As part of the more extensive project concerned with atherosclerosis precursors in Finnish children, this article aims at describing the method developed for epidemiological estimation of habitual physical activity, discussing the reliability and validity of the method and reporting the results of the application of this strategy in the measurement of habitual physical activity among 3 to 18-year-old Finnish boys and girls. The questionnaire for the measurement of physical activity was addressed to the parents of 3- and 6-year-old subjects (younger group) and to the subjects themselves in 9- to 18-year-olds (older group). Using four variables in the younger group and nine variables in the older group, sum indices of physical activity were made. Internal consistency coefficients (Kuder--Richardson) varied in the younger group from .57 to .63 and in the older group from .56 to .79. Most Finnish children and adolescents were physically active during their leisure-time. For comparison of passive and active children, screening for passive ones was difficult. Differences between East and West Finland associated with many risk factors, were not detected in the physical activity patterns of children and adolescents. On the other hand, the physical activity pattern was significantly determined by the local environment. In sparsely populated areas, young people were more inactive than in densely populated areas.

Atherosclerosis precursors in Finnish children and adolescents. X. Leisure-time physical activity.

Performance scores on both a simple detection task and a complex visual judgment task, together with subjective alertness ratings, were collected 4-hourly from 19 watchkeepers working a “4-on/8-off” routine, and from 20 dayworkers, over consecutive days of voyages on merchant ships. Adaptation of the circadian rhythms in the measures to the shifted hours of work of the three sections of the watchkeeping crews was at best only partial. These rhythms resulted in a depression of the levels of most measures during the night hours, which was exacerbated by the effects of recent awakening from sleep. It is suggested that these unwanted variations in operational effectiveness could be largely removed by replacing the 4-on/8-off watchkeeping system, with its associated “split” sleep pattern, by one which allows a single full length sleep each day. Such a system would encourage better adaptation of the rhythms; effects of recent awakening could be avoided by the provision of an adequate “waking up” period before duty begins.

Work at sea: a study of sleep, and of circadian rhythms in physiological and psychological functions, in watchkeepers on merchant vessels. III. Rhythms in physiological functions

The recording of occupational activities with a standardized diary method according to Edholm was carried out on 120 men in six branches of industry. Heart rate and activities were recorded continually over the shift, heart rate being used as a control for the strain in single activity categories. The result showed that the changes in activities were overestimated in branch-specific and position-specific groups without particular physical work. The overestimation of activity changes was found both in cases where the diary was kept by the subject and where trained observers were used. It is concluded that the classification of occupational activities should be carefully controlled with parallel recording of heart rate. To improve the applicability of diary methods limiting values of heart rate and relative load for single activity categories are suggested.

The Applicability of The Edholm Scale for Activity Studies in Industry

The cardiovascular system is well organized in time. Mechanisms of regulation and pathophysiological events are not evenly distributed over the 24-h scale. Moreover, certain diseases may even alter...

Chronopharmacology of cardiovascular medications

The work-related aspects of coronary heart disease have been studied from the viewpoint of work physiology. The purpose of the following three studies has been to clarify how physical load at work and at leisure affects the risk of developing coronary heart disease.The first study included 120 men, mean age 41 years. They were intensively studied in the laboratory and field conditions, and were classified into four activity categories according to their work and leisure time activities. The results indicated that the highest prevalence rates of obesity, hypertension and angina pectoris symptoms were found among men doing heavy physical work and having no sporting leisure activities. The second study included a postal questionnaire to Finnish municipal employees in 1981 and 1985. Altogether 1999 women and 1419 men responded in both years. Their mean ages at the two survey times were 50.5 and 54.7 years, respectively. The 4-year incidence rates of coronary heart diseases diagnosed by the doctor (myocardial ...

Work and cardiovascular health: viewpoint of occupational physiology.

Es wird uber die kontinuierliche Registrierung der Herzfrequenz mit einem transportablen Cardiocorder berichtet, der die minutliche Erfassung der Herzfrequenz fur Zeiten bis zu 24 Std erlaubt. Das GerAt besteht im Prinzip aus einem zweikanaligen TonbandgerAt, dessen Laufgeschwindigkeit so untersetzt ist, da\ eine normale Tonbandkassette C 60 fur eine Herzfrequenzregistrierung von 2×24 Std Dauer ausreicht. Auf der ersten Spur des Tonbandes werden die R-Zacken des EKG als Biosignale registriert; auf der zweiten Spur wird in minutlichen AbstAnden eine Zeitmarke aufgegeben. Mit Hilfe eines WiedergabegerAtes wird die 24stundige Aufnahme in ca. 15 min abgespielt. Durch einen eingebauten Impulsformer werden die Signale beider Spuren in digitale Rechteckimpulse umgewandelt. Diese in serieller Form vorliegenden Impulse werden durch ein Interface in einen ZAhler mit Hilfe der Zeitmarke in minutlichen AbstAnden gezAhlt; diese Werte stehen in BCD-Code parallel zur Weitergabe fur PeripheriegerAte wie: Schnelldrucker, Rechner, Kompensationsschreiber etc. zur Verfugung. Wird gleichzeitig die korperliche AktivitAt, standardisiert durch Selbstoder Fremdbeobachtung, ermittelt, so lassen sich diese Verhaltensmuster mit den Herzfrequenzwerten zur weiteren statistischen Verarbeitung zusammenbringen.

J. Rutenfranz

Papers

[Experiences with a cardiorecorder system for continuous 24-hour registration of heart rate].