Cold Exposure Time Research Articles

The Potential Roles of Myokines in Adipose Tissue Metabolism with Exercise and Cold Exposure.

Exercise and cold exposure are two stimuli that have been suggested as solely effective to modulate adipose tissue metabolism and improve metabolic health in obese populations. The two primary organs involved in energy metabolism during exercise and/or cold exposure are skeletal muscle and adipose tissue. Adipose tissue can be divided mainly into two types: white adipose tissue (WAT), which primarily stores energy, and brown adipose tissue (BAT), known as the primary source of thermogenesis. The exercise-stimulated release of myokines allows for crosstalk between skeletal muscle and adipose tissue, partially mediating the beneficial effects of exercise. Cold exposure is another trigger for the regulation of myokine secretions, thus increasing adipose tissue metabolism, especially via activation of BAT. Therefore, this has generated the hypothesis that exercise in conjunction with cold exposure might be the optimal regimen to regulate myokine profiles and gain more beneficial health effects. However, to date, human experimental data regarding different exercise (frequency, type, time and intensity) and cold exposure (temperature, time and frequency) patterns are scarce. In this review, we will summarize the current human clinical trials investigating the regulation of myokines induced by exercise combined with cold exposure, to elaborate on the roles of myokines in mediating adipose tissue metabolism.

Future projections of rice exposure to cold stress in China throughout the 21st century

Rice exposure to cold stress will be alleviated by the decrease of cold extremes under climate change. The disappearance time of cold exposure and its response to different potential scenes in the 21st century, should be particularly important to make long-term adaptations in China. Given these issues unresolved, here we assessed the decadal changes of rice exposure to cold stress in China throughout the 21st century, and compared the patterns under different combinations of Representative Concentration Pathways (RCP) scenarios, rice phenology shifts and cold tolerance enhancements. Under RCP4.5 with no changes in rice phenology and cold tolerance (i.e., the baseline scene), cold exposure would disappear mainly after the 2030s, 2040s, 2060s and 2080s in Liaoning, Fujian, Jilin and Hunan, respectively. But in Heilongjiang, northern Yunnan, southern Sichuan, western Hunan and northwestern Zhejiang, cold exposure would remain until the end of this century. Compared with the baseline pattern in these provinces, RCP8.5 and cold-tolerance enhancements would make cold exposure disappear 2–3 decades early and reduce the intensity by more than 40%. In southern China, when rice thermal-sensitive stage is moved 10/15 days forward, the disappearance of cold exposure would be 2–4 decades early relative to the baseline pattern. Comparison of the patterns under the baseline scene and other potential scenes suggests cautious optimism about the effectiveness of adjustments in crop phenology and provides quantitative support to the enhancement in cold tolerance. This has broad implications for the research community relative to adaptation planning under climate change.

Effects of cold storage on the developmental biology of Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) at different larval stages

Being able to store insects at low temperature is important in the mass breeding of insects for commercial purposes. The aim of this study is to investigate the effect of cold storage on pupal and adult weight, adult emergence time and proportion and adult deformation proportion of different weight Tenebrio molitor L., 1758 (Coleoptera: Tenebrionidae) larvae. This study was conducted between 2018-2019 in the Biology Laboratory of Science Teaching Department, Sinop University. Trials were performed at 27 ± 2 and 4ºC, 65 ± 5% RH and continuous darkness. After the larvae began to form, they were weighed and divided into three groups according to their weight. They were exposed to 4ºC for 5, 10, 20, 30 and 60 d in separate Petri dishes. With increased cold storage time, the proportion of deformation increased and the proportion of adult emergence decreased. Adult weight, pupal weight and longevity depended on both larval weight and cold exposure time. In conclusion, it is recommended that mass producers or researchers pay attention to the size of the larvae and the cold exposure times to obtain the best quality product and high production efficiency.

Influence of cold temperature and exposure time on egg overwintering survival in the white-whiskered grasshopper (Orthoptera: Acrididae)

The effect of cold temperatures and exposure time on egg survival and hatching success were examined in the white-whiskered grasshopper, Ageneotettix deorum. Temperature treatments ranged from 4°C to -35°C, with treatment times ranging from 48 to 240 hours. Both decreasing temperatures and exposure time negatively affected egg survival, with a temperature below -25°C being lethal. Similar lethal temperatures are known for several North American grasshopper species. The relatively shallow location of A. deorum egg pods would result in increased vulnerability of eggs to cold temperatures in the absence of snow.

506 Anticoagulation After Thrombolytic Treatment for Frostbite: A Case Series

Abstract Introduction Historically, management of frostbite followed the adage “freeze in January and amputate in July.” While rapid rewarming primarily addresses the ice crystal formation phase of damage, vascular injury and resulting thrombosis result in the overall tissue damage. Over the last two decades, limb salvage for frostbite has been widely employed. The use of tissue plasminogen activator (tPA) to prevent vascular thrombosis has been found to reduce the number of digit amputations and benefit of systemic thrombolytic therapy has been demonstrated. Post-thrombolysis anticoagulation has changed as well. Our institution has changed its protocol from using warfarin after tPA therapy to aspirin (ASA) for ease of adherence. This study evaluates the use of warfarin or aspirin for management after tPA therapy. Methods This was a retrospective review of patients who received tPA for frostbite between January 2008 and April 2019. Data collected included age, height, weight, sex, past medical history, contributing factors to development of frostbite, toxicology screen on admission, cold exposure time, rewarming time, number of digits/limbs affected, and highest grade of injury. Outcomes data included medications received, number of digits/limbs amputated, length of stay, and number of follow up visits. Results Ten patients were included in the statistical analysis, 7 patients in the ASA group and 3 patients in the warfarin group. Baseline demographics were similar between groups, except the ASA group was significantly younger (31.9 vs 64.7 years, p < 0.001) and weighed less (70.3 vs 86.8 kg, p = 0.02) than the warfarin group. Statistical analysis demonstrated no significant difference in outcomes when comparing patients managed with ASA 325 milligrams (mg) versus warfarin after tPA therapy. The average number of limbs amputated for patients taking ASA was 0 + 0.0 and was 0.7 + 1.2 for those taking warfarin (p=0.42). Average number of digits amputated for patients taking ASA and warfarin was 0.1 + 0.4 and 3.7 + 5.5, respectively (p=0.38). For patients who took ASA, length of hospital stay averaged at 8.0 + 4 days, while those who took warfarin stayed for 9.4 + 7.2 days (p= 0.64). Finally, the average number of follow up visits for patients who took ASA and warfarin was 3.9 + 4.7 and 8.0 + 9.6, respectively (p=0.37). Conclusions These findings indicate that there may not be a significant difference in clinical outcomes when comparing patients who took ASA to warfarin after tPA therapy. It is common for patients to have a delayed presentation and prolonged rewarming time, resulting in ineligibility to receive tPA. Single center frostbite studies are limited due to sample size and multi-centered studies are necessary for future studies. Applicability of Research to Practice ASA 325 mg daily may be a suitable alternative to warfarin therapy after tPA administration following a frostbite injury.

Effects of Cold-inducible RNA-binding Protein (CIRP) on Liver Glycolysis during Acute Cold Exposure in C57BL/6 Mice.

Cold-inducible RNA-binding protein (CIRP) is a stress-responsive protein involved in several signal transduction pathways required for cellular function, which are associated with apoptosis and proliferation. The present study aimed to investigate the possible effects of CIRP-mediated regulation of glucose metabolism in the liver following acute cold exposure. The livers and serum of male C57BL/6 mice were collected following cold exposure at 4 °C for 0 h, 2 h, 4 h, and 6 h. Glucose metabolic markers and the expression of glucose metabolic-related proteins were detected in the liver. Acute cold exposure was found to increase the consumption of glycogen in the liver. Fructose-1,6-diphosphate (FDP) and pyruvic acid (PA) were found to show a brief increase followed by a sharp decrease during cold exposure. Anti-apoptotic protein (Bcl-2) expression was upregulated. CIRP protein expression displayed a sequential increase with prolonged acute cold exposure time. Acute cold exposure also increased the level of protein kinase B (AKT) phosphorylation, and activated the AKT-signaling pathway. Taken together, these findings indicate that acute cold exposure increased the expression of CIRP protein, which regulates mouse hepatic glucose metabolism and maintains hepatocyte energy balance through the AKT signaling pathway, thereby slowing the liver cell apoptosis caused by cold exposure.

Quantum-like decreased embryogenesis time with increased cold exposure time

Three theoretical models have been proposed to explain lifespan extension resulting from exposure to extreme conditions in microscopic animals: individuals become completely dormant and stop aging, continue to age or age but at a diminished rate. Here we show that the earliest life history stages, embryonic cell divisions, in the tardigrade species Hypsibius dujardini are retarded when eggs are reared at 0 °C. Compared to control specimens reared at 22 °C, juveniles that hatched from eggs exposed to 0 °C for 4 days and returned to 22 °C experienced a three-day lag, indicating that their biological age was less than their chronological age. As cold exposure duration increased (days = 10, 20, 40), incubation period at 22 °C decreased incrementally (days = 3, 2, 1), suggesting that tardigrades involve a threshold-determined, quantum-like, energetic-based system for controlling embryogenesis.

Cold plasma pretreatment enhances drying kinetics and quality attributes of chili pepper (Capsicum annuum L.)

Chili pepper is difficult to dry as the outermost surface is covered with an epicuticular wax layer, which hinders moisture transfer. Chemical dipping pretreatments and thermal blanching methods are often employed to enhance its drying process. However, chemical pretreatments hold the issues of chemical additives residue and thermal blanching methods tend to result in a high loss of bioactive compounds. Cold plasma is an ionized gas that contains different electrons, ions, and reactive neutral species. In current work, the feasibility of cold plasma as a non-thermal pretreatment technology for chili pepper drying is explored. The effects of different cold plasma pretreatment time (15, 30, 45, 60 s) on hot air drying kinetics and quality attributes of chili pepper, such as colour, red pigment retention, antioxidant activity, and microstructure were investigated. Results indicate that cold plasma can enhance the drying rate and the exposure time of 30 s achieves the optimum result. Microstructure observations show the existence of micro-holes, which explain how plasma treatment can enhance the drying kinetics. Quality attributes showed that the colour parameters had no significant changes under various treatment times. The retention of red pigment content was improved by plasma treatment of 30 s, whereas longer exposure times had a negative effect. The antioxidant activity of samples increased with the increase of cold plasma exposure time. Results indicate that cold plasma is a promising pretreatment technology for chili peppers as it enhances drying kinetics and quality attributes of chili pepper.

Differences in winter cold hardiness reflect the geographic range disjunction of Neophasia menapia and Neophasia terlooii (Lepidoptera: Pieridae)

Predicting how rapid climate change will affect terrestrial biota depends on a thorough understanding of an organism’s biology and evolutionary history. Organisms at their range boundaries are particularly sensitive to climate change. As predominantly terrestrial poikilotherms, insects are often geographically limited by extremes in ambient temperatures. We compared the cold hardiness strategies of two geographically widespread butterflies, the pine white, Neophasia menapia, and the Mexican pine white, N. terlooii (Lepidoptera: Pieridae), at the near-contact zone of their range boundaries. Eggs are laid on pine needles and are exposed to harsh winter conditions. Eggs were collected from wild-caught butterflies, and we determined the supercooling point (SCP) and lower lethal temperature (LLT50) of overwintering eggs. The SCP of Neophasia menapia eggs (−29.0 ± 0.6 °C) was significantly lower than that of N. terlooii eggs (−21.8 ± 0.7 °C). Both species were freeze-intolerant and capable of surviving down to their respective SCPs (LLT50 of N. menapia between −30 and −31 °C, N. terlooii between −20 and −21 °C). Cold exposure time did not affect the survival of N. menapia, but N. terlooii experienced somewhat greater mortality at sub-freezing temperatures during longer exposures. Our results, coupled with an analysis of microclimate data, indicate that colder winters in northern Arizona may contribute to the northern range limit for N. terlooii. Furthermore, careful analysis of historical weather data indicates that mortality from freezing is unlikely in southern Arizona but possible in northern Arizona. Movements of Neophasia range boundaries could be monitored as potential biological responses to climate change.

Analytical expressions for estimating endurance time and glove thermal resistance related to human finger in cold conditions

Frostbite is considered the severest form of cold injury and can lead to necrosis and loss of peripheral appendages. Therefore, prediction of endurance time of limb's tissue in cold condition is not only necessary but also crucial to estimate cold injury intensity and to choose appropriate clothing. According to the previous work which applied a 3-D thermal model for human finger to analyze cold stress, in this study, an expression is presented for endurance time in cold conditions to prevent cold injury. A formula is also recommended to select a proper glove with specific thermal resistance based on the ambient situation and cold exposure time. By employing linear extrapolation and real physical conditions, the proposed formulas were drawn out from numerical simulation. Analytical results show good agreement with numerical data. The used numerical data had been also validated with experimental data existed in the literature. Furthermore, the effect of different parameters such as glove thermal resistance and ambient temperature is investigated analytically.

No association between hand and foot temperature responses during local cold stress and rewarming

PurposeThe purpose was to examine whether associations exist between temperature responses in the fingers vs. toes and hand vs. foot during local cold-water immersion and rewarming phases.MethodsSeventy healthy subjects (58 males, 12 females) immersed their right hand or right foot, respectively, in 8 °C water for 30 min (CWI phase), followed by a 15-min spontaneous rewarming (RW) in 25 °C air temperature.ResultsTemperature was lower in the toes than the fingers during the baseline phase (27.8 ± 3.0 vs. 33.9 ± 2.5 °C, p < 0.001), parts of the CWI phase (min 20–30: 8.8 ± 0.7 vs. 9.7 ± 1.4 °C, p < 0.001), and during the RW phase (peak temperature: 22.5 ± 5.1 vs. 32.7 ± 3.6 °C, p < 0.001). Cold-induced vasodilatation (CIVD) was more common in the fingers than in the toes (p < 0.001). Within the first 10 min of CWI, 61% of the subjects exhibited a CIVD response in the fingers, while only 6% of the subjects had a CIVD response in the toes. There was a large variability of temperature responses both within and between extremities, and there was a weak correlation between finger- and toe temperature both during the CWI (r = 0.21, p = 0.08) and the RW phases (r = 0.26, p = 0.03).ConclusionsResults suggest that there is generally a lower temperature in the toes than the fingers after a short time of local cold exposure and that the thermal responses of the fingers/hands are not readily transferable to the toes/foot.

Simulation of cryolipolysis as a novel method for noninvasive fat layer reduction.

Regarding previous problems in conventional liposuction methods, the need for development of new fat removal operations was appreciated. In this study we are going to simulate one of the novel methods, cryolipolysis, aimed to tackle those drawbacks. We think that simulation of clinical procedures contributes considerably in efficacious performance of the operations. To do this we have attempted to simulate temperature distribution in a sample fat of the human body. Using Abaqus software we have presented the graphical display of temperature-time variations within the medium. Findings of our simulation indicate that tissue temperature decreases after cold exposure of about 30 min. It can be seen that the minimum temperature of tissue occurs in shallow layers of the sample and the temperature in deeper layers of the sample remains nearly unchanged. It is clear that cold exposure time of more than the specific time (t > 30 min) does not result in considerable changes. Numerous clinical studies have proved the efficacy of cryolipolysis. This noninvasive technique has eliminated some of drawbacks of conventional methods. Findings of our simulation clearly prove the efficiency of this method, especially for superficial fat layers.

Changes in Cell Ca2+ Distribution in Loquat Leaves and Its Effects on Cold Tolerance

Calcium has been associated with improved cold tolerance in many crops. The aim of this study was to investigate the changes in leaf cell <TEX>$Ca^{2+}$</TEX> distribution and cell organelle ultrastructure of loquat (Eriobotrya japonica Lindl.) plants in response to cold stress at <TEX>$-3^{\circ}C$</TEX>, using transmission electron microscopy (TEM). Two loquat accessions, Zaozhong 6 (a commercial cultivar) and oakleaf loquat (a wild relative) were used. Cold tolerance, as measured by leaf browning rate, was higher in oakleaf plants, and calcium treatment improved cold tolerance in both species. Cold stress first induced inward transport of <TEX>$Ca^{2+}$</TEX> from the intracellular space. Then, the imported <TEX>$Ca^{2+}$</TEX> was aggregated around the chloroplast membrane, finally entering the chloroplast. This pattern of <TEX>$Ca^{2+}$</TEX> distribution in leaf cells occurred earlier in Zaozhong 6 than in the wild loquat. With increasing time of cold exposure, the chloroplast membranes of Zaozhong 6 leaves were damaged, blurred and even disappeared, while those of wild oakleaf loquat leaves maintained their structure longer. In Zaozhong 6, cold stress induced a clear cavity between poorly structured granal thylakoids and vesicles appearing inside the chloroplast, while in oakleaf leaves cold stress had little effect on the ultrastructure of chloroplasts (although chloroplast membranes looked blurred). Loquat leaves accumulated free calcium ions around chloroplasts in response to cold stress, with earlier calcium accumulation occurring in the cold-sensitive cultivar Zaozhong 6 than in wild oakleaf loquat. These results demonstrate that these two loquat species have differences in both cold tolerance and calcium accumulation dynamics.

Parental phase status affects the cold hardiness of progeny eggs in locusts

Summary1. The capacity to adapt to low temperature is critical for the persistence of insect populations in heterogeneous environments. Locusts show remarkable phenotypic plasticity, termed ‘phase change’, in response to local population density.2. In this study, the hypothesis that population density, as a social factor, affects the cold hardiness of progeny is validated in the migratory locust, Locusta migratoria, which shows remarkable density‐dependent phase changes between gregarious and solitarious phases.3. We demonstrated that eggs of gregarious and solitarious migratory locusts significantly differ not only in size and weight, but also in cold hardiness. Eggs of solitarious locusts are more resistant to cold stress compared with those of gregarious locusts, with longer 50% lethal time at different low temperatures and under different acclimation treatments of cooling rates or cold exposure time, lower upper limit of chill injury zone, and lower sum of injurious temperature resulting from temperature–time regression. The lowest cooling rate (0·05 °C min−1) yields the highest survival of cold for eggs.4. A custom‐made microarray covering 9154 unigenes of the migratory locust demonstrated quite different gene expression profiles in the two phases in response to normal or low temperature. Under cold stress, the gregarious‐phase eggs have higher transcriptional levels of heat‐shock proteins, DOPA decarboxylases and tyrosine hydroxylase, whereas the solitarious‐phase eggs exhibit stimulated lipid metabolism and carboxylic acid transport.5. Hybridization between the two phases showed that the cold hardiness of eggs from the hybrid with solitarious females is significantly higher than that of the hybrid with gregarious females, and the cold hardiness of eggs from each reciprocal hybrid is close to their maternal origins. These results indicate that the cold hardiness of progeny is affected by the parental phase status.

Temporal heterogeneity of cold acclimation phenotypes in Arabidopsis leaves

To predict the effects of temperature changes on plant growth and performance, it is crucial to understand the impact of thermal history on leaf morphology, anatomy and physiology. Here, we document a comprehensive range of leaf phenotypes in 25/20 degrees C-grown Arabidopsis thaliana plants that were shifted to 5 degrees C for up to 2 months. When warm-grown, pre-existing (PE) leaves were exposed to cold, leaf thickness increased due to an increase in mesophyll cell size. Leaves that were entirely cold-developed (CD) were twice as thick (eight cell layers) as their warm-developed (WD) counterparts (six layers), and also had higher epidermal and stomatal cell densities. After 4 d of cold, PE leaves accumulated high levels of total non-structural carbohydrates (TNC). However, glucose and starch levels declined thereafter, and after 45 d in the cold, PE leaves exhibited similar TNC to CD leaves. A similar phenomenon was observed in delta(13)C and a range of photosynthetic parameters. In cold-treated PE leaves, an increase in respiration (R(dark)) with cold exposure time was evident when measured at 25 degrees C but not 5 degrees C. Cold acclimation was associated with a large increase in the ratio of leaf R(dark) to photosynthesis. The data highlight the importance of understanding developmental thermal history in determining individual phenotypic traits.

Effects of low temperature on functions of learning, memory and activities of ATPase in brain tissue of mice

To explore the effects of low temperature on the functions of learning and memory and activities of ATPase in brain tissue of mice. 120 mice were randomly divided into 3 groups of A, B, and C with different cold exposure time. After low temperature test, learning and memory ability and activities of ATPase in brain tissue of the mice were measured. Compared with corresponding control group, in the test of learning ability, the total electric shock period [(41.00 +/- 12.06), (45.90 +/- 13.61) min], the total electric times (85.00 +/- 15.81, 89.00 +/- 17.29), and the error reaction times (33.60 +/- 10.69, 39.00 +/- 11.63) were increased in group A and group C significantly (P < 0.01, P < 0.05), but the rate of right reaction (53.60% +/- 11.23%, 54.59% +/- 6.14%) were decreased in group A and group C significantly (P < 0.01, P < 0.05). In the test of memory ability, the total electric shock period [(19.00 +/- 4.62), (51.70 +/- 15.19) min] in group A and group C were increased significantly (P < 0.05, P < 0.01), the rate of right reaction (86.17% +/- 6.34%, 65.92% +/- 8.17%) in group A and group C were decreased significantly (P < 0.05). In test of activities of ATPase in brain tissue, the activities of Na(+)-K(+)-ATPase and activities of Ca(2+)-Mg(2+)-ATPase in brain tissue in group A and group C were decreased significantly (P < 0.05, P < 0.01). Low temperature could decrease the functions of learning and memory and the activities of Na+-K+-ATPase and Ca(2+)-Mg(2+)-ATPase in brain tissue of mice.

Cold Assessment Criteria and Prediction of Cooling Risk in Humans: The Russian Perspective

Protection of humans working in open areas during a cold period is of great importance. Cold influences human heat state, health and functional capacity. The assessment criteria for optimal permissible heat state during work time and maximum permissible heat state demanding regulation of cold exposure time are described. They form the basis for estimation and forecast of cold risk. Classification of cooling risk is made on the basis of factors such as mean skin temperature, heat deficit, strain of thermo regulative reactions, thermal sensation, and occupational conditions. Cooling risk is also dependent on human factors such as metabolic rate and clothing thermal insulation and ambient conditions such as air temperature, wind velocity, and exposure time. For evaluation of the cooling risk a regression equation is presented for determination of the integral index of cooling conditions (IICC). On basis of the IICC value, presented in a nomogram it is possible to predict the probability of cooling risk of various rates. In consideration of the shifting climate conditions of Russia, requirements for thermal insulation of protective clothing for four major climate regions of the country are presented.

Increased thermoregulation in cold-exposed transgenic mice overexpressing lipoprotein lipase in skeletal muscle: an avian phenotype?

LPL is an enzyme involved in the breakdown and uptake of lipoprotein triglycerides. In the present study, we examined how the transgenic (Tg) overexpression of human LPL in mouse skeletal muscle affected tolerance to cold temperatures, cold-induced thermogenesis, and fuel utilization during this response. Tg mice and their nontransgenic controls were placed in an environmental chamber and housed in metabolic chambers that monitored oxygen consumption and carbon dioxide production with calorimetry. When exposed to 4 degrees C, an attenuation in the decline in body temperature in Tg mice was accompanied by an increased metabolic rate (15%; P < 0.001) and a reduction in respiratory quotient (P < 0.05). Activity levels, the expression of uncoupling proteins in brown fat and muscle, and lean mass failed to explain the enhanced cold tolerance and thermogenesis in Tg mice. The more oxidative type IIa fibers were favored over the more glycolytic type IIb fibers (P < 0.001) in the gastrocnemius and quadriceps muscles of Tg mice. These data suggest that Tg overexpression of LPL in skeletal muscle increases cold tolerance by enhancing the capacity for fat oxidation, producing an avian-like phenotype in which skeletal muscle contributes significantly to the thermogenic response to cold temperatures.

Effects of low temperatures on pupal survival of the stone leek leafminer Liriomyza chinensis (Diptera: Agromyzidae)

The cold-hardiness of Liriomyza chinensis pupae was measured in the laboratory by observing pupal mortality at low temperatures. Pupal mortality increased with decreasing temperature and with extended cold exposure time. No recently pupated pupae (6 h) were able to survive after 16 days of chilling at 0, 2.5 and 5°C, but 42.9% survival was observed at 10°C. Pupae at different developmental stages showed significant difference in mortality, with very low levels of mortality observed for older pupae (4 and 7 days) after exposure to 0°C for 16 days. The lethal time for 50% survival (LT50) increased with increasing age of pupae. LT50 for 4-day-old pupae exposed to 0°C was 52.1 days. Analysis of mean temperatures at several localities indicated that L. chinensis is able to overwinter outdoors in southern regions, but is unable to overwinter in open fields in northern regions of Japan, suggesting that overwintering in these regions would only occur in greenhouses.

Factors affecting outdoor exposure in winter: population-based study

The extent of outdoor exposure during winter and factors affecting it were examined in a cross-sectional population study in Finland. Men and women aged 25-74 years from the National FINRISK 2002 sub-study (n=6,591) were queried about their average weekly occupational, leisure-time and total cold exposure during the past winter. The effects of gender, age, area of residence, occupation, ambient temperature, self-rated health, physical activity and education on cold exposure were analysed. The self-reported median total cold exposure time was 7 h/week (8 h men, 6 h women),<1 h/week (2 h men, 0 h women) at work, 4 h/week (5 h men, 4 h women) during leisure time and 1 h/week (1 h men, 1.5 h women) while commuting to work. Factors associated with increased occupational cold exposure among men were: being employed in agriculture, forestry and industry/mining/construction or related occupations, being less educated and being aged 55-64 years. Factors associated with increased leisure-time cold exposure among men were: employment in industry/mining/construction or related occupations, being a pensioner or unemployed, reporting at least average health, being physically active and having college or vocational education. Among women, being a housewife, pensioner or unemployed and engaged in physical activity increased leisure-time cold exposure, and young women were more exposed than older ones. Self-rated health was positively associated with leisure time cold exposure in men and only to a minor extent in women. In conclusion, the subjects reported spending 4% of their total time under cold exposure, most of it (71%) during leisure time. Both occupational and leisure-time cold exposure is greater among men than women.