In our normal bodily positions like standing or sitting, the head is above the heart. Pumping the blood from the heart up to the head requires fighting the effects of gravity, so blood pressure in the head is higher than other parts of the body.
When we adjust the position of the body, as we often do in yoga practice, the head sometimes goes below the heart. When this happens, gravity pulls blood into the head, raising the blood pressure. Our body adjusts by decreasing the blood pressure in the head to protect the brain and face. This effect can be both positive and negative depending on our health and our bodies' ability to adjust the pressure.
If we are healthy, the shifting of the blood pressure up and down can be beneficial, teaching our systems how to respond to changing conditions. This is why healthy people should put the head below the heart.
If we have high blood pressure we must be very careful. Whenever the head goes below the heart, it is possible that the blood pressure will get dangerously high before the body responds. Or the body may not respond effectively and let the blood pressure stay too high for too long. So those of us with high blood pressure should take care when putting the head below the heart.
We can do gentle "inversions" by bringing the head even with the heart or only slightly below. This can be done in forward folding positions and kneeling positions like Half Tortoise or Child's Pose.
Our feet are where the body contacts the floor/earth. Every ounce of our body's weight goes through them with each step, whether we have a light step or plod heavily. So they are vitally important to our physical health. Poorly functioning feet lead to a poorly functioning body much the same way that damaged wheels make a poorly functioning car.
We have all heard of "flat feet," where the inside arch of the foot collapses toward the floor, often creating painful repercussions in the ankle, knee, hip and even back. This condition commonly refers to just one of the arches of the foot---of which there are four---the medial longitudinal arch (labeled above, #1). That is a fancy way of saying the lengthwise (longitudinal) arch on the inside (medial) of the foot. Most of us just know it as the "arch."
This well-known arch of the foot is not structured like a weight-bearing arch. It is built more like a spring that bends when we put weight on it and bounces back as we release. This is how some of the "spring in our step" occurs, as the arch recoils. This arch can be bolstered with muscular strength, like lifting the inner ankles up and pulling the ball of the foot toward the heel.
The second major arch of the foot is the lateral longitudinal arch, which means the lengthwise (longitudinal) arch on the outside (lateral) of the foot. It is labeled in the picture above with #2. This arch goes from the heel area toward the pinky toe. It is a very stable arch, with bone structure like a traditional weight-bearing arch. Due to its structure, this arch rarely collapses or gives us trouble, so we don't even realize it's there.
The third arch of the foot goes across the foot, so it is called a transverse arch. Since it is closer to the ankle, it is called the proximal (near to the body) transverse arch, labeled #3 in the picture above. This arch, like #2 above, is structurally very stable and rarely collapses or gives us trouble. This arch is also called the anterior (forward) transverse arch.
The fourth arch of the foot is sometimes not considered an arch at all because it is not formed by arch-like bony structures. Instead, this arch is made of soft tissues like ligaments, muscles and fascia, stretching from the big toe to the baby toe. It is called the distal (far from the body) transverse arch, labeled #4 in the picture above. Since it is not a bony-structured arch, this often gives us trouble due to weakness and under-use, especially since we wear shoes that decrease our body's need to access it. It can be strengthened though simple exercises like making fists with the toes.
Try standing with bare feet. Shift your weight around your feet, from front to back and side to side. Pay close attention and see if you can feel the arches and structures in your feet. They are important!
It has become popular in the sport, fitness and yoga worlds to drink alkaline water, water with a pH higher than regular water and higher than our blood. Some use alkalizing filters for their home or studio, while others buy alkaline water straight from the store in bottles.
The supposed benefits of drinking alkaline water range from better hydration and improving acid reflux to curing headaches and even cancer. But, according to a recent New York Times article, "there is no science to back it up."
"Despite the claims, there’s no evidence that water marketed as alkaline is better for your health than tap water," the article says.
There are two elements to look at here. The first is whether drinking alkaline water actually changes the pH of the body, and the second is whether a change in pH will provide benefits. The answer to both of these queries seems to be no.
"Blood is tightly regulated at around pH 7.4." Our stomach secretes hydrochloric acid to digest our food and kill germs, and this acidic environment "quickly neutralizes" any alkaline substance before it makes its way into the rest of our digestive system or blood. So drinking water that is slightly alkaline won't affect the pH of our blood or body.
Also, there no evidence that alkaline water provides health benefits. To the contrary, there are known risks including impaired growth and damage to cardiac muscle. "The only health effects that we know of are danger signs, so for people to continue to market alkaline water — they’re really as bad as the snake oil salesmen of yesteryear."
We hope you stay hydrated, but you probably only need to drink regular water!
Excerpts from: Is Alkaline Water Really Better for You? in the New York Times
Most of us know that our breath functions automatically most of the time. This function---breathing without thinking---is controlled by the autonomic nervous system in one of the oldest parts of our brain: the brain stem, located at the base, where the spinal chord turns into the brain.
Most of us also know that we can control our breath consciously, choosing the speed at which we breathe and even stopping it altogether, for a short while at least. This conscious control of our breath is done by the somatic nervous system, the part that controls voluntary functions like walking, writing or playing baseball. It is located on the surface of the brain at the very back of the frontal lobe, in a place called the motor cortex.
Whenever we consciously control our breathing, the motor cortex overrides the brain stem. This process takes a lot of effort from the brain, which is why it has the effect of focusing us. As an experiment, try to control your breath while doing a math problem in your head. It is difficult. When we consciously control the breath, the brain becomes still.
This phenomenon is one of the key principles of pranayama (breath control) and even the most simple breathing exercises. Even for a true beginner, counting the breath or trying to control it at all calms the mind and leaves them feeling very focused.
Uddiyana and Nauli are traditional yogic practices. They date back more than 500 years to at least the Hatha Pradipika.
To do Uddiyana, one holds the breath out and then expands the ribcage as if inhaling. What results is a vacuum in the abdomen which sucks the belly, intestines and organs up. Uddiyana means 'flying up.' "This practice is called Uddiyana because the diaphragm is made to fly up from its original position and held very high in the thoracic cavity." (Yoga Mimamsa, Vol. 1, Oct. 1924)
In the early 1920s, Swami Kuvalayananda began a school and laboratory, using modern scientific equipment to test traditional yogic practices and publish the results. His newsletter is Yoga Mimamsa, which started in 1924 and continues today. The first edition was dedicated to the study of Uddiyana.
They performed two ground-breaking studies, one involving early X-Ray technology to view the intestines, and the other measuring the internal pressure of the abdominal cavity during Uddiyana. "This exercise has been studied under the X-Ray. Very interesting and valuable data have been collected. Two X-Ray experiments are published...and an article discussing the therapeutic value of this Yogic practice is included..." (ibid.)
The pictures above are from the 1960s, when Dr. Gouri Shankar Mukerji performed a similar experiment. These pictures are much clearer than the ones from 1924, which is why we post them here. The x-rays from 1924 are cloudy and difficult to discern. In the above pictures, one can clearly see that Uddiyana pulls the intestines and organs up into the thoracic cavity.
The second test measured pressure in the intestines and rectum during the practice. They found that internal pressure is reduced, creating a partial vacuum. "As soon as the muscles were moved for Nauli, the mercury fell through 40 mm. indicating a clear partial vacuum." (ibid.) The discovery of this vacuum was significant, since scientists of the time hypothesized that Nauli reversed the peristaltic movement of the intestines, which would be detrimental to health. The discovery of the partial vacuum refuted this idea. Kulvalayananda named his discovery the "Madhavadasa Vacuum," after his esteemed teacher.
This week I picked up Time Magazine's "The Science of Exercise" special issue, as it promised to illuminate the most recent discoveries in movement and health. It is interesting to think about what this means for the future of yoga practice. I recognize that yoga is traditionally not an exercise regime, but it has become quite physical over the past 100 years, to the point that it now fills the fitness quota in many people's lives.
Exercise Will Become More Individualized and Prescriptive
As the medical community recognizes the preventive value of exercise, it will be recommended more to patients of all ages, both to combat disease and to prevent it. Physical activity reduces the risk of heart disease, many forms of cancer and several mental disorders like depression. In the future, each person will be assigned or "prescribed" a different exercise regime based on their health, ability and needs.
This is not unlike the method of prescriptive yoga that has been in India for hundreds of years. "Young and old," wrote Bishnu Ghosh in 1930, "there is a different exercise for each of you--an experienced trainer can only rightly select them."
Lifting Weights Is Important For Strength and Health
Muscular strength and bone density are two important factors in keeping us healthy and pain-free. Weak muscles lead to imbalance, injury and painful joints. Keeping our bodies strong, especially around the spine, hips, knees and shoulders reduces the risk of injury as we age. Keeping the bones strong is also important, reducing the likelihood of breaks. Both of these things are improved by lifting weights. Thus, weightlifting should be a regular activity for pretty much everyone.
Yoga exercises increase strength to a certain degree, using the bodyweight as resistance. More often, though, yoga practices are focused on flexibility at the expense of stability and strength. Our overall health will be better served if we focus at least part of our physical practice on strength. Flexibility is useful when it restores functional range of motion to stiff joints, but it can also be detrimental when pushed too far. A balanced practice of flexibility and strength, even including weight lifting, will be more effective in keeping us healthy in the long term.
Our recent blog about the myth of oxygenation got a big response. Lots of surprise, some disbelief and a lot of requests for more information. Specifically, if deep breathing does not have a positive impact on our oxygen levels, why do we do it?
There are three huge benefits to practices of breathing: activating and balancing the muscles of breathing, which in turn affects the nervous system; balancing the hemispheres of the brain through the nostrils; and awareness and minor control of the breath-regulating parts of the brain.
THE MUSCLES & THE NERVOUS SYSTEM
You may have heard that some people are belly breathers and some are chest breathers. Most of us have at least a slight imbalance between the abdomen and chest, while others have extreme imbalance. This doesn’t necessarily have an effect on our ability to get oxygen, but it does have an impact on our nervous system.
Generally speaking, abdominal breathing that uses the diaphragm and relaxes the abdominal muscles stimulates the parasympathetic nervous system. The opposite is true for chest breathing that uses the intercostal muscles. This stimulates the sympathetic nervous system.
Neither of these is a problem until our breathing patterns become imbalanced and we breathe primarily through only one of the systems. When years or decades go by, one part of the nervous system chronically gets stimulated while the other gets suppressed. Belly breathers will be more relaxed, sleep more, have lower body temperature, be more lethargic. Chest breathers will be more energetic, more stressed, warmer, sleep less.
It is vital for progress in yoga to have balance in the nervous systems. So the first step of breathing practice is to learn to use both parts of the breath, strengthening the muscles and evening the nervous systems.
The olfactory nerves in the nose go straight to the brain. They have the most direct connection to the brain of any of the senses, so their stimulation through the nostrils is potent. The breathing practice of Alternate Nostril, which goes by many names, is one of the oldest yogic techniques. By alternating which nostril we breathe into, we vary the hemisphere of the brain that we stimulate. This has a further effect on the sympathetic and parasympathetic nervous systems, and goes even further to balancing the dual nature of the body and mind.
PARTS OF THE BRAIN
The breath is controlled by the brain stem, the oldest part of our brain. Most of the time, we breathe with no conscious thought. But the newer parts of the brain, specifically the cortex, have the ability to override the brain stem to some extent, especially with practice. This awareness and control is very difficult and not appropriate for beginning practitioners, but it is the ultimate reason for breathing practices. Gradually we come to realize the true nature of the breath, which brings us closer to realizing the true nature of the self. (Apologies for the abstract yogi talk, but I don’t know of a clearer way to put it.)
So breathing is powerful. If we use it correctly it has the ability to balance our nervous system, the hemispheres of the brain, and even put us in touch with some deep and essential parts of our being. To me, this is all way more exciting than oxygenating the body!!
How many times have you heard a yoga teacher tell you that deep breathing "oxygenates the blood?"
It isn't true. At the very least it is misleading.
Our nervous system forces us to breathe at the necessary rate to fully oxygenate our blood at all times. This is true when we're resting as well as when we're running a marathon. The body's oxygen requirements are different depending on our activity, and the nervous system automatically adjusts to oxygenate the blood fully. Normal blood oxygenation is 95-100%.
When we are at rest, we breathe slower since the body's oxygen demands are less. Breathing more or deeper while the body is at rest does not "oxygenate" the blood. It hyper-ventilates, which is just a way of saying breathing (ventilating) more than necessary.
Anytime we breathe more than the body requires, the big change we are causing is the removal of carbon dioxide, one of the body's metabolic wastes. Hyperventilation removes more carbon dioxide than the body produces, and this leads to a whole host of physiological effects. Most significantly, the blood vessels in the brain constrict, limiting blood flow to the brain. This makes us light-headed.
So that light-headed feeling you get when breathing deeply isn't energization or "oxygenation," but constricted blood vessels in the brain. Your brain is actually getting less oxygen than if you were to breathe normally!
A study in Finland checked the frequency of sauna usage against the rate of hypertension, or high blood pressure, by following more than 1,500 middle aged men for an average of 25 years. The New York Times wrote about it a couple days ago.
The study found that, when compared to subjects who used the sauna only once per week, those who used it 2 or 3 times were 24% less likely to have high blood pressure. Those who used it 4-7 times were 46% less likely.
"The warmth of the sauna...improves the flexibility of the blood vessels which eases blood flow, and the warmth and subsequent cooling down of a typical Finnish sauna induces a general relaxation that is helpful in moderating blood pressure. Also, sweating removes excess fluid, acting as a natural diuretic. Diuretics are among the oldest drugs used to treat hypertension." (NY Times)
The New York Times just reposted an interview with exercise physiologist Dr. Oliver Jay, asking if there are health benefits associated with sweating, and if more sweat means more benefit. This is a question that hits home to us as yogis who strive to build inner heat, and especially as part of the Bikram and Hot yoga communities where lots of extra heat is added for supposed increased benefits.
“There’s this entrenched idea that it’s good to ‘sweat things out,’” Dr. Jay said, but in fact “sweating, per se, provides no health benefits,” apart from preventing overheating.
Exercise, especially vigorous exercise, raises the internal body temperature. "The benefits derive from the exercise itself," not the accompanying rise in body temperature or the sweat that is meant to cool us. Perspiring, in and of itself, does not provide or amplify those effects, Dr. Jay said.
That situation doesn’t change if you’re sweating due to a hot environment. “Sweat is sweat,” he said. You will perspire more if the air is humid, he said, because sweat doesn’t evaporate efficiently in humidity, and it’s evaporation that actually cools your body. But you aren’t gaining extra health benefits from drenching your clothing with perspiration.
CONSIDERING "HOT" YOGA
We got our start in Bikram's class, where the temperature is 105 degrees and you sweat like crazy. There is a continuing trend toward making yoga hot to induce more sweating and increase muscle flexibility (which largely happens through numbing the nervous system, but that's another story).
Also there is the "sauna therapy" argument, that when exposed to high temperatures the heart rate increases and the blood vessels dilate, improving cardiac and vascular function.
There is new research that practicing yoga in high heat may have a positive impact on cholesterol levels. Contrarily, there is new research that many of the vascular benefits of yoga and stretching are gained at room temperature just as well as in a heated room.
There are 3 main arguments for practicing yoga or exercising in the heat: 1) increased effectiveness of the exercise, as indicated by rise in body temperature and amount of sweat; 2) increased mobility and flexibility; and 3) benefits to the cardiac and especially vascular system.
Argument #1 is simply not true. An exercise is not more beneficial when done in heat, and more sweat - even higher body temperature - does not mean more benefit (see the NY Times article).
Argument #2 is a double-edged sword. Heat-induced flexibility may be beneficial to certain parts of the population, like the elderly or injured, but it is detrimental to those who are already flexible, encouraging hyper-mobility. For the general public it's a toss-up.
Argument #3 is a good one, and it's gaining clarity with each passing study. Pure Action is funding research to try to tease out the vascular benefits that may come from heat without yoga, those that may come from yoga without heat, and those that are accentuated when the two are put together.
Scott & Ida are Yoga Acharyas (Masters of Yoga). They are the head teachers of Ghosh Yoga. This blog is about their experience with yoga practice, study and teaching.
- Understanding Chair Posture
- 5 Reasons To Backbend
- Lock the Knee History
- Why Teaching Is Not a Personal Practice
- The 113 Postures of Ghosh Yoga
- When You Take a Class, Take the Class
- Make the Hamstrings Strong, Not Long
- Should We Be Teaching Advanced Postures in a Beginning Class?
- The Yogi Becomes Invisible
- Bow Pose (Dhanurasana)
- The Oxygenation Myth
- The Art and Skill of Teaching