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This Article Full Text Full Text (PDF) All Versions of this Article: 107/3/725    most recent 91265.2008v1 Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Google Scholar Articles by Okazaki, K. Articles by Nose, H. PubMed PubMed Citation Articles by Okazaki, K. Articles by Nose, H.

Impact of protein and carbohydrate supplementation on plasma volume expansion and thermoregulatory adaptation by aerobic training in older men

Departments of ¹Sports Medical Sciences and ²Anesthesiology and Resuscitation, Shinshu University Graduate School of Medicine, Matsumoto; and ³Saga Nutraceuticals Research Institute, Otsuka Pharmaceutical Co. Ltd., Higashisefuri, Kanzaki, Japan

Submitted 21 September 2008 ; accepted in final form 13 July 2009

We examined whether protein-carbohydrate (CHO) supplementation immediately after exercise each day during aerobic training facilitated plasma volume (PV) expansion and thermoregulatory and cardiovascular adaptations in older men. Fourteen moderately active older men [68 ± 5 (SD) yr] were divided into two groups so as to have no significant differences in anthropometric measures, PV, and peak oxygen consumption rate (O_2peak). Each group was provided with a mixture of protein and CHO (3.2 kcal, 0.18 g protein/kg body wt, Pro-CHO, n = 7) or a non-protein and low-calorie placebo (0.5 kcal, 0 g protein/kg body wt, CNT, n = 7) immediately after cycling exercise (60–75% O_2peak, 60 min/day, 3 days/wk) each day for 8 wk at 19°C ambient temperature (T_a) and 43% relative humidity (RH). Before and after training, we measured PV, cardiac stroke volume (SV), and esophageal temperature (T_es) during 20-min exercise at 60% of pretraining O_2peak at 30°C T_a and 50% RH. Moreover, we determined the sensitivity of the chest sweat rate (SR/T_es) and forearm vascular conductance (FVC/T_es) in response to increased T_es during exercise. After training, PV increased by 6% in Pro-CHO (P < 0.001), with an 10% increase in SV during exercise (P < 0.001), but not in CNT (P > 0.07). FVC/T_es increased by 80% and SR/T_es by 18% in Pro-CHO (both P < 0.01) but not in CNT (P > 0.07). Moreover, we found a significant interactive effect of group x training on PV, SV, and FVC/T_es (all P < 0.02) but with no significant effect of group (P > 0.4), suggesting that the supplement enhanced these responses to aerobic training. Thus postexercise protein-CHO supplementation during training caused PV expansion and facilitated thermoregulatory and cardiovascular adaptations, possibly providing a new training regimen for older men.

exercise; aging; hypervolemia; stroke volume

This article has been cited by other articles:

				K. Okazaki, H. Hayase, T. Ichinose, H. Mitono, T. Doi, and H. Nose Protein and carbohydrate supplementation after exercise increases plasma volume and albumin content in older and young men J Appl Physiol, September 1, 2009; 107(3): 770 - 779. [Abstract] [Full Text] [PDF]