The Effects of Acute Ingestion of a High-fat Solution, compared to a High-Carbohydrate Solution, on Skeletal Muscle Oxygenation, Fat Oxidation and Performance During a 2-hour Cycling Effort Followed by a Short Time Trial in Cyclists and Triathletes

This study aimed to determine the effects of consuming a high fat solution (HFS) compared to a high carbohydrate solution (HCS) during a cycling effort on substrate oxidation, muscle oxygenation and performance with cyclists and triathletes. Thirteen men participated in this study (age: 30.4 ± 6.3 y; height: 178.7 ± 6.1 cm; weight: 74.9 ± 6.5 kg; V̇O2 peak: 60.5 ± 7.9 mlO2×kg-1×min-1). The solutions were isocaloric (total of 720 kcal) and were consumed every 20 minutes. Each solution of HFS contained 12.78 g of lipids, 1.33 g of carbohydrates and 0.67 g of proteins, and each solution of HCS contained 28 g of carbohydrates. We measured pulmonary oxygen consumption and skeletal muscle oxygenation, using a Near Infrared Spectrometer (NIRS) during a cycling effort consisting of 2 hours at 65 % of maximal aerobic power (MAP) followed immediately by a 3-minute time-trial (TT). We observed that the consumption of the HFS increased the rate of fat oxidation at the end of the sub-maximal effort (0.61 ± 0.14 vs 0.53 ± 0.17 g×min-1, p < 0.05). We have also shown that the HFS negatively affected the performance in the TT (mean Watts: HCS: 347.0 ± 77.4 vs HFS: 326.5 ± 88.8 W; p < 0.05) and the rating of perceived exertions during the sub-maximal effort (modified Borg Perceived Exertion scale: 1–10) (mean: 3.62 ± 0.58 for HCS vs 4.16 ± 0.62 for HFS; p < 0.05). We did not observe a significant effect of the acute consumption of the HFS compared to the HCS on muscle oxygenation during the cycling effort. Finally, we observed that cyclists who demonstrated a high skeletal muscle deoxygenation relative to their pulmonary oxygen consumption (DHHb/V̇O2) had a higher fat oxidation capacity (higher Fatmax). In conclusion, even though the consumption of HFS increased the rate of fat oxidation at the end of a sub-maximal effort, it did not affect muscle oxygenation and it negatively affected performance and perceived exertion during a time-trial and caused gastro-intestinal distress in some participants. Keywords: Fat oxidation, Skeletal muscle oxygenation, Lipid supplementation, Carbohydrate supplementation, Near Infrared Spectroscopy (NIRS), Cycling, Triathlon.

Oral Carbohydrate Administration in Patients Undergoing Cephalomedullary Nailing for Proximal Femur Fractures: An Analysis of Clinical Outcomes and Patient Satisfaction

Purpose: The purpose of this study was to investigate the clinical effects of oral carbohydrate intake for cephalomedullary nailing on proximal femoral fractures and patient satisfaction. Subjects and Methods: 88 patients were admitted to our hospital with proximal femoral fracture from July 2019 to December 2019. All patients were treated with closed reduction and internal fixation (CR&IF, Cephalomedullary nailing) under spinal anesthesia. The exclusion criteria included the presence of endocrine disorders including diabetes mellitus (DM), patients treated with steroids, and cognitive impairment. Additionally, those with fasting blood glucose levels above 126 mg / dl or HbA1C> 6.5% were considered as having undiagnosed DM. After obtaining informed consent, the subjects were randomized into either the preoperative oral carbohydrate (POC) group or control group. Patients who were assembled into the control group fasted including water from midnight of the day of the surgical procedure according to the conventional method. Patients assembled into the POC group received 400 ml of oral carbohydrate solution (Nucare NONPO, DAESANG, 12.8%, 1 kcal/ml)) between 21-24 hours on the day before operation and 400 ml oral carbohydrate solution 2 hours before the administration of anesthesia. Serum glucose on the day before operation at 7 am (before breakfast, baseline), immediately before anesthesia, at skin incision, 1 hour, 4 hours, 6 hours, 24 hours after anesthesia, and 3 days after surgery (before breakfast) was measured, and insulin, cortisol, and IL-6 were measured at baseline 7 am at day before operation, immediately before anesthesia, 4 hours and 24 hours after anesthesia, and 3 days after surgery (before breakfast). The patients completed questionnaires about their satisfaction (thirst, hunger, nausea and vomiting, and anxiety) in the morning (before the surgery) on the day of the surgery. Additionally, the length of hospital stay (LOS) and preoperative opioid usage was also investigated. Results: The operative characteristics of the patients did not differ between the groups except for the actual fasting time. The glucose levels were higher in the control group at skin incision; however, there were no significant differences in both groups at other time points. Additionally, insulin, insulin resistance, cortisol, and IL-6 also did not differ significantly between the 2 groups at all time-points. Among the factors related to patient satisfaction, the POC group showed significantly higher scores for thirst and hunger factors and shorter LOS than the control group. Conclusion: The intake of oral carbohydrates in patients treated with closed reduction and internal fixation for proximal femoral fractures does not affect the improvement of post-operative insulin resistance. However, there was significant improvement in patients’ thirst and hunger before surgery and LOS.

Quinine Ingestion During the Latter Stages of a 3,000-m Time Trial Fails to Improve Cycling Performance

The ingestion of quinine, a bitter tastant, improves short-term (30 s) cycling performance, but it is unclear whether this effect can be integrated into the last effort of a longer race. The purpose of this study was to determine whether midtrial quinine ingestion improves 3,000-m cycling time-trial (TT) performance. Following three familiarization TTs, 12 well-trained male cyclists (mean ± SD: mass = 76.6 ± 9.2 kg, maximal aerobic power = 390 ± 50 W, maximal oxygen uptake = 4.7 ± 0.6 L/min) performed four experimental 3,000-m TTs on consecutive days. This double-blind, crossover design study had four randomized and counterbalanced conditions: (a) Quinine 1 (25-ml solution, 2 mM of quinine); (b) Quinine 2, replicate of Quinine 1; (c) a 25-ml sweet-tasting no-carbohydrate solution (Placebo); and (d) 25 ml of water (Control) consumed at the 1,850-m point of the TT. The participants completed a series of perceptual scales at the start and completion of all TTs, and the power output was monitored continuously throughout all trials. The power output for the last 1,000 m for all four conditions was similar: mean ± SD: Quinine 1 = 360 ± 63 W, Quinine 2 = 367 ± 63 W, Placebo = 364 ± 64 W, and Control = 367 ± 58 W. There were also no differences in the 3,000-m TT power output between conditions. The small perceptual differences between trials at specific 150-m splits were not explained by quinine intake. Ingesting 2 mM of quinine during the last stage of a 3,000-m TT did not improve cycling performance.

Effects of supplementing with an 18% carbohydrate-hydrogel drink versus a placebo during whole-body exercise in −5 °C with elite cross-country ski athletes: a crossover study

Background Whilst the ergogenic effects of carbohydrate intake during prolonged exercise are well-documented, few investigations have studied the effects of carbohydrate ingestion during cross-country skiing, a mode of exercise that presents unique metabolic demands on athletes due to the combined use of large upper- and lower-body muscle masses. Moreover, no previous studies have investigated exogenous carbohydrate oxidation rates during cross-country skiing. The current study investigated the effects of a 13C-enriched 18% multiple-transportable carbohydrate solution (1:0.8 maltodextrin:fructose) with additional gelling polysaccharides (CHO-HG) on substrate utilization and gastrointestinal symptoms during prolonged cross-country skiing exercise in the cold, and subsequent double-poling time-trial performance in ~ 20 °C. Methods Twelve elite cross-country ski athletes (6 females, 6 males) performed 120-min of submaximal roller-skiing (69.3 ± 2.9% of $$ \dot{\mathrm{V}} $$V̇O2peak) in −5 °C while receiving either 2.2 g CHO-HG·min− 1 or a non-caloric placebo administered in a double-blind, randomized manner. Whole-body substrate utilization and exogenous carbohydrate oxidation was calculated for the last 60 min of the submaximal exercise. The maximal time-trial (2000 m for females, 2400 m for males) immediately followed the 120-min submaximal bout. Repeated-measures ANOVAs with univariate follow-ups were conducted, as well as independent and paired t-tests, and significance was set at P < 0.05. Data are presented as mean ± SD. Results Exogenous carbohydrate oxidation contributed 27.6 ± 6.6% to the total energy yield with CHO-HG and the peak exogenous carbohydrate oxidation rate reached 1.33 ± 0.27 g·min− 1. Compared to placebo, fat oxidation decreased by 9.5 ± 4.8% with CHO-HG, total carbohydrate oxidation increased by 9.5 ± 4.8% and endogenous carbohydrate utilization decreased by 18.1 ± 6.4% (all P < 0.05). No severe gastrointestinal symptoms were reported in either trial and euhydration was maintained in both trials. Time-trial performance (8.4 ± 0.4 min) was not improved following CHO-HG compared to placebo (− 0.8 ± 3.5 s; 95% confidence interval − 3.0 to 1.5 s; P = 0.46). No sex differences were identified in substrate utilization or relative performance. Conclusions Ingestion of an 18% multiple-transportable carbohydrate solution with gelling polysaccharides was found to be well-tolerated during 120 min of submaximal whole-body exercise, but did not improve subsequent maximal double-poling performance.

PRE-OPERATIVE FASTING: WHY ABBREVIATE?

ABSTRACT Introduction : Considering the practice of preoperative fasting based on observations on the gastric emptying delay after induction and the time of this fast is closely linked to organic response to trauma, arise the question about preoperative fasting period necessary to minimize such response and support the professional with clinical and scientific evidence. Aim : To review the aspects related to the abbreviation of preoperative fasting from the metabolic point of view, physiology of gastric emptying, its clinical benefits and the currently recommendations. Method : Literature review was based on articles and guidelines published in English and Portuguese, without restriction of time until January 2017, in PubMed, SciELO and Cochrane with the descriptors: surgery, preoperative fasting, carbohydrate. From the universe consulted, 31 articles were selected. Results : The literature suggests that the abbreviation of fasting with beverage added carbohydrates until 2 h before surgery, can bring benefits on glycemic and functional parameters, reduces hospitalization, and does not present aspiration risk of healthy patients undergoing elective surgery. Another nutrient that has been added to the carbohydrate solution and has shown promising results is glutamine. Conclusion : The abbreviation of preoperative fasting with enriched beverage with carbohydrates or carbohydrate and glutamine seems to be effective in the care of the surgical patient, optimizing the recovery from of postoperative period.