• Appetite and gut hormone responses to moderate-intensity continuous exercise versus high-intensity interval exercise, in normoxic and hypoxic conditions

      Bailey, Daniel Paul; Smith, Lindsey Rachel; Chrismas, Bryna C.; Taylor, Lee; Stensel, David J.; Deighton, Kevin; Douglas, Jessica A.; Kerr, Catherine J.; University of Bedfordshire; Oxford Brookes University; et al. (Elsevier, 2015-06)
      This study investigated the effects of continuous moderate-intensity exercise (MIE) and high-intensity interval exercise (HIIE) in combination with short exposure to hypoxia on appetite and plasma concentrations of acylated ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). Twelve healthy males completed four, 2.6 h trials in a random order: (1) MIE-normoxia, (2) MIE-hypoxia, (3) HIIE-normoxia, and (4) HIIE-hypoxia. Exercise took place in an environmental chamber. During MIE, participants ran for 50 min at 70% of altitude-specific maximal oxygen uptake (View the MathML sourceV˙O2max) and during HIIE performed 6 × 3 min running at 90% View the MathML sourceV˙O2max interspersed with 6 × 3 min active recovery at 50% View the MathML sourceV˙O2max with a 7 min warm-up and cool-down at 70% View the MathML sourceV˙O2max (50 min total). In hypoxic trials, exercise was performed at a simulated altitude of 2980 m (14.5% O2). Exercise was completed after a standardised breakfast. A second meal standardised to 30% of participants' daily energy requirements was provided 45 min after exercise. Appetite was suppressed more in hypoxia than normoxia during exercise, post-exercise, and for the full 2.6 h trial period (linear mixed modelling, p < 0.05). Plasma acylated ghrelin concentrations were lower in hypoxia than normoxia post-exercise and for the full 2.6 h trial period (p < 0.05). PYY concentrations were higher in HIIE than MIE under hypoxic conditions during exercise (p = 0.042). No differences in GLP-1 were observed between conditions (p > 0.05). These findings demonstrate that short exposure to hypoxia causes suppressions in appetite and plasma acylated ghrelin concentrations. Furthermore, appetite responses to exercise do not appear to be influenced by exercise modality.
    • The association between cardiorespiratory fitness and cardiometabolic risk in children is mediated by abdominal adiposity: the HAPPY study

      Bailey, Daniel Paul; Savory, Louise A.; Denton, Sarah J.; Kerr, Catherine J.; University of Bedfordshire; Newcastle University; Oxford Brookes University (Human Kinetics, 2014-10-13)
      Background: It is unclear whether cardiorespiratory fitness (CRF) is independently linked to cardiometabolic risk in children. This study investigated a) the association between CRF level and presence of cardiometabolic risk disorders using health-related cut points, and b) whether these associations were mediated by abdominal adiposity in children. Methods: This was a cross-sectional design study. Anthropometry, biochemical parameters and CRF were assessed in 147 schoolchildren (75 girls) aged 10-14 years. CRF was determined using a maximal cycle ergometer test. Children were classified as ‘fit’ or ‘unfit’ according to published thresholds. Logistic regression was used to investigate the odds of having individual and clustered cardiometabolic risk factors according to CRF level and whether abdominal adiposity mediated these associations. Results: Children classified as unfit had increased odds of presenting individual and clustered cardiometabolic risk factors (p < 0.05), but these associations no longer remained after adjusting for abdominal adiposity (p > 0.05). Conclusions: This study suggests that the association between CRF and cardiometabolic risk is mediated by abdominal adiposity in 10-14 year-old children and that abdominal adiposity may be a more important determinant of adverse cardiometabolic health in this age group.
    • Associations between cardiorespiratory fitness, physical activity and clustered cardiometabolic risk in children and adolescents: the HAPPY study

      Bailey, Daniel Paul; Boddy, Lynne M.; Savory, Louise A.; Denton, Sarah J.; Kerr, Catherine J.; University of Bedfordshire (2012-03-15)
      Clustering of cardiometabolic risk factors can occur during childhood and predisposes individuals to cardiometabolic disease. This study calculated clustered cardiometabolic risk in 100 children and adolescents aged 10-14 years (59 girls) and explored differences according to cardiorespiratory fitness (CRF) levels and time spent at different physical activity (PA) intensities. CRF was determined using a maximal cycle ergometer test, and PA was assessed using accelerometry. A cardiometabolic risk score was computed as the sum of the standardised scores for waist circumference, blood pressure, total cholesterol/high-density lipoprotein ratio, triglycerides and glucose. Differences in clustered cardiometabolic risk between fit and unfit participants, according to previously proposed health-related threshold values, and between tertiles for PA subcomponents were assessed using ANCOVA. Clustered risk was significantly lower (p < 0.001) in the fit group (mean 1.21 ± 3.42) compared to the unfit group (mean -0.74 ± 2.22), while no differences existed between tertiles for any subcomponent of PA. Conclusion These findings suggest that CRF may have an important cardioprotective role in children and adolescents and highlights the importance of promoting CRF in youth.
    • Breaking up prolonged sitting with light-intensity walking improves postprandial glycemia, but breaking up sitting with standing does not

      Bailey, Daniel Paul; Locke, Christopher D.; University of Bedfordshire (Elsevier, 2015-05)
      Objectives: To explore the effects of breaking up prolonged sitting time with standing or light-intensity walking on a range of cardiometabolic risk markers. Design: A randomised three-period, three-treatment acute crossover trial. Methods: Ten non-obese adults took part in three trials: (1) uninterrupted sitting; (2) seated with 2-min bouts of standing every 20 min; and (3) seated with 2-min bouts of light-intensity walking every 20 min. Two standardised test drinks (total 80.3 carbohydrate, 50 g fat) were provided after an initial 1-h period of uninterrupted sitting. Plasma glucose and blood pressure were assessed hourly to calculate area under the curve. Total cholesterol, HDL, and triglycerides were assessed at baseline and 5-h. ANOVAs were used to explore between-trial differences. Results: Glucose area under the curve was lower in the activity-break condition compared to the uninterrupted sitting and standing-break conditions: mean area under the curve 18.5 (95% CI 17, 20), 22.0 (20.5, 23.5), and 22.2 (20.7, 23.7) mmol L/5-h, respectively, p < 0.001; no difference between uninterrupted sitting and standing-break conditions (p > 0.05). Systolic and diastolic blood pressure area under the curve did not differ significantly between conditions, nor did responses in lipid parameters (p > 0.05). Conclusions: This study suggests that interrupting sitting time with frequent brief bouts of light-intensity activity, but not standing, imparts beneficial postprandial responses that may enhance cardiometabolic health. These findings may have importance in the design of effective interventions to reduce cardiometabolic disease risk.
    • The mediating influence of unconditional self-acceptance and labile self-esteem on the relationship between multidimensional perfectionism and exercise dependence

      Hall, Howard K.; Hill, Andrew P.; Appleton, Paul Richard; Kozub, Stephen A.; University of Bedfordshire (2009)
    • Oxidant stress in healthy normal-weight, overweight, and obese individuals.

      Brown, Louise A.; Kerr, Catherine J.; Whiting, Paul; Finer, Nicholas; McEneny, Jane; Ashton, Tony; University of Bedfordshire (2009-03)
      This study was undertaken to investigate the association among BMI and lipid hydroperoxide (LH), total antioxidant status (TAS), superoxide dismutase (SOD), and reduced glutathione (GSH). Ninety (n = 90) healthy males and females (n = 23/67) (29 normal weight (BMI: 22.74 +/- 0.25 kg/m(2)), 36 overweight (BMI: 27.18 +/- 0.23 kg/m(2)), and 25 obese (33.78 +/- 0.48 kg/m(2))) participated in the study. Data collected included anthropometric measures, fasting blood glucose, lipid profile, LH, TAS, and enzymatic antioxidants (SOD, and reduced GSH). The results of the study showed that obese individuals had significantly increased LH levels compared to normal-weight individuals (obese vs. normal weight (0.88 +/- 0.05 vs. 0.67 +/- 0.03 micromol/l, P < 0.01)) but the increased levels were not significantly different when compared to the overweight group (obese vs. overweight (0.88 +/- 0.05 vs. 0.79 +/- 0.05 micromol/l)). No other consistent significant differences in TAS, SOD, and GSH were identified between groups. This study concluded that only obesity and not moderate overweight elevates LH levels. Furthermore, the levels of TAS, SOD, and GSH in obesity do not explain the increased LH levels observed in obesity.
    • Perfectionism and burnout in junior elite soccer players: The mediating influence of unconditional self-acceptance

      Hill, Andrew P.; Hall, Howard K.; Appleton, Paul Richard; Kozub, Stephen A.; University of Bedfordshire (2008)
    • Selenium supplementation and exercise: effect on oxidant stress in overweight adults

      Savory, Louise A.; Kerr, Catherine J.; Whiting, Paul; Finer, Nicholas; McEneny, Jane; Ashton, Tony; University of Bedfordshire (Wiley, 2012-04)
      Both obesity and acute high-intensity exercise increase oxidant stress levels. This study investigates whether selenium (Se) supplementation could be a potential effective therapy to reduce obesity-associated oxidant stress and exercise-induced oxidant stress. Ten normal-weight (NW) (22.80 ± 0.41 kg/m(2)) and ten overweight (OW) healthy subjects (28.00 ± 0.81 kg/m(2)) were assessed during a randomized double-blind Se supplementation study (200 µg sodium selenite/day for 3 weeks) with a 3-week placebo control and inversion of treatment periods. Blood levels of lipid hydroperoxide (LH), superoxide dismutase (SOD), erythrocyte glutathione (GSH), and total antioxidant status (TAS), were measured at rest, pre-, and postexercise (30 min 70% VO(2) max before and after treatment (pretreatment (week 0 and 12) and post-treatment (week 3 or 15)). At rest, compared to placebo, Se supplementation had no significant effect on LH, SOD, GSH, and TAS levels. However, Se supplementation decreased LH levels in the OW group, immediately postexercise (-0.25 ± 0.12 µmol/l, P = 0.05) compared to placebo treatment. Postexercise, with or without Se supplementation, no changes in TAS, SOD, and GSH levels were observed in both the NW and OW group. This study has highlighted a potential benefit of Se in reducing LH levels postexercise in OW individuals. Given that oxidant stress is a predictor of coronary events, it is imperative to better understand oxidant stress-related responses to lifestyle factors (in particular "high-risk" population groups) and potential antioxidant therapy.
    • Student investment in a research methods course: the influence of achievement goals on motivational patterns

      Hall, Howard K.; Hill, A.P.; Appleton, Paul Richard; Kozub, Stephen A.; University of Bedfordshire (2009)
    • The triglyceride to high-density lipoprotein ratio identifies children who may be at risk of developing cardiometabolic disease

      Bailey, Daniel Paul; Savory, Louise A.; Denton, Sarah J.; Davies, Ben Rhys; Kerr, Catherine J.; University of Bedfordshire; Newcastle University; Oxford Brookes University; University of Bedfordshire; Newcastle University; et al. (Wiley, 2014-08)
      Aim: It is important to develop simple, reliable methods to identify high-risk individuals who may benefit from intervention. This study investigated the association between the triglyceride to high-density lipoprotein cholesterol (TG/HDL) ratio and cardiometabolic risk, cardiorespiratory fitness and physical activity in children. Methods: Anthropometric, biochemical parameters, cardiorespiratory fitness and accelerometry determined physical activity were assessed in 155 children (80 girls) from 10 to 14 years of age from Bedfordshire, UK. Participants were grouped into high and low TG/HDL ratio groups, according to published thresholds. MANCOVA and logistic regression were used in the analysis. Results: Cardiometabolic risk factor levels were significantly higher in participants with a high TG/HDL ratio (p < 0.05). The odds of having high waist circumference (OR = 13.99; 95% CI 2.93, 69.25), elevated systolic blood pressure (5.27; 1.39, 20.01), high non-HDL cholesterol (19.47; 4.42, 85.81) and ≥2 cardiometabolic risk factors (15.32; 3.10, 75.79) were higher in participants with a high TG/HDL ratio. The TG/HDL ratio values were significantly lower in those with high cardiorespiratory fitness (p = 0.01), but there was no association with physical activity. Conclusion: These findings support the use of the TG/HDL ratio to identify children with cardiometabolic risk factors who may be at risk of developing cardiometabolic disease.