Effects of Prior Acute Exercise on Circulating Cytokine Concentration Responses to a High-fat Meal

High-fat meal consumption alters the circulating cytokine profile and contributes to cardiometabolic diseases. A prior bout of exercise can ameliorate the triglyceride response to a high-fat meal, but the interactive effects of exercise and high-fat meals on cytokines that mediate cardiometabolic risk are not fully understood. We investigated the effects of prior exercise on the responses of circulating tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), IL-8, leptin, retinol-binding protein 4 (RBP4), vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), placental growth factor (PlGF), and soluble fms-like tyrosine kinase-1 (sFlt-1) to a high-fat meal. Ten healthy men were studied before and 4 h after ingestion of a high-fat meal either with or without ~50 min of endurance exercise at 70% of VO2 max on the preceding day. In response to the high-fat meal, lower leptin and higher VEGF, bFGF, IL-6, and IL-8 concentrations were evident (P \u3c 0.05 for all). There was no effect of the high-fat meal on PlGF, TNF-a, or RBP4 concentrations. We found lower leptin concentrations with prior exercise (P \u3c 0.05) and interactive effects of prior exercise and the high-fat meal on sFlt-1 (P \u3c 0.05). The high-fat meal increased IL-6 by 59% without prior exercise and 218% with prior exercise (P \u3c 0.05). In conclusion, a prior bout of endurance exercise does not affect all high-fat meal–induced changes in circulating cytokines, but does affect fasting or postprandial concentrations of IL-6, leptin, and sFlt-1. These data may reflect a salutary effect of prior exercise on metabolic responses to a high-fat meal

Prior exercise and antioxidant supplementation: effect on oxidative stress and muscle injury

<p>Abstract</p> <p>Background</p> <p>Both acute bouts of prior exercise (preconditioning) and antioxidant nutrients have been used in an attempt to attenuate muscle injury or oxidative stress in response to resistance exercise. However, most studies have focused on untrained participants rather than on athletes. The purpose of this work was to determine the independent and combined effects of antioxidant supplementation (vitamin C + mixed tocopherols/tocotrienols) and prior eccentric exercise in attenuating markers of skeletal muscle injury and oxidative stress in resistance trained men.</p> <p>Methods</p> <p>Thirty-six men were randomly assigned to: no prior exercise + placebo; no prior exercise + antioxidant; prior exercise + placebo; prior exercise + antioxidant. Markers of muscle/cell injury (muscle performance, muscle soreness, C-reactive protein, and creatine kinase activity), as well as oxidative stress (blood protein carbonyls and peroxides), were measured before and through 48 hours of exercise recovery.</p> <p>Results</p> <p>No group by time interactions were noted for any variable (P > 0.05). Time main effects were noted for creatine kinase activity, muscle soreness, maximal isometric force and peak velocity (P < 0.0001). Protein carbonyls and peroxides were relatively unaffected by exercise.</p> <p>Conclusion</p> <p>There appears to be no independent or combined effect of a prior bout of eccentric exercise or antioxidant supplementation as used here on markers of muscle injury in resistance trained men. Moreover, eccentric exercise as used in the present study results in minimal blood oxidative stress in resistance trained men. Hence, antioxidant supplementation for the purpose of minimizing blood oxidative stress in relation to eccentric exercise appears unnecessary in this population.</p

Influence of Prior Exercise on VO2 Kinetics Subsequent Exhaustive Rowing Performance

Prior exercise has the potential to enhance subsequent performance by accelerating the oxygen uptake (VO2) kinetics. The present study investigated the effects of two different intensities of prior exercise on pulmonary VO2 kinetics and exercisetime during subsequent exhaustive rowing exercise. It was hypothesized that in prior heavy, but not prior moderateexercise condition, overall VO2 kinetics would be faster and the VO2 primary amplitude would be higher, leading to longerexercise time at VO2max. Six subjects (mean 6 SD; age: 22.964.5 yr; height: 181.267.1 cm and body mass: 75.563.4 kg)completed square-wave transitions to 100% of VO2max from three different conditions: without prior exercise, with priormoderate and heavy exercise. VO2 was measured using a telemetric portable gas analyser (K4b2, Cosmed, Rome, Italy) andthe data were modelled using either mono or double exponential fittings. The use of prior moderate exercise resulted in afaster VO2 pulmonary kinetics response (t1 = 13.4163.96 s), an improved performance in the time to xhaustion(238.8650.2 s) and similar blood lactate concentrations ([La2]) values (11.861.7 mmol.L21) compared to the onditionwithout prior exercise (16.065.56 s, 215.3660.1 s and 10.761.2 mmol.L21, for t1, time sustained at VO2max and [La2], respectively). Performance of prior heavy exercise, although useful in accelerating the VO2 pulmonary kinetics responseduring a subsequent time to exhaustion exercise (t1 = 9.1861.60 s), resulted in a shorter time sustained at VO2max(155.5646.0 s), while [La2] was similar (13.561.7 mmol.L21) compared to the other two conditions. Although both priormoderate and heavy exercise ulted in a faster pulmonary VO2 kinetics response, only prior moderate exercise lead to improved rowing performance.info:eu-repo/semantics/publishedVersio

The effect of prior exercise on the thermic effect of carbohydrate versus fat feeding in man

Prior exercise potentiates the thermic effect of a carbohydrate meal. The purpose of this study was to determine if the potentiating effect of exercise is unique to carbohydrate meals or whether prior exercise also potentiates the thermic effect of a fat meal. Subjects were 15 healthy females (24 years, 60 KG, 20% body fat). Each subject completed an exercise and a control trial for each meal, each trial on a separate day. Meal size was 2510 KJ (600 kcal) and consisted of 100% carbohydrate, compared with 90% fat combined with 10% carbohydrate. Subjects exercised for 45 minutes at 70% of VO{dollar}\sb2{dollar} max on a cycle ergometer. Once VO{dollar}\sb2{dollar} had returned to baseline following exercise, subjects ingested a test meal. As a control, subjects ingested a test meal without prior exercise. The thermic effect of food (TEF) was determined by indirect calorimetry over a 2 hour period following meal ingestion. The thermic effect of the carbohydrate meal was 50% greater than that of the fat meal (p {dollar}\u3c{dollar} 0.05). Thermic effect of food was increased by 59% over control when the carbohydrate meal was ingested after exercise (E = 124 {dollar}\pm{dollar} 19 vs C = 78 {dollar}\pm{dollar} 17 kJ/2hr, P {dollar}\u3c{dollar} 0.01). However, TEF was not increased significantly over control with the fat meal after exercise (E = 75 {dollar}\pm{dollar} vs C = 61 {dollar}\pm{dollar} 10 kJ/2hr). These results suggest that the potentiation of the thermic effect of a meal by prior exercise depends on the composition of the meal, essentially excluding meals consisting primarily of fat

Exercise Alleviates Lipid-Induced Insulin Resistance in Human Skeletal Muscle–Signaling Interaction at the Level of TBC1 Domain Family Member 4

Excess lipid availability causes insulin resistance. We examined the effect of acute exercise on lipid-induced insulin resistance and TBC1 domain family member 1/4 (TBCD1/4)-related signaling in skeletal muscle. In eight healthy young male subjects, 1 h of one-legged knee-extensor exercise was followed by 7 h of saline or intralipid infusion. During the last 2 h, a hyperinsulinemic-euglycemic clamp was performed. Femoral catheterization and analysis of biopsy specimens enabled measurements of leg substrate balance and muscle signaling. Each subject underwent two experimental trials, differing only by saline or intralipid infusion. Glucose infusion rate and leg glucose uptake was decreased by intralipid. Insulin-stimulated glucose uptake was higher in the prior exercised leg in the saline and the lipid trials. In the lipid trial, prior exercise normalized insulin-stimulated glucose uptake to the level observed in the resting control leg in the saline trial. Insulin increased phosphorylation of TBC1D1/4. Whereas prior exercise enhanced TBC1D4 phosphorylation on all investigated sites compared with the rested leg, intralipid impaired TBC1D4 S341 phosphorylation compared with the control trial. Intralipid enhanced pyruvate dehydrogenase (PDH) phosphorylation and lactate release. Prior exercise led to higher PDH phosphorylation and activation of glycogen synthase compared with resting control. In conclusion, lipid-induced insulin resistance in skeletal muscle was associated with impaired TBC1D4 S341 and elevated PDH phosphorylation. The prophylactic effect of exercise on lipid-induced insulin resistance may involve augmented TBC1D4 signaling and glycogen synthase activation

Prior exercise training and experimental myocardial infarction: A systematic review and meta-analysis

Exercising prior to experimental infarction may have beneficial effects on the heart. The objective of this study was to analyze studies on animals that had exercised prior to myocardial infarction and to examine any benefits through a systematic review and meta-analysis. The databases MEDLINE, Google Scholar, and Cochrane were consulted. We analyzed articles published between January 1978 and November 2018. From a total of 858 articles, 13 manuscripts were selected in this review. When animals exercised before experimental infarction, there was a reduction in mortality, a reduction in infarct size, improvements in cardiac function, and a better molecular balance between genes and proteins that exhibit cardiac protective effects. Analyzing heart weight/body weight, we observed the following results - Mean difference 95% CI - -0.02 [-0.61,0.57]. Metaanalysis of the infarct size (% of the left ventricle) revealed a statistically significant decrease in the size of the infarction in animals that exercised before myocardial infarction, in comparison with the sedentary animals -5.05 [-7.68, -2.40]. Analysis of the ejection fraction, measured by echo (%), revealed that animals that exercised before myocardial infarction exhibited higher and statistically significant measures, compared with sedentary animals 8.77 [3.87,13.66]. We conclude that exercise performed prior to experimental myocardial infarction confers cardiac benefits to animals

Dynamics of the power-duration relationship during prolonged endurance exercise and influence of carbohydrate ingestion

This is the author accepted manuscript. The final version is available from the American Physiological Society via the DOI in this recordWe tested the hypotheses that the parameters of the power-duration relationship, estimated as the end-test power (EP) and work done above EP (WEP) during a 3-min all out exercise test (3MT), would be reduced progressively following 40 min, 80 min and 2 h of heavy-intensity cycling, and that carbohydrate (CHO) ingestion would attenuate the reduction in EP and WEP. Sixteen participants completed a 3MT without prior exercise (control), immediately after 40 min, 80 min and 2-h of heavy-intensity exercise while consuming a placebo beverage, and also after 2-h of heavy-intensity exercise while consuming a CHO supplement (60 g/h CHO). There was no difference in EP measured without prior exercise (260 ± 37 W) compared to EP following 40 min (268 ± 39 W) or 80 min (260 ± 40 W) of heavy-intensity exercise; however, after 2-h, EP was 9% lower compared to control (236 ± 47 W; P<0.05). There was no difference in WEP measured without prior exercise (17.9 ± 3.3 kJ) compared to after 40 min of heavy-intensity exercise (16.1 ± 3.3 kJ), but WEP was lower (P<0.05) than control after 80 min (14.7 ± 2.9 kJ) and 2-h (13.8 ± 2.7 kJ). Compared to placebo, CHO ingestion negated the reduction of EP following 2-h of heavy-intensity exercise (254 ± 49 W) but had no effect on WEP (13.5 ± 3.4 kJ). These results reveal a different time course for the deterioration of EP and WEP during prolonged endurance exercise and indicate that EP is sensitive to CHO availability

Prior Exercise Reduces Fast-Start Duration and End-Spurt Magnitude during Cycling Time-Trial

We examined the pacing strategy and the magnitude of the end spurt during a 200-kJ cycling time trial performed 12–14 h after an exercise protocol designed to reduce muscle glycogen content. 9 physically-active men performed 5 familiarization sessions and 2 experimental 200-kJ time trials in either a control condition (CON) or after an exercise protocol performed the previous evening that was designed to induce muscle glycogen depletion (EP). Mean total time was faster and power output was higher in the CON than in the EP (P<0.01). A fast-start was maintained until the 50-kJ section in CON, but only the 25-kJ section for EP (P<0.05). The power outputs during the 50-, 150- and 200-kJ sections, and the magnitude of the end-spurt, were significantly higher for the CON than for the EP condition (P<0.05). There was no significant difference in the rating of perceived exertion (overall feeling and feeling in legs) between conditions. In conclusion, a protocol designed to decrease muscle glycogen stores reduced the duration of the fast-start and the magnitude of the end spurt during a 200-kJ cycling time trial, impairing the overall performance