This study examined the effect of carbohydrate (CHO) and protein (PRO) co-ingestion on energy substrate metabolism, sense of effort, and affective responses during prolonged strenuous endurance exercise. In a four-stage randomized cross-over design, 10 male endurance runners (age: 27.3 ± 1.4 yrs; height: 172.9 ± 1.1 cm, weight: 63.5 ± 1.6 kg; body fat: 9.0 ± 1.4%; V̇O₂max: 62.9 ± 1.8 ml/kg/min) ran on a treadmill at 70% of their individual V̇O₂max for 90 min. There were two CHO and PRO treatments (CA: CHO + alpha-lactalbumin and CW: CHO + whey PRO isolate), one CHO treatment (CC: CHO + CHO), and a placebo control (CON). On each occasion, subjects consumed 5 ml/kg according to their body weight (kg) immediately before and 2 ml/kg every 15 min during exercise. Blood samples were collected at 0 min, 30 min, 60 min and 90 min of exercise to measure glucose, lactate, insulin, and cortisol levels. The extent of physical sensation (abdominal discomfort, leg muscle pain), the sense of effort (rating of perceive exertion, RPE), and affective responses (pleasure-displeasure, arousal) were evaluated by numeric scales before, during, and immediately after exercise. Blood glucose and insulin concentrations in the CA, CW, and CC treatments were higher than in the CON at 90 min (P < 0.05). Muscle pain (evaluated by a single item, 0 to 10 pain intensity scale from “no pain at all” to “extremely unbearable”) was lower following CA ingestion than CON and CW ingestion, at 75 min (vs. CON and CW, 1.95 ± 0.61 vs. 3.70 ± 1.00 and 3.60 ± 1.02, P < 0.05) and 90 min (vs. CON & CW: 2.40 ± 0.76 vs. 4.20 ± 0.99 and 4.05 ± 1.1, P < 0.05). RPE (evaluated by a 15-point, 6 to 20 rating scale ranging from “very, very light” to “very, very hard”) following treatment with CA was lower than with CON and CW at 90 min (vs. CON and CW: 11.30 ± 1.14 vs. 14.20 ± 1.30 and 13.30 ± 1.24, P < 0.05). Compared with CON and CW, CA enhanced the feeling of pleasure (evaluated by feeling scale from − 5, “very bad” to + 5, “very good”) at 90 min (vs. CON and CW, 2.20 ± 0.67 vs. − 0.30 ± 0.94 and 0.20 ± 0.91, P < 0.05). Co-ingestion of CHO and alpha-lactalbumin protein attenuates muscle pain, and therefore alleviates the sense of effort and enhances affective responses during 90 min of strenuous running at 70% V̇O₂max. Copyright © 2017 Elsevier Inc.
CitationQin, L., Wong, S. H., Sun, F.-H., Huang, Y., Sheridan, S., & Sit, C. H. P. (2017). The effect of carbohydrate and protein co-ingestion on energy substrate metabolism, sense of effort, and affective responses during prolonged strenuous endurance exercise. Physiology & Behavior, 174, 170-177.
- Perceived exertion