How does cold affect blood pressure

Blood pressure measurement under standardized indoor condition may mask seasonal blood pressure variation in men with mildly elevated blood pressure. Clinical and Experimental Hypertension. Stergiou GS, et al. Seasonal variation in meteorological parameters and office, ambulatory and home blood pressure: Predicting factors and clinical implications.

Hypertension Research. Takagi H, et al. Meta-analysis of seasonal incidence of aortic dissection. The American Journal of Cardiology. McGuire DK, et al. The environment and high blood pressure.

Philadelphia, Pa. Accessed Feb. Chen Z, et al. Onset seasons and clinical outcomes in patients with Stanford type A acute aortic dissection: An observational retrospective study. BMJ Open. See also Medication-free hypertension control 6 surprising signs you may have obstructive sleep apnea After a flood, are food and medicines safe to use? Alcohol: Does it affect blood pressure? Beta blockers: How do they affect exercise?

Blood pressure chart Blood pressure cuff: Does size matter? Blood pressure: Does it have a daily pattern? Blood pressure medication: Still necessary if I lose weight? Blood pressure medications: Can they raise my triglycerides? Blood pressure readings: Why higher at home? Metoprolol is widely used as a treatment for hypertension, but there is no published information about the effects of metoprolol in whole-body cold exposure.

The aim of the present study was to test the effects of metoprolol on BP and heart rate HR in hypertensive subjects during whole-body cold exposure, simulating normal outdoor winter cold exposure.

The study protocol was approved by the Ethics Committee of the Medical faculty at the University of Oulu. The subjects were informed about the test and they gave their written consent. Five subjects were excluded from the study: two because of the white-coat phenomenon, two did not follow the study protocol and one had a respiratory infection with fever during the weeks of the test procedures.

The final study group comprised seven subjects. Their mean age was 30 years s. The tests were carried out during the winter in a climate chamber and wind tunnel. The study procedures were carried out as described in detail by Komulainen et al. Subjective ratings of thermal sensation 10 and cold pain 7-point scale were asked just before the cold exposure and three times during the cold exposure.

Compared to placebo, metoprolol decreased BP Table 1 significantly in the test group before the cold exposure. During the cold exposure, BP increased rapidly. BP was significantly lower with metoprolol than placebo during the cold exposure. BP was significantly lower with metoprolol than with placebo after the cold exposure.

BP decreased slowly after the cold exposure, and BP remained elevated during the min recovery period after the cold exposure both with placebo and metoprolol.

The cold-induced increase in BP was not significantly affected by metoprolol. Metoprolol decreased HR before, during and after cold exposure compared to placebo Table 1. Metoprolol did not affect general or local thermal sensations during cold exposure. Metoprolol lowered mean and peak BP significantly, but it did not prevent the cold-induced rise of the BP during cold exposure that simulated normal outdoor exposure in winter.

Carvedilol, 9 which was studied earlier in the same test procedures, decreased the level of BP slightly more than metoprolol, while the amount of cold-induced rise of BP was on the same level. The present results with mildly hypertensive subjects differ from previous studies with healthy subjects: DBP 11 and MAP 12 were higher with atenolol and propranolol compared to placebo and the amount of cold-induced rise was greater than with placebo during cold exposure.

Your body — and blood vessels — may react to abrupt changes in humidity, atmospheric pressure, cloud cover or wind in much the same way it reacts to cold. These weather-related variations in blood pressure are more common in people age 65 and older.

Other seasonal causes of higher blood pressure include the weight gain and decreased physical activity that are common in winter. If you have high blood pressure already, continue to monitor your blood pressure readings as the seasons change and talk to your doctor.

The receptor, known as angiotensin II receptor type 1A, or AT1A, is part of the renin-angiotensin system, which regulates blood pressure in mammals, he said. AT1A receptors are located in the heart, blood vessels, kidneys and brain. The drug losartan blocks the receptors from receiving angiotensin and commonly is prescribed to treat hypertension. For now, physicians treating hypertensive patients with medication should be alert to seasonal changes in blood pressure, he said. People can take other simple precautions to help lower risk, Sun added.

People whose jobs require prolonged or repeated exposure to cold, such as farmers, construction workers, meat cutters and law enforcement officers, should be particularly mindful of precautions, he said. Sun conducted the study with collaborators Xiuqing Wang, Ph. Robert Cade, M. The UF findings suggest that further research would help explain whether cold-induced blood pressure increases are controlled by AT1A receptors located in blood vessels, or elsewhere, said angiotensin expert Irving H.