Stensvold D, Tjønna AE, Skaug EA, Aspenes S, Stølen T, Wisløff U, Slørdahl SA. Strength training versus aerobic interval training to modify risk factors of metabolic syndrome. J Appl Physiol 108: 804-810, 2010. First published January 21, 2010 doi:10.1152/japplphysiol.00996.2009.-Metabolic syndrome is characterized by central obesity, elevated blood pressure, high fasting glucose and triglyceride levels, and low HDL levels. Regular physical activity can improve the metabolic profile and reduce the risks of cardiovascular diseases and premature mortality. However, the optimal training regime to treat metabolic syndrome and its associated cardiovascular abnormalities remains undefined. Fortythree participants with metabolic syndrome were randomized to one of the following groups: aerobic interval training (AIT; n ϭ 11), strength training (ST; n ϭ 11), a combination of AIT and ST (COM; n ϭ 10) 3 times/wk for 12 wk, or control (n ϭ 11). Risk factors comprising metabolic syndrome were evaluated before and after the intervention. Waist circumference (in cm) was significantly reduced after AIT [95% confidence interval (CI): Ϫ2.5 to Ϫ0.04], COM (95% CI: Ϫ2.11 to Ϫ0.63), and ST (95% CI: Ϫ2.68 to Ϫ0.84), whereas the control group had an increase in waist circumference (95% CI: 0.37-2.9). The AIT and COM groups had 11% and 10% increases in peak O2 uptake, respectively. There were 45% and 31% increases in maximal strength after ST and COM, respectively. Endothelial function, measured as flow-mediated dilatation (in %), was improved after AIT (95% CI: 0.3-3), COM (95% CI: 0.3-3), and ST (95% CI:

These data represent the largest reference material of objectively measured VO2peak in healthy men and women age 20-90 yr. Even in people considered to be fit, VO2peak was clearly associated with levels of conventional cardiovascular risk factors.

The nonexercise regression model developed in the present study was fairly accurate in predicting V·O 2peak in this healthy population of men and women. The model might be generalized to other healthy populations and might be a valid tool for a rough assessment of cardiorespiratory fitness in an outpatient setting.

Aerobic fitness, measured as maximal oxygen uptake (VO2max), is a good indicator of cardiovascular health, and a strong predictor of cardiovascular mortality. Biomarkers associated with low VO2max may therefore represent potential early markers of future cardiovascular disease (CVD). The aim of this study was to assess whether circulating microRNAs (miRs) are associated with VO2max-level in healthy individuals. In a screening study, 720 miRs were measured in serum samples from healthy individuals (40–45 yrs) with high (n = 12) or low (n = 12) VO2max matched for gender, age and physical activity. Candiate miRs were validated in a second cohort of subjects with high (n = 38) or low (n = 38) VO2max. miR-210 and miR-222 were found to be higher in the low VO2max-group (p<0.05). In addition, miR-21 was increased in male participants with low VO2max (p<0.05). There were no correlations between traditional risk factors for CVD (blood pressure, cholesterol, smoking habit, or obesity) and miR-21, miR-210 and miR-222. DIANA-mirPath identified 611 potential gene-targets of miR-21, miR-210 and miR-222, and pathway analysis indicated alterations in several important signaling systems in subjects with low VO2max. Potential bias involve that blood was collected from non-fasting individuals, and that 8 performed exercise within 24 h before sampling. In conclusion, we found that miR-210, miR-21, and miR-222 were increased in healthy subjects with low VO2max. The lack of association between these three miRs, and other fitness related variables as well as traditional CVD risk factors, suggests that these miRs may have a potential as new independent biomarkers of fitness level and future CVD.

The distribution of FMD in this study is representative of the respective age and gender groups of a healthy population and may be a useful reference for future studies. The high proportion of endothelial dysfunction came as a surprise. Its age and gender distribution suggest that FMD ≤0% precedes cardiovascular disease and that it may be a powerful non-invasive biomarker for identifying high-risk individuals.

Competitive swimming has a long history and is currently one of the largest Olympic sports, with 16 pool events. Several aspects separate swimming from most other sports such as (i) the prone position; (ii) simultaneous use of arms and legs for propulsion; (iii) water immersion (i.e. hydrostatic pressure on thorax and controlled respiration); (iv) propulsive forces that are applied against a fluctuant element; and (v) minimal influence of equipment on performance. Competitive swimmers are suggested to have specific anthropometrical features compared with other athletes, but are nevertheless dependent on physiological adaptations to enhance their performance. Swimmers thus engage in large volumes of training in the pool and on dry land. Strength training of various forms is widely used, and the energetic systems are addressed by aerobic and anaerobic swimming training. The aim of the current review was to report results from controlled exercise training trials within competitive swimming. From a structured literature search we found 17 controlled intervention studies that covered strength or resistance training, assisted sprint swimming, arms-only training, leg-kick training, respiratory muscle training, training the energy delivery systems and combined interventions across the aforementioned categories. Nine of the included studies were randomized controlled trials. Among the included studies we found indications that heavy strength training on dry land (one to five repetitions maximum with pull-downs for three sets with maximal effort in the concentric phase) or sprint swimming with resistance towards propulsion (maximal pushing with the arms against fixed points or pulling a perforated bowl) may be efficient for enhanced performance, and may also possibly have positive effects on stroke mechanics. The largest effect size (ES) on swimming performance was found in 50 m freestyle after a dry-land strength training regimen of maximum six repetitions across three sets in relevant muscle-groups (ES 1.05), and after a regimen of resisted- and assisted-sprint training with elastic surgical tubes (ES 1.21). Secondly, several studies suggest that high training volumes do not pose any immediate advantage over lower volumes (with higher intensity) for swim performance. Overall, very few studies were eligible for the current review although the search strategy was broad and fairly liberal. The included studies predominantly involved freestyle swimming and, overall, there seems to be more questions than answers within intervention-based competitive swimming research. We believe that this review may encourage other researchers to pursue the interesting topics within the physiology of competitive swimming.

BackgroundCardiovascular disease (CVD) is a leading cause of death worldwide, and the number of people at risk is continuously growing. New methods for early risk prediction are therefore needed to actuate prevention strategies before the individuals are diagnosed with CVD. Several studies report that aerobic fitness level, measured as maximal oxygen uptake (VO2max), is the single best predictor of future CVD mortality in healthy people. Based on this, we wanted to study differences between healthy individuals with a large difference in VO2max-level to identify new biomarkers of low aerobic fitness that may also have potential as early biomarkers of CVD risk.Methodology/Principal FindingsSerum samples from 218 healthy individuals with a low VO2max (n = 108, 63 women) or high VO2max (n = 110, 64 women) were analysed with MR metabolomics. In addition, standard clinical-chemical analyses for glucose, lipids, liver enzymes, micro-CRP, and colorimetric analysis on circulating choline were performed. Individuals in the low VO2max-group had increased serum levels of free choline, decreased phosphatidylcholine, increased glucosę and decreased unsaturated fatty acids compared to the individuals in the high VO2max–group.Conclusions/SignificanceAerobic fitness dependent differences in serum levels of free choline and phosphatidylcholine are observed. They should be further studied as potential early markers of CVD risk.

Physical activity level at baseline was positively associated with directly measured cardiorespiratory fitness (VO(2peak)) 23 yr later. People who changed from low to high activity during the observation period had substantially higher V˙O(2peak) at follow-up compared with people whose activity remained low.