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:t from the sitc. They weight, and u moderate *3    • subjects

years of age, 5 women be-

l uptake of k mg depart-

e surface tem-

1 l_

Cold-storagc

room

2—5

0.1—03

64—75

2—6

*

tween 19 and 35 years of age in the pack-aging department. The subjects wore their ordinary workclothing during the work sessions. White cotton clothing was sup-plied by the company. Most workers wore a short iacket. trousers. underpants. one or two pftirs of socks, clogs, and sometimes also undershirts. cotton gloves, aprons or a cap. The estimated clo values varie3 from 0.8 to 1.2 (3). Clothing in the pąckaging department was supplemented with an insulating vest and trousers which increased the estimated clo values to JX)— L5.

Each subject was studied for 2 h during ordinary work on two different occasions. At 20- to 30-min intervals during the mea-surement sessions the subjects estimated their perceotion of temperaturę and dis-comjoTt from heat or cold in their body, hands and feet with the ald of two 20-point rating scales. Each scalę had a neutral midpoint and verbally defined end-points (+10 and — 10), termcd maxi-mal warmth/discomfort from warmth and maximal cold/discomfort from cold, re-spectively.

Body temperaturę was measured with an orał (butchers and packers) or rectal (dairy workers) thermometer before and after each session. Skin temperaturę was recorded with slx linear thermistors (accu-racy: ±0.5°C) taped on the right side of the body (e.g., the top of the index finger, back of the hand, chest, shoulder or fore-head, heel or leg, and big toe). The signals were recorded on a portable, 2-channel tape recorder which also recorded heart ratę.

In order for the energy requirements of the work to be calculated, orygen uptake was determined in the subjects on two different occasions during each work session with the aid of the Douglas-bag technique. The volume of expiratory air from 2—5 min of work was measured with a gas meter, and ventilation (BTPS) was calculated. The oxygen (Beckman OM11) and carbon dioxide (Beckman LB2) con-centrations were determined. Oxygen uptake (STPD) was then calculated. Energy requirements were calculated on the basis of oxygen uptake according to the following relationship: 11 O^/min « 350 W»5 kcal/min.

During each measurement session, sub

ject activity was noted and regular climat ic measurements were madę. The sur face temperaturę of the goods, the tablc the floor, and the walls was measured witl an infrared meter (Raynger).

RESULTS

Orygen uptake and heart ratę

The work ratę in the dairy cold storę} was governed by the need to load the deliv-ery trucks rapidly. This was especially the case during early moming sessions In conjunction with these sessions, th« values for oxygen uptake were found tc vary from 0.5 to 1.51/min with individual peaks exceeding 2 l/min (fig. 2). The mean heart ratę dyring work varied from 90 to 130 beats/min during the early moming and late morning sessions (fig. 3). The work was essentially intermittent with periods of high work intensity with peaks in heart ratę exceeding 140 beats/min suc-ceeded by rest pauses or lighter work. The individual variation in heart ratę was largely ascribable to individual variations in physical work capacity (maximal oxygen uptake). In an assessment of the physio-logical work load. it was found that the workers periodically utjlized 50—70⁹/a nf. their physical work capacity in conjunction with work peaks.

Physical reąuirements were lower during the afternoon session. A varying work load resulted in individual values for oxygen uptake ranging from 0.4 to 1.8 1/ min. The mean heart ratę during afternoon work varied from 75—110 beats/min and was generally lower than in the moming.

The butchers could usually determine their own work intensity, and they select-ed an even and moderate work ratę. During cuttiny-dotun work the mean heart ratę varied from 100—110 beats/min. Oxygen uptake was found to amount to 0.8—2.1 l/min during work, corresponding to 3S—50 °/o of the respectiyę indrnduaTs j physical work capacity. The highest work I loads were obtained in conjunction with the cutting down of bul) carcasses, espe-cially in work on hard or tough meat. Indi-vidual peaks in heart ratę of about 140

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