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Is frequent sauna bathing beneficial? That's what one study suggests. When the study started all 1621 men (aged 42 to 60) had normal blood pressure and none had been diagnosed with hypertension, and the follow-up was about 22 years later. The study took place in Finland, where sauna bathing is an important part of the culture - for all men, from all walks of life. The study found that frequent sauna bathing lowered the risk of developing hypertension - 46% when comparing men who sauna bathed once a week vs those who sauna bathed 4 to 7 times a week.

How could sauna bathing have these effects? There are several possibilities, but one is that sauna bathing produces "acute vasodilation" of the blood vessels, which leads to a significant drop in blood pressure. The temperature in the sauna is usually from 80 °C to 100 °C (176 to 212 degrees Fahrenheit), and the average sauna session (in this study) lasted an average of 14.4 minutes. From Science Daily:

Frequent sauna bathing keeps blood pressure in check

Frequent sauna bathing reduces the risk of elevated blood pressure, according to an extensive follow-up population-based study carried out at the University of Eastern Finland. The risk of developing elevated blood pressure was nearly 50% lower among men who had a sauna 4-7 times a week compared to men who had a sauna only once a weekThe same researchers have previously shown that frequent sauna bathing reduces the risk of sudden cardiac death, and cardiovascular and all-cause mortality. Elevated blood pressure is documented to be one of the most important risk factors of cardiovascular diseases.

The Kuopio Ischaemic Heart Disease Risk Factor Study (KIHD) involved 1,621 middle-aged men living in the eastern part of Finland. Study participants without elevated blood pressure of over 140/90 mmHg or with diagnosed hypertension at the study baseline were included in this long-term follow-up study. Based on their sauna bathing habits, men were divided into three sauna frequency groups: those taking a sauna once a week, 2-3 times a week, or 4-7 times a week. During an average follow-up of 22 years, 15.5% of the men developed clinically defined hypertension. The risk of hypertension was 24% decreased among men with a sauna frequency of 2-3 times a week, and 46% lowered among men who had a sauna 4-7 times a week.

Sauna bathing may decrease systemic blood pressure through different biological mechanisms. During sauna bathing, the body temperature may rise up to 2 °C degrees, causing vessels vasodilation. Regular sauna bathing improves endothelial function, i.e. the function of the inside layer of blood vessels, which has beneficial effects on systemic blood pressure. Sweating, in turn, removes fluid from the body, which is a contributing factor to decreased blood pressure levels. Additionally, sauna bathing may also lower systemic blood pressure due to overall relaxation of the body and mind.

[NOTE: Above photo is of interior of a modern Finnish sauna. Credit: Wikipedia]

Mediterranean Diet is Healthy Eating – A Good Option for Seniors Nothing new here, but good to have it discussed again: eating foods high in potassium and low in sodium (salt) lowers blood pressure. Why should we care? Hypertension (high blood pressure) is a global health issue. The World Health Organization estimates that hypertension is responsible for at least 51 percent of deaths due to stroke and 45 percent of deaths due to heart disease.

Eating the potassium rich foods seems to be key. Some foods high in potassium: bananas, baked potatoes, sweet potatoes, dark leafy greens (e.g., spinach, kale), tomatoes, mushrooms, beans (e.g., white beans, pinto beans), lentils, nuts, broccoli, apricots, milk. In other words, eat an assortment of fruits, vegetables, beans, and nuts to get potassium. And coincidentally these same foods are low in sodium (salt) - a win-win for heath. From Science Daily:

Fruits and vegetables' latest superpower? Lowering blood pressure

Eating potassium-rich foods like sweet potatoes, avocados, spinach, beans, bananas -- and even coffee -- could be key to lowering blood pressure, according to Alicia McDonough, PhD, professor of cell and neurobiology at the Keck School of Medicine of the University of Southern California (USC). "Decreasing sodium intake is a well-established way to lower blood pressure," McDonough says, "but evidence suggests that increasing dietary potassium may have an equally important effect on hypertension."

McDonough explored the link between blood pressure and dietary sodium, potassium and the sodium-potassium ratio in a review article....McDonough's review found several population studies demonstrating that higher dietary potassium (estimated from urinary excretion or dietary recall) was associated with lower blood pressure, regardless of sodium intake. Interventional studies with potassium supplementation also suggested that potassium provides a direct benefit.

McDonough reviewed recent studies in rodent models, from her own lab and others, to illustrate the mechanisms for potassium benefit. These studies indicated that the body does a balancing act that uses sodium to maintain close control of potassium levels in the blood, which is critical to normal heart, nerve and muscle function. "When dietary potassium is high, kidneys excrete more salt and water, which increases potassium excretion," McDonough says. "Eating a high potassium diet is like taking a diuretic." "If you eat a typical Western diet," McDonough says, "your sodium intake is high and your potassium intake is low. This significantly increases your chances of developing high blood pressure." 

But how much dietary potassium should we consume? A 2004 Institute of Medicine report recommends that adults consume at least 4.7 grams of potassium per day to lower blood pressure, blunt the effects of dietary sodium and reduce the risks of kidney stones and bone loss, McDonough says. Eating ¾ cup of black beans, for example, will help you achieve almost 50 percent of your daily potassium goal. [Original study.]

 Interesting idea - that perhaps our community of gut microbes being out of whack (dysbiosis) leads to hypertension. This study was done in both humans and mice - with an analysis of bacteria in both hypertensive individuals and pre-hypertensives, and also healthy individuals (the controls). Then the microbes from 2 hypertensive individuals were transplanted into mice (fecal microbiota transplants). And lo and behold - the mice became hypertensive with an alteration of their gut microbes. This is amazing!

The study showed that transplanting microbes from hypertensives to non-hypertensives caused an elevation in blood pressure in the formerly healthy group. This shows the direct influence of gut microbes on blood pressure. The bacteria found in both the pre-hypertensives and hypertensives (especially an overgrowth of Prevotella and Klebsiella bacteria) are those linked to inflammation. And what kind of diet is linked to that bacteria? A high fat diet. Yes, the Western diet with lots of fat and highly processed foods.

The researchers talked about other research also showing Prevotella being associated not only with hypertension, but also other diseases (e.g., periodontal diseases and rheumatoid arthritis). On the other hand, Faecalibacterium, Oscillibacter, Roseburia, Bifidobacterium, Coprococcus, and Butyrivibrio, which were "enriched" in healthy controls, were lower in pre-hypertensive and hypertensive persons. In the past I have posted about a "special" bacteria that is even called  a "keystone" gut bacteria - Faecalibacterium prausnitziithat is linked to health and is low or absent in the gut in a number of diseases ((here and here). It is not available in a supplement at this time (because it dies within a few minutes upon exposure to oxygen), but diet influences it. A high animal meat, high animal fat, high sugar, highly processed foods, and low fiber diet (the typical Western diet) lowers F. prausnitzii numbers, while a high-fiber, low meat diet increases F. prausnitzii numbers.

What you can do: Feed the beneficial gut microbes by increasing the amount of fruits, vegetables, whole grains, seeds, nuts that you eat. And cut back on the greasy, high fat processed and fast foods.

The following excerpt is misleading - for example, it ignores the first part of the actual study which looked at the gut bacteria of pre-hypertensives, hypertensive, and healthy people. Then gut bacteria from hypertensive people were transplanted into healthy mice, and gut bacteria from healthy people were transplanted into hypertensive mice. Also, it wasn't rats, but mice used in the study. It goes to show why it's important to look at original studies - not just believe articles out there blindly. [See original study.] From Science Daily: Unhealthy gut microbes a cause of hypertension, researchers find

Researchers have found that the microorganisms residing in the intestines (microbiota) play a role in the development of high blood pressure in rats mice....Scientists studied two sets of rats mice, one group with high blood pressure ("hypertensive") and one with normal blood pressure ("normal").... All animals were then given antibiotics for 10 days to reduce their natural microbiota. After the course of antibiotics, the researchers transplanted hypertensive microbiota to normal blood pressure rats mice and normal microbiota to the hypertensive group. 

The researchers found that the group treated with hypertensive microbiota developed elevated blood pressure. A more surprising result is that the rats mice treated with normal microbiota did not have a significant drop in blood pressure, although readings did decrease slightly. This finding is "further evidence for the continued study of the microbiota in the development of hypertension in humans and supports a potential role for probiotics as treatment for hypertension," wrote the researchers. "Studies showing that supplementing the diet with probiotics (beneficial microorganisms found in the gut) can have modest effects on blood pressure, especially in hypertensive models."

NOTE that the actual study said in its CONCLUSIONS:  "Taken together, we have described clearly the disordered profiles of gut microbiota and microbial products in human patients with pre-hypertension and hypertension, established the relationship between gut dysbiosis and hypertension, and provided important evidence for the novel role of gut microbiota dysbiosis as a key factor for blood pressure changes. Our findings point towards a new strategy aimed at preventing the development of hypertension and reducing cardiovascular risks through restoring the homeostasis of gut microbiota, by improving diet and lifestyle or early intervening with drugs or probiotics."

I bet eating fresh blueberries daily instead of blueberry powder would not only be more delicious, but also have even more health benefits. From Science Daily:

Blueberries may help reduce blood pressure and arterial stiffness

Just one cup of blueberries per day could be the key to reducing blood pressure and arterial stiffness, both of which are associated with cardiovascular disease. .... Johnson said she is interested in looking at how functional foods -- foods that have a positive impact on health beyond basic nutrition -- can prevent and reverse negative health outcomes, particularly for postmenopausal women.

Over an eight-week period, 48 postmenopausal women with pre- and stage-1 hypertension were randomly assigned to receive either 22 grams of freeze-dried blueberry powder -- the equivalent to one cup of fresh blueberries -- or 22 grams of a placebo powder. Participants, meanwhile, continued their normal diet and exercise routines.

At the end of the eight weeks, participants receiving the blueberry powder on average had a 7 mmHg (5.1 percent) decrease in systolic blood pressure, which is the top number in the blood pressure reading that measures the pressure in the arteries when the heart beats. They also saw a 5 mmHg (6.3 percent) reduction in diastolic blood pressure, or the bottom number measuring the pressure in the arteries between heartbeats.

Additionally, participants in the blueberry-treated group had an average reduction of 97 cm/second (6.5 percent) in arterial stiffness.They also found that nitric oxide, a blood biomarker known to be involved in the widening of blood vessels, increased by 68.5 percent. That is important, Johnson said, because arterial stiffness and the narrowing of blood vessels are both a part of hypertension. This rise in nitric oxide helps explain the reductions in blood pressure.

Further reasons to try to consume foods and beverages from glass containers and avoid cans and plastic bottles. Note that the BPA caused changes within 2 hours, and that BPA-free alternatives may be no better than BPA. Some researchers are speculating whether the high incidence of hypertension is linked to the prevalence of BPA in our environment. From Medical Xpress:

Cans lined with Bisphenol A may increase blood pressure

Drinking or eating from cans or bottles lined with Bisphenol A (BPA) could raise your blood pressure, according to new research reported in the American Heart Association's journal Hypertension. BPA, a chemical used as an epoxy lining for cans and plastic bottles, is everywhere, and its consumption has been associated with high blood pressure and heart rate variability. Previous studies have shown that BPA can leach into foods and drinks.

"A 5 mm Hg increase in systolic blood pressure by drinking two canned beverages may cause clinically significant problems, particularly in patients with heart disease or hypertension," said Yun-Chul Hong, M.D., Ph.D., study author... "A 20 mm Hg increase in systolic blood pressure doubles the risk of cardiovascular disease."

In this study, researchers conducted a randomized crossover trial recruiting 60 adults, mostly Korean women, over the age of 60 from a local community center. Each trial member visited the study site three times and was randomly provided with soy milk in either glass bottles or cans. Later urine was collected and tested for BPA concentration, blood pressure and heart rate variability two hours after consumption of each beverage.

Urinary BPA concentration increased by up to 1,600 percent after consuming canned beverages compared to after consuming the glass-bottled beverages.. Soy milk was the ideal beverage for the test because it has no known ingredient that elevates blood pressure, researchers said.

UPDATE: The NY Times has a nice write-up of this research with further details:

BPA in Cans and Plastic Bottles Linked to Quick Rise in Blood Pressure

A single instance of increased blood pressure may not be particularly harmful. But the findings suggest that for people who drink from multiple cans or plastic bottles every day, the repeated exposure over time could contribute to hypertension, said Dr. Karin B. Michels, an expert on BPA who was not involved in the new research.

BPA has been used since the 1960s to make countless everyday products like plastic bottles, food containers, contact lenses, and even sippy cups and baby bottles. The chemical can leach into food, and studies show that the vast majority of Americans who are tested have BPA in their urine.

The chemical is an endocrine disrupter that can mimic estrogen. In 2012, the Food and Drug Administration said BPA could no longer be used in baby bottles and children’s drinking cups. Canadian regulators formally declared BPA a toxic substance in 2010 and banned it from all children’s products.

Because of growing consumer concerns, some bottles and packaged food products now carry “BPA free” claims on their labels. However, these products often contain chemically similar alternatives – like bisphenol S. One study in the journal Environmental Health Perspectives found that plastic products advertised as BPA-free still leached chemicals with estrogenic activity – and some of these chemicals were even more potent than BPA.

Think lifestyle changes, not medications. From Medical Daily:

Mild Hypertension Should Be Treated With Advice On Lifestyle Changes, Not Medication

In 2013, Dr. Iona Heath, a retired general practitioner published an article in the Journal of  the American Medical Association, in which she spoke about the side effects of overtreatment and overdiagnosis of mild hypertension. Now, in a new study, researchers revisit this idea, saying that unnecessary treatment of mild hypertension in low-risk patients is harming them and putting a burden on health care resources. They also argue that there's a need to reexamine criteria for diagnosing hypertension and treating blood pressure. 

About 40 percent of the world’s population, including 67 million American adults, have hypertension. Over half are classified as having mild hypertension. 

More than half of people with mild hypertension are treated with drugs, but there has been no evidence to suggest that blood pressure-lowering drugs prevent heart attacks. Instead of prescribing drugs to control mild hypertension, the authors urge clinicians to recommend healthier lifestyles to patients, which include exercising, quitting smoking, and decreased alcohol consumption. They also urge clinics to improve the accuracy of blood pressure-measuring instruments and to inform patients about measuring blood pressure at home. 

From Medical Xpress:

Experts raise concern over unnecessary treatment of mild hypertension in low risk people

Lowering the drug threshold for high blood pressure has exposed millions of low-risk people around the world to drug treatment of uncertain benefit at huge cost to health systems, warn US experts in BMJ today. Dr Stephen Martin and colleagues argue that this strategy is failing patients and wasting healthcare resources.

Over half of people with mild hypertension are treated with medication. Yet treating low risk mildly hypertensive patients with drugs has not been proven to reduce cardiovascular disease or death. The authors argue that overemphasis on drug treatment "risks adverse effects, such as increased risk of falls, and misses opportunities to modify individual lifestyle choices and tackle lifestyle factors at a public health level."

And for those over 65 the levels can be even higher. From Science News:

'Mild' control of systolic blood pressure in older adults is adequate: 150 is good enough

A broad review of the use of medications to reduce blood pressure has confirmed that "mild" control of systolic pressure is adequate for adults age 65 or older -- in the elderly, there's no clear benefit to more aggressive use of medications to achieve a lower pressure. Historically, most medical practitioners tried to achieve control of systolic pressure -- the higher of the two blood pressure readings -- to 140 or less. Recently changed guidelines now suggest that for adults over 60, keeping the systolic pressure at 150 or less is adequate, and this extensive analysis confirms that.

From the Medical Daily:

High Blood Pressure In Teens, Young Adults A Sign Of Hardened Arteries Down The Road

Your blood pressure during your teens and early twenties, though often naturally low due to youth, may have something to do with your cardiovascular health in later years, according to new research from Northwestern University Feinberg School of Medicine. In the new study, which was published in JAMA, researchers found that having higher blood pressure during your teens and twenties was actually linked to hardened arteries at age 40.

The study, led by epidemiologist Norrina Allen, points out the significance of maintaining cardiovascular health at a young age.

The study reviewed 4,600 men and women throughout several different states and followed them for 25 years. They found that 19 percent of them had blood pressure that was much higher than their peers, and that another 5 percent started with high blood pressure that gradually rose. Though these blood pressure readings fell within “normal” range for their age, it was higher than average and thus they were more likely to develop hypertension by age 40. Hypertension is also known as high blood pressure or arterial hypertension.

“While you wouldn’t prescribe medications for this group, you might have conversations with those individuals about ways they can improve their diet or increase physical activity,” Allen told NPR. She notes that “many of these cardiovascular risk factors are cumulative,” meaning they often occur over a long period of time and are a combination of things, from smoking to living a sedentary lifestyle.