Effects of bench step exercise intervention on work ability in terms of cardiovascular risk factors and oxidative stress: a randomized controlled study.

Work ability is partly determined by physical and mental fitness. Bench step exercise can be practiced anywhere at any time. The aim of this study was to determine the effects of a bench step exercise on work ability by examining cardiovascular risk factors and oxidative stress. Thirteen volunteers working in a warehousing industry comprised the bench step exercise group (n=7) and the control group (n=6). The participants in the step exercise group were encouraged to practice the step exercise at home for 16 weeks. The step exercise improved glucose metabolism and antioxidative capacity and increased work ability by reducing absences from work and improving the prognosis of work ability. The improvement in work ability was related to a reduction in oxidative stress. These results suggest that a bench step exercise may improve work ability by reducing cardiovascular risk factors and oxidative stress.

Stretching versus transitory icing: which is the more effective treatment for attenuating muscle fatigue after repeated manual labor?

PURPOSE: Effective recovery from muscle fatigue, especially during rest intervals between periods of high-intensity activity, is important to ensure optimal subsequent performance. Stretching and icing are two types of treatment used for muscle recovery in such situations. However, their effectiveness remains unclear because of a lack of adequate evidence and/or discrepant results of previous studies. We performed a study to elucidate the effects of stretching and icing on muscle fatigue in subjects performing alternating muscle contraction and rest. METHODS: Sixteen healthy male subjects aged 21-27 years were evaluated. Each subject performed repeated isometric muscle contraction exercises that involved lifting and holding a dumbbell to induce muscle fatigue. Four treatments were performed during the rest periods between isometric muscle contraction: static stretching, ballistic stretching, no stretching, or icing. Electromyography and relative muscle oxygen saturation measurements were performed during the exercises. Muscle fatigue was indirectly estimated by the decline in the median frequency of the electromyographic signal. RESULTS: Stretching between alternate isometric muscle contraction exercises resulted in a significantly lower median frequency of the electromyographic signal than did no stretching. There was no significant difference in the change in the median frequency between static and ballistic stretching. Conversely, icing between alternate exercises did not decrease the median frequency. CONCLUSIONS: Stretching, whether static or ballistic, is not beneficial for recovery from muscle fatigue and may actually inhibit recovery. Icing may more effectively induce such recovery and thus may be a better choice between the two treatment techniques.

The relationship between work ability and oxidative stress in Japanese workers.

Work ability is based on the balance between personal resources and work demand. This study focused on the personal resources component of work ability. The aims of this study were to elucidate the association between work ability and cardiovascular (CV) risk factors, particularly oxidative stress, and to estimate the effect of a community-implemented lifestyle modification programme on work ability and CV risk factors. Urinary 8-iso-prostaglandin F2α (PGF2α), a biomarker of oxidative stress, was negatively correlated with psychological resources, as measured by the Work Ability Index (WAI). Overall WAI score was unchanged following the programme, while CV risk factors and antioxidative activity improved. A reduction in PGF2α levels was correlated with an improvement in subjective work ability relative to job demands, as assessed by a WAI item. Taken together, the results suggest that lifestyle modification programmes enhance the personal resources component of work ability and are associated with a reduction in oxidative stress.

Sense of coherence is significantly associated with both metabolic syndrome and lifestyle in Japanese computer software office workers.

OBJECTIVES: Sense of coherence (SOC) is an individual characteristic related to a positive life orientation, leading to effective coping. Little is known about the relationship between SOC and metabolic syndrome (MetS). This cross-sectional study aimed at testing the hypothesis that workers with a strong SOC have fewer atherosclerotic risk factors, including MetS, and healthier lifestyle behaviors. MATERIAL AND METHODS: One hundred and sixty-seven computer software workers aged 20-64 years underwent a periodical health examination including assessment of body mass index, waist circumference, blood pressure, blood lipid levels, fasting blood sugar (FBS) levels and lifestyle behaviors (walking duration, smoking status, nutrition, alcohol consumption, and sleep duration). During this period, the participants also completed a 29-item questionnaire of SOC and the Brief Job Stress Questionnaire to assess job stressors such as job strain and workplace social support. RESULTS: Our results showed that the participants with a stronger SOC were likely to walk for at least 1 h a day, to eat slowly or at a moderate speed, and to sleep for at least 6 h. Compared with the participants with the weakest SOC, those with the strongest SOC had a significantly lower odds ratio (OR) for being overweight (OR = 0.31; 95% confidence interval (CI): 0.11-0.81), and having higher FBS levels (OR = 0.11; 95% CI: 0.02-0.54), dyslipidemia (OR = 0.29; 95% CI: 0.09-0.84), and MetS (OR = 0.12; 95% CI: 0.02-0.63), even after adjusting for age, gender and job stressors. CONCLUSIONS: High SOC is associated with a healthy lifestyle and fewer atherosclerotic risk factors, including MetS.

Effects of transitory stimulation interval exercise on physical function: a randomized controlled pilot study among Japanese Subjects.

Interval training is effective for promoting aerobic capacity and general health. However, it involves repeated high-intensity activity, which could pose cardiovascular risks for the elderly or people who are less fit. We developed a transitory stimulation interval exercise (TSIE) in which the duration of strenuous exertion was reduced to 30 seconds at 75% VO2max of intensity. This pilot study aims to explore the effects of this mode of exercise. Thirty women were randomized and stratified into the TSIE group, the continuous moderate exercise (CME) group, or the no-exercise (NE) group. The two exercise groups performed exercises for 12 weeks. Significant positive changes were observed in the TSIE group compared with the NE group in the relative change ratio from baseline in body weight and VO2max, but no significant differences were observed between the CME group and the NE group. Glycated hemoglobin A1c (HbA1c) decreased significantly in both exercise groups compared with the NE group. Overall, there were few significant differences between the CME group and the TSIE group. There might not be any differences between the TSIE and the CME in a long term intervention with equalized training volumes.

[Current trends in the effects of stretching: application to physical exercise in the workplace].

A review of the Survey on the State of Employees' Health by the Ministry of Health, Labour and Welfare (2008) shows that the most commonly implemented aspect as an activity of worksite health promotion is "Health counseling", and the second is "Workplace physical exercise." Physical exercise, "Taiso", is acceptable and sustainable for workers, as it is easy to do in a group or alone. Various modes of stretching are implemented for workplace physical exercise. However, articles suggesting negative or contradictory effects of stretching have increased in recent years. Several review articles have revealed that static stretching may induce impairments of muscle power performance and no stretching will prevent or reduce muscle soreness after exercise. There are various aims of workplace physical exercise, so we have to consider the situational method when we apply stretching to occupational health.

Assessments by HR and %HRR of occupational work exertion for alternating periods of rest and manual labor.

OBJECTIVES: Metabolic equivalents (METs) and relative metabolic rate (RMR) as calculated by oxygen uptake (VO(2)) are often used to assess physical exertion. In practice, accurate measurements of VO(2) are difficult; heart rate (HR) values represent an alternate index of physical exertion. We investigated whether one can assess physical exertion based on HR in the workplace, even if the physical task in question involves alternating periods of strenuous anaerobic activity and rest. We also examined the potential usefulness of assessments based on percentage of heart rate reserve (%HRR) and percentage of oxygen uptake reserve (% VO(2)R). METHODS: Six healthy men were asked to perform several physical movements. HR and VO(2) were recorded in real time. RESULTS: HR and VO(2) are significantly correlated even under conditions of various repeated intermittent movements including anaerobic exertion. Cumulative fatigue results in inadequate recovery in various parameters indicating sufficient rest times, whereas VO(2) values recover immediately. One movement may generate large differences in HR among individuals, but not in VO(2). We found no significant differences between dispersion for %HRR and VO(2)R. However, as with HR, %HRR values indicated insufficient recovery after strenuous exertion. CONCLUSIONS: VO(2) alone does not adequately reflect the exertion entailed by certain physical activities. HR is more useful than VO(2) in evaluating the exertion required by physical labor in individual workers. While we can use %HRR and % VO(2)R to compare physical exertion from individual to individual, %HRR is more valuable, since % VO(2)R can underestimate physical exertion in recovery periods for the same reasons as VO(2).

[Setting of workloads for the exercise testing of women with lower fitness levels].

The values for the lowest workload for submaximal exercise testing with bicycle ergometers currently recommended by the Japan Medical Association and the American College of Sports Medicine (ACSM) is 25-50-75-100 W, depending on the gender and fitness of the individual. However, some women are unable to complete the test suite before reaching a steady state in the third stage. The purpose of the present study is to explore this problem and identify possible solutions. Using a multi-stage incremental ergometer test with the workload between 20 W and 120 W, 22 (26.2%) of the 84 adult female subjects had predicted workloads of less than 75W as the criterion for terminating the submaximal test, based on the 70% heart rate reserve (HRR) method. Moreover, 29 of the 84 female subjects (34.5%) reported the workload as being "Hard" (> 15 on the Borg scale) at workloads of 75 W or less in tests in which the rating of perceived exertion of "Hard" is the criterion for terminating the test. Of the 84 subjects, 19 (22.6%) reported this rating at loads of 60W or below. However, only two subjects (2.4%) reported this rating at 50W or below. Therefore, it may be more useful and effective to use a lower workload value as an option (for example, a third load of 60 W), due to the typically slight build of women. To set the protocol, on the other hand, we generally account for the subject's body weight when predicting the load for 70% HRR. In our group of subjects, the correlation between the load at 70% HRR and body weight was only r = 0.269. However, when we used fat-free mass (FFM) instead of body weight, the correlation proved stronger (r = 0.404). Therefore, it is suggested that using FFM in place of body weight can improve the precision in predicting the appropriate workload when setting the protocol for submaximal exercise testing using bicycle ergometers.

Urea, the most abundant component in urine, cross-reacts with a commercial 8-OH-dG ELISA kit and contributes to overestimation of urinary 8-OH-dG.

Urinary 8-OH-dG is commonly analyzed as a marker of oxidative stress. For its analysis, ELISA and HPLC methods are generally used, although discrepancies in the data obtained by these methods have often been discussed. To clarify this problem, we fractionated human urine by reverse-phase HPLC and assayed each fraction by the ELISA method. In addition to the 8-OH-dG fraction, a positive reaction was observed in the first eluted fraction. The components in this fraction were examined by the ELISA. Urea was found to be the responsible component in this fraction. Urea is present in high concentrations in the urine of mice, rats, and humans, and its level is influenced by many factors. Therefore, certain improvements, such as a correction based on urea content or urease treatment, are required for the accurate analysis of urinary 8-OH-dG by the ELISA method. In addition, performance of the ELISA at 4 degrees C reduced the recognition of urea considerably and improved the 8-OH-dG analysis.