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The New Low For High Blood Pressure
One night back in May, I went to sleep with perfectly normal blood pressure, an unremarkable 120/80. The next day, I woke up in a blood pressure danger zone. What happened? My blood pressure didn't spike overnight; instead, government officials issued revised blood pressure guidelines that included a new category: prehypertension.
Anyone with a systolic (top number) reading of 120 or over, or a diastolic (bottom) reading of 80 or over, now has prehypertension, which means we're at increased risk of heart disease and stroke.
Between those of us with newly-minted prehypertension (some 23% of the population), and people who have full-blown hypertension (at least another 25%), danger-zone blood pressure is an emerging epidemic in this country. Nearly half of all American adults over 18 are in one category or the other.
Are so many of us really so unhealthy? I'm only 36. I run three miles every other day. (Well, okay, sometimes I skip a day.) I almost never eat fried foods. I'm just one of thousands of people in their 30s, 40s and 50s who thought we were paragons of health until the new numbers were released. Are the doctors just trying to scare us?
"This is a wake-up call. We've changed what normal is, because we now know that blood pressure in the prehypertension range is not normal," says Sheldon Sheps, MD, medical editor of MayoClinic.Com's High Blood Pressure Center. He served on the committee that drafted the new guidelines.
"There is increasing evidence of the relationship between an elevated blood pressure and future problems with heart attack and stroke. With each level of increase in pressure, you get increased risk," he tells WebMD. Consider these startling statistics:
Starting as low as 115/75, the risk of heart attack and stroke doubles for every 20-point jump in systolic blood pressure or every 10-point rise in diastolic blood pressure.
"We've also learned that people age 55 and older, who currently have normal blood pressure, have a 90% risk of developing high blood pressure down the road," says Aram Chobanian, MD, Dean of Boston University School of Medicine, who chaired the guidelines committee.
"We have a lot of concern about this rise in blood pressure over the course of our lifetimes, and to try to prevent that from happening, we have identified a 'prehypertension' group in which lifestyle changes can make a difference," Chobanian says.
But if so many people are already likely to go on to develop high blood pressure, can we really avoid it? Maybe high blood pressure is just an inevitable consequence of aging. Not so, says Chobanian.
"There are populations in the world where age-related rises in blood pressure are minimal. In areas of Mexico, certain areas of the South Pacific, and other parts of the world with very low salt intake, there's not anywhere near the age-related rise in blood pressure that we see in the United States."
So if rising blood pressure and aging don't -- or shouldn't -- go hand in hand, what should the millions of us who now have prehypertension do about it? The good news: we shouldn't be looking for a new pill. "Unless you have diabetes or kidney disease, people with prehypertension don't need to be on medication," says Sheps.
That's also the bad news. Preventing high blood pressure means lifestyle changes, which is usually harder than popping a pill. Number one on the blood pressure reduction hit parade: preventing or treating obesity. As our pants sizes get smaller, so do our blood pressure numbers. Of course, the opposite is true as well. With our nation on a supersizing binge and a growing percentage of adults and children becoming overweight or obese, it's no surprise that rates of high blood pressure have skyrocketed as well.
You can get your weight down by any number of methods, but ultimately, staying healthy means choosing a plan you can live with long-term. Of the trendy high-protein, low-carb plans like Atkins and South Beach, Sheps says, "If you want to try them to get a jump-start on weight loss, go ahead for a month or two months. That's about all people can stand before they get bored to tears.
"But for life, the diet you need to be on for life is the DASH diet, which is not specifically designed for weight loss. The Holy Grail is a healthier lifestyle and we know from untold numbers of studies that if you follow a diet rich in fruits and vegetables and low in fat, you'll live longer and better."
High in whole grains, fruits, and vegetables, and low in total saturated fats, DASH (Dietary Approaches to Stop Hypertension) has been found to be as effective in reducing blood pressure as blood pressure medication. "It's not clear what it is about DASH that works, but it's high in potassium and calcium and low in saturated fat and sodium," says Chobanian. "It's a sensible diet that you can realistically follow for the rest of your life."
Studies have also shown that DASH is even more effective in controlling weight and reducing blood pressure when combined with a regular exercise program. If you can't fit in the newly-recommended one hour of physical activity a day, half an hour daily still beats never breaking a sweat.
Ultimately, say experts, those of us with prehypertension need to be more aware of our changing blood pressure rates. Sheps suggests monitoring your blood pressure on your own between doctor's visits, using a home blood pressure device. "Just make sure the cuff size is appropriate," he says. "It needs to cover at least 80% of the circumference of the arm."
Putting the brakes on the high blood pressure epidemic won't be easy. "It's always an uphill battle to get people to change their lifestyles," says Chobanian. Yet these days, when half of American adults are at risk for heart attack or stroke because of their blood pressure, doctors say it's time for a major public health effort.
How To Read Your Blood Pressure And Understand What It Means For You
High blood pressure is known as the "silent killer" because it usually doesn't come with symptoms, and it can be dangerous if left untreated.
The only way to know your blood pressure and keep track of your heart health is through accurate readings and frequent measurements.
Here's what you need to know about your blood pressure reading and what it means for you.
Blood pressure readingsBlood pressure is the force of blood pushing against the arteries in your body. It is measured by two numbers:
Blood pressure is measured in millimeters of mercury (mm Hg). To determine whether someone has high blood pressure, known medically as hypertension, doctors classify blood pressure readings into different categories.
Shayanne Gal/Insider Normal blood pressureNormal blood pressure is considered:
If you have a blood pressure reading around this number, it generally means your heart is healthy. However, even if you have normal blood pressure, certain factors can increase your risk of developing hypertension over time.
These include:
Sometimes, blood pressure can be lower than normal. Low blood pressure is considered:
Low blood pressure isn't always cause for concern — in fact, it's often harmless, and can even indicate good health.
"If you're an athlete, an exerciser, or someone who does a lot of things to take care of their body, it can be normal to have a relatively low blood pressure," says Jordana Cohen, MD, a hypertension expert at Penn Medicine.
However, you should check in with your doctor when low blood pressure is accompanied by the following symptoms:
This may be a result of certain conditions or medications. Low blood pressure typically occurs with Parkinson's disease, hormonal changes, and pregnancy.
Elevated blood pressureElevated blood pressure is considered:
This is the first warning sign for hypertension — and it's often called pre-hypertension. Your doctor will talk with you about implementing lifestyle changes that can effectively lower blood pressure, including:
Hypertension is considered:
Medication is generally not considered necessary to treat hypertension at this level, and you should instead commit to making those healthier lifestyle choices to lower blood pressure, says Cohen.
If you have to focus your energy on one blood-pressure-reducing activity, Cohen recommends exercise, as it not only lowers blood pressure on its own, but it can also reduce stress, which is another cause of high blood pressure.
Hypertension: Stage 2Hypertension becomes worse when it rises to:
While intensive lifestyle modification to reduce high blood pressure is still necessary, Cohen says medication is also typically required to lower someone's stage 2 hypertension.
If left untreated, blood pressure this high can lead to the following health threats:
A hypertensive crisis is considered:
This can be very dangerous and require immediate medical attention, especially if it's combined with the following symptoms:
A hypertensive crisis can result in organ damage, and indicates a heightened risk for stroke, heart attack, and other life-threatening consequences. If you're experiencing blood pressure this high along with any of these symptoms, call 911 immediately.
How often should you measure blood pressure?If you have normal blood pressure, and your doctor thinks you're at a low risk for developing hypertension, you'll likely only get your blood pressure measured once a year, at a routine check-up.
However, if you're at risk or have hypertension, your doctor may recommend that you check blood pressure at home.
If you have a clinician-approved at-home blood pressure measuring kit, you should measure your blood pressure twice in the morning and twice in the evening, waiting a minute between readings, says Cohen.
Additionally, she says it's important to calmly wait five minutes before measuring your blood pressure, as it can affect the accuracy of your reading.
"If you're checking your blood pressure when you're exercising, moving around, or without taking that five minute break, then it's just not a useful blood pressure," Cohen says.
Cohen recommends using a blood pressure measuring device from an accredited source, such as Validate BP. Devices are independently reviewed by experts associated with the American Heart Association to see which ones provide the best, clinically accurate results.
Insufficient Sleep And High Blood Pressure May Raise Risk Of Brain Aging
While some studies have shown a link between insufficient sleep and the risk of cognitive impairment and dementia, other studies have failed to find a similar association between sleep duration and cognitive function.
A new study published in the Journal of the American Heart Associationshows that individuals with high blood pressure who also slept for a shorter duration were more likely to show poor cognitive function and increased levels of markers of brain aging and injury. Individuals who slept for a shorter duration but had normal blood pressure did not show these deficits in cognitive function or increased levels of brain injury markers.
The role of high blood pressure in influencing the impact of sleep duration on cognitive health could explain the mixed results found in previous studies.
The study also paves the way for early identification of individuals at risk of cognitive decline and randomized trials investigating treatments for normalizing sleep patterns and high blood pressure to prevent or delay cognitive decline.
The study's author, Matthew Pase, PhD, associate professor at Monash University, told Medical News Today:
"The results underscore the importance of having healthy blood pressure levels and prioritizing adequate sleep to maintain a healthy brain into old age. Doctors should be reminded to check patients' blood pressure levels regularly and manage high blood pressure appropriately. Similarly, the medical world is now starting to appreciate the importance of good sleep, and getting good sleep should be considered part of a healthy lifestyle."
Shorter sleep duration, besides its association with cognitive decline, is also linked to an increased risk of high blood pressure.
Moreover, studies show that high blood pressure in midlife is independently associated with cognitive impairment and dementia later in life. High blood pressure can cause cerebral small vessel disease, which is associated with an increased risk of stroke and cognitive decline.
Cerebral small vessel disease is a heterogeneous condition involving damage to the small blood vessels in the brain, leading to brain tissue damage and atrophy of the brain structures.
The tissue in the brain can be classified into white matter and gray matter. Gray matter contains the cell bodies of the nerve cells, whereas white matter consists of nerve fibers that transmit information between nerve cells.
Cerebral small vessel disease can cause lesions in the white matter and a decrease in gray or white matter volume. Gray matter forms the brain's outermost layer and is involved in several important functions, including cognition, whereas white matter is essential to maintain connectivity between regions of grey matter. White matter damage and a decrease in the volume of gray matter are observed in old age and are associated with cognitive decline.
In the present study, the researchers examined whether hypertension influenced the relationship between sleep duration and cognition. In addition, the researchers also examined the impact of hypertension on the association between sleep duration and imaging markers of white matter damage and brain aging.
The study consisted of 682 individuals over 40 years of age enrolled in the Framingham Health Study, a multi-generational longitudinal study designed to examine the risk factors for cardiovascular conditions. The study only included participants who did not have dementia or a history of stroke.
The researchers collected sleep data using a questionnaire and a home-based sleep study (polysomnographic evaluation). In addition, the researchers measured the daytime blood pressure of the participants at the time of the sleep assessment. Around 3.3 years after the sleep assessment, the participants underwent cognitive assessments and magnetic resonance imaging (MRI) scans to assess changes in brain structure.
The researchers did not find an association between sleep duration and cognitive function or brain imaging markers, except gray matter volume. In the latter case, self-reported short sleep duration was associated with larger gray matter volume.
The researchers then analyzed the impact of sleep duration on cognitive health after segregating the participants into groups with normal and high blood pressure. They found that sleep duration influenced cognitive function and the levels of brain imaging biomarkers only in individuals with high blood pressure.
Increased brain age, tissue injury with shorter sleep
Specifically, among individuals with high blood pressure, a shorter sleep duration was associated with deficits in executive function, which includes higher-level mental processes involved in planning, reasoning, and decision-making.
Moreover, individuals with high blood pressure and shorter sleep durations also showed higher levels of brain imaging markers for aging and tissue injury. Among individuals with high blood pressure, those with self-reported shorter sleep durations showed higher levels of white matter lesions, whereas those with shorter sleep durations, as measured by the sleep study, showed lower gray matter volumes.
The association between sleep duration and cognitive function or brain imaging markers was absent in individuals with normal blood pressure. In other words, these results suggest that shorter sleep duration interacts with high blood pressure to increase the risk of poor cognitive function and greater brain injury.
One of the study's strengths was its large sample size. However, due to its observational nature, the study does not establish a causal relationship between sleep duration and cognitive health.
The sleep study was only conducted over a single night, so the data on sleep duration may not represent long-term sleep patterns. Blood pressure decreases by 10% at the time of sleep onset, and shorter sleep duration can eliminate this drop in blood pressure. Blood pressure was collected during the daytime, and it is possible that the impact of sleep patterns on the drop in blood pressure at sleep onset was missed.
Furthermore, Christopher Berg, MD, a board certified cardiologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA, noted, "The strength of their findings was unimpressive. For instance, they evaluated cognitive function via six tests, only 1 of which showed a significant relationship with sleep duration in those with hypertension."
"They also evaluated six MRI-based parameters, and again, only one of the six showed an association with sleep duration in those with hypertension. How much those particular parameters meaningfully correlate with their actual cognitive performance or, say, risk of dementia is uncertain as is what extrapolation can be made from these findings," said Berg.
Lastly, he added that individuals show considerable variation in the daily amount of sleep needed.
"A blanket rule of 'each person needs x hours of sleep,' I'm not sure, is supported by the literature and doesn't seem to be the case in practice. However, this study would support the general recommendation that it is important for each person to get adequate sleep (whatever is the adequate amount ) is important for mental and physical health, and potentially more so in patients with hypertension," he said.
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