Three surveys (1969/1970, 1979/1980 and 1989/1990) have examined the impact of acculturation to a sedentary lifestyle on the pulmonary function of a circumpolar native Inuit community. The sample comprised more than 50% of those aged 20-60 yrs, most recently 119 males and 92 females. Forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and maximal mid-expiratory flow (MMEF) were measured by standard spirometric techniques, and information was obtained on smoking habits and health. Multiple regression equations showed that lung function was affected by height and age, but usually not by age squared. Cross-sectional age coefficients for FVC and FEV1 increased over the period 1969/1970 to 1989/1990. Parallel longitudinal trends were seen in FEV1 (males only). Multiple analysis of variance (MANOVA) showed age-decade*cohort effects for FVC and FEV1 (males but not females). Almost all of the population now smoke (mean +/- SD males 13 +/- 8 cigarettes.day-1; females 11 +/- 7 cigarettes.day-1). However, smoking bears little relationship to lung function perhaps due to limited variance in consumption. About a third of the community have physician-diagnosed and/or radiographically visible chest disease, but with little effect upon pulmonary function. We conclude that an apparent secular trend to a faster ageing of lung function in men is not explained by disease or domestic air pollution. Possible factors include increased lung volumes in young adults, greater pack-years of cigarette exposure, nonspecific respiratory disease, increased inspiration of cold air or altered chest mechanics due to operation of high-speed snowmobiles, and loss of physical fitness.
Ten men spent one week in a cold climatic facility performing a simulated arctic military exercise demanding an energy expenditure of 13-16 MJ-day-1. Although the ration pack was adequate, extensive plate wastage led to a negative energy balance of 2.2 MJ-day-1. Fluid intake was also insufficient, with a 3.25% decrease of body weight, and a 9.7% decrease in skin thickness over the cold exposure. Extensive fat mobilization was indicated by a decrease of skinfold thicknesses, an increase of body density, and associated ketonuria and glycosuria. The fat breakdown far exceeded the calculated energy deficit, and it is postulated that much of the "surplus" energy was required for synthesis of additional muscle protein. In the arctic environment, both energy and fluid balances are better maintained because there are few distraction from the simple pleasure of preparing and eating meals.
The history, physical characteristics and fitness status of 60 persons who had sustained a spinal cord injury at least 3 years previously were considered in relation to current occupation. All subjects had completed their education, 39 being gainfully employed and 21 unemployed. The general characteristics of the sample, mainly beneficiaries of the Quebec Automobile Insurance Plan, were typical of spinal cord injured individuals in North America. The working group had a significantly higher current level of education than those who were unemployed (p less than .01). In terms of physical fitness, the workers were lighter, with a lower body mass index and a higher aerobic power (p less than .05). Isokinetic testing suggested a trend toward a higher peak torque in the workers. The total work performed (Nm.kg-1) during an isokinetic endurance test (25 biphasic contraction at 180 degrees.sec-1) was significantly higher in the workers, suggesting that such muscular endurance might be even more useful than greater peak isokinetic strength during vocational activities. However, the likelihood of employment was unrelated to habitual patterns of either aerobic exercise or overall physical activity. No significant differences of physical fitness or physical activity habits were found between workers holding sedentary versus physically demanding jobs. The results verified the positive relationship between physical fitness (body composition, aerobic power, muscular endurance) and the gainful employment of paraplegics, but failed to show any significant relationship between physical fitness and the acceptance of physically demanding work by such individuals.