Seasonal Variation In Blood Pressure Research Articles

Abstract 18440: Hypertension Control in all Age Groups - a VA 10 Year Multicenter Analysis

Introduction: While the benefits of blood pressure (BP) control are well known, BP control is rarely studied in large populations. Elderly patients have been considered difficult to control. We reviewed blood pressure control in a large cohort of VA patients. Methods: From September 2000 to August 2010, we assessed BP control in 582,851 hypertensive patients from 15 VA hospitals in various geographic locations around the United States. Patients were divided in 4 groups based on age: G1: <55 (N=176,604), G2: 55 - <70 (N=214,967), G3: 70 - <80 (N=139,103), G4: >80 (N=52,177). Medical interventions to control BP included use of electronic medical records with automated reminders, medical regimen adjustments, and frequent visits to both specialty and nurse run clinics. Results: Control rates (BP≤140/90) in FY00 were: 50.0% in G1, 45.5% in G2, 45.5% in G3 and 47.8% in G4. After 10 years of follow up, BP control improved to 73.6% in G1, 74.5% in G2, 75.1% in G3 and 73.2% in G4 (p<0.0001 for all groups compared to baseline). In all age groups, BP levels were lower during summer as compared to winter. Diastolic BP for patients over the age of 55 approached that of those < 55. Systolic and diastolic BP fell more rapidly in the first 6 years than the last 4 years. The stable diastolic BP achieved in the last 4 years permits BP control without deleterious low levels of diastolic BP in elderly patients. Conclusions: 1) All age groups can be well controlled, with lower rates of control in average systolic and diastolic BP in the last 4 years. 2) Older patients > 70 yo respond well and achieve higher control rates without deleterious lowering of diastolic BP. 3) Seasonal BP variation is seen independent of age.

The effectiveness of intensive nursing care on seasonal variation of blood pressure in patients on peritoneal dialysis

This article is a report of a study to reduce the seasonal variation of blood pressure in patients on peritoneal dialysis through an intensive programme of nursing care. The seasonal variation of blood pressure is a common phenomenon in patients on maintenance dialysis. Whether or not this variation can be reduced through a given intervention is unknown. The programme of intensive nursing care including education on volume control, home blood pressure monitoring and intensified antihypertensive treatment, was implemented from December 2006. The blood pressure, fluid and sodium removal and defined daily doses of antihypertensive agents were measured at 1-monthly intervals and averagely quarterly for seasonal values for spring, summer, autumn and winter, respectively, before (December 2005-November 2006) and after intervention (December 2006-November 2007). A total of 76 clinically stable patients on peritoneal dialysis were enrolled and finally analysed. The mean age was 60·6 years, and dialysis duration was 23·2 months. Before intervention, there were important seasonal variations in systolic and diastolic blood pressure. After intensive nursing care was implemented, the seasonal variation of systolic blood pressure disappeared. The diastolic blood pressure still represented a season pattern, but the discrepancy between winter and summer decreased. There were no seasonal patterns of total fluid and sodium removal before and after intervention. Intensive nursing care reduced the seasonal variation of blood pressure in patients on peritoneal dialysis. These data provided an evidence for implementing nurse-centred interventions in this population.

The seasonal variation of blood pressure in hypertensive patents treated with combination therapy in chief trial

SubjectThe aim was to investigate the seasonal variation of BP level and BP control rate in patients with well-controlled BP by combination therapy.MethodsThis study as a branch of Chinese Hypertension...

O1-4.3 Seasonal variation in blood pressure among Chinese adults: the Kadoorie Biobank Study of 0.5 million people in China

IntroductionSeasonal variation in blood pressure and its association with outdoor air temperature has been reported in several studies. However, large population-based studies are few and data from developing countries such...

A cross-sectional evaluation of seasonality as a determinant of endothelial function

Endothelium-dependent vasodilation is impaired in obese versus lean humans. We set out to evaluate whether agonist-mediated endothelium-dependent vasodilation varies by season in a cross-sectional dataset of lean and obese humans, and whether this effect differed by obesity status.All vascular studies performed in our laboratory over a 12year period from 1997 to 2009 were evaluated. Endothelium-dependent vasodilation was measured invasively using thermodilution in the leg as the response to intra-arterially infused methacholine chloride. Resting blood pressure was measured concurrently by cuff and intra-arterially. The association of endothelium-dependent vasodilation and blood pressure measurements with season was evaluated, comparing responses in lean and obese subjects.Endothelium-dependent vasodilation differed between lean and obese subjects, and varied across seasons (p=0.02), but without an interaction between season effect and obesity status. The proportion of obese versus lean subjects differed significantly across seasons in our dataset, and after adjusting for this factor the apparent seasonal variation in endothelium-dependent vasodilation was lost (p=0.12), and was not present in either lean or obese subjects separately. Systolic arterial blood pressure varied across seasons, and this effect remained significant after adjusting obesity status (p=0.019 and p=0.043 for blood pressures measured intra-arterially and by cuff respectively).In our cross-sectional dataset, seasonal variations in blood pressure were seen but we did not observe an association between season and endothelium-dependent vasodilation in lean or obese subjects.

Seasonal Variation in Home Blood Pressure Measurements and Relation to Outside Temperature in Japan

Previous studies have suggested that outside temperature affects blood pressure (BP) levels. However, recently, due to a spreading heating system, the seasonal variation in BP levels might be smaller, especially in colder seasons when more heat is used. We used continuous measurements of home BP data to track seasonal variations of BP to analyze the relation between outside temperature and BP values. Among 213 volunteers who were asked to measure BP in September 2000, 79 participants (mean age 72.7 years, 60.0% women) measured BP at least once per month until August 2003 (36 months). The mean number of measurements was 19.0 times/month. Information on outside temperature was provided by the Japan Meteorological Agency. We used general linear models to analyze the relation between outside temperature and BP values. Blood pressure levels were lowest in the warmest months. However, the highest BP levels were not observed in the coldest month, but rather in March. A clear inverse association between temperature and BP values was evident only in periods when outside temperatures were above 10°C. When the outside temperature was ≥ 10°C, 1°C increment of outside temperature correspond to 0.40 and 0.28 mmHg decrease of systolic blood pressure (SBP) and diastolic blood pressure (DBP), whereas the corresponding values were 0.06 and 0.01 mmHg when the outside temperature was <10°C. In conclusion, inverse association between outside temperature and BP was observed only in warmer seasons.

A study on seasonal variation of blood pressure in patients with essential hypertension

Objective To study seasonal variation of blood pressure (BP) in patients with essential hypertension (EH) and its association with meteorological elements. Methods In total, 1800 patients with essential hypertension were recruited by cluster sampling from three townships and towns in Qingzhou,Shandong province, 1155 men and 645 women, with an average age of 61.3 years (ranging from 29 to 85years). BP was measured for all of them in sitting position at 8:00 in the morning every seven to 14 days during July 2008 to June 2009. Local meteorological data were collected accordingly such as temperature,humidity and atmospheric pressure, and multivariate regression analysis was performed to show their association. Results In general, BP in patients with EH presented a decreasing trend during the first half year of observation, with the lowest in the summer ( May to August). From September to October, their BP began to increase gradually, and reached the peak in the winter ( November to February nest year). There was significant difference in systolic BP (SBP) and diastolic BP (DBP) between various seasons (Pspring-summer = 0.002 and 0.000, Pwinter-spring = 0.001 and 0.000, Psummer-autumn = 0.045 and 0.000,Psummer-winter =0. 000 and 0. 000, Pautumn-winter =0. 000 and 0. 000, respectively), except for those between the spring and autumn. Both SBP and DBP reversely associated with outdoor air temperature and room temperature(beta= -0.08, t = -2.39, P ＜0.05 and beta = -0.24, t = -6.21, P ＜0.01,respectively), (beta = -0.08, t = -2.39, P ＜0.05 and beta = -0.24, t = -6.21, P ＜0.01,respectively). Conclusions BP in patients with EH reveals seasonal variation, with the lowest in the summer and the highest in the winter and evident fluctuation in the spring and autumn, especially in SBP,which associates with room temperature and their blood vessel elasticity. Key words: Hypertension; Blood pressure; Seasons

Impact of outdoor temperature on prewaking morning surge and nocturnal decline in blood pressure in a Japanese population

Seasonal variations in blood pressure (BP) have often been attributed to meteorological factors, especially changes in outdoor temperature. We evaluated the direct association between meteorological factors and circadian BP variability. Twenty-four-hour ambulatory BP was monitored continuously for 7 days in 158 subjects. Mean awake, asleep, morning (first 2 h after waking) BP, prewaking morning BP surge (morning systolic BP (SBP)-mean SBP during the 2-h period before waking) and nocturnal BP decline were measured each day. We compared BP values for the lowest and highest days with regard to the daily mean outdoor temperature and mean atmospheric pressure. Morning BP and prewaking morning BP surge on the coldest day were significantly higher than those on the warmest day (morning SBP, 136.6 ± 1.6 vs. 133.1 ± 1.5 mm Hg, P = 0.002; morning diastolic BP, 84.4 ± 0.9 vs. 82.6 ± 0.9 mm Hg, P = 0.02; and prewaking morning BP surge, 20.8 ± 1.3 vs. 15.3 ± 1.3 mm Hg, P = 0.0004). The magnitude of nocturnal BP decline on the coldest day was significantly greater than that on the warmest day (15.8 ± 0.7 vs. 13.9 ± 0.7%, P = 0.01). Outdoor temperature is an important determinant of morning BP, prewaking morning BP surge and the magnitude of nocturnal BP decline. These findings may have important implications in management of hypertension and prevention of cardiovascular events.

Seasonal changes in blood pressure in chronic kidney disease patients

Seasonal variation in blood pressure (BP) in different populations has been described. However, no study has concentrated on the change of blood pressure in chronic kidney disease (CKD) patients, a large and growing population worldwide. Furthermore, the role of volume status in seasonal blood pressure variations remains controversial. 109 CKD patients in a single center were followed between January 1, 2007 and December 31, 2007. Systolic and diastolic blood pressure, level of serum creatinine and body weight were measured in these patients and studied along with climatology data obtained from Beijing Weather Bureau. Blood pressure varied throughout the year, following a cyclic pattern. It increased from the autumn months toward winter, and decreased toward the spring and warmer months. The seasonal variation of blood pressure in CKD patients appeared not to correlate with CKD stage and similar seasonal variations were observed. Blood pressure values in the cohort of CKD patients were inversely correlated with outdoor temperatures (SBP: r = -0.882, p < 0.001; DBP: r = -0.860, p < 0.001). Furthermore, there was no significant difference in body weight between summer and winter (p > 0.05) in this group of CKD patients. Our results suggest that the blood pressure of CKD patients varied with the seasonal variation. The seasonal variation of blood pressure in CKD patients seemed to have no correlation with stage of CKD or change of body weight but was inversely associated with outdoor temperatures. These results suggested that volume status might not be a key mechanism causing seasonal variation in blood pressure.

Seasonal Blood Pressure Variation and Its Relationship to Environmental Temperature in Healthy Elderly Japanese Studied by Home Measurements

The purpose of the present study was to examine seasonal blood pressure variation and its relationship to environmental temperature in healthy elderly Japanese, as studied by home measurements. Fifteen healthy elderly Japanese (79.3 ± 5.9 yrs) measured their blood pressure at home each morning for more than 25 times per month for 3 years. Monthly mean outdoor temperatures were obtained from the Takamatsu meteorological Observatory. The highest levels of systolic and diastolic blood pressure measured at home were observed in February (129 ± 14 and 81 ± 13 mmHg). The lowest levels of systolic and diastolic blood pressure measured at home were observed in August (117 ± 11 and 73 ± 10 mmHg). Likewise, the lowest and highest means of outdoor temperature were observed in February (5.0°C) and August (29.2°C), respectively. Hence, both systolic and diastolic blood pressure demonstrated a close inverse correlation with the means of outdoor temperature (r = −0.973, p < 0.001 and r = −0.985, p < 0.001, respectively). A 1°C decrease in the mean outdoor temperature was associated with rises of 0.43 mmHg in systolic blood pressure (SBP) and 0.29 mmHg in diastolic blood pressure (DBP). Seasonal variations in home blood pressure and outdoor temperature showed complete correspondence in healthy elderly Japanese, with the blood pressures being inversely related to the ambient temperature. These seasonal home blood pressure variations should be kept in mind when controlling blood pressure in elderly patients.

Seasonal Variation of Blood Pressure in Normotensive Females Aged 18 to 40 Years in an Urban Slum of Delhi, India

Season is one of the factors affecting blood pressure. The objectives of this study are to quantify the magnitude of seasonal changes in blood pressure among normotensive women aged 18 to 40 years and to find out the association of blood pressure variation between winter and summer with body mass index, temperature, humidity, day length, and salt intake. The study was carried out on 132 women, included 4 home visits during the seasons of spring, summer, autumn, and winter. Mean increase in systolic blood pressure (SBP)/diastolic blood pressure (DBP) in winter was 11.07/6.79 mm Hg during summer (P < .001). No significant relationship in blood pressure variation with change in environmental variables was observed. Mean increase in SBP/DBP in winter was more among underweight than individuals who were normal/overweight/obese (P < .05). There was significant increase in SBP/DBP during winter compared with summer. This seasonal factor should be considered while evaluating individual blood pressure and comparing community studies.

Abstract 4903: Control of Hypertension in All Age Groups in a Large Multiyear Multicenter Analysis From the Department of Veterans Affairs

Introduction: Benefits of blood pressure (BP) control have been well elucidated, but overall BP control remains poor. Elderly patients are considered resistant or difficult to control. Thus, we assessed the effect of organized interventions to control blood pressure in a large cohort of patients in the Department of Veteran Affairs. Methods: From January of 2000 to December 2007, we assessed BP control in 478,099 patients from 15 VA hospitals in various geographic locations around the United States. Patients were divided in 4 groups based on age: G1 &lt;55 (N = 105,119), G2 55- &lt;70 (N = 174,418), G3 70- &lt;80 (N = 129,516), G4 ≥ 80 (N = 69,046). Medical interventions to control BP included use of electronic medical records with automated reminders, medical regimen adjustments, and frequent visits to both specialty and nurse run clinics. Results : Control rates (BP ≤ 140/90) at baseline were: 49.5% in G1, 43.6% in G2, 43.5% in G3 and 44.0% in G4. After 7 years of follow up BP control improved to 69.9% in G1, 70.9% in G2, 72.3% in G3 and 71.6% in G4 (p &lt;0.0001 for all groups compared to baseline). Average blood pressure changes are shown (figure ). Patients over the age of 70 achieved the greatest systolic BP reduction. Diastolic BP decreased in all age groups over the age of 55, but remained unchanged in the younger age group. BP levels were lower during the summer time as compared to winter in all age groups. Conclusions: High rates of BP control can be achieved even among the very old. Older patients respond well to appropriate interventions. Diastolic BP decreased in all age groups over the age of 55, but remained unchanged in younger patients. Seasonal BP variation is seen independent of age.

Abstract 4899: Improved Blood Pressure Control and Lack of Gender Bias in a Large Veterans Affairs Population

Introduction: Despite the proven benefits, blood pressure (BP) control rates remain low. Gender bias has emerged in several aspects of treatment of cardiovascular disease. Thus, we assessed the effect of interventions to control blood pressure in men and women in the Department of Veteran Affairs. Methods: From January of 2001 to December 2007, we assessed BP control in 460,278 men and 17,821 women patients from 15 VA hospitals in the United States. Medical interventions to control BP included use of electronic medical records with automated reminders, medical regimen adjustments, and frequent visits to both specialty and nurse run clinics. Results : Control rates (BP ≤ 140/90) over time are shown (Figure ). In Jan 2001 control rates were: 43.8% for men and 47.0% for women (p &lt; 0.001) and in June 2001 were 51.8% for men and 54.2% for women (p &lt; 0.001). After 7 years of follow up, control rates improved in both genders as follows: Jan 2007, 67.3% for men and 67.6 for women (p = NS), June 2007, 72.9% for men and 72.9% for women (p = NS, p &lt; 0.001 for seasonal differences). Overall during the follow up period while there was a 23.1% increase in control rates for men and 19.2% for women (p = 0.007), the final control rate was the same. Conclusions: High rates of BP control can be achieved in both men and women. Although early on more women than men were controlled, the control rates were identical at the end of the follow up period. No gender bias was detected for blood pressure treatment and control in this cohort. Seasonal BP variation was seen in both genders throughout the follow up period.

Seasonal variation in haemodynamics and blood pressure-regulating hormones

Seasonal variation in blood pressure (BP) has been described in some people, although the variation is small for both systolic and diastolic BPs. The aim of this study was to elucidate underlying haemodynamic and hormonal mechanisms that may occur to defend seasonal changes in BP. Participants were 27 men and 7 women with either normal BP or early hypertension. Measurements of haemodynamics (cardiac output by dual-gas rebreathing) and hormones (resting catecholamines, renin activity, and aldosterone by radioenzymatic assay or radioimmunoassay) were performed during the summer, fall, winter, and spring seasons. Student's paired t-test with Bonferroni modification and regression analyses were used to examine the data with a significance level of P<0.05. Systolic and diastolic BP remained relatively constant across seasons. Cardiac output and stroke volume significantly decreased 10 and 15%, respectively, from summer to winter, whereas heart rate and systemic vascular resistance significantly increased 5 and 11%, respectively. Plasma aldosterone (PA) significantly increased 59% from summer to winter, whereas plasma norepinephrine (PNE), plasma epinephrine, and plasma renin activity (PRA) increased 19, 2, and 17%, respectively (pNS for each). Across the four seasons, mean arterial pressure significantly correlated with PRA and PA, whereas systemic vascular resistance significantly correlated with PNE and PRA. There are dramatic counterregulatory haemodynamic and hormonal adaptations to maintain a relatively constant BP. Norepinephrine, PRA, and aldosterone have a function in mediating the changes in haemodynamics.

Relationship Between Blood Pressure and Outdoor Temperature in a Large Sample of Elderly Individuals

Seasonal variations of blood pressure-related diseases have been described in several populations. However, few studies have examined the seasonal variations of blood pressure in the elderly, a segment of the population particularly exposed to vascular diseases. The association of blood pressure with season and outdoor temperature was examined in 8801 subjects 65 years or older from the Three-City study, a population-based longitudinal study. Blood pressure was measured at baseline and 2-year follow-up examinations. Daily outdoor temperature measured at 11 am was provided by the local meteorological offices. Both systolic and diastolic blood pressure values differed significantly across the 4 seasons and across the quintiles of the distribution of outdoor temperature. Systolic blood pressure decreased with increasing temperature, with an 8.0-mm Hg decrease between the lowest (< 7.9 degrees C) and the highest (> or = 21.2 degrees C) temperature quintile. Intraindividual differences in blood pressure between follow-up and baseline examinations were strongly correlated with differences in outdoor temperature. The higher the temperature at follow-up compared with baseline, the greater the decrease in blood pressure. Longitudinal changes in blood pressure according to difference in outdoor temperature were larger in subjects 80 years or older than in younger participants. Outdoor temperature and blood pressure are strongly correlated in the elderly, especially in those 80 years or older. During periods of extreme temperatures, a careful monitoring of blood pressure and antihypertensive treatment could contribute to reducing the consequences of blood pressure variations in the elderly.

Seasonal Changes in Preprandial Glucose, A1C, and Blood Pressure in Diabetic Patients

The American Diabetes Association has recommended glycemic goals for nonpregnant diabetic individuals (1). These goals are aimed at controlling blood glucose levels, blood pressure, and lipid profiles. In addition, seasonal variation of blood pressure has been recognized and found to exist in both normotensive subjects and hypertensive patients (2). However, the relation between blood pressure patterns, as well as blood glucose levels and lipid profiles, in diabetic patients and seasonal cycles remains unclear. We collected data from all patients who received treatment at the endocrinology and metabolism clinic at Da Chien Hospital (Miaoli, Taiwan) at least two times per year from 2003 to 2006. The clinic opened in May 2002, and data excluding personal information were retrieved from the hospital data bank; this procedure was approved by Da Chien Hospital. There were diabetic patients treated at the clinic in 2003 ( n = 465), 2004 ( n = 615), 2005 ( n = 599), and 2006 ( n = 662). Some patients ( n = 212) were retained throughout the entire study period, while others only attended the clinic for a fraction of the 2003–2006 time frame. The mean diabetes duration in these patients was 7.89 years, and the …

Arterial stiffness is related to augmented seasonal variation of blood pressure in hypertensive patients

Background. Seasonal variation in blood pressure (BP), a usual tendency of both systolic (SBP) and diastolic BP (DBP) to rise during winter in hypertensive patients, may be related to the higher cardiovascular mortality in winter. However, it is not yet clear what factors are relevant to the seasonal BP changes. We hypothesized that arterial stiffness is related to the BP changes between summer and winter. Methods and results. Eighty‐five elderly (>55 years) patients with essential hypertension (33 males, 64±6.0 years) were enrolled. Seasonal BP profiles over at least 2 years were studied along with arterial stiffness and clinical variables (age, gender, smoking, duration of hypertension, anti‐hypertensive medications and body mass index). Both SBP and DBP were significantly higher during winter compared with three other seasons (spring 128±10.0/79±7.3 mmHg, summer 127±9.8/78±7.1 mmHg, autumn 127±10.3/78±8.0 mmHg, winter 136±12.5/81±7.6 mmHg; SBP changes; p<0.001, DBP changes; p<0.001). There were no significant seasonal differences among spring, summer and autumn. Pulse wave velocity (PWV), a widely used clinical indicator of arterial stiffness was correlated with winter–summer differences in SBP (r = 0.272, p = 0.012), but not in DBP (r = 0.188, p = 0.085). Age, which was correlated with PWV strongly (p<0.001), was not significantly related to the seasonal changes in BP (SBP changes; p = 0.114, DBP changes; p = 0.298). No other clinical variables had significant correlation with seasonal BP changes. Multivariate regression analysis revealed that PWV is the only significant predictor for winter–summer SBP changes. Conclusions. Our results established a feasible link between arterial stiffness and seasonal BP variation. These findings may partly explain higher cardiovascular risk in patients with increased arterial stiffness.

Seasonal Variation in Blood Pressure of Patients on Continuous Ambulatory Peritoneal Dialysis

Background: A seasonal variation in blood pressure (BP) has been observed in hemodialysis and renal transplant patients. However, this phenomenon in continuous ambulatory peritoneal dialysis (CAPD) patients, whose hemodynamics are different from hemodialysis patients, has not been reported before. In addition, the contribution of extracellular water (ECW) in the seasonal variation in BP is not clear. Methods: All stable CAPD patients (n = 122) dialyzed in a single center from January 1, 2003 to December 12, 2004 were studied. Systolic blood pressure (SBP), diastolic blood pressure (DBP), weight and ECW (by bioimpedance analysis) were measured in every patient. Climatic data were obtained from the Beijing Weather Bureau. These data were pooled together and grouped according to the calendar month. Results: In general, an apparent seasonal variation in BP was observed in CAPD patients. BP began to decrease from spring and reached the lowest level in summer, then increased from autumn and reached its peak in winter. The seasonal variation in BP in male patients was similar to that in female patients, but in comparison to non-diabetic patients there was no apparent seasonal variation in the BP of diabetic patients. SBP and DBP negatively correlated with the average atmospheric temperature (r = –0.768, p < 0.001 and r = –0.764, p < 0.001, respectively). BP also negatively correlated with rainfall and humidity, but this correlation disappeared when temperature was controlled in partial correlation analysis. Weight and ECW fluctuated throughout the year but showed no seasonal variation. Conclusion: On the whole there was an apparent seasonal variation in blood pressure in CAPD patients. As opposed to non-diabetic patients, there was no apparent seasonal variation in BP in diabetic patients. The seasonal variation in BP was influenced more by temperature than rainfall and humidity, and the change in ECW was not seasonal, suggesting that other mechanisms such as total peripheral resistance might play a more important role in this phenomenon.

Seasonal Variation in Blood Pressure Among Multiethnic Children

Seasonal Variation in Blood Pressure Among Multiethnic Children

Selected climatic variables and blood pressure in Central European patients with chronic renal failure on haemodialysis treatment

Background/aims. Higher blood pressure (BP) in winter has been documented in healthy and hypertensive adults. It may potentially contribute to the observed excess winter cardiovascular mortality in the general population. The aim of the study was to assess whether BP varies similarly among patients with chronic renal failure on haemodialysis treatment, who present an increased risk of cardiovascular death. Methods. We retrospectively analysed values of pre‐dialysis BP and parameters of fluid retention – pre‐dialysis body weight and inter‐dialytic weight gain measured in 49 patients (23 male, 26 female; aged 46.0±13.5 years) from 1995 to 1998. For each patient we calculated deviations of monthly mean values of systolic BP, diastolic BP, pre‐dialysis body weight and inter‐dialytic weight gain from the lowest monthly means of these parameters in a given year. Monthly means of these deviations for the whole study group (dSBP, dDBP, dBW, dWG, respectively) were subsequently computed. Monthly means of air temperature (T), air relative humidity (H) and atmospheric pressure (AP) were provided by the local Institute of Meteorology. The Wilcoxon paired test was applied to compare mean values of BPs and parameters of fluid retention of every patient in three warmest and three coldest months of each year. Spearman rank correlation analysis was employed to evaluate relationships between dSBP, dDBP and climatic variables, dBW or dWG. Results. Systolic BP was higher in summer than in winter (146.6±20.5 vs 143.4±18.9 mmHg; p<0.00001). Diastolic BP was also higher in summer than in winter (82.6±8.5 vs 79.6±7.3 mmHg; p<10−9). Pre‐dialysis body weight and inter‐dialytic weight gain did not differ between summer and winter (66.0±13.2 vs 66.0±13.2 kg; p = 0.98 and 2.27±0.6 vs 2.29±0.5 kg; p = 0.53). There was a positive correlation between dSBP and T (RS = 0.424, p<0.003), as well as dDBP and T (RS = 0.591, p<0.00001) and an inverse correlation between dSBP and H (RS = −0.372, p<0.01), as well as dDBP and H (RS = −0.408, p<0.004). There were no significant associations between BPs and AP, dBW or dWG. Conclusions. In haemodialysed patients from southern Poland, BP is higher in summer than in winter. Changes in BP are related to seasonal changes in climatic variables – air temperature and air relative humidity. Seasonal variation in BP is not associated with variation in fluid retention. Possible alteration of cardiovascular reactivity to changes in climatic environment in haemodialysed chronic renal failure patients may be one of the potential explanations of these observations.