Uchida K, et al. - This study resolved to examine the effect of interval walking training (IWT) and nutritional intake in the elderly cohort. It was deduced that plasma volume (PV) was proportional to the number of IWT days for 12 months. A carbohydrate (CHO) + whey protein supplementation during the 5-month IWT prevented PV reduction for the period of no supplementation. This could partly be associated with blood glucose control mechanisms.

Methods

• The recruitment included 17 male and 10 female subjects (∼69 yr), having performed IWT for >=24 months before the study.
• After pre-intervention measurement (PRE) of PV, plasma albumin content (Albcont), fasting glucose concentration ([Glc]f), and HbA1c, enrollees were randomly divided into two groups: CHO and Pro-CHO, either consuming CHO (22.5 g) alone or CHO (15 g) + whey protein (10 g), respectively, during additional 5-month IWT from May to November, 2009.
• Same variables were estimated again (post-intervention measurement, POST), after the additional IWT.

Results

• A prominent link was found between the baseline PV and Albcont with the number of IWT days for the 12 months preceding PRE (r=0.716, P<0.001 and r=0.671, P<0.001, respectively).
• In POST, PV and Albcont, marginally decreased in CHO from the baselines (P=0.081 and P=0.130, respectively) with increased HbA1c (P<0.001) after correction for the baseline [Glc]f by ANCOVA.
• However, these values were unchanged in Pro-CHO (both, P>0.74).
• It exhibited marked variations in the changes between groups (P=0.020, P=0.041, and P=0.018 respectively).