17 research outputs found
A measure of dietary protein requirement in endurance trained women : a thesis submitted in the partial fulfilment of the requirements for the degree of Master of Science in Sport and Exercise Science, Massey University, (Wellington, New Zealand)
No full textPurpose: Inference from dietary surveys and experimental models suggest that the female endurance athlete dietary protein requirement is 15-20% less than their male counterparts, but to date empirical measurement of the habitual protein requirement has not been undertaken. Methods: 72-h nitrogen balance (NBAL) was determined in 10 female cyclists training 10.8 h·w-1 (SD: 2.82), following two habituated protein intakes: a) a diet representing normal habitual intake (NH) (Protein: 85g.d-1 Energy: 9078kJ·d-1), b) an isolcaloric high-protein diet (HP) (Protein: 166g·d-1, Energy: 8909kJ·d-1). Total 72-h nitrogen intake was determined from Leco total combustion analysis from samples of the ingested food items, while total loss was determined from micro-kjeldahl analysis of total 72-h urine, urea nitrogen concentration of regional resting and exercise sweat sampling, and literature-based estimates of fecal and miscellaneous nitrogen losses. Habituated protein requirement was estimated by the mean regression of the two estimates of 72-h nitrogen balance vs. nitrogen intake. Results: Mean (SD) 24-h dietary protein intake during the 72-h sampling period was NH: 85 (11g), HP: 166 (19g). Mean 24-h urinary nitrogen during the NH and HP blocks were 13.19 (2.39 g·d-1) and 21.53 (3.94 g·d-1) respectively. Sweat urea nitrogen excretion was NH: 0.33 (0.08 g·d-1) and HP: 0.54 (0.12 g·d-1). Normal habitual and high-protein intakes resulted in a mean negative and positive nitrogen balance, respectively (mean ± SD) (NH: -0.59 ± 1.64, HP: 2.69 ± 3.09). Estimated mean protein requirement to achieve NBAL was calculated to be 1.63 g·kg-1·d-1 (95% confidence interval: 1.14–3.77). Conclusions: Our data shows that the dietary protein requirement for well-trained females taking part in daily moderate intensity and duration endurance training is within the range of measured requirement for similarly trained men and suggests that the current estimated range of protein requirement for females may be inadequate
Multiple-transportable Carbohydrate Has Minimal Impact On Long-distance Triathlon Race Performance
No full text
Dietary thiols in exercise: oxidative stress defence, exercise performance, and adaptation
No full textEndurance athletes are susceptible to cellular damage initiated by excessive levels of aerobic exercise-produced reactive oxygen species (ROS). Whilst ROS can contribute to the onset of fatigue, there is increasing evidence that they play a crucial role in exercise adaptations. The use of antioxidant supplements such as vitamin C and E in athletes is common; however, their ability to enhance performance and facilitate recovery is controversial, with many studies suggesting a blunting of training adaptations with supplementation. The up-regulation of endogenous antioxidant systems brought about by exercise training allows for greater tolerance to subsequent ROS, thus, athletes may benefit from increasing these systems through dietary thiol donors. Recent work has shown supplementation with a cysteine donor (N-acetylcysteine; NAC) improves antioxidant capacity by augmenting glutathione levels and reducing markers of oxidative stress, as well as ergogenic potential through association with delayed fatigue in numerous experimental models. However, the use of this, and other thiol donors may have adverse physiological effects. A recent discovery for the use of a thiol donor food source, keratin, to potentially enhance endogenous antioxidants may have important implications for endurance athletes hoping to enhance performance and recovery without blunting training adaptations.FALS
Addicted To Winning: Can Nicotine Administration Improve 1-h Cycling Time-trial Performance?
No full textNicotine Supplementation Does Not Influence Performance of a 1h Cycling Time-Trial in Trained Males
No full textThe use of nicotine amongst professional and elite athletes is high, with anecdotal evidence indicating increased prevalence amongst cycling sports. However, previous investigations into its effects on performance have not used high-validity or -reliability protocols nor trained cyclists. Therefore, the present study determined whether nicotine administration proved ergogenic during a ∼1 h self-paced cycling time-trial (TT). Ten well-trained male cyclists (34 ± 9 years; 71 ± 8 kg; O2max: 71 ± 6 ml ⋅ kg−1 ⋅ min−1) completed three work-dependent TT following ∼30 min administration of 2 mg nicotine gum (GUM), ∼10 h administration of 7 mg ⋅ 24 h−1 nicotine patch (PAT) or color- and flavor-matched placebos (PLA) in a randomized, crossover, and double blind design. Measures of nicotine’s primary metabolite (cotinine), core body temperature, heart rate, blood biochemistry (pH, HCO3−, La−) and Borg’s rating of perceived exertion (RPE) accompanied performance measures of time and power output. Plasma concentrations of cotinine were highest for PAT, followed by GUM, then PLA, respectively (p < 0.01). GUM and PAT resulted in no significant improvement in performance time compared to PLA (62.9 ± 4.1 min, 62.6 ± 4.5 min, and 63.3 ± 4.1 min, respectively; p = 0.73), with mean power outputs of 264 ± 31, 265 ± 32, and 263 ± 33 W, respectively (p = 0.74). Core body temperature was similar between trials (p = 0.33) whilst HR averaged 170 ± 10, 170 ± 11, and 171 ± 11 beats ⋅ min−1 (p = 0.60) for GUM, PAT, and PLA, respectively. There were no differences between trials for any blood biochemistry (all p > 0.46) or RPE with mean values of 16.7 ± 0.9, 16.8 ± 0.7, and 16.8 ± 0.8 (p = 0.89) for GUM, PAT, and PLA, respectively. In conclusion: (i) nicotine administration, whether via gum or transdermal patch, did not exert an ergogenic or ergolytic effect on self-paced cycling performance of ∼1 h; (ii) systemic delivery of nicotine was greatest when using a transdermal patch; and (iii) nicotine administration did not alter any of the psycho-physiological measures observed
Correction: Epidemiology and outcomes of early-onset AKI in COVID-19-related ARDS in comparison with non-COVID-19-related ARDS: insights from two prospective global cohort studies (Critical Care, (2023), 27, 1, (3), 10.1186/s13054-022-04294-5)
No full textFollowing publication of the original article [1], the authors identified that the collaborating authors part of the collaborating author group CCCC Consortium was missing. The collaborating author group is available and included as Additional file 1 in this article
Association of Country Income Level With the Characteristics and Outcomes of Critically Ill Patients Hospitalized With Acute Kidney Injury and COVID-19
No full textIntroduction
Acute kidney injury (AKI) has been identified as one of the most common and significant problems in hospitalized patients with COVID-19. However, studies examining the relationship between COVID-19 and AKI in low- and low-middle income countries (LLMIC) are lacking. Given that AKI is known to carry a higher mortality rate in these countries, it is important to understand differences in this population.
Methods
This prospective, observational study examines the AKI incidence and characteristics of 32,210 patients with COVID-19 from 49 countries across all income levels who were admitted to an intensive care unit during their hospital stay.
Results
Among patients with COVID-19 admitted to the intensive care unit (ICU), AKI incidence was highest in patients in LLMIC, followed by patients in upper-middle income countries (UMIC) and high-income countries (HIC) (53%, 38%, and 30%, respectively), whereas dialysis rates were lowest among patients with AKI from LLMIC and highest among those from HIC (27% vs. 45%). Patients with AKI in LLMIC had the largest proportion of community-acquired AKI (CA-AKI) and highest rate of in-hospital death (79% vs. 54% in HIC and 66% in UMIC). The association between AKI, being from LLMIC and in-hospital death persisted even after adjusting for disease severity.
Conclusions
AKI is a particularly devastating complication of COVID-19 among patients from poorer nations where the gaps in accessibility and quality of healthcare delivery have a major impact on patient outcomes
The value of open-source clinical science in pandemic response: lessons from ISARIC
No full textInternational audienc
An appraisal of respiratory system compliance in mechanically ventilated covid-19 patients
No full textInternational audienceAbstract Background Heterogeneous respiratory system static compliance ( C RS ) values and levels of hypoxemia in patients with novel coronavirus disease (COVID-19) requiring mechanical ventilation have been reported in previous small-case series or studies conducted at a national level. Methods We designed a retrospective observational cohort study with rapid data gathering from the international COVID-19 Critical Care Consortium study to comprehensively describe C RS —calculated as: tidal volume/[airway plateau pressure-positive end-expiratory pressure (PEEP)]—and its association with ventilatory management and outcomes of COVID-19 patients on mechanical ventilation (MV), admitted to intensive care units (ICU) worldwide. Results We studied 745 patients from 22 countries, who required admission to the ICU and MV from January 14 to December 31, 2020, and presented at least one value of C RS within the first seven days of MV. Median (IQR) age was 62 (52–71), patients were predominantly males (68%) and from Europe/North and South America (88%). C RS , within 48 h from endotracheal intubation, was available in 649 patients and was neither associated with the duration from onset of symptoms to commencement of MV ( p = 0.417) nor with PaO 2 /FiO 2 ( p = 0.100). Females presented lower C RS than males (95% CI of C RS difference between females-males: − 11.8 to − 7.4 mL/cmH 2 O p < 0.001), and although females presented higher body mass index (BMI), association of BMI with C RS was marginal ( p = 0.139). Ventilatory management varied across C RS range, resulting in a significant association between C RS and driving pressure (estimated decrease − 0.31 cmH 2 O/L per mL/cmH 2 0 of C RS , 95% CI − 0.48 to − 0.14, p < 0.001). Overall, 28-day ICU mortality, accounting for the competing risk of being discharged within the period, was 35.6% (SE 1.7). Cox proportional hazard analysis demonstrated that C RS (+ 10 mL/cm H 2 O) was only associated with being discharge from the ICU within 28 days (HR 1.14, 95% CI 1.02–1.28, p = 0.018). Conclusions This multicentre report provides a comprehensive account of C RS in COVID-19 patients on MV. C RS measured within 48 h from commencement of MV has marginal predictive value for 28-day mortality, but was associated with being discharged from ICU within the same period. Trial documentation: Available at https://www.covid-critical.com/study . Trial registration : ACTRN12620000421932
