Effects of exercise mode, energy, and macronutrient interventions on inflammation during military training - PubMed (original) (raw)

Randomized Controlled Trial

doi: 10.14814/phy2.12820.

Lee M Margolis 2, Nancy E Murphy 2, Holy L McClung 2, Svein Martini 3, Yngvar Gundersen 3, John W Castellani 4, James P Karl 2, Hilde K Teien 3, Elisabeth H Madslien 3, Pal H Stenberg 5, Andrew J Young 2, Scott J Montain 2, James P McClung 2

Affiliations

Randomized Controlled Trial

Effects of exercise mode, energy, and macronutrient interventions on inflammation during military training

Stefan M Pasiakos et al. Physiol Rep. 2016 Jun.

Abstract

Load carriage (LC) exercise may exacerbate inflammation during training. Nutritional supplementation may mitigate this response by sparing endogenous carbohydrate stores, enhancing glycogen repletion, and attenuating negative energy balance. Two studies were conducted to assess inflammatory responses to acute LC and training, with or without nutritional supplementation. Study 1: 40 adults fed eucaloric diets performed 90-min of either LC (treadmill, mean ± SD 24 ± 3 kg LC) or cycle ergometry (CE) matched for intensity (2.2 ± 0.1 VO2peak L min(-1)) during which combined 10 g protein/46 g carbohydrate (223 kcal) or non-nutritive (22 kcal) control drinks were consumed. Study 2: 73 Soldiers received either combat rations alone or supplemented with 1000 kcal day(-1) from 20 g protein- or 48 g carbohydrate-based bars during a 4-day, 51 km ski march (~45 kg LC, energy expenditure 6155 ± 515 kcal day(-1) and intake 2866 ± 616 kcal day(-1)). IL-6, hepcidin, and ferritin were measured at baseline, 3-h post exercise (PE), 24-h PE, 48-h PE, and 72-h PE in study 1, and before (PRE) and after (POST) the 4-d ski march in study 2. Study 1: IL-6 was higher 3-h and 24-h post exercise (PE) for CE only (mode × time, P < 0.05), hepcidin increased 3-h PE and recovered by 48-h, and ferritin peaked 24-h and remained elevated 72-h PE (P < 0.05), regardless of mode and diet. Study 2: IL-6, hepcidin and ferritin were higher (P < 0.05) after training, regardless of group assignment. Energy expenditure (r = 0.40), intake (r = -0.26), and balance (r = -0.43) were associated (P < 0.05) with hepcidin after training. Inflammation after acute LC and CE was similar and not affected by supplemental nutrition during energy balance. The magnitude of hepcidin response was inversely related to energy balance suggesting that eating enough to balance energy expenditure might attenuate the inflammatory response to military training.

Keywords: Endurance exercise; energy deficit; iron status; macronutrients.

© 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

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Figures

Figure 1

Figure 1

Study designs. (A) Experimental design for assessing the inflammatory responses to acute, 90‐min load carriage (LC) or cycle ergometry (CE) intensity‐matched exercise bouts, with or without combined essential amino acid and carbohydrate supplementation. Biochemical assays were performed using blood collected at baseline, 3‐h postexercise (PE), 24‐h PE, 48‐h PE, and 72‐h PE. Dietary intake was individually prescribed to maintain body mass and provided to research volunteers as US military combat rations. (B) Experimental design for assessing the effects of carbohydrate and protein supplementation on inflammation before (PRE) and immediately after (POST) completing a 4‐day arctic military training operation.

Figure 2

Figure 2

Inflammatory responses to load carriage and cycle ergometry exercise, with or without combined essential amino acid and carbohydrate supplementation. Data are mean ± SD, n = 10 per group. Repeated measures ANOVA was used to determine time, exercise mode, and dietary treatment effects and their interactions. Overall mean different from baseline*, 3‐h PE†, 24‐h PE‡, and 48‐h PE#, main effects of time, P <0.05. Overall mean for CE 3‐h and 24‐h PE˄ different than baseline and overall mean for CE 48‐h and 72‐h different from CE 24‐h PExy, mode‐by‐time, P <0.05. PE, postexercise, CE, conventional endurance exercise; LC, load carriage; CON, control; and SUPP, essential amino acid + carbohydrate supplement.

Figure 3

Figure 3

Effects of carbohydrate and protein supplementation on inflammation and associated outcomes before (PRE) and after (POST) a 4‐day arctic military training operation. Data are mean ± SD for CON (control, n = 18), CHO (carbohydrate, n = 27), and PRO (protein, n = 28) dietary groups (G). A repeated measures ANOVA was used to determine time main effects and time by group interactions. Overall mean for postarctic military training (POST) different than baseline (PRE)*, P <0.0001. CK, creatine kinase, and IL‐6, interleukin‐6.

Figure 4

Figure 4

Relationships between energy expenditure (A), energy intake (B), energy balance (C), and hepcidin concentrations after (POST) completing a 4‐day arctic military training operation using Pearson correlation coefficients.

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