Mark Lidegaard

The Combined Relationship of Occupational and Leisure-Time Physical Activity With All-Cause Mortality Among Men, Accounting for Physical Fitness

The aim of this study was to assess the combined relationship of occupational physical activity and leisure-time physical activity with all-cause mortality among men, while accounting for physical fitness. The prospective Belgian Physical Fitness Study included 1,456 male workers aged 40-55 years who were free of coronary heart disease at baseline. Baseline data were collected through questionnaires and clinical examinations from 1976 to 1978. To estimate physical fitness, a submaximal graded exercise test was performed on a bicycle ergometer. Total mortality was registered during a mean follow-up period of 16.9 years. Main results were obtained through Cox proportional hazards regression analysis. A total of 145 deaths were registered during follow-up. After adjustment for confounders, a significantly increased mortality rate was observed in workers who had low levels of both physical activity types (hazard ratio = 2.07, 95% confidence interval: 1.03, 4.19) but also in workers combining high occupational physical activity and low leisure-time physical activity (hazard ratio = 2.04, 95% confidence interval: 1.07, 3.91); the latter finding was particularly pronounced among workers with a low physical fitness level. The present results confirm the existence of a complex interplay among different physical activity settings and fitness levels in predicting mortality.

Does aerobic exercise improve or impair cardiorespiratory fitness and health among cleaners?: A cluster randomized controlled trial

OBJECTIVE It is unknown if aerobic exercise overloads or improves the cardiovascular system among workers with high occupational physical activity. This was investigated in a worksite randomized controlled trial (RCT) of aerobic exercise among cleaners. METHODS We randomized 116 cleaners between 18-65 years. The aerobic exercise group (N=57) performed worksite aerobic exercise (30 minutes twice a week) and the reference group (N=59) received lectures. Cardiorespiratory fitness, blood pressure (BP) and diurnal heart rate (HR) for measuring aerobic workload [% HR reserve (% HRR)] were collected at baseline and after four months. A repeated measure 2×2 multi-adjusted mixed-model design was applied to compare the between-group differences in an intention-to-treat analysis. RESULTS Between-group differences (P<0.01) were found: cardiorespiratory fitness 2.2 [standard error (SE) 0.8] ml O 2 × min -1 × kg -1 [95% confidence interval (95% CI) 0.6-3.8], aerobic workload - 3.5 (SE 1.2) % HRR (95% CI - 5.9- -1.0), resting HR -3.8 (SE 1.2) bpm (95 % CI -6.1- - 1.4), sleeping HR -3.8 (SE 1.1) bpm (95% CI - 5.9- - 1.7), and systolic BP 3.6 (SE 1.3) mmHg (95% CI 1.1-6.0). CONCLUSIONS Worksite aerobic exercise seems to improve cardiorespiratory fitness, aerobic workload, and resting and sleeping HR, but increase systolic BP among cleaners. Beneficial physiological cardiovascular effects are seen from aerobic exercise, but also a harmful effect is evident. Therefore, recommendations should take into consideration the potential cardiovascular overload from additional aerobic exercise on workers with high levels of occupational physical activity.

Effect of Brief Daily Resistance Training on Occupational Neck/Shoulder Muscle Activity in Office Workers with Chronic Pain: Randomized Controlled Trial

Purpose. This study investigates the acute and longitudinal effects of resistance training on occupational muscle activity in office workers with chronic pain. Methods. 30 female office workers with chronic neck and shoulder pain participated for 10 weeks in high-intensity elastic resistance training for 2 minutes per day (n = 15) or in control receiving weekly email-based information on general health (n = 15). Electromyography (EMG) from the splenius and upper trapezius was recorded during a normal workday. Results. Adherence to training and control interventions were 86% and 89%, respectively. Compared with control, training increased isometric muscle strength 6% (P < 0.05) and decreased neck/shoulder pain intensity by 40% (P < 0.01). The frequency of periods with complete motor unit relaxation (EMG gaps) decreased acutely in the hours after training. By contrast, at 10-week follow-up, training increased average duration of EMG gaps by 71%, EMG gap frequency by 296% and percentage time below 0.5%, and 1.0% EMGmax by 578% and 242%, respectively, during the workday in m. splenius. Conclusion. While resistance training acutely generates a more tense muscle activity pattern, the longitudinal changes are beneficial in terms of longer and more frequent periods of complete muscular relaxation and reduced pain.

The Relation of Ambulatory Heart Rate with All-Cause Mortality among Middle-Aged Men: A Prospective Cohort Study

The aim of this study was to investigate the association between average 24-hour ambulatory heart rate and all-cause mortality, while adjusting for resting clinical heart rate, cardiorespiratory fitness, occupational and leisure time physical activity as well as classical risk factors. A group of 439 middle-aged male workers free of baseline coronary heart disease from the Belgian Physical Fitness Study was included in the analysis. Data were collected by questionnaires and clinical examinations from 1976 to 1978. All-cause mortality was collected from the national mortality registration with a mean follow-up period of 16.5 years, with a total of 48 events. After adjustment for all before mentioned confounders in a Cox proportional hazards regression analysis, a significant increased risk for all-cause mortality was found among the tertile of workers with highest average ambulatory heart rate compared to the tertile with lowest ambulatory heart rate (Hazard ratio = 3.21, 95% confidence interval: 1.22–8.44). No significant independent association was found between resting clinic heart rate and all-cause mortality. The study indicates that average 24-hour ambulatory heart rate is a strong predictor of all-cause mortality independent from resting clinic heart rate, cardiorespiratory fitness, occupational and leisure time physical activity and other classical risk factors among healthy middle-aged workers.

Long Term Effects on Risk Factors for Cardiovascular Disease after 12-Months of Aerobic Exercise Intervention: A Worksite RCT among Cleaners

Objectives Occupational groups exposed to high occupational physical activity have an increased risk for cardiovascular disease (CVD). This may be explained by the high relative aerobic workload. Enhanced cardiorespiratory fitness reduces the relative aerobic workload. Thus, the aim was to evaluate the 12-months effects of worksite aerobic exercise on risk factors for CVD among cleaners. Methods One hundred and sixteen cleaners aged 18–65 years were randomized to a group performing aerobic exercise and a reference group receiving lectures. Outcomes were collected at baseline and after 12-months. A repeated measures 2×2 multi-adjusted mixed-model design was applied to compare the between-group differences using intention-to-treat analysis. Results Between-group differences (p<0.05) were found favouring the aerobic exercise group: cardiorespiratory fitness 2.15 (SE 1.03) mlO2/min/kg, aerobic workload -2.15 (SE 1.06) %HRR, resting HR -5.31 (SE 1.61) beats/min, high sensitive C-reactive protein -0.65 (SE 0.24) μg/ml. The blood pressure was unaltered. Stratified analyses on relative aerobic workload at baseline revealed that those with relative aerobic workloads ≥30% of HRR seems to impose a notable adverse effect on resting and ambulatory blood pressure. Conclusion This long-term worksite aerobic exercise intervention among cleaners led to several beneficial effects, but also potential adverse effects among those with high relative aerobic workloads. Trial Registration Controlled-Trials.com ISRCTN86682076

Decrease in musculoskeletal pain after 4 and 12 months of an aerobic exercise intervention: a worksite RCT among cleaners

Background: Prevalence of musculoskeletal pain is high in jobs with high physical work demands. An aerobic exercise intervention targeting cardiovascular health was evaluated for its long term side effects on musculoskeletal pain. Objective: The objective was to investigate if aerobic exercise affects level of musculoskeletal pain from baseline to 4- and 12-months follow-up. Methods: One-hundred-and-sixteen cleaners aged 18–65 years were cluster-randomized. The aerobic exercise group (n = 57) received worksite aerobic exercise (30 min twice a week) and the reference group (n = 59) lectures in health promotion. Strata were formed according to closest manager (total 11 strata); clusters were set within strata (total 40 clusters, 20 in each group). Musculoskeletal pain data from eight body regions was collected at baseline and after 4- and 12-months follow-up. The participants stated highest pain in the last month on a scale from 0, stating no pain, up to 10, stating worst possible pain. A repeated-measure 2 × 2 multi-adjusted mixed-models design was applied to compare the between-groups differences in an intention to treat analysis. Participants were entered as a random effect nested in clusters to account for the cluster-based randomization. Results: Clinically significant reductions (>30%, f 2 > 0.25) in the aerobic exercise group, compared to the reference group, in pain intensity in neck, shoulders, arms/wrists were found at 12-months follow-up, and a tendency (p = 0.07, f 2 = 0.18) to an increase for the knees. At 4-months follow-up the only significant between-group change was an increase in hip pain. Conclusions: This study indicates that aerobic exercise reduces musculoskeletal pain in the upper extremities, but as an unintended side effect may increase pain in the lower extremities. Aerobic exercise interventions among workers standing or walking in the majority of the working hours should tailor exercise to only maintain the positive effect on musculoskeletal pain.

Association Between Trapezius Muscle Tenderness and Tension-Type Headache in Female Office Workers: A Cross-sectional Study

Objective: The purpose of the study was to determine the association between trapezius muscle tenderness and tension‐type headache among female office workers. Methods: Through a questionnaire survey, 256 female office workers with tension‐type headaches reported the level of palpable tenderness (“no,” “some,” or “severe tenderness”) in the trapezius muscle. The number of days with headache (“0–7,” “8–14,” or “>14”), intensity (“low,” “moderate,” or “high”), duration of headache (“<8 hours per day,” “>8 hours per day,” and “all day”), and use of analgesic medications were reported. Odds ratio (OR) for tenderness in the trapezius muscle (“no/some” vs “severe tenderness”) as a function of days with headache, intensity of headache, duration of headache, and use of analgesic medications were calculated using a binary logistic regression controlling for age and body mass index. Results: After adjustments for confounders, a strong association was found between the level of trapezius muscle tenderness and intensity of headache (moderate intensity, OR 2.45; 95% confidence interval [CI] 1.08–5.54; high intensity, OR 7.51 [95% CI 2.65–21.29]) and days with headache (>14 days, OR 4.75 [95% CI 1.41–15.89]). No association was observed for duration of headache or use of analgesic medications. Conclusions: For the participants studied, there was a strong association between trapezius muscle tenderness and the level of intensity and the number of days with a headache among female office workers. No association was seen for duration of headaches or use of analgesic medications.

Chronicle Workshops as Data Collection Method in Evaluation of National Work Environment Intervention

When evaluating national work environment initiatives, it is important to choose methods through which it is possible to gather necessary and relevant information in a time efficient way for researchers and involved organisations. This article evaluates the usefulness of chronicle workshops as a data collection method to help assess the effectiveness of national work environment initiatives aiming to create interventions in organisations. Chronicle Workshops were used as one of three methods in case studies evaluating a national guideline on moving and handling people. Chronicle workshops were found to be an efficient method to identify specific interventions, when they occurred, who had been instrumental in implementing them, what contextual factors had influenced the intervention and factors facilitating and hindering intervention. They lacked specificity on individual strategies and why these did or did not work. Thus Chronicle workshops are good at creating an overview of implementation efforts but need to be supplemented with other methods to gain more detailed information.

Barriers and Facilitators in Implementing a Moving and Handling People Programme – An Exploratory Study

Health care workers, including nurses, have one of the highest musculoskeletal injury incidence rates of any profession, especially work-related back injuries. The majority of musculoskeletal disorders (MSD) in health care are caused by moving and handling of people (MHP). In order to reduce MSDs due to MHP, some national health care sector authorities worldwide have developed intervention programmes or guidelines that can be used by their health care organisations. However, very few of the national interventions have been evaluated for their efficacy or impact. In those that have, the effort to reduce the incidence of MSDs caused by MHP has been largely unsuccessful, often because of barriers. This study aimed to identify what barriers, and facilitators, existed in health care organisations in relation to implementation of the New Zealand MHP guidelines. It was found that implementing a MHP programme especially requires sufficient resources for training and strong support based on evidence, or legislation. Management support for equipment purchase or maintenance is also essential, as is sufficient training for changing the culture of the workplace. It is also important to assess staff MHP knowledge and practices. MHP programmes need to be designed to be suitable for different sectors such as age care, and different users such as a foreign work force.