Very little is known about how long-term (>6 months) adaptation to a low-carbohydrate, high-fat (LCHF) diet affects insulin signaling in healthy, well-trained individuals. This study compared glucose tolerance; skeletal muscle glucose transporter 4 (GLUT4) and insulin receptor substrate 1 (IRS1) content; and muscle enzyme activities representative of the main energy pathways (3-hydroxyacetyl-CoA dehydrogenase, creatine kinase, citrate synthase, lactate dehydrogenase, phosphofructokinase, phosphorylase) in trained cyclists who followed either a long-term LCHF or a mixed-macronutrient (Mixed) diet. On separate days, a 2-hr oral glucose tolerance test was conducted, and muscle samples were obtained from the vastus lateralis of fasted participants. The LCHF group had reduced glucose tolerance compared with the Mixed group, as plasma glucose concentrations were significantly higher throughout the oral glucose tolerance test and serum insulin concentrations peaked later (LCHF, 60 min; Mixed, 30 min). Whole-body insulin sensitivity was not statistically significantly different between groups (Matsuda index: LCHF, 8.7 ± 3.4 vs. Mixed, 12.9 ± 4.6; p = .08). GLUT4 (LCHF: 1.13 ± 0.24; Mixed: 1.44 ± 0.16; p = .026) and IRS1 (LCHF: 0.25 ± 0.13; Mixed: 0.46 ± 0.09; p = .016) protein content was lower in LCHF muscle, but enzyme activities were not different. We conclude that well-trained cyclists habituated to an LCHF diet had reduced glucose tolerance compared with matched controls on a mixed diet. Lower skeletal muscle GLUT4 and IRS1 contents may partially explain this finding. This could possibly reflect an adaptation to reduced habitual glucose availability rather than the development of a pathological insulin resistance.

Introduction: Poor mental health of athletes is major concern in sport. Typically, incidence/prevalence of mental health symptoms in athletes is studied using symptom-specific questionnaires. For symptoms of depression/anxiety, one such self-reporting questionnaire is the 12-item General Health Questionnaire (GHQ-12). Objective: The aim of this review was to synthesise and compare studies using the GHQ-12 in athletes to inform future research by identifying trends and gaps in the literature. Methods: A systematic search of five electronic databases (Google Scholar, PubMed, PsychINFO, Scopus and Web of Science) was conducted on all published studies up to 1 January 2019. 1) participants were able-bodied athletes; 2) studies measured anxiety/depression using the GHQ-12; 3) studies were full original articles from peer-reviewed journals; 4) studies were published in English. Results: 32 studies were included in the review. Prevalence and incidence of symptoms of anxiety/depression ranged from 21-48% and 17-57% respectively. The majority of studies screening anxiety/depression using the GHQ-12 were cross-sectional. Almost 70% of studies used the traditional scoring method. The majority of study populations sampled all-male cohorts comprising football (soccer) players. Conclusion: The traditional scoring of 0-0-1-1 should be used with the cut-off set at ≥3. Also, the mean GHQ-12 score should be reported. Potential risk factors for symptoms of anxiety/depression (i.e. recent adverse life events, injury and illness, social support, pressure to perform and career transitioning) and a lack of prospective studies were identified. Future research should also broaden the spectrum of athlete populations used and try to improve response rates.

The purpose of this study was to i) determine the prevalence of anxiety/depression symptoms in professional cricketers and ii) identify factors associated with symptoms of anxiety/depression. Onehundred and seventy-seven (n=177, response rate of 76%) professional cricketers completed the General Health Questionnaire 12 (GHQ-12). Odd ratios (OR) for anxiety/depression symptoms were related to players' career, family and education. Prevalence of symptoms of anxiety/depression was 59% (n=104/177). Anxiety/depression symptoms increased when players were contracted for more than 2 years (OR: 5.0; 95% CI: 1.2-21.3; p=0.028) and if they played their last offseason overseas (OR: 3.5; 95% CI: 1.3-9.6; p=0.013). Anxiety/depression symptoms decreased by 70% when players made 'productive use' of their time in the offseason (OR: 0.3; 95% CI: 0.1-0.9; p=0.036) and contracted for 2 years (OR: 0.3; 95% CI: 0.1-1.0; p=0.049). These findings can be incorporated into cricket mental health literacy programmes to improve awareness and understanding, and to encourage early help-seeking.

No abstract