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Biomedical subjects

K Rodahl

Publications and source records attributed to K Rodahl.

At least 19 recordsLinked to original sources
PubMed1991

Working in the cold.

Physiologically speaking, working in the cold is primarily a matter of maintaining thermal balance, since both energy metabolism and neuromuscular function is temperature dependent. Body temperature is also subject to variations due to circadian rhythms. While local acclimatization to cold is well established, and may be of considerable practical benefit, general acclimatization to cold, if in fact a reality, is at best of limited practical value compared to know-how, experience, and environmental protection. Some of the major problems associated with the performance of physical work in the cold, are consequences of the hobbling effect of the protective clothing, as well as the obstructive effects of snow and ice, and the chilling effect of wind.

Body Temperature Regulation↗
PubMed1990

[Blood pressure elevation among industrial workers exposed to stress].

A standardized, annual medical examination of a group of heat workers exposed to, and another group not exposed to heat in a Norwegian ferro-alloy plant over a period of six years showed no statistically significant difference in blood pressure between the two groups. However, following three years of stable blood pressure and heart rates, both parameters increased markedly in both groups. The occurrence of this sudden increase in blood pressure coincided with the plant being threatened with the possibility of closure due to inability to operate at a profit. This threat persisted for more than two years, but even afterwards, when it was quite clear that jobs at the plant were no longer threatened, the blood pressure remained markedly elevated. These findings emphasize the importance of being aware of the possible relationship between prolonged mental stress and hypertension.

Adult↗
PubMed1987

Assessment of physical activity by questionnaire and personal interview with particular reference to fitness and coronary mortality.

Physical work capacity was measured by means of a symptom limited, near maximal cycle ergometer exercise test in two populations: a random sample of 95 military officers, and 2014 apparently healthy working males, 40-59 years old. Physical activity during leisure hours was assessed by means of a standardized questionnaire and by a personal interview with the officers and with 1769 of the other men. A 3 year total incidence of coronary heart disease (CHD) was recorded in the case of the officers and a 7 year CHD incidence and of CHD deaths was obtained for the 2014 working men. The data show that: A marked underestimation of the habitual levels of physical activity of the officers was obtained from the standardized questionnaire, as compared with that shown by the interview data. A far better agreement between the questionnaire and interview data on leisure time activity was observed among the mainly sedentary men. Physical work capacity was fairly well predicted from the questionnaire data in the sedentary men, but poorly predicted in the officers. CHD mortality in the sedentary men was highly correlated with working capacity in all age groups. Of 58 who died from CHD, 28 belonged to the lowest physical fitness quartile. This study indicates that questionnaires should be used with caution when assessing levels of habitual physical activity. It also suggests that a low physical work capacity is an important risk factor in CHD mortality.

Adult↗
PubMed1983

Factors preceding the onset of meningococcal disease, with special emphasis on passive smoking, symptoms of ill health.

In a prospective study of 115 patients with systemic meningococcal disease, 61 control patients and 293 population controls, environmental and other factors which preceded the illness and which might have influenced the acquisition and case fatality rate of the meningococcal disease were investigated. Passive smoking in children under 12 year of age, stressful events, and symptoms and signs of preceding illness within the last two weeks were significantly more frequent in meningococcal patients than among the population controls. In contrast, those patients who had been exposed to stressful events, or who had symptoms or signs of ill-health preceding the meningococcal disease, had significantly reduced case fatality rates as compared to those who had not had any such experiences. Passive smoking remains a factor of great interest for further studies and intervention.

Adolescent↗
PubMed1982

Regional differences in the lipolytic response of the subcutaneous fat depots to prolonged exercise and severe energy deficiency.

After five days of almost continuous strenuous combat exercise and energy deficiency, 12 well-trained young men had a mean body fat loss of 2.7 kg and the average fat cell size was reduced from 0.34 microgram to 0.24 microgram. No significant changes were found in the total number of fat cells. For the group as a whole, the decrease in fat cell size was most pronounced in the gluteal subcutaneous region, followed by the abdominal region. No significant decrease in fat cell size was encountered in tissue samples from the femoral site. Before the course, and on the last day, the subjects accomplished a short-term bicycle exercise at 50% of the individual's VO2. On day 5, positive correlations were found between the fat cell weights estimated in the gluteal tissue samples and the pre-exercise free fatty acid (FFA) levels (r = 0.87, p less than 0.01), and also with the plasma free glycerol obtained five minutes after the bicycle exercise (r = 0.93, p less than 0.001). These correlations were not apparent in the control experiment performed before the course. Further, no such relationship was found between the plasma metabolites and the fat cell size of the other body sites investigated. This finding may indicate that gluteal fat deposits are more important for energy provision than abdominal and, especially, femoral deposits.

Adipose Tissue↗
PubMed1982

Latent ischemic heart disease in sea captains.

For 110 apparently healthy Norwegian captains on ocean-going ships a near maximal bicycle exercise test revealed a pathological exercise electrocardiogram for 10.0%, while the corresponding results for a comparable group of Oslo men and a group of Norwegian sea pilots were 4.6 and 11.8%, respectively. The significant difference in prevalence between the captains and Oslo men could not be explained by differences in serum lipids, blood pressure, or a family history of coronary heart disease. The captains were taller and more physically fit than the Oslo men, but they were significantly heavier and had a more rapid age decline in physical performance capacity and a higher prevalence of heavy smokers. Ten of the 11 captains with a pathological exercise electrocardiogram were, or had been, heavy smokers (greater than or equal to 20 cigarettes/d). A high caloric intake in relation to caloric expenditure, heavy smoking, and poorly defined factors such as stress, irregular workhours, and varying climatic conditions are factors to be considered as explanations for these findings. The claim by captains that they have a higher risk than average for developing coronary heart disease was to some extent corroborated in the present study.

Adult↗
PubMed1981

Coronary heart disease in Norwegian sea-pilots: part of the occupational hazard?

A near maximal bicycle exercise test revealed a prevalence of positive exercise ECG's of 8/68 among apparently healthy sea-pilots and 93/2014 among apparently healthy men of comparable age in Oslo (P less than 0.01). This difference could not be explained in terms of differences in commonly accepted coronary heart disease risk factors (cholesterol/triglycerides, smoking habits and blood pressure). Reasons for the difference should be sought in the working environment of the pilots as well as in possible unfavourable life habits adapted during leisure time as indicated by a relative increase in body weight and somewhat lower working capacity in pilots than in age matched counterparts from Oslo.

Adult↗
PubMed1979

Resting heart rate in apparently healthy middle-aged men.

Resting heart rate (fcrest) was measured by a standardized technique in 2,014 men aged 40-59 years during a cardiovascular survey. All men were thought to be healthy prior to the survey examination. According to the survey findings, the material was subdivided into 5 clinical subgroups, according to survey findings of coronary heart disease (CHD), or suspect symptoms, or signs. Coronary angiography was performed in 105 subjects with particularly strong suspicions of CHD. FCrest varied between 61-63 among the 5 groups (p greater than 0.10). In 1832/2014 defined as "normals" the following findings were made: 1. Mean fcrest 61 (SD 9.7), and almost identical values obtained by auscultation and from resting ECGs in the same persons. 2. Linear drop in fcrest by age (-0.126 beats/year, p less than 0.001). 3. Increase in fcrest with increasing systolic blood pressure. Since there is no generally accepted technique for measuring fcrest it is suggested that the wide variation in fcrest reported in the literature at least in part may be due to differences in techniques.

Adult↗
PubMed1979

Seasonal variation in work performance and heart rate response to exercise. A study of 1,835 middle-aged men.

A near maximal bicycle exercise test in 1,835 presumably healthy Norwegian men indicated a seasonal variation in physical fitness. Thus, the total amount of work performed was significantly higher, and the work pulse on equivalent loads significantly lower during the summer than during the autumn. Although the differences were small, they may invalidate comparisons made between exercise tests in populations tested at different seasons of the year. In particular, there was a considerable and sudden change in the above mentioned parameters from June--August to September--October.

Adult↗
PubMed1977

Work stress in long-line bank fishing.

The circulatory strain on three Faroe Island and two Norwegian fishermen during long-line bank fishing was assessed by the computerized analysis of their heart rates continuously recorded by portable tape recorders. The urinary excretion of catecholamines was assayed as an indicator of stress response. The average work load of the three Faroe Island deckhands was rather moderate; it corresponded to 26--33% of the heart rate reserve (HRR). However, heart rates higher than 50% of the HRR (9--18 min/24 H) as well as peak heart rates up to 165 beats/min indicated periods of intense physical strain, especially when the fish were being unhooked, an operation which, as a rule, cannot be endured for more than about 25 min at a time and which necessitates a work schedule of job rotation. These observations were confirmed by the findings made on board the Norwegian vessel. The urinary catecholamine excretion rates were lower than those of coastal fishermen and of the same order of magnitude as the excretion rates observed in trawler fishermen. It is concluded that, contrary to general belief, bank fishing need not be unsuitable for older fishermen, provided an effective system of job rotation is practiced and the size of the crew is large enough to allow for an adequate amount of sleep even during periods of exceptionally good fishing.

Adult↗
PubMed1975

Oxygen uptake/heart rate relationship in leg and arm exercise, sitting and standing.

The effect of leg exercise and of arm exercise in sitting and standing body positions on energy output and on some cardiorespiratory parameters was studied in seven male subjects. Oxygen uptake (VO2), heart rate (fH), pulmonary ventilation (VE) and respiratory frequency were measured at rest, in the 7-8th min of submaximal work (300, 600, 900 kpm/min), and at maximal effort. Significantly higher Vo2, fH, and VE in arm cranking than in cycling were found at submaximal work loads above 300 kpm/min. Though the maximal work load in arm exercise was 50-60% of that in cycling, Vo2 in arm work was at maximal effort only 22% lower than in leg exercise while the difference in fH was insignificant. No differences were found in arm work between the results obtained at any work level in sitting and standing body positions. The only postural difference in arm work was a 13% higher work load achieved at maximal effort when standing than when sitting. Differences in fH between arm and leg exercise were much smaller for the same Vo2 than for the same work load and were time dependent. While fH quickly leveled off in leg exercise, fH in arm cranking rose steadily during the first 6 min of work which created the fH differences observed in the 7-8 min of submaximal arm arm and leg exercise. At submaximal work levels a tendency to synchronize the respiratory frequency with the frequency of the rotatory movements was more apparent in arm cranking than in cycling.

Adult↗