Kombinirani učinci smjenskog rada i faktora okoline (vrućina, buka, toksični agensi)

The paper deals with the results of studies or discussions concerning the problem of nightwork combined with other adverse working conditions. Special emphasis is laid on the untoward effect of high temperature during nightwork, as well as on noise and exposure to chemicals. It is shown that there is no substantial influence of heat stress on the circadian rhythm of adrenaline excretion under sitting working conditions with the subject performing a difficult mental task at warm climates up to 30 °C BET. Shiftwork and noise induce independent different effects which can be explained in terms of activation for shiftwork and in terms of tension for noise. The combination of both adverse exposures is therefore partly subtractive but partly additive as night work and noise negatively affect daysleep. Practical experience in the field of combined effects of shiftwork and chemical agents is lacking, but theoretical speculations lead to the conclusion that there may exist a time of day dependence of some chemicals, used at workplaces.U radu su prikazani rezultati istraživanja i iznesena je teorijska rasprava o problemu smjenskog rada povezanim s drugim nepovoljnim uvjetima rada. Naročito je naglašeno moguće negativno djelovanje visoke temperature za vrijeme smjenskog rada, kao i utjecaj buke i izloženost kemikalijama. Nađeno je da nema značajnog utjecaja toplinskog stresa na dnevni ritam izlučivanja adrenalina pri sjedećem teškom mentalnom radu sve dok temperatura ne pređe 30 ° BET. Smjenski rad i buka imaju neovisno djelovanje koje se može razjasniti aktivnošću u smjenskom radu i napetošću uzrokovanom bukom. Stoga je djelovanje ovih dvaju negativnih utjecaja djelomično suprotno, a djelomično aditivna, budući da noćni rad i buka negativno utiču na san slijedećeg dana. Nedostaju iskustva o kombiniranom djelovanju smjenskog rada i kemijskih spojeva u radnoj okolini, no teorijske pretpostavke dovode do zaključka da bi mogle postojati razlike u toksičnosti pojedinih kemikalija s obzirom na doba dana

Aerobic capacity, activity levels and daily energy expenditure in male and female adolescents of the kenyan nandi sub-group

The relative importance of genetic and socio-cultural influences contributing to the success of east Africans in endurance athletics remains unknown in part because the pre-training phenotype of this population remains incompletely assessed. Here cardiopulmonary fitness, physical activity levels, distance travelled to school and daily energy expenditure in 15 habitually active male (13.9±1.6 years) and 15 habitually active female (13.9±1.2) adolescents from a rural Nandi primary school are assessed. Aerobic capacity ([Formula: see text]) was evaluated during two maximal discontinuous incremental exercise tests; physical activity using accelerometry combined with a global positioning system; and energy expenditure using the doubly labelled water method. The [Formula: see text] of the male and female adolescents were 73.9±5.7 ml(.) kg(-1.) min(-1) and 61.5±6.3 ml(.) kg(-1.) min(-1), respectively. Total time spent in sedentary, light, moderate and vigorous physical activities per day was 406±63 min (50% of total monitored time), 244±56 min (30%), 75±18 min (9%) and 82±30 min (10%). Average total daily distance travelled to and from school was 7.5±3.0 km (0.8-13.4 km). Mean daily energy expenditure, activity-induced energy expenditure and physical activity level was 12.2±3.4 MJ(.) day(-1), 5.4±3.0 MJ(.) day(-1) and 2.2±0.6. 70.6% of the variation in [Formula: see text] was explained by sex (partial R(2) = 54.7%) and body mass index (partial R(2) = 15.9%). Energy expenditure and physical activity variables did not predict variation in [Formula: see text] once sex had been accounted for. The highly active and energy-demanding lifestyle of rural Kenyan adolescents may account for their exceptional aerobic fitness and collectively prime them for later training and athletic success

Studies of shiftwork. /

FOE.29