Øystein Nordrum Wiggen

Concurrent strength and endurance training improves physical capacity in patients with peripheral arterial disease.

Peripheral arterial disease (PAD) patients suffer from reduced blood flow to the lower extremities, which causes impaired walking ability. Plantar flexion (PF) endurance training and maximal strength training (MST) induce distinct types of improvements in walking ability in PAD. However, the combined effects of both exercises are still not explored in these patients. This study examined whether concurrent MST and PF training would induce similar training responses as each training mode alone. Ten patients with PAD underwent 8 weeks of concurrent leg press MST and PF training, three times a week. The reference group (n=10) received recommended exercise guidelines. The training group improved treadmill peak oxygen consumption and incremental protocol time to exhaustion with 12.7 ± 7.7% and 12.6 ± 13.2%. Leg press maximal strength and rate of force development improved with 38.3 ± 3.1% and 140.1 ± 40.3%, respectively, along with a 5.2 ± 6.2% within group work economy improvement. No changes appeared in the reference group. Compared with previous studies, concurrent MST and PF training appear to induce similar training responses in PAD patients as when each training mode is executed alone, and without any adverse effects.

Effect of ambient temperature on female endurance performance.

Ambient temperature can affect physical performance, and an ambient temperature range of -4 °C to 11 °C is optimal for endurance performance in male athletes. The few similar studies of female athletes appear to have found differences in response to cold between the genders. This study investigated whether ambient temperature affects female endurance performance. Nine athletes performed six tests while running on a treadmill in a climatic chamber at different ambient temperatures: 20, 10, 1, -4, -9 and -14 °C and a wind speed of 5 m s(-1). The exercise protocol consisted of a 10-min warm-up, followed by four 5-min intervals at increasing intensities at 76%, 81%, 85%, and 89% of maximal oxygen consumption. This was followed by an incremental test to exhaustion. Although peak heart rate, body mass loss, and blood lactate concentration after the incremental test to exhaustion increased as the ambient temperature rose, no changes in time to exhaustion, running economy, running speed at lactate threshold or maximal oxygen consumption were found between the different ambient temperature conditions. Endurance performance during one hour of incremental exercise was not affected by ambient temperature in female endurance athletes.

A user-centred design process of new cold-protective clothing for offshore petroleum workers operating in the Barents Sea

Petroleum operations in the Barents Sea require personal protective clothing (PPC) to ensure the safety and performance of the workers. This paper describes the accomplishment of a user-centred design process of new PPC for offshore workers operating in this area. The user-centred design process was accomplished by mixed-methods. Insights into user needs and context of use were established by group interviews and on-the-job observations during a field-trip. The design was developed based on these insights, and refined by user feedback and participatory design. The new PPC was evaluated via field-tests and cold climate chamber tests. The insight into user needs and context of use provided useful input to the design process and contributed to tailored solutions. Providing users with clothing prototypes facilitated participatory design and iterations of design refinement. The group interviews following the final field test showed consensus of enhanced user satisfaction compared to PPC in current use. The final cold chamber test indicated that the new PPC provides sufficient thermal protection during the 60 min of simulated work in a wind-chill temperature of −25°C. Conclusion: Accomplishing a user-centred design process contributed to new PPC with enhanced user satisfaction and included relevant functional solutions.

Protective jacket enabling decision support for workers in cold climate

The cold and harsh climate in the High North represents a threat to safety and work performance. The aim of this study was to show that sensors integrated in clothing can provide information that can improve decision support for workers in cold climate without disturbing the user. Here, a wireless demonstrator consisting of a working jacket with integrated temperature, humidity and activity sensors has been developed. Preliminary results indicate that the demonstrator can provide easy accessible information about the thermal conditions at the site of the worker and local cooling effects of extremities. The demonstrator has the ability to distinguish between activity and rest, and enables implementation of more sophisticated sensor fusion algorithms to assess work load and pre-defined activities. This information can be used in an enhanced safety perspective as an improved tool to advice outdoor work control for workers in cold climate.

Towards a wearable sensor system for continuous occupational cold stress assessment

This study investigated the usefulness of continuous sensor data for improving occupational cold stress assessment. Eleven volunteer male subjects completed a 90–120-min protocol in cold environments, consisting of rest, moderate and hard work. Biomedical data were measured using a smart jacket with integrated temperature, humidity and activity sensors, in addition to a custom-made sensor belt worn around the chest. Other relevant sensor data were measured using commercially available sensors. The study aimed to improve decision support for workers in cold climates, by taking advantage of the information provided by data from the rapidly growing market of wearable sensors. Important findings were that the subjective thermal sensation did not correspond to the measured absolute skin temperature and that large differences were observed in both metabolic energy production and skin temperatures under identical exposure conditions. Temperature, humidity, activity and heart rate were found to be relevant parameters for cold stress assessment, and the locations of the sensors in the prototype jacket were adequate. The study reveals the need for cold stress assessment and indicates that a generalised approached is not sufficient to assess the stress on an individual level.

Low temperatures and wind; challenges, applicability and limitations from an industrial perspective

The effect of low temperature and wind on the cooling of exposed skin has been a field of interest since the first study by Siple and Passel in 1945[1]. This resulted in the Wind Chill Index (WCI), which expressed the rate of heat loss of a cylinder per unit surface mass. The WCI remained unchanged for many years, and is still regarded as an established and well-defined framework for assessing cold stress. However, in recent years, the Wind Chill Equivalent Temperature (WCT) has supplanted the WCI. WCT is a calculated air temperature based on dry-bulb temperature and wind speed. In the last number of years, these equations have undergone several revisions, in an attempt to develop a tool that is easy to understand and use, and is scientifically valid. The rise in industrial activity in the High North has brought new challenges and a need for better winterisation standards in installations and vessels designed to operate in extremely cold climates. Reducing the need for winterisation without compromising the health and safety of the workers will reduce both building costs and the weight of offshore installations. The aim of this study was to compare the wind-chill recommendations in ISO 11079 and NORSOK S-002, Working Environment.

Muscle activity during simulated work in the cold.

The abundance of natural resources in the Barents region is encouraging growth and development in the far North, exposing more workers to outside work in the cold (average temperature and wind velocity at Rognsundet in Finnmark last winter were -2.6 °C and 9.8 m.s-1, with extreme values of -15.3 °C and 27.5 m.s-1). The aim of this study was to investigate the effect of realistic cold exposure on muscle activity, while wearing the cold-weather protective clothing used in the mining industry.