People with hypertension are likely to see an increase in blood pressure during the winter months, according to study results shared at a recent American Heart Association (AHA) hypertension session.
Researchers found that on average, systolic blood pressure (the top number of a blood pressure reading) increased by up to 1.7 mm Hg in the winter months compared to the summer months.
They also noted that efforts to control blood pressure decreased by 5% when compared to the summer months.
"I have personally seen this effect in my practice quite regularly," said Nitin Gera, MD, a cardiologist at OhioHealth. "The same patient may have a well-controlled blood pressure when I see them in the summer and then when they come back six months later it can be elevated."
While the AHA report did not indicate specifically the consequences of these seasonal fluctuations, earlier research has shown that changes in blood pressure may increase the risk of cardiovascular events, stroke, and other complications.
"When blood pressure is higher during cold weather, there is a potentially higher risk of kidney or cardiac damage associated with high blood pressure," Wanpen Vongpatanasin, MD, FAHA, the clinical chair of the AHA Hypertension 2023 Executive Committee told Health. "That鈥檚 why it is important for high blood pressure patients to monitor home blood pressure regularly."
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Experts speculate that these fluctuations in blood pressure between summer and winter months may have to do with how cold weather can impact blood vessels.
"Exposure to cold temperatures can cause constriction of blood vessels and increase blood pressure so perhaps there could be some factor from cold weather in winter months," said Jim Liu, MD, a cardiologist and clinical assistant professor of internal medicine at The Ohio State University Wexner Medical Center.
Gera explained that colder weather activates your sympathetic nervous system, which leads to the body releasing increased catecholamines (like epinephrine, norepinephrine, and dopamine). These substances cause constriction of blood vessels, which leads to higher blood pressure.
"In colder months vitamin D levels also decrease which leads to activation of the renin-angiotensin-aldosterone system," Gera said.
This system regulates blood pressure, fluid and electrolyte balance, and systemic vascular resistance, he explained, which further explains why the cold may cause an increase in blood pressure.
Additionally, lifestyle factors can have an impact on blood pressure, Liu said. People may exercise less or eat a less nutritious diet in winter months, which would both affect blood pressure.
"People tend to eat more in terms of quantity and worse in terms of quality during colder months, especially around the holidays," Gera said. "I see a bit of a vicious cycle when it is very cold, bleak, and dark where patients feel some degree of seasonal depression and then tend to eat worse and exercise less."
Liu emphasized the importance of monitoring your blood pressure on a regular basis, particularly during the winter months.
Starting with simple, sustainable habits is key. You should exercise consistently, pay close attention to your diet, limit sodium intake, and monitor vitamin D levels, he said.
Gera encourages people to use awareness of seasonal fluctuation in blood pressure to their benefit.
"The way to incorporate this [information] into a treatment plan and hopefully avoid complications is by having heightened vigilance about blood pressure during this period," he said. "I also recommend anyone with a hypertension diagnosis have a home blood pressure cuff and make sure it is accurate."
Aside from monitoring blood pressure regularly and reporting changes to your healthcare provider, it's important to exercise consistently.
"Regular exercise over time causes the release of substances that dilate blood vessels and lower blood pressure," Gera said.
This is the opposite of what cold weather does to blood vessels鈥攃onstricts them.
The Centers for Disease Control and Prevention recommends the following for managing high blood pressure:
Gera also advises older people to maintain an adequate level of indoor heating during cold periods and wear proper protective clothing when exposed to cold.
"[We also should be checking] vitamin D levels and replacing vitamin D as needed as it also can have a positive impact on blood pressure in the winter months," he said.
Lastly, there is some evidence that limiting sodium intake may reduce blood pressure. This point may be especially important to consider around the holidays when salty food is more readily available.
The AHA recommends no more than 1,500 mg of sodium per day for those with high blood pressure. The organization notes that even cutting back your salt intake to 1,000 mg a day can improve blood pressure and heart health.
Ultimately, doing as much as possible to maintain a healthy lifestyle is the best way to combat winter blood pressure changes.
"It is important to focus extra hard on keeping a healthy lifestyle even when the cold weather makes this more difficult," said Gera. "Regular physical activity by itself benefits blood pressure and in my experience can really help to break the vicious cycle of weight gain and depression."聽
