Energy Deficiency During Cold Weather Mountain Training in NSW SEAL Qualification Students

Abstract

Special Operation Forces (SOF) participating in Mountain Warfare/Cold Weather (MWCW) training have higher energy demands, but adequate fueling is difficult to achieve. The purpose of the study was to determine energy expenditure relative to energy intake and examine fueling patterns during 3 days of MWCW training in Naval Special Warfare SEAL Qualification Training (SQT) Students. Ten SQT Students (age: 23.3±1.8yrs, height: 182.3±6.4 cm, weight: 83.6±4.5 kg) were fitted for heart rate and accelerometer monitors during MWCW training. Total daily energy expenditure (TDEE) was determined using a combination of direct observation and HR-VO2 regression. Total daily energy intake (TDEI) was collected using the Automated Self-Administered 24-hour recall (ASA24). TDEE for River Crossing (RC), Alpine Skills (AS), and Mountain Patrol (MP) were 3913±293, 4207±400, and 5457±828 kcals, respectively. Reported TDEIs were 2854±657 (RC) and 2289±680 kcals (MP), producing 1044±784 and 3112±1420 kcal deficits respectively. SQT Students consumed 258±95 grams (3.1±1.3 g/kg/day) of carbohydrates, 130±55 grams (1.6±0.7 g/kg/day) of protein, and 113±39 grams (1.4±0.5 g/kg/day) of fat. MWCW training evolutions elicited high TDEE and inadequate energy intake, especially before and during active training sessions, which may lead to decreased work output, early onset fatigue and increased risk of injury. Increasing TDEI by providing fuel/fluids primarily carbohydrates during the planned breaks and "down times" of each training evolution and focusing on provision of the balance of calories/macronutrients needed for a more complete and expedited recovery over dinner and evening snacks will help to bridge the energy gap.

Non-Invasive Physiological Monitoring for Physical Exertion and Fatigue Assessment in Military Personnel: A Systematic Review

“…As most of the studies performed heart rate measurements [45][46][47][48][49][50][51][54][55][56][57][58]61,62,64], significant increases in mean heart rate values during the most demanding stages of the applied protocols were a consistent finding among the retrieved papers. Due to the heterogeneity of outcome measures within this review, a comparison of obtained values could not be performed.…”

“…Only regular baseline conditions were considered for analysis from the two studies addressing interventions [47,48]. Of the 20 manuscripts, 16 described experimental moments that occurred during different training activities (mountain warfare cold-weather training [64]; chemical, biological, radiological, nuclear and explosive materials defence [58]; combat [50,51,53]; captivity survival [59,60]; usual military practices [45,49,[55][56][57][61][62][63]). Two were applied during operations [46,54].…”

“…Two others involved both scenarios [47,48]. Furthermore, considering continuously assessed variables through non-invasive methods, most of the papers (n = 15) examined different heart rate-related variables [45][46][47][48][49][50][51][54][55][56][57][58]61,62,64] while 10 monitored variables related to the estimation of physical activity mainly based on accelerometer counts [46,[50][51][52][53][54]56,57,60,63]. Three studies were also found that assessed thermal responses, two recording core temperature measurements [54,58] and one evaluating body skin temperature [57].…”

“…However, they were diverse among the studies. Beals et al [64] made reference to the three-level scale for physical intensity based on maximal heart rate percentage from Garber et al [75]. For the same purpose, Pihlainen et al [55] used Howley et al's [65] six categories, while Fallowfield et al [45] suggested the same authors [65] for determining the level of cardiovascular strain with five heart rate reserve percentage categories.…”

Are humans evolved specialists for running in the heat? Man vs. horse races provide empirical insights

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