College student's attidudes and beliefs about the consequences of smoking: development and normative scores of a new scale.

PURPOSE: To develop an instrument that could be used to assist young adults to determine their perceived consequences about cigarette smoking. The new instrument consisted of 27 items measuring attitudes about smoking selected from the literature and to a convenience sample of 172 undergraduate college students. Psychometric assessment using an exploratory factor analysis revealed four factors (subscales) that explained 48% of the variance. These were labeled attitudes and beliefs about smoking related to emotional benefits, health hazards, self-confidence, and body image. CONCLUSIONS: Statistically significant differences between mean scores of smokers and nonsmokers were found on attitudes and beliefs about the benefits of smoking related to emotional benefits, self-confidence, and body image; smokers' answers indicated that they perceived these as positive consequences of their smoking behavior. IMPLICATIONS FOR PRACTICE: The newly constructed instrument may be a useful assessment of college students' reasons for smoking. This approach offers new hope for successful cessation counseling and for smoking prevention programs. Currently antismoking methods emphasize the health hazards of cigarette smoking and have not been sufficient in reducing the rate of smoking in the young adult population. Some young people may use smoking as strategy for dealing with stressful situations, weight control, and lack of self-confidence. Thus, smoking cessation programs should also include strategies to use in place of smoking during periods when stress and lack of self-confidence are high.

Effects of thermal, personal and behavioural factors on the physiological strain, thermal comfort and productivity of Australian shearers in hot weather.

Multiple-regression analyses were used to evaluate the separate and combined effects of factors that are commonly expected to influence strain and productivity in a hot workplace. Forty-three men were studied throughout 54 man-days of shearing sheep and pressing wool bales, in air temperatures 19-41 degrees C and Wet-bulb Globe Temperature index (WBGT) 16-29 degrees C; 43% of the observations of WBGT exceeded 26.7 degrees C, the Threshold Limit Value (TLV) for the subjects' work rate of 400 W. Subjects were men of age 18-59 years, fat-free mass 44-77 kg, and body fat content 11-26%, who had drunk an estimated 0-207 g alcohol the previous evening. Afternoon mean values of rectal temperature (Tre) exceeded 38.0 degrees C (maximum 38.4 degrees C) in 4 of the 15 observations made when WBGT > TLV, and in none of those made when WBGT < TLV. Over the 10 h work day the subjects sweated 2.4-9.9 kg, but they replaced their sweat losses so successfully that warmer weather and heavier sweating were not accompanied by significantly greater dehydration. Surprisingly, the fatter men felt cooler, and those who had drunk more alcohol the previous evening had lower Tre and tended to be more productive. Age was not associated with any measured response. All factors together explained barely half the observed variation in Tre and thermal comfort, and almost none of the variation in productivity. The findings highlight the uncertainty inherent in attempts to define safe limits for occupational heat stress; they show how such uncertainty could restrict the usefulness in the shearing industry of the current heat-stress guidelines; and they demonstrate the effectiveness of the behavioural responses that permit shearers to perform sustained strenuous work in a hot environment without excessive physiological strain.

Effects of acclimatization to cold baths on men's responses to whole-body cooling in air.

The purpose of this study was to investigate the thermoregulatory mechanisms underlying artificial acclimatization to cold and to compare them with those of naturally acclimatized men. Six white men were cooled, nude, in air at 10 degrees C for 2 h before and after they had been acclimatized by ten daily cold (15 degrees C) baths of 30-60 min followed by rapid rewarming in hot (38-42 degrees C) water, and again 4 months later after acclimatization had decayed. Six control subjects also underwent the same tests, providing an opportunity to discriminate between changes caused by the immersions and those caused by extraneous influences. Acclimatization significantly reduced heat production and heat loss (P < 0.05) but did not change heat debt. The reduced heat production was accompanied by reductions in shivering (P < 0.10) and in cold-induced muscle tenseness; no evidence of nonshivering thermogenesis or active brown fat was found. These findings are attributed to increased tissue insulation, mediated by an enhanced vascular response to cold that did not involve the cutaneous circulation and was probably located in skeletal muscle. Thermal sensation and discomfort did not change, although perceived strain tended to increase (P = 0.08). Acclimatization was accompanied by, but was unrelated to, slower cooling of the finger and toe. The main conclusions, and many specific findings, agree with those of two previous studies made by the same techniques in naturally acclimatized men wintering in Antarctica. Other significant findings included changes--in particular reduced thermoneutral rectal temperature and a delayed onset of shivering--that are commonly regarded as evidence of acclimatization but were in fact unrelated to it as they also occurred in the control group. They are attributed to extraneous influences, in particular the relaxation of heightened arousal ('first-time effects') found in the baseline tests.

Cardiovascular and metabolic responses to noradrenaline in men acclimatized to cold baths.

The purpose of this study was to see whether artificial acclimatization to cold would reduce the pressor response to noradrenaline (NA) as natural acclimatization has been shown to do, and whether it would induce nonshivering thermogenesis. Three white men were infused with NA at four dosage levels between 0.038 and 0.300 microgram.kg-1.min-1 (2-23 micrograms.min-1), before and after artificial acclimatization to cold and again 4 months later when acclimatization had decayed. Acclimatization was induced by ten daily cold (15 degrees C) baths of 30-60 min followed by rapid rewarming in hot (38-42 degrees C) water, and was confirmed by tests of the subjects' responses to whole-body cooling in air. Three control subjects also underwent the first and third tests. Acclimatization substantially reduced the pressor response to NA at 0.150 and 0.300 micrograms.kg-1.min-1, confirming earlier findings by the same technique in naturally acclimatized men, and its decay increased this response to beyond its initial levels (P < 0.05 for both changes). Acclimatization did not change the response to NA of heart rate, subjective impressions, skin temperature of finger and toe, pulmonary ventilation, or plasma free fatty acids and ketone bodies. At no time did NA increase oxygen consumption, or increase skin temperature or heat flow over reported sites of brown fat. These findings would seem to show that acclimatization to cold reduces sensitivity to the pressor effect of NA but does not induce nonshivering thermogenesis, and that the reduced sensitivity is replaced by a hypersensitivity to NA when acclimatization decays.

Effects of fitness, fatness, and age on men's responses to whole body cooling in air.

Simple and multiple regression analyses were used to assess the influence of 12 white men's fitness (aerobic capacity 44-58 ml O2.min-1.kg fat-free mass-1), fatness (mean skin-fold thickness 5-20 mm, body fat content 15-36%), and age (26-52 yr) on their thermal, metabolic, cardiovascular, and subjective responses to 2 h of whole body cooling, nude, in air at 10 degrees C. Fitter men had slower heart rates, and fatter men had higher blood pressures. Fitness had no effect (P greater than 0.39) on any measured response to cold. Fatness was associated (P less than 0.01) with reduced heat loss, heat production, and mean skin temperature; unchanged heat debt; and increased tissue insulation. Age had the opposite effects. When the confounding effects of fatness were held constant by multiple regression, older men responded to cold as though they were 1 mm of skinfold thickness leaner for each 3-4 yr of age. We conclude that aging, even between the relatively youthful ages of 26 and 52 yr, is accompanied by a progressive weakening of the vasoconstrictor response to cold.

Fire fighters' exposure to carbon monoxide during Australian bushfires.

Fatal entrapments of Australian bushfire fighters have led to suggestions that carbon monoxide (CO) poisoning could have contributed to these accidents by impairing the fire fighters' judgement. Carboxyhemoglobin saturation (COHb%) levels were assessed from alveolar CO levels in 24 fire fighters working with handtools and in 12 accompanying scientific observers, before and after fire fighting (duration 37-187 min) on 15 experimental bushfires. Carboxyhemoglobin levels increased on average by 0.7% per hour in the fire fighters and by 0.3% per hour in the observers. Nonsmoking fire fighters had lower COHb% after fires than the smokers had before fires. Estimates of environmental CO concentrations (including cigarette smoke) during the fires averaged 31 parts per million (ppm) for the smokers, 17 ppm for the nonsmoking crew members, and 11 ppm for the observers, none of whom smoked. The highest estimates of environmental CO arising solely from bushfire smoke were 40 to 50 ppm. Smokers were exposed to as much CO from their cigarettes as from bushfire smoke. Carboxyhemoglobin levels at the end of 8-hr fire fighting shifts, predicted from these levels of environmental CO, averaged about 5% (maximum 11%) in smokers and about 3% (maximum 7%) in nonsmokers. Acute levels of COHb% of this degree are not considered to have significant effects on health or performance. These results indicate that bushfire fighters are generally unlikely to experience hazardous levels of CO exposure.

Ergonomic aspects of cold stress and cold adaptation.

In contrast to the simplified, unvarying, and rigidly controlled conditions that characterize laboratory studies of human responses to cold, normal work in cold regions is characterized by a complex and unstable thermal environment, intermittent cold exposure and exercise, and the freedom to adjust clothing and activity for comfort. These "ergonomic" aspects profoundly modify the impact of a cold environment on people's health, comfort, and performance. A review of recent field studies in the Antarctic shows that the supposed "tropical microclimate" of clothed people in the cold is an over-simplification. People tend to be alternately chilled and overheated, and the accompanying exercise of the vascular responses provides a potential stimulus for vasomotor adaptation. Significant and substantial changes in men's responses to standardized whole-body cold exposures, observed on eight Antarctic expeditions, show that general acclimatization to cold develops as an increase in tissue insulation, which is mediated by an enhanced vascular response to cold.

Behavioural temperature regulation during a motor-toboggan traverse in Antarctica.

Ten men, members of the International Biomedical Expedition to the Antarctic (IBEA), regularly recorded their thermal comfort, clothing, and activity for 60 days while travelling by motor toboggan and living in tents on the Antarctic plateau. Air temperature averaged -14 degrees C (range +2 degrees to -29 degrees C) and wind speed 11 m s-1 (range 0 to 22 m s-1); on half the days there was wind-blown ("drift") snow. Almost 2,000 sets of observations, evenly distributed throughout the 12 h sampling period 0700 h to 1900 h, were made. Daily (24 h) energy expenditure averaged 14.6 MJ on travelling days, 12.7 MJ on days when men worked in camp, and 13.3 MJ for the whole traverse. Men were outdoors for 7.6 h of the 12 h sampling period on travel days and for 3.6 h on camp days. Bulky down-filled clothing, typical of that used by present-day polar expeditions, adequately protected the trunk from cold at the cost of overheating during exercise. Face, hands, and feet were less well protected, and they experienced cold-induced numbness and pain in 33%, 19%, and 12%, respectively, of the observations made in the coldest weather. Because men could not conveniently reduce clothing insulation to the extent required, sweating and discomfort from warmth increased with energy expenditure and were present in 60% of the observations made during heavy work. The results suggest that there is a need for improvements in clothing design which will permit a more complete adjustment to changes in activity. The residual cold stress might possibly have been enough to induce cold acclimatization, although the accompanying heat stress was probably insufficient to induce acclimatization to heat.

The physical characteristics of the members during the International Biomedical Expedition to the Antarctic.

Twelve male medical scientists formed the International Biomedical Expedition to the Antarctic (IBEA). Their physical characteristics and maximum oxygen uptakes (VO2max) were measured in association with three series of thermal tolerance tests in Sydney, twice before and once after going to the Antarctic. In the Antarctic they lived in tents and spent 15 days travelling by motor toboggan. Their body mass (BM) and skinfold thickness (SFT) were measured four times during the 69 days the expedition spent in the field. The characteristics of the group were (ranges): age 26-52 years, height 1680-1889 mm, BM 58.5-103.4 kg, fatness 16-34% BM and VO2max 33-49 ml X kg-1 X min-1. In the Antarctic 9 men lost between 0.7 and 5.5 kg (mean 2.7 kg) of BM with a decrease in SFT, whilst 2 men increased BM by 1.2 and 1.9 kg without change in SFT. One man retired early from the expedition. BM and SFT were regained and physical fitness lost during the return voyage to Australia. Consequently there was no difference in average SFT between the pre- and post-Antarctic laboratory tests, but BM was greater after the Antarctic implying gains in fat free mass. VO2max was lower in the final laboratory tests than in the tests before Antarctica.

Urinary excretion of adrenal steroids, catecholamines and electrolytes in man, before and after acclimatization to cold in Antarctica.

1. Urine samples were collected from four men before and during test cold exposures in Melbourne, Australia, and Mawson, Antarctica. Changes in the response of body temperature to the test exposures showed that the men had acclimatized to cold at Mawson.2. Excretion rates of 17-hydroxycorticosteroids and 17-ketosteroids were significantly greater at Mawson than in Melbourne, in both the pre-exposure and exposure periods.3. Excretion rates of noradrenaline, adrenaline, sodium, potassium and creatinine did not differ significantly between Mawson and Melbourne, nor did urine flow rates.4. During the cold exposure significant increases occurred, to the same extent at Mawson as in Melbourne, in urine flow rate and in all measured urinary constituents except creatinine.

Skin temperature, thermal comfort, sweating, clothing and activity of men sledging in Antarctica.

1. Three men were studied while dog-sledging 320 km in 12 days in Antarctica. Conventional Antarctic clothing (;sweaters and windproofs') was worn. Four hundred observations were made of medial thigh skin temperature, thermal comfort, sweating, clothing, activity and environmental conditions.2. Work occupied an average of 11.0 hr/day and sleep 7.5 hr. Estimated daily energy expenditure averaged 5100 kcal (range 2740-6660 kcal).3. Skin temperature fell on exposure to cold despite the clothing worn, but was not changed by the level of activity. Sweating, and thermal comfort, were directly related to both skin temperature and activity.4. Inside the tent, the modal value of skin temperature was 33 degrees C (range 27-36 degrees C) and the men were comfortable in 94% of observations.5. During the 9.2 hr/day spent outdoors the modal value of skin temperature was 27 degrees C (range 18-33 degrees C) and the men felt too cold (but did not shiver) in 11% (range 7-20%) of observations, suggesting that cold stress was not negligible. However, they also felt too hot in 20% of observations and were sweating in 23%.