Frostbites in circumpolar areas

Circumpolar areas are associated with prolonged cold exposure where wind, precipitation, and darkness further aggravate the environmental conditions and the associated risks. Despite the climate warming, cold climatic conditions will prevail in circumpolar areas and contribute to adverse health effects. Frostbite is a freezing injury where localized damage affects the skin and other tissues. It occurs during occupational or leisure-time activities and is common in the general population among men and women of various ages. Industries of the circumpolar areas where frostbite occurs frequently include transportation, mining, oil, and gas industry, construction, agriculture, and military operations. Cold injuries may also occur during leisure-time activities involving substantial cold exposure, such as mountaineering, skiing, and snowmobiling. Accidental situations (occupational, leisure time) often contribute to adverse cooling and cold injuries. Several environmental (temperature, wind, wetness, cold objects, and altitude) and individual (behavior, health, and physiology) predisposing factors are connected with frostbite injuries. Vulnerable populations include those having a chronic disease (cardiovascular, diabetes, and depression), children and the elderly, or homeless people. Frostbite results in sequelae causing different types of discomfort and functional limitations that may persist for years. A frostbite injury is preventable, and hence, unacceptable from a public health perspective. Appropriate cold risk management includes awareness of the adverse effects of cold, individual adjustment of cold exposure and clothing, or in occupational context different organizational and technical measures. In addition, vulnerable population groups need customized information and care for proper prevention of frostbites

Physical activity, residential greenness, and cardiac autonomic function

Purpose: This population-based study examines the associations between physical activity (PA), residential environmental greenness, and cardiac health measured by resting short-term heart rate variability (HRV). Methods: Residential greenness of a birth cohort sample (n=5433) at 46 years was measured with normalized difference vegetation index (NDVI) by fixing a 1km buffer around each participant's home. Daily light PA (LPA), moderate PA (MPA), vigorous PA (VPA), and the combination of both (MVPA) were measured using a wrist-worn accelerometer for 14days. Resting HRV was measured with a heart rate monitor, and generalized additive modeling (GAM) was used to examine the association between PA, NDVI, and resting HRV. Results: In nongreen areas, men had less PA at all intensity levels compared to men in green areas. Women had more LPA and total PA and less MPA, MVPA, and VPA in green residential areas compared to nongreen areas. In green residential areas, men had more MPA, MVPA, and VPA than women, whereas women had more LPA than men. GAM showed positive linear associations between LPA, MVPA and HRV in all models. Conclusions: Higher LPA and MVPA were significantly associated with increased HRV, irrespective of residential greenness. Greenness was positively associated with PA at all intensity levels in men, whereas in women, a positive association was found for LPA and total PA. A positive relationship of PA with resting HRV and greenness with PA was found. Residential greenness for promoting PA and heart health in adults should be considered in city planning

Baroreflex sensitivity following acute upper-body exercise in the cold among stable coronary artery disease patients

Background: A cold environment and exercise separately affect the autonomic nervous system (ANS), baroreflex sensitivity (BRS), and blood pressure variability (BPV) but their combined effects on post-exercise recovery are not known. Our cross-over trial examined these responses following upper-body static and dynamic exercise performed in a cold and neutral environment in patients with coronary artery disease (CAD). Methods: 20 patients with stable coronary artery disease performed both graded static (10%–30% of maximal voluntary contraction) and dynamic (light, moderate and high perceived intensity) upper-body exercise at −15°C and +22°C for 30 min. Electrocardiogram and continuous blood pressure were measured to compute post-exercise (10 and 30 min after exercise) spectral powers of heart rate (HR), blood pressure variability and BRS at low (0.04–0.15 Hz) and high (0.15–0.4 Hz) frequencies. Results: Static upper-body exercise performed in a cold environment increased post-exercise high frequency (HF) spectral power of heart rate (HF RR) (p Conclusion: Static upper-body exercise in the cold increased post-exercise BRS and overall vagal activity but without reduced systolic blood pressure. Dynamic upper-body exercise in the cold reduced post-exercise vagal BRS but did not affect the other parameters. The influence of cold exposure on post-exercise autonomic and cardiovascular responses following static upper-body exercise require further studies. This information helps understanding why persons with cardiovascular diseases are vulnerable to low environmental temperature. ClinicalTrials.gov: NCT02855905 (04/08/2016)

Self-reported exposure to dust and diesel exhaust, respiratory symptoms, and use of respiratory protective equipment among Arctic miners

Arctic miners face significant risks from diesel exhaust and dust exposure, potentially leading to adverse respiratory health. Employers must limit harmful exposures, using personal protective equipment (PPE) as a last line of defense. This study explored the association between reported respiratory exposure and symptoms, and PPE training and usage. Data from the MineHealth study (2012–2014) included a total of 453 Arctic open pit miners in Norway, Sweden, and Finland. Participants answered questions on exposure to dust and diesel exhaust, respiratory symptoms, and PPE use, in addition to age, gender, BMI, smoking, and self-rated health. Estimated exposure to dust was common, reported by 91%, 80%, and 82% and that of diesel exhaust by 84%, 43%, and 47% of workers in Sweden, Finland, and Norway, respectively. Reported dust exposure was significantly related to respiratory symptoms (OR 2.2, 95% CI 1.3–3.7), diesel exposure increased the occurrence of wheezing (OR 2.6, 95% CI 1.3–5.4). PPE use varied between the studied mines. Non-use was common and related to reduced visibility, wetness, skin irritation and fogging of the respiratory PPE. Future research should employ more precise exposure assessment, respiratory function as well as explore the reasons behind the non-compliance of PPE use

Hypertension does not alter the increase in cardiac baroreflex sensitivity caused by moderate cold exposure

Exposure to cold increases blood pressure and may contribute to higher wintertime cardiovascular morbidity and mortality in hypertensive people, but the mechanisms are not well established. While hypertension does not alter responses of vagally-mediated heart rate variability to cold, it is not known how hypertension modifies baroreflex sensitivity and blood pressure variability during cold exposure. Our study assessed this among untreated hypertensive men during short-term exposure comparable to habitual winter time circumstances in subarctic areas. We conducted a population-based recruitment of 24 untreated hypertensive and 17 men without hypertension (age 55-65 years) who underwent a whole-body cold exposure (-10°C, wind 3m/s, winter clothes, 15 min, standing). Electrocardiogram and continuous blood pressure were measured to compute spectral powers of systolic blood pressure and heart rate variability at low (0.04-0.15 Hz) and high frequency (0.15-0.4 Hz) and spontaneous baroreflex sensitivity at low frequency. Comparable increases in baroreflex sensitivity were detected in hypertensive men, from 2.6 (2.0, 4.2) to 3.8 (2.5, 5.1) ms/mmHg (median (interquartile range)), and in control group, from 4.3 (2.7, 5.0) to 4.4 (3.1, 7.1) ms/mmHg. Instead, larger increase (p<0.05) in low frequency blood pressure variability was observed in control group; response as median (interquartile range): 8 (2, 14) mmHg², compared with hypertensive group (0 (-13, 20) mmHg²). Untreated hypertension does not disturb cardiovascular protective mechanisms during moderate cold exposure commonly occurring in everyday life. Blunted response of the estimate of peripheral sympathetic modulation may indicate higher tonic sympathetic activity and decreased sympathetic responsiveness to cold in hypertension