有酸素運動後の栄養摂取で筋蛋白合成増加

有酸素運動で必須アミノ酸＋スクロース摂取後に栄養血流と筋蛋白合成が増加するという研究を紹介します。対象が6人のクロスオーバー研究ですので、パイロット研究と考えます。

Timmerman KL, Dhanani S, Glynn EL, Fry CS, Drummond MJ, Jennings K, Rasmussen BB, Volpi E. A moderate acute increase in physical activity enhances nutritive flow and the muscle protein anabolic response to mixed nutrient intake in older adults. Am J Clin Nutr. 2012 May 9. [Epub ahead of print]

リサーチクエスチョンは以下の通りです。

P：必須アミノ酸＋スクロースを摂取する高齢者に
I：有酸素運動（エアロバイク）を行うと、
C：有酸素運動（エアロバイク）を行わない場合と比較して
O：栄養血流、筋蛋白合成、インスリンシグナリングが増加する
D：クロスオーバー研究

抄録しか読んでいないので詳細不明ですが、有酸素運動を行うと必須アミノ酸＋スクロースを摂取した場合に、栄養血流と筋蛋白合成は有意に増加しました。一方、インスリンシグナリングは運動の有無にかかわらず、両群で有意に増加しました。

これより有酸素運動を先に行うことで、必須アミノ酸＋スクロース摂取後の筋蛋白合成を増加させることができるという結論です。

パイロット研究レベルですので限度はありますが、レジスタンストレーニングでなくても運動後のBCAA＋糖質摂取は筋肉量増加に有用かもしれません。訓練内容にかかわらず、PT・OT直後にタンパク質10g以上、BCAA2g以上と糖質を含む栄養剤を飲むことがサルコペニアに有効な可能性があります。

Abstract
BACKGROUND:
Nutrient stimulation of muscle protein anabolism is blunted with aging and may contribute to the development and progression of sarcopenia in older adults. This is likely due to insulin resistance of protein metabolism and/or endothelial dysfunction with a reduction in nutritive flow, both of which can be improved by aerobic exercise.
OBJECTIVE:
Our objective was to determine whether increasing physical activity can enhance the muscle protein anabolic effect of essential amino acid (EAA) + sucrose intake in older subjects by improving nutritive flow and/or insulin signaling.
DESIGN:
Using a randomized crossover design, we measured in older subjects [n = 6, 70 ± 3 y of age, BMI (in kg/m(2)) of 25 ± 1] the acute effects of increasing physical activity with aerobic exercise, as compared with normal sedentary lifestyle, on the response of blood flow, microvascular perfusion, insulin signaling, and muscle protein kinetics to EAA+sucrose intake.
RESULTS:
No differences between treatment groups were found in the basal state. The change from the basal state in blood flow, muscle perfusion, phenylalanine delivery, net balance, and muscle protein synthesis during the consumption of EAA+sucrose was significantly higher after the exercise than after the control treatment (P < 0.05). Insulin signaling increased during EAA+sucrose ingestion in both groups (P < 0.05).
CONCLUSIONS:
Our data indicate that a prior bout of aerobic exercise increases the anabolic effect of nutrient intake in older adults. This effect appears to be mediated by an exercise-induced improvement in nutrient-stimulated vasodilation and nutrient delivery to muscle rather than to improved insulin signaling. This trial was registered at clinicaltrials.gov as NCT00690534.