Inversions and Cardiovascular Problems

Have you ever been suspicious of the contraindication, “Don’t do an inversion if you have a cardiovascular problem”? After all, how dangerous can Matsyasana or
Padahastasana — or Balasana, for goodness’ sake — really be?

This is a safe and conservative guideline for new teachers, but the more we learn about anatomy and physiology, the more we see when this can be too conservative. In addition, as medical perspectives evolve, so does the notion of “conservative.”

So I’d like to address the issue of how — and to what extent — cardiovascular problems really contraindicate inverted poses. I want to thank Suzanne Ilgun, RN, an Ananda Village member who helped research and write this article. Suzanne’s experience includes intensive care, coronary care, and trauma care.

To augment her own medical expertise and experience, Suzanne interviewed a number of physicians for their perspectives on inversions and cardiovascular issues. She also measured blood pressure for a number of volunteers as they were doing various postures. The results follow.

(Note: this wasn’t an in-depth study, so until more research is done, we must go with physicians’ best judgment, supplemented by our own common sense.)

What Are We Talking About Here?

“Cardiovascular problems” (CP’s) means one or more of the following: hardened arteries, heart disease, history of stroke or heart attack, un-medicated high blood pressure, aneurysm, etc. (Most physicians regard “medicated high blood pressure” as, for all practical purposes, “normal blood pressure.” More on this later.)

“Inverted poses” are asanas in which the head is lower than the heart. Alternatively, one could ally this definition more closely with Ananda Yoga’s® energy-to-the-brain perspective by calling them “poses in which some part of the spine is inverted.”

In the context of asana practice, these two definitions are virtually equivalent.
In her research, Suzanne found that, although “Don’t do an inversion if you have a CP” is certainly a safe guideline, there are many inverted poses and CP’s for which it is overly conservative. Let’s explore why.

How Blood Pressure Rises

CP’s contraindicate any pose that makes the heart work “too hard” and thus increases blood pressure “too much.” There are a number of factors that explain why inverted poses can do this (although as I’ll explain, some of these factors should not be of concern in Ananda Yoga practice):

Head below heart: Blood “floods the brain” in inversions, right? — and that would be a problem for CP’s, especially stroke victims. Well, certainly blood can travel to the
head more easily when the head is below the heart, for there is no gravitational resistance. Also, venous blood tends to remain in the head longer than when upright,
due to the lack of gravitational assistance.

However, the body has a very good system for regulating the amount of blood in the brain at any given time in any given position, so not much additional blood enters the head during inversions. Yes, there is increased blood pressure in the head, but the physicians that Suzanne interviewed felt that, so long as the student does not strain or hold the breath, and the room is not too hot, then the mere fact that the head is below the heart will not increase blood pressure enough to cause concern — unless, of course, the position is held for too long a time.

Pumping Against Gravity

Even when you are upside down, the heart still has to pump blood to the legs and feet. If the legs are way up in the air, the heart has to pump it a long distance against the force of gravity (whereas normally gravity is helping to bring blood to the legs). To accomplish this, the heart has to pump harder (which raises blood pressure) — not only because of the distance, but because the heart must pump against the weight of all the blood that is already in the arteries.

(Think of a tall cylinder, filled with water. The water pressure at the bottom of the cylinder would be quite high, so a pump would have to exert more force to pump water that’s at the bottom of the cylinder up to the top, because it has to push up all the rest of the water as well.)

Increased Intrathoracic Pressure

When you are upside down, the abdominal organs (stomach, intestines, liver, bladder, etc.) — plus the remnants of your most recent meal — press on the diaphragm. That’s why it’s harder to inhale while inverted: the diaphragm has to lift all that weight against the force of gravity.

When you’re exhaling, that weight presses the diaphragm down — a nice stretch
for the diaphragm, but it compresses the contents of your thorax (in effect, the contents of the rib cage); in particular, it presses on the heart. In order to continue doing its
job in the face of that added pressure, the heart must therefore pump harder, which raises blood pressure.

Strain

Blood pressure rises with any appreciable muscular effort, but in this article we are distinguishing between “effort” and “strain,” the latter meaning that effort has
escalated into a tense struggle to achieve and/or hold a pose (inversion or not). Strain stimulates the sympathetic (“fight or flight”) nervous system, which automatically
raises blood pressure to handle the “emergency.”

Holding the Breath

Students often hold the breath — usually unconsciously — in challenging asanas (not just inversions). This “gripping” is strain that, as noted above, raises blood pressure.

(Note: There’s no problem when the breath stops of its own accord, as in deep meditation, because the body’s metabolic processes also stop, so they don’t require the intake of oxygen as fuel or the expulsion of carbon dioxide as waste. However, at other times — such as when expending effort to hold an asana — the body still needs to receive oxygen and expel carbon dioxide. Holding the breath at these times causes carbon dioxide buildup, too much of which can literally cause body cells to burst and die. Not good.)

Heat

An overly warm environment — as in “hot yoga” — also increases cardiovascular strain, raising blood pressure. It’s not the heat itself that stresses the cardiovascular
system; rather, it’s the resulting electrolyte imbalance.

Here’s How It Works

The more we perspire, the more we deplete the body’s electrolytes and hydration; the added component of exercise causes even more depletion. Many of the body’s electrolytes (such as sodium, calcium, and potassium) are directly involved in the contraction and relaxation of muscles. When we upset the balance among these electrolytes, muscles must work harder to do their jobs. This increased exertion in turn makes the cardiovascular system — in particular, the heart — work harder.

So What’s the Problem?

Okay, in all these cases the heart works harder and blood pressure rises. Why is that a problem? After all, our heart works harder when we exercise, and that’s supposed to be beneficial. Besides, almost all asanas require some effort, which means that almost all asanas raise blood pressure.

Well, it’s not a problem for a healthy circulatory system; in fact, it helps build a stronger cardiovascular system. But if the heart — or more likely, the arteries — is/are compromised (as is true for those with CP’s), it’s like putting a stronger flow of water into a weak-walled, closed-off garden hose: the increased pressure can cause the hose to burst. And you really don’t want one of your “blood hoses” to burst.

Of course, excessive heat has no place in Ananda Yoga, nor does strain or holding the breath during asanas. There is physical effort, but we ask students to practice relaxation in the midst of effort (rather than struggling in the pose until they collapse), and to breathe smoothly and regularly. If we see a student straining or holding the breath, we can ask him/her to exit the pose, or we can offer an asana variation.

(Yes, it can be difficult to spot strain and holding of breath — and besides, some people may think they’re relatively relaxed in the midst of effort, when in fact they’re straining.  Well, we teachers just have to do the best we can.)

That eliminates all but two of the above factors — intrathoracic pressure and the heart having to pump against gravity — that make inversions a concern for CP’s. The many of these poses, intrathoracic pressure is mild, and gravity is a minor factor with respect to blood pressure, so the bodily positions are fine for students with CP’s.

However, even though the bodily positions may be okay, holding some of those positions is so likely to entail strain that the poses should be modified — or omitted altogether — for those with CP’s. For example, use only an easy version of Purvotanasana. Hold Adho Mukha Shvanasana only briefly.  And since Chakrasana (Wheel Pose) almost always involves strain and/or irregular breathing, you can cross it off your list for students with CP’s.

Common Sense: Don’t Leave Home Without It

Even though all this suggests that many inversions are okay for persons with CP’s, remember: these are only the question is, when does an inversion involve enough of either or both of these factors to contraindicate the pose?

Sorting Out the Inverted Poses

As you might expect, there isn’t universal agreement on an answer. (In fact, one physician told Suzanne, “Any yoga posture is just fine for CP’s.” Suzanne and I discreetly discarded that data point.) But here’s what we can say:

The more inverted the legs and/or torso, the harder the heart must work to pump against gravity, and hence the higher the blood pressure. The more inverted the torso, the greater the intrathoracic pressure, and hence the higher the blood pressure.
Now let’s apply this to specific postures (see the “Inversion Checklist” below for a summary of what follows).

Almost No Inversion at All

The above discussion makes it clear that gentle poses in which the torso and legs are barely inverted, if at all — e.g., Balasana (child) and Matsyasana (fish) — are safe for CP’s.

Torso Inverted / Legs Inverted

At the other extreme, we can rule out asanas with both torso and legs inverted: e.g., Sarvangasana (shoulderstand), Sirshasana (headstand), and Viparita Karani (Simple Inverted Pose). The problems due to both gravity and intrathoracic pressure are simply too pronounced.

Little or No Inversion of Torso / Legs Inverted

There aren’t many of these, but legs-up-the-wall pose is an example. Technically, it’s not an inversion at all, since no part of the spine is inverted, but it’s worth discussing. Yes, the heart has to work harder to bring blood to the feet in this pose than when standing or sitting, but not all that much harder because the torso is not inverted.

Also, there’s no thoracic compression. So the pose is fine for CP’s. (If you put a cushion under the pelvis, or if you want to be extra careful, place a cushion under the student’s head to avoid raising blood pressure in the head.)

Another example is full Salabhasana (Full Locust Pose), in which the legs and pelvis — and perhaps even the abdomen — are off the floor. This pose almost always entails
significant strain and/or irregular breathing, so it’s definitely not for students with CP’s.

Torso Fully Inverted / Legs Not Inverted

These include Halasana (Plow Pose), Karnapirasana (Ear-Closing Pose), and Ardha Sirshasana (half-headstand: legs horizontal and feet on wall). Because the complete inversion of the torso causes significant intrathoracic pressure, persons with CP’s should avoid these poses.

Torso Somewhat Inverted, Little or No Inversion of Legs

This diverse group of poses includes Padahastasana (Jackknife Pose), Sasamgasana (Hare Pose), Adho Mukha Shvanasana (Downward-Facing Dog Pose), and Setu Bandhasana (Bridge Pose). For opinions of physicians (who, despite their enthusiasm for yoga, may not know much about it).

Pending more research, we teachers still need to use common sense and be conservative.
For example, students with CP’s should not hold significantly inverted positions (e.g.,
Sasamgasana) for a long time, say, two minutes.

Also, students who have had a cardiovascular “injury” (heart attack, stroke, etc.) within the past six months should not do such an inversion at all; in fact, they should be in a special class for people with these conditions, not a general yoga class.

Then there’s the question of  whether medicated high blood pressure contraindicates inversions. Many physicians feel that inversions are okay when blood pressure is “under control.”  However, the effect of blood pressure pills wears off after some hours (that’s why people have to keep taking them), and blood pressure rises once again.

So the question is, at the specific time that you lead an inversion in your class, is your student’s blood pressure normal, or is it too high for safety? Neither you nor your student is likely to know, so be cautious: watch for strain, holding the breath, redness of face, and other signs of discomfort.

By the way, there are CP’s for which “safe” inversions (e.g., Setu Bandhasana) are contraindicated even if there is no strain or holding of breath. Fortunately, people with those conditions are unlikely to be in your class. They’re quite sick, and if by chance one such person did arrive, even a quick glance would tell you that s/he doesn’t belong in your class.

Creating a “Game Plan”

To summarize, what if a person with CP’s (on medications or not) wants to take your Ananda Yoga® class? Is it okay? Yes — usually — provided you:

• Are conservative as you get to know this student and his/her capabilities
• Make sure that the student avoids holding the breath and/or straining
  in all poses (a teacher can often guess when a student won’t be able
  to do a pose without strain)
• Have the student avoid certain poses and modify others, as noted above
• Don’t superheat your classroom Stay very observant at all times
• Use your common sense

When in doubt, have a CP-student play it extra-safe in his or her first class, then contact the student’s physician. It’s not always easy to get a response, but one approach is to send the physician a medical clearance form, which describes what you ask of students and asks whether this would be okay for this patient.

The physician doesn’t have to write much; s/he just needs to check a box (“Yes, it’s okay,” or “No, it’s not okay.”) and sign his or her name. Do also provide space for the physician to indicate specific things that your student should not do.

I hope that all this information helps you relax — and lowers your blood pressure — about teaching inversions to students with CP’s. It sure did for me.