BackgroundWhile overall physical activity is clearly associated with a better short-term and long-term health, prolonged strenuous physical activity may result in a rise in acute levels of blood-biomarkers used in clinical practice for diagnosis of various conditions or diseases. In this study, we explored the acute effects of a full Ironman-distance triathlon on biomarkers related to heart-, liver-, kidney- and skeletal muscle damage immediately post-race and after one week’s rest. We also examined if sex, age, finishing time and body composition influenced the post-race values of the biomarkers.MethodsA sample of 30 subjects was recruited (50% women) to the study. The subjects were evaluated for body composition and blood samples were taken at three occasions, before the race (T1), immediately after (T2) and one week after the race (T3). Linear regression models were fitted to analyse the independent contribution of sex and finishing time controlled for weight, body fat percentage and age, on the biomarkers at the termination of the race (T2). Linear mixed models were fitted to examine if the biomarkers differed between the sexes over time (T1-T3).ResultsBeing male was a significant predictor of higher post-race (T2) levels of myoglobin, CK, and creatinine levels and body weight was negatively associated with myoglobin. In general, the models were unable to explain the variation of the dependent variables. In the linear mixed models, an interaction between time (T1-T3) and sex was seen for myoglobin and creatinine, in which women had a less pronounced response to the race.ConclusionOverall women appear to tolerate the effects of prolonged strenuous physical activity better than men as illustrated by their lower values of the biomarkers both post-race as well as during recovery.

ObjectiveIt has been suggested that the mechanism behind cardiac troponin elevation after strenuous exercise is passage through a cell membrane with changed permeability rather than myocardial cell death. We hypothesised that an increase of cardiac specific myosin heavy chain-alpha (MHC-α; 224 kDa compared with cardiac troponin T’s (cTnT) 37 kDa) could hardly be explained by passage through a cell membrane.MethodsBlood samples were collected from 56 athletes (15 female, age 42.5±9.7, range 24–70 years) before, directly after and on days 1–8 after an Ironman. Biomarkers (C reactive protein (CRP), cTnT, creatine kinase (CK), MHC-α, myoglobin (MG), creatinine (C) and N-terminal prohormone of brain natriuretic peptide (NT-proBNP) were measured.ResultsThe course of MHC-α concentration (µg/L) was 1.33±0.53 (before), 2.57±0.78 (directly after), 1.51±0.53 (day 1), 2.74±0.55 (day 4) and 1.83±0.76 (day 6). Other biomarkers showed a one-peaked increase with maximal values either directly after the race or at day 1: cTnT 76 ± 80 ng/L (12–440; reference<15), NT-proBNP 776±684 ng/L (92–4700; ref.<300), CK 68±55 µkat/L (5–280; ref.<1.9), MG 2088±2350 µg/L (130–17 000; ref.<72) and creatinine 100±20 µmol/L (74–161; ref.<100), CRP 49±23 mg/L (15–119; ref.<5).ConclusionMHC-α exhibited a two-peaked increase which could represent a first release from the cytosolic pool and later from cell necrosis. This is the first investigation of MHC-α plasma concentration after exercise.

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Acute administration of resistin markedly affects the blood perfusion of both the pancreas and subcutaneous white adipose tissue depots. At present it is unknown whether resistin exerts a direct effect on the vasculature, or works through local or systemic activation of endothelial cells and/or macrophages. The extent to which this might contribute to the insulin resistance caused by resistin is yet unknown.

In this study we have investigated the effectiveness of a one day school-based intervention with recreational fishing (in Swedish called Klassdraget) in increasing environmental awareness, interest in nature and recreational fishing in pupils aged between 8 and 12. Our results suggest a weak positive association between exposure to natural environments in a recreational fishing context and interest in nature and recreational fishing. We found the intervention to have no effect on the frequency of fishing, interest in fishing more, or number of visits in nature during spare time. Knowledge about nature and possibly also environmental awareness are positively affected and these effects can be traced as long as three years after the intervention. Our findings also reveal a low correlation between frequency of nature visits and self-reported interest in nature. The observed effects of Klassdraget are small but appear to be larger for girls, who are traditionally less interested in recreational fishing when compared with boys.