The Validity of a Novel Staged Exercise Test for Measuring Lactate Metabolism and Performance in Cyclists

Several types of lactate threshold (Tlac) protocols have been developed over the years to maximize accuracy and reliability while maintaining ease of measurement and application to training and performance. PURPOSE: The purpose of this study was to determine the validity of a novel staged maximal lactate steady state exercise test (sMLSS) in predicting the MLSS using the Lactate Plus® (Nova Biomedical, Waltham, MA) analyzer. METHODS: Blood lactate concentration (BLC) was measured in duplicate for all tests. Seven trained cyclists (20 miles per week) performed a V̇O2max test starting at 100W and increasing by 30W every three minutes until volitional fatigue. Lactate threshold was defined as the previous workload to a 2 mmol•L-1 increase in BLC. Next, the sMLSS test was performed starting at the Tlac workload, determined previously, then increasing 10W every 15 minutes for a total of three stages. BLC was measured every 3 minutes. MLSS was predicted by visual inspection and defined as \u3c 1.0 mmol•L-1 increase in the final 6 minutes of the stage. Finally, cyclists then performed two to six MLSS exercise tests, adjusting by 5W depending on lactate response, to validate the sMLSS. MLSS was determined at the maximal workload with \u3c 1 mmol•L-1 increase in BLC in the final 20 minutes. Dependent T-test and Pearson correlation coefficient was used to determine reliability between lactate trials. Bland-Altman plots, One-way ANOVA, and regression analyses were used to analyze differences between the types of exercise tests. RESULTS: There were no significant differences for duplicate BLC trials for all tests (p= 0.21; r=0.982). The sMLSS was significantly correlated with the MLSS workload and percentage of max workload (r = 0.997; p=0.001, r = 0.978, p=0.01), respectively. There was no bias noted between sMLSS and MLSS protocols for predicting lactate accumulation. CONCLUSION: This novel protocol was determined to be a valid and efficient means determining lactate performance in recreationally trained cyclists. The sMLSS was effective at reducing testing time from 12 days to 3 days

Physical Activity Levels and Measures of High-Sensitivity C-reactive Protein in Apparently Healthy Male Firefighters

Heart attack or stroke is the number one cause of on-duty death in firefighters. High-sensitivity C-reactive protein (hs-CRP) is a nontraditional risk factor that has been linked to increased risk of future cardiac events. Purpose: The purpose of this study was to determine if physically active firefighters are less likely to have elevated levels of high-sensitivity C-reactive protein (hs-CRP) than sedentary firefighters. Methods: Self-Reported Physical Activity was determined using the International Physical Activity Questionnaire (IPAQ) in 62 male firefighters from Central Texas. Descriptive measures and blood lipid and metabolic measures were taken to determine cardiovascular risk. After participants were screened for exclusion criteria, a total number of 60 (N=60) firefighters completed the experiment process. The firefighters completed the IPAQ and where placed into two groups based on their score, physically active or sedentary. Participants’ anthropometric measurements (body mass index, body composition), blood pressure, hs-CRP and cholesterol levels were measured. Venous blood samples were collected, centrifuged, and sent to an off-site facility for lipid, glucose, and hs-CRP testing. In addition, each firefighter was asked the total number of years involved in the occupation, and approximate number of fires they have worked. A two-way ANOVA with age as a covariate, was used to detect differences in active and inactive firefighters. Pearson product-moment correlations coefficient were used to determine relationships between activity level, cardiac risk and hs-CRP. Significant markers from the ANOVA and correlation coefficients were used to develop a regression equation to predict hs-CRP. Results: There was a significant difference in the number of MET*minutes/wk between volunteer (VT) and career (CT) firefighters (VT: 1927 ± 1369, CT: 2727 ± 1284). This study also determined that hs-CRP risk scores were not correlated to traditional cardiovascular risk factors including total cholesterol (r= 0.014, p= 0.916), LDL-Cholesterol (r= 0.095, p= 0.480), HDL-Cholesterol (r= 0.140, p= 0.295), glucose (r= 0.082, p= 0.540), age (r= 0.021, p= 0.876), and Framingham risk score (FRS)-TC (r= 0.061, p= 0.295). For fire departments that do not have the financial means to pay for hs-CRP testing for all their firefighters, we have devised a regression formula, using significant correlations, to estimate hs-CRP levels. The formula below uses SBP, activity level, weight, body fat percent and waist circumference to estimate hs-CRP (hs-CRP = -2.907 + 0.015(SBP) – 0.487(Act) + 0.032(Wt kg) + 0.048(BF%) – 0.010 (Waist cm). Conclusion: Both FRS and hs-CRP risk levels should be used when evaluating risk of CVD in firefighters, and an exercise prescription should be recommended to those firefighters with increased CVD risk

e-GRASP: an integrated evolutionary and GRASP resource for exploring disease associations

Abstract Background Genome-wide association studies (GWAS) have become a mainstay of biological research concerned with discovering genetic variation linked to phenotypic traits and diseases. Both discrete and continuous traits can be analyzed in GWAS to discover associations between single nucleotide polymorphisms (SNPs) and traits of interest. Associations are typically determined by estimating the significance of the statistical relationship between genetic loci and the given trait. However, the prioritization of bona fide, reproducible genetic associations from GWAS results remains a central challenge in identifying genomic loci underlying common complex diseases. Evolutionary-aware meta-analysis of the growing GWAS literature is one way to address this challenge and to advance from association to causation in the discovery of genotype-phenotype relationships. Description We have created an evolutionary GWAS resource to enable in-depth query and exploration of published GWAS results. This resource uses the publically available GWAS results annotated in the GRASP2 database. The GRASP2 database includes results from 2082 studies, 177 broad phenotype categories, and ~8.87 million SNP-phenotype associations. For each SNP in e-GRASP, we present information from the GRASP2 database for convenience as well as evolutionary information (e.g., rate and timespan). Users can, therefore, identify not only SNPs with highly significant phenotype-association P-values, but also SNPs that are highly replicated and/or occur at evolutionarily conserved sites that are likely to be functionally important. Additionally, we provide an evolutionary-adjusted SNP association ranking (E-rank) that uses cross-species evolutionary conservation scores and population allele frequencies to transform P-values in an effort to enhance the discovery of SNPs with a greater probability of biologically meaningful disease associations. Conclusion By adding an evolutionary dimension to the GWAS results available in the GRASP2 database, our e-GRASP resource will enable a more effective exploration of SNPs not only by the statistical significance of trait associations, but also by the number of studies in which associations have been replicated, and the evolutionary context of the associated mutations. Therefore, e-GRASP will be a valuable resource for aiding researchers in the identification of bona fide, reproducible genetic associations from GWAS results. This resource is freely available at http://www.mypeg.info/egrasp