Chocolate milk and endurance exercise recovery: Protein balance, glycogen, and performance

Exercise Science Department, Southern Connecticut State University, Moore Field House, Room 169, New Haven, CT 06515, USA.
Medicine and science in sports and exercise (Impact Factor: 3.98). 09/2011; 44(4):682-91. DOI: 10.1249/MSS.0b013e3182364162
Source: PubMed


This study examined effects of fat-free chocolate milk (MILK) consumption on kinetic and cellular markers of protein turnover, muscle glycogen, and performance during recovery from endurance exercise.
Male runners participated in two trials separated by 1 wk and consumed either MILK or a nonnitrogenous isocaloric carbohydrate (CHO) control beverage (CON) after a 45-min run at 65% of V˙O(2peak). Postexercise muscle protein fractional synthetic rate (FSR) and whole-body protein turnover were determined during 3 h of recovery using muscle biopsies and primed constant infusions of L-[ring-²H₅]phenylalanine and L-[1-¹³C]leucine, respectively. Phosphorylation of translational signaling proteins and activity of proteolytic molecules were determined using Western blotting and enzymatic activity assays. Muscle glycogen was quantified, and treadmill time to exhaustion was determined after the recovery period.
Consuming MILK after exercise resulted in higher mixed muscle FSR with lower whole-body proteolysis and synthesis compared with CON (P ≤ 0.05). Phosphorylation of eIF4E-BP1 and FOXO3a was higher for MILK (P < 0.01), whereas Akt phosphorylation was lower during recovery regardless of dietary treatment (P < 0.05). Enzymatic activity assays indicated lower caspase-3 activity during recovery for MILK (P < 0.01) and higher 26S proteasome activity for CON (P < 0.01). Muscle glycogen was not affected by either dietary treatment; however, time to exhaustion was greater for MILK than for CON (P < 0.05).
The effects of consumption of MILK after endurance exercise on FSR, signaling molecules of skeletal muscle protein turnover, leucine kinetics, and performance measures suggest unique benefits of milk compared with a CHO-only beverage.

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    • "The consistency of our data is enhanced by the specificity of the test used, time-to-exhaustion, which is the determining variable for performance in street running. This protocol has been the one most used by researchers to evaluate specific performance in endurance runners (Lunn et al. 2012; Meamarbashi and Rajabi 2013; Peschek et al. 2014) and cyclists (Kalpana et al. 2013; Muggeridge et al. 2014; Pritchett and Pritchett 2012). Fig. 3. Effects of red grape juice on serum concentrations of vitamins A (panel A) and E (panel B), uric acid (panel C), and total antioxidant capacity (panel D). "
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    ABSTRACT: Recent studies have indicated that certain food products have ergogenic potential similar to that of sports supplements. The present study aimed to investigate the potential ergogenic effect of integral purple grape juice on the performance of recreational runners. Twenty eight volunteers of both genders (39.8 ± 8.5 years; peak oxygen consumption [VO2peak] of 43.2 ± 8.5 mL/kg/min) were randomized into either a group that received grape juice (grape juice group – GJG, n=15; 10 mL/kg/min for 28 days) or a group that received an isocaloric, isoglycemic and isovolumetric control beverage (control group – CG, n=13). A time-to-exhaustion exercise test, anaerobic threshold test and aerobic capacity test were performed, together with assessments of markers of oxidative stress, inflammation, immune response and muscle injury, performed at baseline and 48 hours after the supplementation protocol. The GJG showed a significant increase (15.3%) in running time-to-exhaustion (p=0.002) without significant improvements in either anaerobic threshold (3.6%; p=0.511) or aerobic capacity (2.2%; p=0.605). In addition, GJG exhibited significant increases in total antioxidant capacity (38.7%; p=0.009), vitamin A (11.8%; p=0.016) and uric acid (28.2%; p=0.005), whereas alpha-1-acid glycoprotein significantly decreased (20.2%; p=0.006) and high-sensitivity C-reactive protein levels remained unchanged. In contrast, no significant changes occurred in any of these variables in the CG. Concluded that supplementation with purple grape juice shows an ergogenic effect in recreational runners by promoting increased time to exhaustion, accompanied by increased antioxidant activity and a possible reduction in inflammatory markers.
    Applied Physiology Nutrition and Metabolism 05/2015; 40(9):150504144059003. DOI:10.1139/apnm-2015-0152 · 2.34 Impact Factor
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    • "Consistent with reports from the resistance exercise literature (Burd et al. 2009), dietary protein ingestion after endurance exercise increases postexercise muscle protein synthesis, possibly as a means to facilitate muscle remodelling and support the recovery process (Breen et al. 2011; Howarth et al. 2009; Levenhagen et al. 2002; Lunn et al. 2012). This is evident in the moderate to large effect sizes on mixed and myofibrillar (but not mitochondrial) protein synthesis after protein ingestion compared with CHO alone (Table 1). "
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    ABSTRACT: Recovery from the demands of daily training is an essential element of a scientifically based periodized program whose twin goals are to maximize training adaptation and enhance performance. Prolonged endurance training sessions induce substantial metabolic perturbations in skeletal muscle, including the depletion of endogenous fuels and damage/disruption to muscle and body proteins. Therefore, increasing nutrient availability (i.e., carbohydrate and protein) in the post-training recovery period is important to replenish substrate stores and facilitate repair and remodelling of skeletal muscle. It is well accepted that protein ingestion following resistance-based exercise increases rates of skeletal muscle protein synthesis and potentiates gains in muscle mass and strength. To date, however, little attention has focused on the ability of dietary protein to enhance skeletal muscle remodelling and stimulate adaptations that promote an endurance phenotype. The purpose of this review is to critically discuss the results of recent studies that have examined the role of dietary protein for the endurance athlete. Our primary aim is to consider the results from contemporary investigations that have advanced our knowledge of how the manipulation of dietary protein (i.e., amount, type, and timing of ingestion) can facilitate muscle remodelling by promoting muscle protein synthesis. We focus on the role of protein in facilitating optimal recovery from, and promoting adaptations to strenuous endurance-based training.
    Applied Physiology Nutrition and Metabolism 05/2014; 39(9):1-11. DOI:10.1139/apnm-2013-0591 · 2.34 Impact Factor
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    • "Noticeably, further studies that mimic human locomotion (that is, running-based studies) investigating the area of post-exercise short-term recovery nutrition need to be conducted. Interestingly, an improvement in subsequent endurance capacity with protein feeding was shown, irrespective of the fact that the glycogen levels were similar to an isocaloric supplement [63]. Albeit in that study, independent groups were used to assess glycogen resynthesis rates and endurance capacity. "
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    ABSTRACT: Muscle glycogen has been well established as the primary metabolic energy substrate during physical exercise of moderate- to high-intensity and has accordingly been implicated as a limiting factor when such activity is sustained for a prolonged duration. However, the role of this substrate during repeated exercise after limited recovery is less clear, with ongoing debate regarding how recovery processes can best be supported via nutritional intervention. The aim of this project is to examine the causes of fatigue during repeated exercise bouts via manipulation of glycogen availability through nutritional intervention, thus simultaneously informing aspects of the optimal feeding strategy for recovery from prolonged exercise. The project involves two phases with each involving two treatment arms administered in a repeated measures design. For each treatment, participants will be required to exercise to the point of volitional exhaustion on a motorised treadmill at 70% of previously determined maximal oxygen uptake, before a four hour recovery period in which participants will be prescribed solutions providing 1.2 grams of sucrose per kilogram of body mass per hour of recovery ( relative to either a lower rate of sucrose ingestion (that is, 0.3 h-1; Phase I) or a moderate dose (that is, 0.8 rendered isocaloric via the addition of 0.4 whey protein hydrolysate (Phase II); the latter administered in a double blind manner as part of a randomised and counterbalanced design. Muscle biopsies will be sampled at the beginning and end of recovery for determination of muscle glycogen resynthesis rates, with further biopsies taken following a second bout of exhaustive exercise to determine differences in substrate availability relative to the initial sample taken following the first exercise bout. Phase I will inform whether a dose-response relationship exists between carbohydrate ingestion rate and muscle glycogen availability and/or the subsequent capacity for physical exercise. Phase II will determine whether such effects are dependent on glycogen availability per se or energy intake, potentially via protein mediated mechanisms.Trial registration: ISRCTN87937960.
    Trials 03/2014; 15(1):95. DOI:10.1186/1745-6215-15-95 · 1.73 Impact Factor
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