The aim of the present study was to compare heart rate variability (HRV) at rest and during exercise using a temporal series obtained with the Polar S810i monitor and a signal from a LYNX® signal conditioner (BIO EMG 1000 model) with a channel configured for the acquisition of ECG signals. Fifteen healthy subjects aged 20.9 ± 1.4 years were analyzed. The subjects remained at rest for 20 min and performed exercise for another 20 min with the workload selected to achieve 60% of submaximal heart rate. RR series were obtained for each individual with a Polar S810i instrument and with an ECG analyzed with a biological signal conditioner. The HRV indices (rMSSD, pNN50, LFnu, HFnu, and LF/HF) were calculated after signal processing and analysis. The unpaired Student t-test and intraclass correlation coefficient were used for data analysis. No statistically significant differences were observed when comparing the values analyzed by means of the two devices for HRV at rest and during exercise. The intraclass correlation coefficient demonstrated satisfactory correlation between the values obtained by the devices at rest (pNN50 = 0.994; rMSSD = 0.995; LFnu = 0.978; HFnu = 0.978; LF/HF = 0.982) and during exercise (pNN50 = 0.869; rMSSD = 0.929; LFnu = 0.973; HFnu = 0.973; LF/HF = 0.942). The calculation of HRV values by means of temporal series obtained from the Polar S810i instrument appears to be as reliable as those obtained by processing the ECG signal captured with a signal conditioner.

Background: Cold water immersion (CWI) is a technique commonly used in post-exercise recovery. However, the procedures involved in the technique may vary, particularly in terms of water temperature and immersion time, and the most effective approach remains unclear. Objectives: The objective of this systematic review was to determine the efficacy of CWI in muscle soreness management compared with passive recovery. We also aimed to identify which water temperature and immersion time provides the best results. Methods: The MEDLINE, EMBASE, SPORTDiscus, PEDro [Physiotherapy Evidence Database], and CENTRAL (Cochrane Central Register of Controlled Trials) databases were searched up to January 2015. Only randomized controlled trials that compared CWI to passive recovery were included in this review. Data were pooled in a meta-analysis and described as weighted mean differences (MDs) with 95 % confidence intervals (CIs). Results: Nine studies were included for review and meta-analysis. The results of the meta-analysis revealed that CWI has a more positive effect than passive recovery in terms of immediate (MD = 0.290, 95 % CI 0.037, 0.543; p = 0.025) and delayed effects (MD = 0.315, 95 % CI 0.048, 0.581; p = 0.021). Water temperature of between 10 and 15 °C demonstrated the best results for immediate (MD = 0.273, 95 % CI 0.107, 0.440; p = 0.001) and delayed effects (MD = 0.317, 95 % CI 0.102, 0.532; p = 0.004). In terms of immersion time, immersion of between 10 and 15 min had the best results for immediate (MD = 0.227, 95 % 0.139, 0.314; p < 0.001) and delayed effects (MD = 0.317, 95 % 0.102, 0.532, p = 0.004). Conclusions: The available evidence suggests that CWI can be slightly better than passive recovery in the management of muscle soreness. The results also demonstrated the presence of a dose–response relationship, indicating that CWI with a water temperature of between 11 and 15 °C and an immersion time of 11–15 min can provide the best results.

Background: Work-related musculoskeletal pain is a major cause of work disability and sickness absence. While pain is a multifactorial phenomenon being influenced by work as well as lifestyle, less is known about the association between specific lifestyle factors and the type of musculoskeletal pain. The aim of the study was to investigate if a dose-response association existed between lifestyle factors and musculoskeletal pain intensity in the low back and neck-shoulder.Methods: Currently employed wage earners (N = 10,427) replied in 2010 to questions about work environment, lifestyle and health. Logistic regression analyses adjusted for various confounders tested the association of alcohol intake, physical activity, fruit and vegetable intake, and smoking (explanatory variables) with low back pain and neck-shoulder pain intensity (outcomes variables, scale 0–9, where ≥4 is high pain).Results: The minimally adjusted model found that physical activity and fruit and vegetable intake were associated with lower risk of musculoskeletal pain, while smoking was associated with higher risk of musculoskeletal pain. In the fully adjusted model, physical activity ≥5 h per week was associated with lower risk of low back pain and neck-shoulder pain with risk ratios (RR) of 0.95 (95% CI 0.90–1.00) and 0.90 (95% CI 0.82–0.99), respectively. No association was found between alcohol intake and pain.Conclusion: Being physically active associated with lower risk of having musculoskeletal pain, while smoking habits and healthy eating were associated with higher pain when adjusting for age and gender. Considering the continuously increasing retirement age in many societies, initiatives to promote healthy habits should still be a political priority to help the workers to stay healthy and cope to their work.

Aim: To evaluate the effects of resistance training on metabolic syndrome risk factors through comparison with a control group.Design: Meta-analysis comparing resistance training interventions with control groups. Two independent reviewers selected the studies and assessed their quality and data. The pooled mean differences between resistance training and the control group were calculated using a fixed-effects model.Data sources: The MEDLINE, PEDro, EMBASE, SPORTDiscus and The Cochrane Library databases were searched from their earliest records to 10 January 2015.Eligibility criteria for selecting studies: Randomised controlled trials that compared the effect of resistance training on metabolic syndrome risk factors with a control group were included. All types of resistance training, irrespective of intensity, frequency or duration, were eligible.Results: Only systolic blood pressure was significantly reduced, by 4.08 mm Hg (95% CI 1.33 to 6.82; p0.05) for fasting plasma glucose, 0.00 (95% CI −0.05, 0.04; p>0.05) for high-density lipoprotein (HDL) cholesterol, 0.03 (95% CI −0.14, 0.20; p>0.05) for triglycerides, 1.39 mm Hg (95% CI −0.19, 2.98; p=0.08) for diastolic blood pressure and 1.09 cm (95% CI −0.12, 2.30; p=0.08) for waist circumference. Inconsistency (I²) for all meta-analysis was 0%.Conclusions: Resistance training may help reduce systolic blood pressure levels, stroke mortality and mortality from heart disease in people with metabolic syndrome.Trial registration number: CRD42015016538.