BACKGROUND: Exposure to cold weather increases blood pressure (BP) and may aggravate the symptoms and influence the prognosis of subjects with a diagnosis of hypertension. We tested the hypothesis that subjects with hypertension alone or in combination with another cardiovascular disease (CVD) experience cold-related cardiorespiratory symptoms more commonly than persons without hypertension. This information is relevant for proper treatment and could serve as an indicator for predicting wintertime morbidity and mortality.
METHODS: A self-administered questionnaire inquiring of cold-related symptoms was obtained from 6591 men and women aged 25-74 yrs of the FINRISK Study 2002 population. BP was measured in association with clinical examinations. Symptom prevalence was compared between subjects with diagnosed hypertensive disease with (n = 395) or without (n = 764) another CVD, untreated diagnosed hypertension (n = 1308), measured high BP (n = 1070) and a reference group (n = 2728) with normal BP.
RESULTS: Hypertension in combination with another CVD was associated with increased cold-related dyspnoea (men: adjusted odds ratio 3.94, 95% confidence interval 2.57-6.02)/women: 4.41, 2.84-6.86), cough (2.64, 1.62-4.32/4.26, 2.60-6.99), wheezing (2.51, 1.42-4.43/;3.73, 2.08-6.69), mucus excretion (1.90, 1.24-2.91/2.53, 1.54-4.16), chest pain (22.5, 9.81-51.7/17.7, 8.37-37.5) and arrhythmias (43.4, 8.91-211/8.99, 3.99-20.2), compared with the reference group. Both diagnosed treated hypertension and untreated hypertension and measured high BP resulted in increased cardiorespiratory symptoms during the cold season.
CONCLUSION: Hypertension alone and together with another CVD is strongly associated with cold-related cardiorespiratory symptoms. As these symptoms may predict adverse health events, hypertensive patients need customized care and advice on how to cope with cold weather.
AIMS: Diabetes and impaired glucose metabolism cause metabolic, neural and circulatory disturbances that may predispose to adverse cooling and related symptoms during the cold season. This study assessed the prevalence of cold-related cardiorespiratory symptoms in the general population according to glycaemic status.
METHODS: The study population consisted of 2436 men and 2708 women aged 45-74years who participated in the National FINRISK cold sub-studies in 2002 and 2007. A questionnaire assessed cold-related symptoms (respiratory, cardiac, peripheral circulation). Glycaemic status was determined based on fasting blood glucose, oral glucose tolerance tests or reported diagnosis of diabetes and categorized into normal glucose metabolism, impaired fasting blood glucose, impaired glucose tolerance, screening-detected type 2 diabetes and type 2 diabetes.
RESULTS: Type 2 diabetes was associated with increased odds for cold-related dyspnoea [Adjusted OR 1.72 (95% CI, 1.28-2.30)], chest pain [2.10 (1.32-3.34)] and respiratory symptoms [1.85 (1.44-2.38)] compared with normal glucose metabolism. Screened type 2 diabetes showed increased OR for cold-related dyspnoea [1.36 (1.04-1.77)], cough [1.41 (1.06-1.87)] and cardiac symptoms [1.51 (1.04-2.20)]. Worsening of glycaemic status was associated with increased odds for cold-related dyspnoea (from 1.16 in impaired fasting glucose to 1.72 in type 2 diabetes, P=0.000), cough (1.02-1.27, P=0.032), chest pain (1.28-2.10, P=0.006), arrhythmias (0.87-1.74, P=0.020), cardiac (1.11-1.99, P=0.000), respiratory (1.14-1.84, P=0.000) and all symptoms (1.05-1.66, P=0.003).
CONCLUSIONS: Subjects with diabetes and pre-diabetes experience more cold-related cardiorespiratory symptoms and need instructions for proper protection from cold weather to reduce adverse health effects.
Patients with Raynaud's phenomenon (RP) have abnormal digital vasoconstriction in response to cold. The aim of the study was to investigate the effects of cooling on sensory perception and manual performance in healthy male subjects and subjects with RP. There were two groups of subjects with primary RP: 12 subjects fulfilled the criteria of Lewis (L) and the other 12 the more critical criteria of Maricq (M). Control group (C) consisted of 19 healthy men. Subjects were exposed to 5 degrees C for 60 min. Skin temperatures were measured. Finger dexterity, pinch strength, abduction/adduction of fingers, pressure perception threshold and vibration perception threshold were tested during the exposure every 15 min. At the beginning of the exposure the mean (S.E.) finger temperature was 2.5 (1.2) degrees C (P
The effects of seasonally adjusted 24-h exposure to cold and darkness on cognitive performance in urban circumpolar residents was assessed in 15 male subjects who spent three 24-h periods in a climatic chamber at 65 degrees latitude during the winter (January-March) and/or summer (August-September). Each subject was exposed to three different environmental conditions in random order: (1) 22 degrees C temperature and 500 lx lighting; (2) 10 degrees C temperature and 500 lx lighting; and (3) 10 degrees C temperature and 0.5-l lx lighting. Accuracy on an addition-subtraction task was significantly greater in the summer than in the winter (p= 0.038), while accuracy on a repeated acquisition task was significantly greater in the winter than in the summer (p
Male volunteers were exposed to +10 degrees C ambient temperature for 2 hours while they were sitting undressed. The levels of endothelin-1 and atrial natriuretic peptide were determined by radioimmunoassays. Control samples were obtained at thermoneutrality. The cold exposure resulted in lowering of the mean skin temperature (from 31.2 +/- 0.3 degrees C-22.6 +/- 2.5 degrees C, mean +/- SEM), which indicates that a marked vasoconstriction took place, as well as a decrease of the body heat content (by 11.2 +/- 0.7 kJ kg-1). However, plasma endothelin-1 levels did not change significantly during the exposure. Thus circulating endothelin-1 does not seem to be responsible for the vasoconstriction associated with cold air exposure. The plasma atrial natriuretic peptide levels exhibited a slight increase towards the end of the cold exposure. This finding is in accord with the notion that atrial natriuretic peptide might contribute to the diuresis frequently observed in the cold.
To determine whether urban circumpolar residents show seasonal acclimatisation to cold, thermoregulatory responses and thermal perception during cold exposure were examined in young men during January-March (n=7) and August-September (n=8). Subjects were exposed for 24 h to 22 and to 10 degrees C. Rectal (T(rect)) and skin temperatures were measured throughout the exposure. Oxygen consumption (VO(2)), finger skin blood flow (Q(f)), shivering and cold (CDT) and warm detection thresholds (WDT) were assessed four times during the exposure. Ratings of thermal sensations, comfort and tolerance were recorded using subjective judgement scales at 1-h intervals. During winter, subjects had a significantly higher mean skin temperature at both 22 and 10 degrees C compared with summer. However, skin temperatures decreased more at 10 degrees C in winter and remained higher only in the trunk. Finger skin temperature was higher at 22 degrees C, but lower at 10 degrees C in the winter suggesting an enhanced cold-induced vasoconstriction. Similarly, Q(f) decreased more in winter. The cold detection threshold of the hand was shifted to a lower level in the cold, and more substantially in the winter, which was related to lower skin temperatures in winter. Thermal sensations showed only slight seasonal variation. The observed seasonal differences in thermal responses suggest increased preservation of heat especially in the peripheral areas in winter. Blunted vasomotor and skin temperature responses, which are typical for habituation to cold, were not observed in winter. Instead, the responses in winter resemble aggravated reactions of non-cold acclimatised subjects.
Twenty healthy male volunteers, dressed in shorts, stayed for 30 min in a room with an ambient temperature of 28 degrees C followed by a stay in a room with a temperature of 10 degrees C for 120 min. The mean skin temperature fell rapidly during the first minutes in the cold but the rectal temperature began to fall as late as at 60 min (0.1 degree C) and was 0.4 degrees C lower at the end of the cold exposure than before it. The metabolic rate, and the systolic and diastolic blood pressures, increased, and the pulse rate fell, in the cold. Serum samples were taken before moving to the cold (10 degrees C) room and after the 2-h stay and assayed for 11 hormones. There were no significant changes in the serum concentration of adrenalin, T3, T4, testosterone, TSH or LH. The serum level of noradrenaline increased from 4.5 to 6.3 nmol l-1 (P less than 0.01) and those of cortisol, GH and prolactin fell by 20, 87 and 48% (all P less than 0.01). The total serum proteins increased by 11% and free fatty acids by 28% (P less than 0.01). Our results show that the short-term exposure of adult man to low ambient temperature does not have any effect on the pituitary-thyroid and pituitary-testis axes and adrenal medulla. The increase of noradrenaline is probably due to general activation of the sympathetic nerves at low temperatures. The decreases in the serum levels of GH and prolactin reflect a true decrease in their secretions and may be mediated by inhibitory hypothalamic mechanisms.