Question

The given graph indicator the effect of exercise intensity on carbohydrate consumption. Carbohydrates (+ lactate production) "Triglycerides 100 (no lactate production) NO 00 Percentage vagy from fats and carbohydrates 20 0 60 NO 100 Exercise Intensity (as measured via %VO, max) At high intensity of exerciso (a) the anaerobic consumption of sugars increases (b) the nerobic consumption of sugars increases the anaerobic consumption of sugars decreases (d) no consumption of sugars takes place * $1 42 In which of the following groups of organisms, food material is broken down​

Answer 1

Answer:

Contemporary stable isotope methodology was applied in combination with muscle biopsy sampling to accurately quantify substrate utilisation and study the regulation of muscle fuel selection during exercise.

Eight cyclists were studied at rest and during three consecutive 30 min stages of exercise at intensities of 40, 55 and 75 % maximal workload (Wmax). A continuous infusion of [U-13C]palmitate and [6,6-2H2]glucose was administered to determine plasma free fatty acid (FFA) oxidation and estimate plasma glucose oxidation, respectively. Biopsy samples were collected before and after each exercise stage.

Muscle glycogen and plasma glucose oxidation rates increased with every increment in exercise intensity. Whole-body fat oxidation increased to 32 ± 2 kJ min−1 at 55 % Wmax, but declined at 75 % Wmax (19 ± 2 kJ min−1). This decline involved a decrease in the oxidation rate of both plasma FFA and triacylglycerol fat sources (sum of intramuscular plus lipoprotein-derived triacylglycerol), and was accompanied by increases in muscle pyruvate dehydrogenase complex activation and acetylation of the carnitine pool, resulting in a decline in muscle free carnitine concentration.

Explanation:

Answer 2

To properly assess substrate utilisation and examine the control of muscle fuel selection during exercise, modern stable isotope technology was used in conjunction with muscle biopsy samples.

Explanation:

At rest and throughout three consecutive 30 minute phases of exercise at intensities of 40, 55, and 75 percent maximum effort, eight cyclists were evaluated (Wmax). To assess plasma free fatty acid (FFA) oxidation and estimate plasma glucose oxidation, a continuous infusion of [U-13C]palmitate and [6,6-2H2]glucose was given. Before and after each workout stage, biopsy samples were taken.

With each increase in exercise intensity, the rates of muscle glycogen and plasma glucose oxidation increased. At 55 percent Wmax, whole-body fat oxidation rose to 32 2 kJ min1, but fell to 19 2 kJ min1 at 75 percent Wmax. This loss was followed by increases in muscle pyruvate dehydrogenase complex activation and acetylation of the carnitine pool, leading in a drop in muscle free carnitine concentration.