Co-expression analysis identifies networks of miRNAs implicated in biological ageing and modulated by short-term interval training.

Exercise training seems to promote healthy biological ageing partly by inducing telomere maintenance, yet the molecular mechanisms are not fully understood. Recent studies have emphasised the importance of microRNAs (miRNAs) in ageing and their ability to mirror pathophysiological alterations associated with age-related diseases. We examined the association between aerobic fitness and leukocyte telomere length before determining the influence of vigorous exercise training on the regulation of leukocyte miRNA networks. Telomere length was positively correlated to aerobic fitness (r = 0.32, p = 0.02). 104 miRNAs were differentially expressed after six weeks of thrice-weekly sprint interval training (SIT) in healthy men (q < 0.05). Gene co-expression analysis (WGCNA) detected biologically meaningful miRNA networks, five of which were significantly correlated with pre-SIT and post-SIT expression profiles (p < 0.001) and telomere length. Enrichment analysis revealed that the immune response, T cell differentiation and lipid metabolism associated miRNAs clusters were significantly down-regulated after SIT. Using data acquired from the Gene Expression Omnibus (GEO), we also identified two co-expressed miRNAs families that were modulated by exercise training in previous investigations. Collectively, our findings highlight the miRNA networks implicated in exercise adaptations and telomere regulation, and suggest that SIT may attenuate biological ageing through the control of the let-7 and miR-320 miRNA families.

Cycling Power Outputs Predict Functional Threshold Power and Maximum Oxygen Uptake.

Denham, J, Scott-Hamilton, J, Hagstrom, AD, and Gray, AJ. Cycling power outputs predict functional threshold power and maximum oxygen uptake. J Strength Cond Res 34(12): 3489-3497, 2020-Functional threshold power (FTP) has emerged as a correlate of lactate threshold and is commonly assessed by recreational and professional cyclists for tailored exercise programing. To identify whether results from traditional aerobic and anaerobic cycling tests could predict FTP and V[Combining Dot Above]O2max, we analyzed the association between estimated FTP, maximum oxygen uptake (V[Combining Dot Above]O2max [ml·kg·min]) and power outputs obtained from a maximal cycle ergometry cardiopulmonary exercise test (CPET), and a 30-second Wingate test in a heterogeneous cohort of cycle-trained and untrained individuals (N = 40, mean ± SD; age: 32.6 ± 10.6 years; relative V[Combining Dot Above]O2max: 46.8 ± 9.1 ml·kg·min). The accuracy and sensitivity of the prediction equations were also assessed in young men (N = 11) before and after a 6-week sprint interval training intervention. Moderate-to-strong positive correlations were observed between FTP, relative V[Combining Dot Above]O2max, and power outputs achieved during incremental and 30-second Wingate cycling tests (r = 0.39-0.965, all p ≤ .05). Whilst maximum power achieved during incremental cycle testing (Pmax) and relative V[Combining Dot Above]O2max were predictors of FTP (r = 0.93), age and FTP (W·kg) estimated relative V[Combining Dot Above]O2max (r = 0.80). Our findings confirm that FTP predominantly relies on aerobic metabolism and indicate that both prediction models are sensitive enough to detect meaningful exercise-induced changes in FTP and V[Combining Dot Above]O2max. Thus, coaches should consider limiting the time and load demands placed on athletes by conducting a maximal cycle ergometry CPET to estimate FTP. In addition, a 20-minute FTP test is a convenient method to assess V[Combining Dot Above]O2max and is particularly relevant for exercise professionals without access to expensive CPET equipment.

Small non-coding RNAs are altered by short-term sprint interval training in men.

Small non-coding RNAs (ncRNAs) are emerging as important molecules for normal biological processes and are deregulated in disease. Exercise training is a powerful therapeutic strategy that prevents cardiometabolic disease and improves cardiorespiratory fitness and performance. Despite the known systemic health benefits of exercise training, the underlying molecular mechanisms are incompletely understood. Recent evidence suggests a role for epigenetic mechanisms, such as microRNAs, but whether other small ncRNAs are modulated by chronic exercise training is unknown. Here, we used small RNA sequencing to explore whether sprint interval training (SIT) controls the abundance of circulating small ncRNAs in human whole blood samples. Ten healthy men performed SIT three times a week for 6 weeks. After training, subjects showed marked improvements in maximal oxygen consumption and cycling performance with concurrent changes to the abundance of diverse species of circulating small ncRNAs (n = 1266 small ncRNAs, n = 13 microRNAs, q < 0.05). Twelve microRNAs altered by 6 weeks of SIT were ubiquitously expressed microRNAs and two regulated important signaling pathways, including p53, thyroid hormone and cell cycle signaling. MicroRNAs altered by 6 weeks of SIT were unchanged after a single session of SIT (n = 24, all P > 0.05). Relative to older individuals, younger subjects exhibited an increased acute SIT-induced fold change in miR-1301-3p (P = 0.02) - a microRNA predicted to target mRNAs involved in alternative splicing, phosphoprotein and chromosomal rearrangement processes (all P < 0.001). Our findings indicate many species of circulating small ncRNAs are modulated by exercise training and that they could control signaling pathways responsible for health benefits achieved from exercise.

Sprint Interval Training Decreases Circulating MicroRNAs Important for Muscle Development.

Small non-coding RNAs, such as microRNAs (miRNAs), have emerged as powerful post-transcriptional regulators of gene expression that play important roles in many developmental and biological processes. In this study, we assessed the abundance of circulating microRNAs important for skeletal muscle and heart adaptations to exercise (miR-1, miR-133a, miR-133b and miR-486), following acute exercise and short-term sprint interval training (SIT). Twenty-eight individuals completed four all-out efforts on a cycle ergometer, and donated blood before and 30 min after the cessation of exercise. A subset of 10 untrained men completed 4-6 efforts of SIT, three times a week for 6 weeks, and donated resting blood samples before and after the intervention. MiRNA TaqMan qPCR was performed and whilst no changes were observed after a single session of SIT (all p>0.05), the 6-wk SIT intervention significantly reduced the whole blood content of all four miRNAs (mean fold-changes: 0.37-0.48, all p<0.01). Our data suggests that circulating miRNAs are responsive to short-term SIT and could have roles in SIT-induced health and performance adaptations. Further work is required to establish whether circulating miRNAs could serve as biomarkers for predicting exercise training responses and monitoring exercise interventions.

Effects of a Mindfulness Intervention on Sports-Anxiety, Pessimism, and Flow in Competitive Cyclists.

BACKGROUND: This study investigated whether mindfulness training increases athletes' mindfulness and flow experience and decreases sport-specific anxiety and sport-specific pessimism. METHODS: Cyclists were assigned to an eight-week mindfulness intervention, which incorporated a mindful spin-bike training component, or a wait-list control condition. Participants completed baseline and post-test measures of mindfulness, flow, sport-anxiety, and sport-related pessimistic attributions. RESULTS: Analyses of covariance showed significant positive effects on mindfulness, flow, and pessimism for the 27 cyclists in the mindfulness intervention condition compared with the 20 cyclists in the control condition. Changes in mindfulness experienced by the intervention participants were positively associated with changes in flow. CONCLUSIONS: Results suggest that mindfulness-based interventions tailored to specific athletic pursuits can be effective in facilitating flow experiences.