Evolutionary history of the ADRB2 gene in humans

No abstract available

Effects of diabetes family history and exercise training on the expression of adiponectin and leptin and their receptors

The daughters of patients with diabetes have reduced insulin sensitivity index (ISI) scores compared with women with no family history of diabetes, but their ISI increase more in response to exercise training(1). The present study aimed to determine whether differences between these groups in exercise-induced changes in circulating adiponectin and leptin concentrations and expression of their genes and receptors in subcutaneous adipose tissue (SAT), could explain differences in the exercise-induced changes in ISI between women with and without a family history of diabetes

Relationship between insulin sensitivity and menstrual cycle is modified by BMI, fitness, and physical activity in NHANES

Context There is evidence demonstrating variation in insulin sensitivity across the menstrual cycle. However, to date, research has yielded inconsistent results. Objective This study investigated variation in insulin sensitivity across the menstrual cycle and associations with BMI, physical activity and cardiorespiratory fitness. Design Data from 1906 premenopausal women in NHANES cycles 1999-2006 were analysed. Main outcome measures Menstrual cycle day was assessed using questionnaire responses recording days since last period. Rhythmic variation of plasma glucose, triglyceride and insulin, homeostatic model of insulin resistance (HOMA-IR) and adipose tissue insulin resistance index (ADIPO-IR) across the menstrual cycle were analysed using cosinor rhythmometry. Participants were assigned low or high categories of BMI, physical activity and cardiorespiratory fitness and category membership included in cosinor models as covariates. Results Rhythmicity was demonstrated by a significant cosine fit for glucose (p= 0.014) but not triglyceride (p= 0.369), insulin (p= 0.470), HOMA-IR (p=0.461) and ADIPO-IR (p= 0.335). When covariates were included, rhythmicity was observed when adjusting for: 1. BMI: glucose (p< 0.001), triglyceride (p< 0.001), insulin (p< 0.001), HOMA-IR (p< 0.001) and ADIPO-IR (p< 0.001); 2. Physical activity: glucose (p< 0.001), triglyceride (p= 0.006) and ADIPO-IR (p= 0.038); 3. Cardiorespiratory fitness: triglyceride (p= 0.041), insulin (p= 0.002), HOMA-IR (p= 0.004) and ADIPO-IR (p= 0.004). Triglyceride amplitude, but not acrophase, was greater in the high physical activity category compared to low (p=0.018). Conclusions Rhythmicity in insulin sensitivity and associated metabolites across the menstrual cycle are modified by BMI, physical activity and cardiorespiratory fitness

The Impact of the Daily Mile™ on School Pupils’ Fitness, Cognition, and Wellbeing: Findings From Longer Term Participation

Background: School based running programmes, such as The Daily Mile™, positively impact pupils’ physical health, however, there is limited evidence on psychological health. Additionally, current evidence is mostly limited to examining the acute impact. The present study examined the longer term impact of running programmes on pupil cognition, wellbeing, and fitness. Method: Data from 6,908 school pupils (mean age 10.2 ± 0.7 years), who were participating in a citizen science project, was examined. Class teachers provided information about participation in school based running programmes. Participants completed computer-based tasks of inhibition, verbal and visual-spatial working memory, as well as the Children’s Feeling scale and Felt arousal scale to determine subjective wellbeing. A multistage 20-m shuttle run test was used to estimate fitness. Results: From our total sample of 6,908 school pupils, 474 participants had been taking part in a running programme for 3 months); and 5,430 did not take part in a running programme. The Longer Term participation group had higher fitness levels than both other groups and this remained significant when adjusted for age, sex and SES. Moderated regression analysis found that for the Shorter Term participation group, higher shuttle distance was associated with better visual-spatial working memory. Effect sizes were small though. Conclusion: We identified small and selective positive impact of participation in school based running programmes on fitness and cognition. While no long term benefit was identified for cognition or wellbeing, the impact on fitness and short term benefit suggest schools should consider participation

Human alpha-actinin-3 genotype association with exercise-induced muscle damage and the repeated-bout effect

Alpha-actinin-3 (ACTN3) is an integral part of the Z line of the sarcomere. The ACTN3 R577X (rs1815739) polymorphism determines the presence or absence of functional ACTN3, which may influence the extent of exercise-induced muscle damage. This study aimed to compare the impact of, and recovery from, muscle-damaging eccentric exercise on subjects with or without functional ACTN3. Seventeen young men (20-33 years old), homozygous for the R (n = 9) or X (n = 8) alleles, performed two bouts of stretch-shortening exercise (50 drop jumps) two weeks apart. Muscle soreness, plasma creatine kinase (CK) activity, jump height, maximal voluntary isometric torque (MVC), peak concentric isokinetic torque (IT), and electrically stimulated knee extension torques at 20 and 100 Hz were measured at baseline and at a number of time points up to 14 days after each bout. There were no significant baseline differences between the groups. However, significant time point &times; genotype interactions were observed for MVC (p = 0.021) and IT (p = 0.011) for the immediate effect of eccentric exercise in bout 1. The RR group showed greater voluntary force decrements (RR vs. XX: MVC, -33.3% vs. -24.5%; IT, -35.9% vs. -23.2%) and slower recovery. A repeated-bout effect was clearly observed, but there were no differences by genotype group. The ACTN3 genotype modulates the response of muscle function to plyometric jumping exercise, although the differences are modest. The ACTN3 genotype does not influence the clearly observed repeated-bout effect; however, XX homozygotes recover baseline voluntary torque values faster and thus may be able to undertake more frequent training sessions

Response to Daly-Smith et al.’s commentary on ‘The Daily Mile makes primary school children more active, less sedentary and improves their fitness and body composition:A quasi-experimental pilot study’

We thank Daly-Smith et al. for taking the time to read the results of our pilot research study, describing it as an important and welcome contribution. Nonetheless, the authors argue six points against our conclusion. We contend that we addressed three of these points in our original discussion and disagree with their remaining points. Overall, their Commentary adds little to the topic of research into the Daily Mile™ that we had not already raised in our discussion. Additionally, they attribute statements to us that we did not make and ignore the raising of key issues in our original article. Given this, we stand by our original peer-reviewed conclusion that introducing the Daily Mile™ to the primary school day appears to be an effective intervention for increasing levels of moderate to vigorous physical activity, reducing sedentary time, increasing physical fitness and improving body composition, and that these findings have relevance for teachers, policy-makers, public health practitioners and health researchers

The Daily Mile:What factors are associated with its implementation success?

Background: Despite the known benefits of a physically active lifestyle, there are few examples of interventions that have been successfully implemented at a population level over a long period of time. One such example is The Daily Mile, a school based physical activity initiative, where a teacher takes their class out daily during class time for a short bout of ambulatory activity. At one school, this activity appears has been sustained over a long period (6 years), has the whole school participating and is now incorporated into its daily routine. The aim of this paper was to understand how The Daily Mile was implemented in primary schools and to assess factors associated with its successful implementation. Methods: Semi-structured interviews with school staff who had a significant role in implementing The Daily Mile were conducted at four primary schools in central Scotland. Interviews were digitally recorded and transcribed verbatim. Data were analysed using thematic analysis and descriptive analysis and interpretation of data undertaken. Details regarding the school grounds and facilities were also noted during the interviews. Results: Having simple core intervention components, flexible delivery that supports teacher autonomy and being adaptable to suit the specific primary school context appear to be key aspects of The Daily Mile that are related to its implementation success. Other factors relating to how The Daily Mile was developed, trialled and rolled out might also have contributed towards its successful implementation. Conclusion: The Daily Mile appears to have several factors which may relate to its implementation success. These are important considerations for others looking to implement The Daily Mile effectively in their primary school or in other contexts

Human Subcutaneous Adipose Tissue Sampling using a Mini-liposuction Technique

Studies on adipose tissue are useful in understanding metabolic and other conditions. Human subcutaneous adipose tissue is accessible. With appropriate training and strict adherence to aseptic technique, subcutaneous adipose samples can be safely and efficiently obtained in a non-clinical setting by researchers. Following the administration of local anesthetic lateral to the umbilicus, a 14 G needle attached to a 5 or 10 mL syringe is inserted through the skin into the subcutaneous tissue. Under suction, the syringe is moved in a reciprocating, slicing motion to isolate fragments of adipose tissue. Withdrawing the plunger is enough to ensure that adipose tissue fragments are aspirated through the needle into the syringe. A single biopsy can collect about 200 mg of tissue. This biopsy technique is very safe for both participants and research staff. Following the biopsy, participants can resume most everyday activities, although they should avoid swimming and overly strenuous activities for 48 h to avoid excessive bleeding. Participants can safely undergo 2 biopsies within a single day, meaning that the technique can be applied in before-after acute intervention studies

Association between menstrual cycle phase and metabolites in healthy, regularly menstruating women in UK Biobank, and effect modification by inflammatory markers and risk factors for metabolic disease

Background: Preliminary evidence demonstrates some parameters of metabolic control, including glycaemic control, lipid control and insulin resistance, vary across the menstrual cycle. However, the literature is inconsistent, and the underlying mechanisms remain uncertain. This study aimed to investigate the association between the menstrual cycle phase and metabolites and to explore potential mediators and moderators of these associations. Methods: We undertook a cross-sectional cohort study using UK Biobank. The outcome variables were glucose; triglyceride; triglyceride to glucose index (TyG index); total, HDL and LDL cholesterol; and total to HDL cholesterol ratio. Generalised additive models (GAM) were used to investigate non-linear associations between the menstrual cycle phase and outcome variables. Anthropometric, lifestyle, fitness and inflammatory markers were explored as potential mediators and moderators of the associations between the menstrual cycle phase and outcome variables. Results: Data from 8694 regularly menstruating women in UK Biobank were analysed. Non-linear associations were observed between the menstrual cycle phase and total (p < 0.001), HDL (p < 0.001), LDL (p = 0.012) and total to HDL cholesterol (p < 0.001), but not glucose (p = 0.072), triglyceride (p = 0.066) or TyG index (p = 0.100). Neither anthropometric, physical fitness, physical activity, nor inflammatory markers mediated the associations between the menstrual cycle phase and metabolites. Moderator analysis demonstrated a greater magnitude of variation for all metabolites across the menstrual cycle in the highest and lowest two quartiles of fat mass and physical activity, respectively. Conclusions: Cholesterol profiles exhibit a non-linear relationship with the menstrual cycle phase. Physical activity, anthropometric and fitness variables moderate the associations between the menstrual cycle phase and metabolite concentration. These findings indicate the potential importance of physical activity and fat mass as modifiable risk factors of the intra-individual variation in metabolic control across the menstrual cycle in pre-menopausal women