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1.
A 2 Week Cross-over Intervention with a Low Carbohydrate, High Fat Diet Compared to a High Carbohydrate Diet Attenuates Exercise-Induced Cortisol Response, but Not the Reduction of Exercise Capacity, in Recreational Athletes.
Terink, R, Witkamp, RF, Hopman, MTE, Siebelink, E, Savelkoul, HFJ, Mensink, M
Nutrients. 2021;(1)
Abstract
Low carbohydrate, high fat (LCHF) diets are followed by athletes, but questions remain regarding effects of LCHF on metabolic adaptation, exercise-induced stress, immune function and their time-course. In this cross-over study, 14 recreational male athletes (32.9 ± 8.2 years, VO2max 57.3 ± 5.8 mL/kg/min) followed a two week LCHF diet (<10 En% carbohydrates (CHO), ~75En% Fat) and a two week HC diet (>50 En% CHO), in random order, with a wash-out period of >2 weeks in between. After 2 days and 2 weeks on either diet, participants performed cycle ergometry for 90 min at 60%Wmax. Blood samples for analysis of cortisol, free fatty acids (FFA), glucose and ketones, and saliva samples for immunoglobin A (s-IgA) were collected at different time points before and after exercise. The LCHF diet resulted in higher FFA, higher ketones and lower glucose levels compared to the HC diet (p < 0.05). Exercise-induced cortisol response was higher after 2 days on the LCHF diet (822 ± 215 nmol/L) compared to 2 weeks on the LCHF diet (669 ± 243 nmol/L, p = 0.004) and compared to both test days following the HC diet (609 ± 208 and 555 ± 173 nmol/L, both p < 0.001). Workload was lower, and perceived exertion higher, on the LCHF diet compared to the HC diet on both occasions. A drop in s-IgA following exercise was not seen after 2 days on the LCHF diet, in contrast to the HC diet. In conclusion, the LCHF diet resulted in reduced workload with metabolic effects and a pronounced exercise-induced cortisol response after 2 days. Although indications of adaptation were seen after 2 weeks on the LCHF diet, work output was still lower.
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2.
Effects of carbohydrate ingestion on acute leukocyte, cortisol, and interleukin-6 response in high-intensity long-distance running.
Ihalainen, JK, Vuorimaa, T, Puurtinen, R, Hämäläinen, I, Mero, AA
Journal of strength and conditioning research. 2014;(10):2786-92
Abstract
The purpose of this study was to investigate the effect of ingestion of fluids with different carbohydrate concentrations (0, 1.5, and 7%) on the acute immune stress responses after high-intensity long-distance running. Continuous 18- to 20-km run was performed at 75% of maximal oxygen uptake with carbohydrate supplementation (CHO7%, 7% carbohydrate solution) and low-carbohydrate supplementation (lowCHO1.5%, 1.5% carbohydrate solution) in a randomized, double-blind, placebo (PLA) controlled design. Seven recreational runners (4 men and 3 women) completed all 3 trials. Blood was collected at baseline (PRE) and immediately after the run (POST). The running task induced significant (p ≤ 0.05) increases in leukocyte (white blood cells), neutrophil, and interleukin-6 (IL-6) counts in every trial. There was a significant (p ≤ 0.05) increase in cortisol with PLA and lowCHO1.5% but not with CHO7%. Increase in total leukocyte and neutrophil concentration was significantly lower with CHO7% compared with PLA (p ≤ 0.05). Postexercise IL-6 levels were significantly elevated when compared with baseline in all conditions (p ≤ 0.05). Interleukin-6 (IL-6) concentrations did not differ significantly between trials. LowCHO1.5% sport drink did not significantly differ from PLA in measured variables, which indicated that the amount and rate of carbohydrate ingestion (15 g, 10 g·h) in low-carbohydrate sport drink was not enough to significantly protect from the stress induced by high-intensity long-distance running, whereas the ingestion of CHO7% (45 g·h) blunted the significant cortisol response and significantly decreased the leukocyte response.
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3.
Effects of carbohydrate beverage ingestion on the salivary IgA response to intermittent exercise in the heat.
Sari-Sarraf, V, Doran, DA, Clarke, ND, Atkinson, G, Reilly, T
International journal of sports medicine. 2011;(9):659-65
Abstract
The purpose of this study was to establish if provision of CHO altered the mucosal immune and salivary cortisol responses to intermittent exercise in the heat. In a double-blind design, 10 males undertook soccer-specific intermittent exercise on a motorized treadmill on 2 occasions, each over 90 min and separated by 1 week. During CHO and placebo trials, subjects were given either a carbohydrate solution (3 ml · kg (-1) body weight) or placebo drink, 5 min before the commencement of exercise, at 15, 30 min, at half time, 60 and 75 min into exercise. Salivary flow rate increased throughout the placebo trial and decreased throughout the CHO treatment; the difference between conditions neared statistical significance (P=0.055). Neither s-IgA concentration nor s-IgA to osmolality ratio was affected by 2 conditions or differed at any time-point post-exercise (P>0.05). The s-IgA secretion rate increased, s-IgA to protein ratio decreased post-exercise and salivary cortisol decreased 24 h post-exercise (P<0.05) compared to pre-exercise. Carbohydrate supplementation whilst exercising in the heat, does not influence rating of perceived exertion, thermal sensation, salivary flow rate, s-IgA concentration, s-IgA secretion rate, s-IgA to osmolality ratio or s-IgA to protein ratio and salivary cortisol but heart rate was increased.
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4.
Stress doses of hydrocortisone in septic shock: beneficial effects on opsonization-dependent neutrophil functions.
Kaufmann, I, Briegel, J, Schliephake, F, Hoelzl, A, Chouker, A, Hummel, T, Schelling, G, Thiel, M
Intensive care medicine. 2008;(2):344-9
Abstract
OBJECTIVE To assess the effects of stress doses of hydrocortisone (HC) on clinical parameters and neutrophil functions in patients with septic shock. DESIGN Prospective, double-blind, randomized, placebo-controlled study. SETTING Intensive care units of a university hospital. PATIENTS AND PARTICIPANTS 30 adult patients with septic shock. INTERVENTIONS Patients were allocated to receive either HC (intravenous bolus of 100 mg preceding a continuous infusion 10 mg/h, n = 15) or placebo (n = 15), respectively. The effects of HC were assessed at baseline and after 24 h. MEASUREMENTS AND RESULTS As compared with placebo-treated patients, administration of HC significantly decreased norepinephrine requirements (from 1.5 to 0.8 mg/h; p < 0.001), interleukin-6 serum concentrations (from 388.8 to 88.8 pg/ml; p < 0.02), and the spontaneous release of hydrogen peroxide (H2O2) by neutrophils (-33.0%; p < 0.05). Additionally, HC treatment preserved the autologous plasma-induced amplification of phagocytosis of zymosan particles [factor of opsonin-induced amplification of phagocytosis of unopsonized particles: 1.80 for placebo vs. 1.75 for HC at baseline (not significant between groups) and 0.50 for placebo vs. 1.75 for HC after 24 h of treatment (p < 0.05)]. These effects were paralleled by respective changes in the phagocytosis-associated H2O2 production. CONCLUSIONS In patients with septic shock stress doses of HC exert beneficial effects in terms of improvements in hemodynamics, decrease in pro-inflammatory mediators, and oxidative stress without the compromise of opsonization-dependent phagocytic neutrophil functions; thus, HC treatment does not aggravate non-specific immunosuppression but instead improves innate immunity in the early stage of septic shock.
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5.
Vitamin C supplementation and salivary immune function following exercise-heat stress.
Carrillo, AE, Murphy, RJ, Cheung, SS
International journal of sports physiology and performance. 2008;(4):516-30
Abstract
PURPOSE Prolonged physical exertion and environmental heat stress may elicit postexercise depression of immune cell function, increasing upper respiratory tract infection (URTI) susceptibility. We investigated the effects of acute and short-term vitamin C (VC) compared with placebo (PL) supplementation on URTI susceptibility, salivary immunoglobulin A (s-IgA), and cortisol responses in healthy individuals following prolonged exercise-heat stress. METHODS Twelve participants were randomized into the VC or PL group in a double-blind design. For 12 days, participants consumed 3x500 mg tablets of VC or PL per day, with testing completed at baseline, then following acute (1 d) and short-term (8 d) supplementation. Participants performed 120.1+/-49.6 min of cycling at 54+/-6% VO2max in a hot (34.8+/-1.0 degrees C and 13+/-3% relative humidity) environment, with saliva samples collected at pre-, post-, and 72 h postexercise. Health logs specifying URTI symptoms were completed for 7 days postexercise. RESULTS A 2x3x3 mixed ANOVA with a post hoc Bonferroni correction factor revealed a significant linear trend in postexercise cortisol attenuation in the VC group, 21.7+/-15.1 nmol/L (mean+/-SD) at baseline, to 13.5+/-10.0 at acute, to 7.6+/-4.2 after short term (P=.032). No differences were detected in ratio of s-IgA to protein or URTI symptoms between groups. CONCLUSIONS These data suggest that vitamin C supplementation can decrease postexercise cortisol in individuals performing exercise similar to that of a half-marathon or marathon in hot conditions. However, no changes in s-IgA and URTI were evident, possibly due to previous moderate training and reduced physical and psychological stress compared with athletes participating in ultramarathons.
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6.
The effect of dietary control and carbohydrate supplementation on the immune and hormonal responses to rowing exercise.
Sellar, CM, Syrotuik, DG, Field, CJ, Bell, GJ
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme. 2006;(5):588-96
Abstract
To determine the effect of carbohydrate supplementation on the immune and stress hormone responses to 1 h of strenuous rowing exercise, 22 male subjects were randomly assigned to a placebo (PLA, n = 11) or carbohydrate (CHO, n = 11) group. Subjects completed 3 d of modified dietary intake, a standardized pre-exercise meal, and consumed either a carbohydrate beverage (1 g.kg body mass(-1)) or a non-caloric placebo drink before, during, and after a 1 h rowing trial. Increases were observed in adrenocorticotrophic hormone, cortisol, blood leukocytes, neutrophils, and natural killer cell concentrations and activity, whereas the ability of peripheral blood monouclear cells (PBMCs) to respond (interleukin-2 (IL-2) production) to stimulation was reduced 5 min after exercise in both groups (p < 0.05). Lymphocytes were also elevated, but in the PLA group only (p < 0.05). One hour after exercise, blood leukocytes remained elevated owing to increased neutrophil concentrations, whereas a number of lymphocyte subsets (CD3+, CD3+/4+, CD3+/8+, CD20+, CD25+, CD4+/25+, CD8+/25+) and the ability of PBMCs to respond to stimulation (IL-2, interferon-gamma (IFN-gamma) production) were lower than resting values in both groups (p < 0.05). Carbohydrate supplementation to athletes in the post-prandial state undergoing a 1 h rowing trial resulted in attenuation of the post-exercise increase in peripheral blood lymphocyte concentration, but had little effect on the ability of PBMCs to produce cytokines following stimulation, natural killer cell activity, stress hormone concentrations, exercise performance, or self-reported incidence of illness during the 14 d period following the experimental trial.
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7.
The effects of a high carbohydrate diet on cortisol and salivary immunoglobulin A (s-IgA) during a period of increase exercise workload amongst Olympic and Ironman triathletes.
Costa, RJ, Jones, GE, Lamb, KL, Coleman, R, Williams, JH
International journal of sports medicine. 2005;(10):880-5
Abstract
The present study observed the effects of a 6-day high carbohydrate (H-CHO) diet on salivary cortisol and IgA during a period of increased exercise workload. Thirty-two competitively trained male triathletes were randomly allocated into a self-selected (SS), or an H-CHO (12 g CHO kgbm (-1) . day (-1)) dietary group. In addition to their training regimes, all subjects performed a 1-hour running exercise bout at 70 % V.O (2max) . d (-1), for six days. Saliva samples were taken pre, immediately post, and morning post-exercise bout on days 1, 4, and 6. The concentrations of s-IgA and cortisol were determined by ELISA assays. There was a significant (p < 0.001) interaction between Group x Time for cortisol, with a marked increase in concentrations occurring in the SS dietary group pre to post exercise, and pre to morning post-exercise (p < 0.01). Conversely, a significant (p = 0.009) Group x Time interaction reflected higher post exercise s-IgA concentrations (p < 0.005) than pre exercise in the H-CHO diet group. Blood glucose concentration decreased pre to post exercise in the SS diet group (p < 0.01), whilst remaining stable in the H-CHO group. It is concluded that the consumption of a high CHO diet throughout a 6-day period of overtraining had a favourable effect on markers of immune activity and thereby reduced the susceptibility of these endurance athletes to upper respiratory tract infection URTI.
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8.
Minimal influence of carbohydrate ingestion on the immune response following acute resistance exercise.
Koch, AJ, Potteiger, JA, Chan, MA, Benedict, SH, Frey, BB
International journal of sport nutrition and exercise metabolism. 2001;(2):149-61
Abstract
The effect of carbohydrate supplementation (CHO) on the lymphocyte response to acute resistance exercise was examined in 10 resistance-trained males. Subjects completed a randomized double-blind protocol with sessions separated by 14 days. The exercise session consisted of a high intensity, short rest interval squat workout. Subjects consumed 1.0 g á kg body mass(-1) CHO or an equal volume of placebo (PLC) 10 min prior to and 10 min following exercise. Blood was collected at rest (REST), immediately post exercise (POST), and at 1.5 hours and 4.0 hours of recovery, and analyzed for plasma glucose, serum cortisol, leukocyte subsets, and phytohemagglutinin (PHA)-stimulated lymphocyte proliferation. A significant Treatment 3 Time effect was observed for lymphocyte proliferation between CHO and PLC, but post hoc analyses revealed no between-treatment differences at any post-exercise time point. Lymphocyte proliferation was significantly depressed below REST at POST (-39.2% for PLC, -25.7% for CHO). Significant fluctuations in leukocyte subset trafficking were observed for both treatments at POST, 1.5 hours, and 4.0 hours. Plasma glucose was significantly increased POST in CHO compared to PLC. Cortisol was significantly increased from REST to POST in both treatments. These data support a minimal effect of carbohydrate ingestion on the lymphocyte response to high-intensity resistance exercise.