Effect of carbohydrate-protein supplementation on endurance training adaptations.

PURPOSE: To examine the influence of post-exercise protein feeding upon the adaptive response to endurance exercise training. METHODS: In a randomised parallel group design, 25 healthy men and women completed 6 weeks of endurance exercise training by running on a treadmill for 30-60 min at 70-75% maximal oxygen uptake (VO2max) 4 times/week. Participants ingested 1.6 g per kilogram of body mass (g kg BM-1) of carbohydrate (CHO) or an isocaloric carbohydrate-protein solution (CHO-P; 0.8 g carbohydrate kg BM-1 + 0.8 g protein kg BM-1) immediately and 1 h post-exercise. Expired gas, blood and muscle biopsy samples were taken at baseline and follow-up. RESULTS: Exercise training improved VO2max in both groups (p ≤ 0.001), but this increment was not different between groups either in absolute terms or relative to body mass (0.2 ± 0.2 L min-1 and 3.0 ± 2 mL kg-1 min-1, respectively). No change occurred in plasma albumin concentration from baseline to follow-up with CHO-P (4.18 ± 0.18 to 4.23 ± 0.17 g dL-1) or CHO (4.17 ± 0.17 to 4.12 ± 0.22 g dL-1; interaction: p > 0.05). Mechanistic target of rapamycin (mTOR) gene expression was up-regulated in CHO-P (+ 46%; p = 0.025) relative to CHO (+ 4%) following exercise training. CONCLUSION: Post-exercise protein supplementation up-regulated the expression of mTOR in skeletal muscle over 6 weeks of endurance exercise training. However, the magnitude of improvement in VO2max was similar between groups.

Influence of Post-Exercise Carbohydrate-Protein Ingestion on Muscle Glycogen Metabolism in Recovery and Subsequent Running Exercise.

We examined whether carbohydrate-protein ingestion influences muscle glycogen metabolism during short-term recovery from exhaustive treadmill running and subsequent exercise. Six endurance-trained individuals underwent two trials in a randomized double-blind design, each involving an initial run-to-exhaustion at 70% VO2max (Run-1) followed by 4-h recovery (REC) and subsequent run-to-exhaustion at 70% VO2max (Run-2). Carbohydrate-protein (CHO-P; 0.8 g carbohydrate·kg body mass [BM-1]·h-1 plus 0.4 g protein·kg BM-1·h-1) or isocaloric carbohydrate (CHO; 1.2 g carbohydrate·kg BM-1·h-1) beverages were ingested at 30-min intervals during recovery. Muscle biopsies were taken upon cessation of Run-1, postrecovery and fatigue in Run-2. Time-to-exhaustion in Run-1 was similar with CHO and CHO-P (81 ± 17 and 84 ± 19 min, respectively). Muscle glycogen concentrations were similar between treatments after Run-1 (99 ± 3 mmol·kg dry mass [dm-1]). During REC, muscle glycogen concentrations increased to 252 ± 45 mmol·kg dm-1 in CHO and 266 ± 30 mmol·kg dm-1 in CHO-P (p = .44). Muscle glycogen degradation during Run-2 was similar between trials (3.3 ± 1.4 versus 3.5 ± 1.9 mmol·kg dm-1·min-1 in CHO and CHO-P, respectively) and no differences were observed at the respective points of exhaustion (93 ± 21 versus 100 ± 11 mmol·kg dm-1; CHO and CHO-P, respectively). Similarly, time-to-exhaustion was not different between treatments in Run-2 (51 ± 13 and 49 ± 15 min in CHO and CHO-P, respectively). Carbohydrate-protein ingestion equally accelerates muscle glycogen resynthesis during short-term recovery from exhaustive running as when 1.2 g carbohydrate·kg BM-1·h-1 are ingested. The addition of protein did not alter muscle glycogen utilization or time to fatigue during repeated exhaustive running.

Blood pressure measurement modalities and indexed left ventricular mass in men with low-risk hypertension confirmed by ambulatory monitoring.

BACKGROUND: Blood pressure (BP) measurement modalities such as ambulatory monitoring (ABPM) and noninvasive central aortic systolic pressure (CASP), have been reported to improve prediction of hypertension-mediated organ damage (HMOD) compared with conventional clinic BP. However, clinic BP is often confounded by poor measurement technique and 'white-coat hypertension' (WCH). We compared prediction of cardiac MRI (cMRI)-derived left ventricular mass index (LVMI) by differing BP measurement modalities in young men with elevated BP, confirmed by ABPM. METHODS: One hundred and forty-three treatment-naive men (<55 years) with hypertension confirmed by ABPM and no clinical evidence of HMOD or cardiovascular disease (37% with masked hypertension) were enrolled. Relationships between BP modalities and cMRI-LVMI were evaluated. RESULTS: Men with higher LVMI (upper quintile) had higher clinic, central and ambulatory SBP compared with men with lower LVMI. Regression coefficients for SBP with LVMI did not differ across BP modalities ( r  = 0.32; 0.3; 0.31, for clinic SBP, CASP and 24-h ABPM, respectively, P  < 0.01 all). Prediction for high LVMI using receiver-operated curve analyses was similar between measurement modalities. No relationship between DBP and LVMI was seen across measurement modalities. CONCLUSION: In younger men with hypertension confirmed by ABPM and low cardiovascular risk, clinic SBP and CASP, measured under research conditions, that is, with strict adherence to guideline recommendations, performs as well as ABPM in predicting LVMI. Prior reports of inferiority for clinic BP in predicting HMOD and potentially, clinical outcomes, may be due to poor measurement technique and/or failure to exclude WCH.

The impact of pre-existing hypertension and its treatment on outcomes in patients admitted to hospital with COVID-19.

The impact of pre-existing hypertension on outcomes in patients with the novel corona virus (SARS-CoV-2) remains controversial. To address this, we examined the impact of pre-existing hypertension and its treatment on in-hospital mortality in patients admitted to hospital with Covid-19. Using the CAPACITY-COVID patient registry we examined the impact of pre-existing hypertension and guideline-recommended treatments for hypertension on in-hospital mortality in unadjusted and multi-variate-adjusted analyses using logistic regression. Data from 9197 hospitalised patients with Covid-19 (median age 69 [IQR 57-78] years, 60.6% male, n = 5573) was analysed. Of these, 48.3% (n = 4443) had documented pre-existing hypertension. Patients with pre-existing hypertension were older (73 vs. 62 years, p < 0.001) and had twice the occurrence of any cardiac disease (49.3 vs. 21.8%; p < 0.001) when compared to patients without hypertension. The most documented class of anti-hypertensive drugs were angiotensin receptor blockers (ARB) or angiotensin converting enzyme inhibitors (ACEi) (n = 2499, 27.2%). In-hospital mortality occurred in (n = 2020, 22.0%), with more deaths occurring in those with pre-existing hypertension (26.0 vs. 18.2%, p < 0.001). Pre-existing hypertension was associated with in-hospital mortality in unadjusted analyses (OR 1.57, 95% CI 1.42,1.74), no significant association was found following multivariable adjustment for age and other hypertension-related covariates (OR 0.97, 95% CI 0.87,1.10). Use of ACEi or ARB tended to have a protective effect for in-hospital mortality in fully adjusted models (OR 0.88, 95% CI 0.78,0.99). After appropriate adjustment for confounding, pre-existing hypertension, or treatment for hypertension, does not independently confer an increased risk of in-hospital mortality patients hospitalized with Covid-19.

Pulse Wave Calibration and Implications for Blood Pressure Measurement: Systematic Review and Meta-Analysis.

[Figure: see text].

Impact of Muscle Glycogen Availability on the Capacity for Repeated Exercise in Man.

PURPOSE: This study aims to examine whether muscle glycogen availability is associated with fatigue in a repeated exercise bout following short-term recovery. METHODS: Ten endurance-trained individuals underwent two trials in a repeated-measures experimental design, each involving an initial run to exhaustion at 70% of VO2max (Run 1) followed by a 4-h recovery and a subsequent run to exhaustion at 70% of VO2max (Run 2). A low-carbohydrate (L-CHO; 0.3 g · kg body mass(-1) · h(-1)) or high-carbohydrate (H-CHO; 1.2 g · kg body mass(-1) · h(-1)) beverage was ingested at 30-min intervals during recovery. Muscle biopsies were taken upon cessation of Run 1, after recovery, and at exhaustion during Run 2 in L-CHO (F2). In H-CHO, muscle biopsies were obtained after recovery, at the time point coincident with fatigue in L-CHO (F2), and at the point of fatigue during the subsequent exercise bout (F3). RESULTS: Run 2 was more prolonged for participants on H-CHO (80 ± 16 min) than for participants on L-CHO (48 ± 11 min; P < 0.001). Muscle glycogen concentrations were higher at the end of recovery for participants on H-CHO (269 ± 84 mmol · kg dry mass(-1)) than for participants on L-CHO (157 ± 37 mmol · kg dry mass(-1); P = 0.001). The rate of muscle glycogen degradation during Run 2 was higher with H-CHO (3.1 ± 1.5 mmol · kg dry mass(-1) · min(-1)) than with L-CHO (1.6 ± 1.3 mmol · kg dry mass(-1) · min(-1); P = 0.05). The concentration of muscle glycogen was higher with H-CHO than with L-CHO at F2 (123 ± 28 mmol · kg dry mass(-1); P < 0.01), but no differences were observed between treatments at the respective points of exhaustion (78 ± 22 mmol · kg dry mass(-1) · min(-1 )for H-CHO vs 72 ± 21 mmol · kg dry mass(-1) · min(-1) for L-CHO). CONCLUSION: Increasing carbohydrate intake during short-term recovery accelerates glycogen repletion in previously exercised muscles and thus improves the capacity for repeated exercise. The availability of skeletal muscle glycogen is therefore an important factor in the restoration of endurance capacity because fatigue during repeated exercise is associated with a critically low absolute muscle glycogen concentration.