The Benefits of Slow Breathing

There are all manner of purported hiccup “cures,” which include everything from chewing on a lemon, inhaling pepper, or, our dog’s favorite, eating a spoonful of peanut butter. In my video How to Strengthen the Mind-Body Connection, I talk about the technique I’m excited to try the next time I get hiccups: “supra-supramaximal inspiration,” where you take a very deep breath, hold for ten seconds, then, without exhaling, breathe in even more and hold for another five seconds, and then take one final, tiny breath in and hold for five last seconds to achieve “an immediate and permanent termination to hiccups…”

When I was a kid, I taught myself to control my own hiccups using slow-paced breathing, and, as an adult, was so excited to see there was finally a case report written up on it.

There’s a nerve—the vagus nerve—that goes directly from our brain, to our chest, and to our stomach, connecting our brain back and forth to our heart and our gut, and even to our immune system. The vagus nerve is like the “‘hard-wired’ connection” that allows our brain to turn down inflammation within our body. When you hear about the mind-body connection, that’s what the vagus nerve is and does. “There has been increasing interest in treating a wide range of disorders with implanted pacemaker-like devices for stimulating the vagal afferent [vagus nerve] pathways,” but certain Eastern traditions like Yoga, QiGong, and Zen figured a way to do it without having electrodes implanted into your body.  

“A healthy heart is not a metronome,” as a study titled exactly that explains. “Your heart rate goes up and down with your breathing. When you breathe in, your heart rate tends to go up. When you breathe out, your heart rate tends to go down.” Test this out on yourself right now by feeling your pulse change as you breathe in and out.

Isn’t that remarkable?

That heart-rate variability is a measure of vagal tone—the activity of your vagus nerve. Next time you’re bored, try to make your heart rate speed up and slow down as much as possible within each breath. This can be done because there’s an entirely other oscillating cycle going on at the same time, as you can see at 2:08 in my video, which is the speeding up and then slowing down of your heart rate, based on moment-to-moment changes in your blood pressure. And, as any physics student can tell you, “all oscillating feedback systems with a constant delay have the characteristic of resonance,” meaning you can boost the amplitude if you get the cycles in sync. It’s like pushing your kid on a swing: If you get the timing just right, you can boost them higher and higher. Similarly, if you breathe in and out at just the right frequency, you can force the cycles in sync and boost your heart rate variability, as you can see at 2:36 in my video.

And what’s the benefit again? According to the neurophysiologic model postulation it allows us to affect the function of our autonomic nervous system via vagal afferents to brainstem nuclei like the locus coeruleus, activating hypothalamic vigilance areas.

Huh?

In other words, it’s not just about curing hiccups. Practicing slow breathing a few minutes a day may have lasting beneficial effects on a number of medical and emotional disorders, including asthma, irritable bowel syndrome, fibromyalgia, and depression. In the United States, we’ve also put it to use to improve batting performance in baseball.

To date, most studies have lacked proper controls and have used fancy biofeedback machines to determine each person’s resonant frequency, but, for most people, it comes out to be about five and a half breaths per minute, which is a full breath in and out about every 11 seconds. You can see the graph at 3:34 in my video. When musicians were randomized into slow-breathing groups with or without biofeedback, slow breathing helped regardless. It’s the same with high blood pressure. As you can see at 3:52 in my video, you can use this technique to significantly drop your blood pressure within minutes. The hope is if you practice this a few minutes every day, you can have long-lasting effects the rest of the day breathing normally.

Practice what exactly? Slow breathing—taking five or six breaths per minute, split equally between breathing in and breathing out. So, that’s five seconds in, then five seconds out, all the while breathing “shallowly and naturally.” You don’t want to hyperventilate, so just take natural, shallow breaths, but be sure to simply breathe really slowly. Try it the next time you get hiccups. Works for me every time!


For more tips, watch my video on How to Stop Hiccups.

And, because slowing down our pulse in general may also have beneficial effects, I encourage you to check out:

Every time I’m amazed by ancient wisdom, I have to remind myself of the video I did on toxic heavy metals—Get the Lead Out. So, though traditional healing methods may offer a plethora of insights, they still need to be put to the test.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

The Foods to Avoid to Lower Stroke Risk

“Stroke remains one of the most devastating of all neurological diseases,” killing about 5 million people a year worldwide, and is “the leading cause of permanent disability in the USA.” But the good news is that about 80 percent of stroke risk may be due to basic lifestyle factors: primarily, improving our diet, stopping smoking, and getting regular exercise.

The best way to stop smoking, evidently, is to have a heart attack. Certainly, once dead, you can’t smoke. Of those who survive a heart attack, strong, repeated advice from their doctor may persuade up to two-thirds to quit and never smoke again in any form as long as they live. “Yes, quitting smoking is very difficult. It doesn’t matter; it has to be done. If you were walking along the lakeshore and one of your grandchildren is drowning, it doesn’t take will power to go into the lake; it just has to be done.” It’s like a healthy diet: Some things just have to be done. Getting up at night to feed a baby can be difficult, too, but it’s not a matter of having willpower—some things in life just have to be done. After all, what we regularly eat every day is indeed a matter of life and death.

For stroke prevention, that means eating a more plant-based diet, like a traditional Mediterranean diet centered around whole grains, fruits, vegetables, lentils, beans, and nuts, as I discuss in my video Best Foods to Reduce Stroke Risk. A vegetarian or vegan diet may also work, but it must be accompanied by a regular, reliable source of vitamin B12, meaning B12-fortified foods or supplements. “Unfortunately, recommending taking B12 supplements may meet opposition among vegetarians because misconceptions regarding this nutrient are prevalent. Many individuals still hold on to the old myth that deficiency of this vitamin is rare and occurs only in a small proportion of vegans…Future studies with vegetarians should focus on identifying ways of convincing vegetarians to routinely take vitamin B12 supplements in order to prevent a deficiency.” The research is clear on that.

What is it about plant-based diets that make them beneficial for stroke prevention? In my video How to Prevent a Stroke, I talked about the role of fiber, which potentially leads to about a 1 percent drop in risk for every 1 gram of fiber ingested per day. Or, even better: A 12 percent drop in risk is associated with every extra 10 grams of fiber a day. In fact, fiber from whole grains is associated with a lower chance of dying not only from heart attack and stroke, but also cancer, diabetes, and respiratory diseases, as well as a lower risk of dying from infections or other causes––in other words, a lower risk of dying prematurely from all causes combined. Why? Perhaps because of the anti-inflammatory effects of fiber, which could explain how it could help across the board. Or, it could be that eating fiber means eating fewer pro-inflammatory foods. Those who eat more whole plant foods, which are where fiber is found, may be eating less processed and animal foods. In fact, the study immediately preceding the meta-analysis of fiber was a meta-analysis on meat, which looked at red meat and processed meat, and found about a 10 percent increased risk for stroke associated with each three and a half ounce daily portion, which is about the size of a deck of playing cards, or about 10 percent increased risk for every “half-deck” of processed meat.

Perhaps this occurs because of the heme iron—the blood and muscle iron—in meat, or because of “its pro-oxidative properties.” (No association was found between stroke and non-heme iron, which is the type of iron that predominates in plants.) Or, perhaps it’s because of some of the toxic pollutants like PCBs that can build up in animal fats. We’ve known, for example, that living next to a toxic waste dump might increase stroke risk, but only recently have we realized that dietary exposure even at so-called safe levels might increase stroke risk—and increase it by as much as eight or nine times for those with the highest levels of these pollutants in their bloodstream.


For more on how to reduce stroke risk with diet, see:

What does vitamin B12 have to do with stroke? Watch my video Vitamin B12 Necessary for Arterial Health to find out.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Proof that Lifelong Cholesterol Reduction Prevents Heart Disease

“It is well accepted that coronary atherosclerosis is a chronic progressive disease that begins early in life and slowly progresses over several decades” before symptoms arise. However, the average age in cholesterol-lowering drug trials is 63; therefore, people have already been exposed to a lifetime of circulating LDL cholesterol. It’s no wonder pharmaceutical therapies typically reduce cardiovascular disease risk by only 20 to 30 percent.

We know LDL, the so-called bad cholesterol, plays “a central role” in the “initiation, development, and progression” of our number-one killer. In fact, more than 100 prospective studies involving more than a million people have demonstrated that those with higher LDL levels are at higher risk.

“It seems reasonable to assume, therefore, that if lowering LCL-C [cholesterol] levels beginning later in life can slow the progression of advanced atherosclerotic plaques…then keeping LDL-C levels low, beginning much earlier in life” might prevent our arteries from getting clogged in the first place. A reasonable assumption, certainly—but let’s not just assume.

“It would be…unethical to set up a controlled clinical trial in which young adults with elevated serum cholesterol levels were treated or not treated over their lifetime”—just as we couldn’t ethically set up a study in which half the young adults are made to start smoking to see if smoking really does cause lung cancer. That’s where observational studies come in. We can follow people who already smoke and compare their disease rates to those who don’t.

It was aroud 40 years ago when the president of the American Heart Association tried to argue we should all stop smoking even though there were no randomized controlled trials. You can see a copy of the “Presidential Address” entitled “The Case for Prevention of Coronary Heart Disease” to the AHA’s 47th Scientific Sessions at 1:34 in my video. Those who smoke have a higher risk of heart attack, and the more we smoke the higher the risk. After we stop smoking, our risk drops. The same can be said for high cholesterol.

Young men 18 through 39 years of age were followed for up to 34 years, and their cholesterol levels, even when they were young, predicted long-term risk of heart disease and death. Men in their 20s and 30s who have a total cholesterol just under 200 have a “substantially longer estimated life expectancy”—around 4 to 9 years longer—than those with levels over 240.

“Evidence from observational studies, however, [is] vulnerable to confounding” factors. Eating a diet that is plant-based enough to lower cholesterol below average, for example, may add years to our lives regardless of what our cholesterol actually is. Ideally, we’d have a long-term, randomized, controlled trial.

Nature may have actually set one up for us. Each of us, at conception, gets a random assortment of genes from our mother and our father, and some of those genes may affect our cholesterol levels. Just like there are rare genetic mutations that result in unusually high cholesterol levels, there are rare genetic mutations that lead to unusually low cholesterol levels, “provid[ing] an ideal system in which to assess the consequences of low LDL cholesterol levels independently of other factors that may modify disease progression,” such as confounding diet and lifestyle factors.

Starting at 3:14 in my video, you can see what I mean. About 1 in 40 African Americans have a mutation that drops their LDL cholesterol from around 130 down toward more optimal levels. Now, this group didn’t eat healthy to get achieve that drop. It’s just in their genes. More than half had high blood pressure and there were a lot of smokers and diabetics in the group, yet those with genetically low LDL levels still had a significant reduction in the incidence of coronary heart disease even in the presence of all those other risk factors. How significant? How much less heart disease? A remarkable 88 percent of heart disease was simply gone.

The astounding finding was that the risk of heart disease in these individuals was reduced by more than 80 percent, whereas the same 20- to 40-point decrease in LDL from drugs only reduces risk around 30 percent. Makes sense, though, because the folks with the mutation had low levels their entire life. They didn’t simply start taking a pill when they were 60.

“The magnitude of the effect of long-term exposure to lower LDL-C [cholesterol] concentrations observed in each of these studies represents a threefold greater reduction in the risk of CHD,” or coronary heart disease, compared to drug treatment started later in life. (As an aside, for all of my fellow research nerds, check out that p value shown in my video at the 4:30 mark. You’d have to do arourd a quintillion studies to get that kind of result by chance!)

“Therefore, a primary prevention strategy that promotes keeping LDL [cholesterol] levels as low as possible, beginning as early in life as possible, and sustaining those low levels of LDL [cholesterol] throughout the whole of one’s lifetime has the potential to dramatically reduce the risk of CHD,” coronary heart disease.


If you don’t know your cholesterol level, you should get it checked—maybe even starting in childhood. See my video Should All Children Have Their Cholesterol Checked? to learn more.

What if you do get tested and your doctor tells you not to worry because your cholesterol’s “normal”? Having a “normal” cholesterol level in the society where it’s normal to drop dead of a heart attack (the number-one killer of men and women) is not really such a good thing. See my video When Low-Risk Means High-Risk.

Check out Optimal Cholesterol Level and What’s the Optimal Cholesterol Level? to find out where you should be.

What if your doctor tells you your LDL is large and fluffy? See my video Does Cholesterol Size Matter?.

In health,
Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations: