ORCID Profile
0000-0003-4257-1971
Current Organisation
Deakin University
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Publisher: Springer Science and Business Media LLC
Date: 28-04-2022
DOI: 10.1186/S40798-022-00447-6
Abstract: To assess the test–retest reliability of submaximal cardiorespiratory fitness in healthy active older adults. This was a retrospective analysis of 41 adults enrolled in a clinical trial [mean (sd) aged 59 yrs (7) 29% females and body mass index 24.5 kg/m 2 (3.3)]. Cardiorespiratory fitness was assessed using a cycle ergometer 6 weeks apart. The initial workload was 1 W per kilogram of free fat mass (W/kg FFM) and increased by 0.5 W/kg FFM every 3 min until participants could not maintain the speed at ≥ 60 rpm, they reached a rating of perceived exertion of 15–17, and/or obtained a respiratory exchange ratio (RER) of 1.000. Reliability of $${V}{\\text{O}}_{2}$$ V O 2 , heart rate and RER was assessed for each workload, and for $${V}{\\text{O}}_{2}$$ V O 2 , when RER reached 1.00. Reliability was examined as the intraclass correlation coefficient (ICC (2,1) ), Bland–Altman plots, standard error of measurement (SEM and SEM%), and the minimal detectable change (MDC). Test–retest agreement ranged between (ICC (2,1) 0.44–0.84) with no discernible systematic differences between assessments. The SEM% for absolute and relative $${V}{\\text{O}}_{2}$$ V O 2 ranged between 13.0 to 20.2%, and 13.8 to 26.3%, respectively . The MDC 90 % for absolute and relative $${V}{\\text{O}}_{2}$$ V O 2 ranged between 30.4% to 47.1%, and 32.2% to 61.4%, respectively. The lowest SEMs% and MDCs% for both absolute and relative $${V}{\\text{O}}_{2}$$ V O 2 were observed for workloads at 2.5 W kg/FFM (~ 13% and ~ 31%, respectively). Although at least modest relative reliability was consistently demonstrated, the smaller measurement error associated with absolute and relative $${V}{\\text{O}}_{2}$$ V O 2 at 2.5 W kg/FFM may indirectly suggest that submaximal cardiorespiratory fitness can be monitored more confidently at higher workloads. Findings provide critical information to determine how much change is considered ‘real change’ in repeated measures of cardiorespiratory fitness using a submaximal graded exercise testing protocol in healthy active older adults.
Publisher: Springer Science and Business Media LLC
Date: 17-05-2021
DOI: 10.1186/S40798-021-00323-9
Abstract: Ageing is associated with a decline in skeletal muscle mass and function (strength and power), known as sarcopenia. Inadequate dietary protein and inactivity have been shown to accelerate sarcopenia outcomes, occurring at different rates in males and females. Regardless, active older adults who often exceed the exercise guidelines still show signs of sarcopenia. This study aimed to explore the link between age, physical activity, protein intake, and biological sex with skeletal muscle mass, strength, power, and physical capacity erformance in active older adults. Fifty-four active older adults were recruited from this trial and grouped according to age (middle aged: 50–59 years, and older age: ≥ 60 years), exercise volume (low: ≥ 90–149 min/week, moderate: ≥ 150–299 min/week, and high: ≥ 300 min/week), protein intake (low: 0.8 g/kg body mass (BM), moderate: ≥ 0.8–1.19g /kg BM, and high: ≥ 1.2 g/kg BM), and biological sex (males and females). Skeletal muscle and fat mass (dual X-ray absorptiometry), strength (1-repetition maximum using leg press, chest press, lateral pull down, and hand grip), power (counter movement jump), and general fitness (cardiorespiratory capacity and gait speed) were assessed. Data were grouped based on variables, and a general linear model (ANCOVA) or an independent t test was used to determine between group differences. Fifty three of the total participants’ data were analysed. The middle-aged group had 18%, 11%, and 10% higher leg press, chest press, and lateral pull down, respectively, compared to the older-aged group ( p .05). There were no significant differences between different levels of training volume and any of the outcomes. Higher protein intakes were associated with significantly less body fat mass ( p = .005) and a trend towards a higher leg press ( p = .053) and higher relative power (W/kg) ( p = .056) compared with the moderate and low protein intake groups. Significant differences based on biological sex were observed for all outcomes except for gait speed ( p = .611) and cardiorespiratory fitness ( p = .147). Contributions of age, physical activity, daily protein intake, and biological sex can explain the in idual variation in outcomes related to changes in body composition, strength, power, and/or cardiorespiratory fitness in a cohort of active older adults. The preprint version of this work is available on Research Square: rticle/rs-51873/v1 . This trial is registered in the ANZCTR.org.au, no. ACTRN12618001088235 ( www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=375286 ).
Publisher: American Physiological Society
Date: 05-2019
DOI: 10.1152/JAPPLPHYSIOL.01032.2018
Abstract: It is commonly believed that gastrointestinal issues during exercise are exacerbated by hypohydration. This study aimed to determine the effect of exercise-induced hypohydration on gastrointestinal integrity, function, symptoms, and systemic endotoxin and inflammatory profiles. In a randomized crossover design, male endurance runners ( n = 11) performed 2 h of running at 70% of maximum oxygen uptake in 25°C ambient temperature with water provision [euhydration (EuH)] and total water restriction [hypohydration (HypoH)] during running, which accounted for 0.6 ± 0.6% and 3.1 ± 0.7% body mass loss, respectively. Blood and fecal s les were collected before and after exercise. Breath s les (H 2 determination) were collected and gastrointestinal symptoms (GIS) recorded before, during, and after exercise. HypoH resulted in a higher, yet insignificant, ∆ preexercise to postexercise plasma cortisol concentration (+286 nmol/l vs. +176 nmol/l P = 0.098) but significantly higher intestinal fatty acid-binding protein (I-FABP) (+539 pg/ml vs. +371 pg/ml P = 0.047) concentration compared with EuH. A greater breath H 2 response ( P = 0.026) was observed on HypoH (1,188 ppm/3 h, peak +12 ppm) vs. EuH (579 ppm/3 h, peak +6 ppm). Despite greater GIS incidence on HypoH (82%) vs. EuH (64%), GIS severity scores were not significant between trials. Exercise-induced leukocytosis (overall pre- to postexercise: 5.9 × 10 9 /l to 12.1 × 10 9 /l) was similar on both trials. Depressed in vitro neutrophil function was observed during recovery on HypoH (−36%) but not on EUH (+6%). A pre- to postexercise increase ( P 0.05) was observed for circulating cytokine concentrations but not endotoxin values. Hypohydration during 2 h of running modestly perturbs gastrointestinal integrity and function and increases GIS incidence but does not affect systemic endotoxemia and cytokinemia. NEW & NOTEWORTHY Despite anecdotal beliefs that exercise-induced hypohydration exacerbates perturbations to gastrointestinal status, the present study reports only modest perturbations in gastrointestinal integrity, function, and symptoms compared with euhydration maintenance. Exercise-induced hypohydration does not exacerbate systemic endotoxemia and cytokinemia compared with euhydration maintenance. Programmed water intake to maintain euhydration results in gastrointestinal symptom severity similar to exercise-induced hypohydration. Maintaining euhydration during exertional stress prevents the exercise-associated depression in bacterially stimulated neutrophil function.
Publisher: Frontiers Media SA
Date: 17-03-2021
Abstract: The study aimed to investigate the independent and combined effects of consuming a high-protein dairy milk beverage, twice daily, with or without a progressive resistance training (PRT) program on outcomes of age-related sarcopenia, in healthy active older (≥50 years) adults. In this 12-week, 2 × 2 factorial study, participants were randomly allocated into one of four groups: dairy milk beverage (DM), exercise and dairy milk beverage (EX+DM), exercise alone (EX), and control (CON). The EX group underwent a 12-week whole-body PRT schedule (three sessions/week) and a high-protein dairy milk beverage (DM) was consumed twice daily (30 g protein/day). At weeks 0, 6, and 12, body composition (iDXA), strength [one-repetition maximum (1RM): leg press, chest press, lateral ( lat ) pull-down, and handgrip], power (countermovement jump), cardiorespiratory fitness ( V O 2 ), and physical performance (gait speed) were measured. Before measurements, blood s les were collected to determine the immune (i.e., leukocyte trafficking and inflammatory cytokines) and hormonal (i.e., insulin, cortisol, IGF-1, testosterone, and estradiol) profiles. Participants ( n = 37) completed the study within the controlled experimental conditions. Protein intake increased in the EX+DM [mean ± SD, 1.2 ± 0.2 to 1.8 ± 0.4 g/kg body mass (BM) per day −1 ] and DM (1.3 ± 0.5 to 1.8 ± 0.6 g kg −1 BM day −1 ) groups during the intervention. Absolute fat-free mass increased in the EX+DM [mean (95% confidence interval) = 0.65 (0.25–1.0) kg] and EX [0.49 (−0.44 to 1.40) kg] groups ( P & 0.001) compared to DM [−0.54 (−1.6 to 0.05) kg]. Relative fat mass decreased (group * time, P = 0.018) in DM [−1.8% (−3.3 to −0.35%)] and EX+DM [−1.3% (−2.3 to −0.31%)], which was a greater reduction than that in the CON [0.10% (−0.80 to 1.0%)] group (P & 0.01). Relative maximal strength increased in both the EX and EX+DM (≥35%, P & 0.05) groups, but not in the DM and CON groups. The change in 1RM strength outcomes was higher in EX+DM compared to all other groups (53–78%, P & 0.01). There was an increase in resting plasma IL-10 concentration in EX+DM (88%), compared to all the other groups ( P = 0.016). No other differences in systemic inflammatory cytokines were observed. There were no significant changes in all hormone concentrations measured among all groups. In conclusion, a high-protein dairy milk beverage providing additional protein did not further enhance the effects of PRT on outcomes of fat-free mass, power, or physical performance. However, there was a significant augmentative effect for high-protein dairy milk consumption on changes to maximal strength outcomes during PRT in healthy active older adults.
Publisher: Human Kinetics
Date: 07-2020
Abstract: The study aimed to determine the impact of a dairy milk recovery beverage immediately after endurance exercise on leukocyte trafficking, neutrophil function, and gastrointestinal tolerance markers during recovery. Male runners ( N = 11) completed two feeding trials in randomized order, after 2 hr of running at 70% , fluid restricted, in temperate conditions (25 °C, 43% relative humidity). Immediately postexercise, the participants received a chocolate-flavored dairy milk beverage equating to 1.2 g/kg body mass carbohydrate and 0.4 g/kg body mass protein in one trial, and water volume equivalent in another trial. Venous blood and breath s les were collected preexercise, postexercise, and during recovery to determine the leukocyte counts, plasma intestinal fatty acid binding protein, and cortisol concentrations, as well as breath H 2 . In addition, 1,000 µl of whole blood was incubated with 1 μg/ml Escherichia coli lipopolysaccharide for 1 hr at 37 °C to determine the stimulated plasma elastase concentration. Gastrointestinal symptoms and feeding tolerance markers were measured preexercise, every 15 min during exercise, and hourly postexercise for 3 hr. The postexercise leukocyte (mean [95% confidence interval]: 12.7 [11.6, 14.0] × 10 9 /L [main effect of time, MEOT] p .001) and neutrophil (10.2 [9.1, 11.5] × 10 9 /L p .001) counts, as well as the plasma intestinal fatty acid binding protein (470 pg/ml +120% p = .012) and cortisol (236 nMol/L +71% p = .006) concentrations, were similar throughout recovery for both trials. No significant difference in breath H 2 and gastrointestinal symptoms was observed between trials. The total (Trial × Time, p = .025) and per cell (Trial × Time, p = .001) bacterially stimulated neutrophil elastase release was greater for the chocolate-flavored dairy milk recovery beverage (+360% and +28%, respectively) in recovery, compared with the water trial (+85% and −38%, respectively). Chocolate-flavored dairy milk recovery beverage consumption immediately after exercise prevents the decrease in neutrophil function during the recovery period, and it does not account for substantial malabsorption or gastrointestinal symptoms over a water volume equivalent.
Publisher: Elsevier BV
Date: 2020
No related grants have been discovered for Zoya Huschtscha.