title: Energy expenditure during 2-day trail walking in the mountains (2,857 m) and the effects of amino acid supplementation in older men and women.
abstract: We compared relative exercise intensity and active energy expenditure (AEE) on trail walking in the mountains, with those of daily exercise training, and whether branched-chain amino acid (BCAA) and arginine supplementation attenuated the release of markers indicating muscle damage and declines in physical performance. Twenty-one subjects (~63 years) were divided into two groups: amino acid (AA, 51 g of amino acids and 40 g of carbohydrate, male/female = 6/4) or placebo (PL, 91 g of carbohydrate, male/female = 6/5) supplementation during 2 days of trail walking in the mountains. We measured heart rate (HR), AEE, fatigue sensation, water and food intake, and sweat loss during walking. In addition, we measured peak aerobic capacity [Formula: see text] and heart rate (HR(peak)) with graded-intensity walking, vertical jumping height (VJ) before and after walking. We found that average HR and AEE during uphill walking were ~100% HR(peak) and ~60% [Formula: see text], while they were ~80 and ~20% during downhill walking, respectively. Moreover, average total AEE per day was sevenfold that of their daily walking training. VJ after walking remained unchanged compared with the baseline in AA (P > 0.2), while it was reduced by ~10% in PL (P < 0.01), although with no significant difference in the reduction between the groups (P > 0.4). The responses of other variables were not significantly different between groups (all, P > 0.2). Thus, trail walking in the mountains required a high-intensity effort for older people, while the effects of BCAA and arginine supplementation were modest in this condition.
authors: Saga Nutraceuticals Research Institute, Otsuka Pharmaceutical Co., Ltd., Higashisefuri, Kanzaki, Saga 842-0195, Japan. m_shimizu@research.otsuka.co.jp
authors: Muneshige
authors: M
authors: Shimizu
authors: Ken
authors: K
authors: Miyagawa
authors: Soh
authors: S
authors: Iwashita
authors: Tsuneyuki
authors: T
authors: Noda
authors: Koichiro
authors: K
authors: Hamada
authors: Hirokazu
authors: H
authors: Genno
authors: Hiroshi
authors: H
authors: Nose
mesh_terms: D000367:Age Factors; D000368:Aged; D000596:Amino Acids / Q000008:administration & dosage / Q000494:pharmacology*; D019587:Dietary Supplements; D004326:Drinking / Q000187:drug effects / Q000502:physiology; D004734:Energy Metabolism / Q000187:drug effects* / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009051:Mountaineering / Q000502:physiology*; D010919:Placebos; D012737:Sex Factors; D013997:Time Factors; D016138:Walking / Q000502:physiology*
chemical_list: D000596:Amino Acids; D010919:Placebos