MYOKINE RESPONSES TO RESISTANCE EXERCISE WITH DIFFERENT NUTRIENT AVAILABILITY ON A CONCURRENT EXERCISE DAY IN YOUNG, HEALTHY, PHYSICAL ACTIVE MALES

• Published in: Annals of nutrition and metabolism 2017-10, Vol.71 (Suppl. 2), p.448
• Main Authors: Mensink, Marco, Knuiman, Pim, Hopman, Maria, Hangelbroek, Roland
• Format: Article
• Language: English
• Subjects: Adaptation; Availability; Carbohydrates; Cytokines; Decorin; Exercise; Glycogen; Insulin; Interleukin 10; Interleukin 15; Interleukin 6; Interleukin 8; Low fat; Males; Meals; Monocyte chemoattractant protein 1; Muscles; Nutrient availability; Oxygen consumption; Plasma; Proteins; Skeletal muscle; Strength training; Tumor necrosis factor-α
• ISSN: 0250-6807; 1421-9697
• DOI: 10.1159/000480486

Background and objectives: Myokines are proteins produced and released by skeletal muscle in response to exercise, and suggested to play a role in exercise-induced adaptations of muscle tissue. Nutrient availability, in particular carbohydrate (CHO), is proposed as a potential regulator of myokine responses. We evaluated the effects of a pre-exercise carbohydrate-rich meal versus a low carbohydrate -high fat- meal on plasma myokine responses to resistance exercise after a glycogen-depleting endurance exercise earlier that day. Methods: Fifteen males performed two experimental days with a 90 min bout of endurance exercise at 70% VO2max in the morning (8.30-10 am) and resistance exercise in the afternoon (2- 2.30 pm):5 x 8 80% 1-RM repetitions of bilateral leg press and extension. Either a high CHO/low fat meal (110g CHO, 52g protein, 9g fat; ~750 kcal) or a iso-caloric low-CHO /high fat meal (20 gr CHO, 52g protein, 51g fat) was provided 2h before resistance exercise (noon). Blood was drawn after an overnight fast and at regular time intervals up to 3 hours after resistance exercise to measure plasma myokine/cytokine levels. Results: Postprandial plasma glucose and insulin levels were higher, and FFA lower, on the high-CHO condition compared to the low-CHO. IL-6 increased post-exercise, and was significantly higher after the low-CHO meal in the post-resistance exercise period compared to the high-CHO meal. IL-8 and IL-10 were only increased after the endurance exercise. IL-15 increased postprandial on the high-CHO condition only, and was increased in the early post-resistance exercise period, with a slightly higher level on the high-CHO condition. TNFα and Decorin did not show a clear response, while ANGPTL4 was slightly elevated post-exercise, and strongly increased in the postprandial period, with no differences between meals. MCP-1 tended, on both occasions, to increase after the endurance exercise with subsequent a reduction below baseline. Conclusions: The composition of the pre-exercise meal did in general not influence myokine responses in the post-resistance exercise period, although plasma IL-6 levels were higher in the low- CHO condition compared with high-CHO. Our findings support the view that pre-resistance exercise carbohydrate availability does not have a major impact on acute responses of myokines.