Habituation of thermal sensations, skin temperatures and norepinephrine in men exposed to cold air

6 sujets masculins ont été exposés à l'intérieur d'une salle climatisée, à une température de 11° C pendant 2 heures. Les sujets ont suivi ce protocole pendant 11 jours durant lesquels plusieurs mesures ont été relevées (évolution métabolique, température corporelle et sensations thermiques notamment au niveau des extrémités (pieds et mains)

The prevalence of heat-related cardiorespiratory symptoms:the vulnerable groups identified from the National FINRISK 2007 Study

Abstract The prevalence of heat-related cardiorespiratory symptoms among vulnerable groups is not well known. We therefore estimated the prevalence of heat-related cardiorespiratory symptoms among the Finnish population and their associations with social and individual vulnerability factors. The data came from the National FINRISK 2007 Study, in which 4007 men and women aged 25–74 answered questions on heat-related cardiorespiratory symptoms in the Oulu Cold and Heat Questionnaire 2007. Logistic regression was used to calculate odds ratios (ORs), their 95% confidence intervals (CIs), and model-predicted prevalence figures. The prevalence of heat-related cardiorespiratory symptoms was 12%. It increased with age, from 3% at the age of 25 years to 28% at the age of 75 years. The symptoms were associated with pre-existing lung (OR 3.93; CI 3.01–5.13) and cardiovascular diseases (OR 2.27; 1.78–2.89); being a pensioner (OR 2.91; 1.65–5.28), unemployed (OR 2.82; 1.47–5.48), or working in agriculture (OR 2.27; 1.14–4.46) compared with working in industry; having only basic vs academic education (OR 1.98; 1.31–3.05); being female (OR 1.94; 1.51–2.50); being heavy vs light alcohol consumer (OR 1.89; 1.02–3.32); undertaking hard vs light physical work (OR 1.48;1.06–2.07); and being inactive vs active in leisure time (OR 1.97; 1.39–2.81). The adjusted prevalence of symptoms showed a wide range of variation, from 3 to 61% depending on sex, age, professional field, education, and pre-existing lung and cardiovascular diseases. In conclusion, heat-related cardiorespiratory symptoms are commonly perceived among people with pre-existing lung or cardiovascular disease, agricultural workers, unemployed, pensioners, and people having only basic education. This information is needed for any planning and targeting measures to reduce the burden of summer heat

High home blood pressure variability associates with exaggerated blood pressure response to cold stress

Abstract Background: Exaggerated sympathetic cardiovascular (CV) reactivity to stress associates with elevated risk for clinical and preclinical end points of CV disease. It would be useful to identify these individuals, preferably from feasible measurements commonly used in health care. Our study examined the association between home blood pressure (BP) variability and cardiac workload response to whole-body cold exposure. Methods: Seventy-five men (55–65 years, 46 hypertensive) measured BP at home twice in the morning and evening for a week. We computed systolic home BP variability as SD of daily means and divided the subjects into groups demonstrating either high or low BP variability. They were exposed to whole-body cold exposure (−10 °C, wind 3 m/second, 15 minutes, winter clothes, standing). BP and heart rate were measured at 3-minute intervals during, and 15 minutes before and after the exposure. Rate-pressure product (RPP) was calculated to represent cardiac workload. Results: Subjects with high systolic home BP variability demonstrated a greater RPP increase in cold conditions compared to those with low BP variability [mean change from baseline (95% CI): 1,850 (1,450 to 2,250) bpm × mm Hg vs. 930 (610, 1,250) bpm × mm Hg, P < 0.01]. This was related to the augmented systolic BP change [31(28, 35) mm Hg vs. 23(20, 26) mm Hg, P < 0.01]. Home BP variability correlated with cold-related RPP (rS = 0.34, P = 0.003) and systolic BP (rS = 0.38, P < 0.001) responses. Conclusions: Moderate whole-body cold exposure increased BP and cardiac workload more among those with higher systolic home BP variability, independently of home BP level. Elevated home BP variability may indicate augmented sympathetically mediated vascular reactivity for environmental stressors. Public trials registry number: Trial Number NCT02007031