Okay. Back to Aging.

by Brad

Okay. It’s been a while, as I’ve been busy with writing NIH grants and papers, as well as traveling. So it's time to get back to one of the central points of this blog: what is aging? It turns out this is no more clear than trying to define yoga. When I joined the Buck Institute for Research on Aging some 11 years ago, I was surprised and a little chagrined to discover how unsettled and wide open this central question of aging biology was.

This was not my original field of study, but as a chemist and structural biologist working at a major teaching university, I saw a prime opportunity to make a career shift by joining the Buck Institute and using my skill to elucidate molecular mechanisms of aging. But I had no idea how many competing theories existed on this subject, ranging from rather oblique terms like ”antagonistic pleotrophy” to more familiar ones—at least to a chemist—like “entropy” and “free radical damage.” So the other day when there was some news coverage in the New York Times of a breakthrough in aging research (see NY Times article here), I saw this as a chance to tackle this subject. The article, titled “In Body’s Shield Against Cancer, a Culprit in Aging May Lurk,” came out of the Mayo Clinic and looked at the role of senescent cells in aging (see original research here).

When cells reach a point of pathological state, either through telomere shortening or some other aberration or damage, a sequence of events are put into place that either sends these cells into a cell death pathway, or into a state of senescence, a kind of limbo non-dividing state. One reason this occurs is to avoid the formation of a cancerous cell, which the organism obviously wants to avoid. Cells that become senescent were usually thought of as sequestered cells that no longer posed a problem to the organism, but were also no longer productive. However, what this new study showed is that these senescent cells appear to have more damaging effects on neighboring cells and tissues, possibly through a secreted inflammatory signal.

Manzanita by Brad Gibson

By constructing a mutant mouse strain where the researchers could target and kill these senescent cells without harming the healthy cells, researchers found that it had a significant beneficial effect on the health of the mice, and that they lived longer. There is a lot of follow-up work to be done to confirm these studies in “normal mice” as well as in humans. In any case, the data are highly intriguing. It is also worth pointing out that when asked whether this would cure aging, the scientists were much more cautious, as they clearly understood that this is probably only one of many mechanisms that are contributing to aging. Nonetheless, it is interesting to see how inflammation comes up repeatedly as a cause or at least a driver of many age-related disease, from Alzheimer’s disease to diabetes.

One question that I would like to get back to is: what can we do as individuals to influence this process? What are the conditions that lead to cellular senescence versus cell death, for example, and what are the physiological and environmental determinants that cause as a cell to enter this critical state in the first place? If we knew the answers to these questions and as well other questions of this type, we might be able to critically examine how we can influence are own rate of aging. This question is related but separate from how we can reduce and/or cope with various age-related losses and pathologies as they emerge. Both questions will be critical to answer to reach an understanding on the practice of healthy aging.  How yoga might be a part of that practice is what we are trying to address here….

What is a Yoga Practice?

by Brad

A year or so ago I was talking with a colleague about a genomics study he was planning that was going to look at exercise and aging. Previously, he and his colleagues had shown that resistance exercise training had a significant effect on the genes that were transcribed in muscle tissue, and that the older people undergoing this training had gene transcription profiles that resembled much younger people. This time around they were planning a more nuanced study and would look at several exercise regimens, including yoga. I remembered asking him what type of yoga practice they planned to use, and was met with a slightly confused look. He wasn’t sure, but thought it was a “standard practice” involving some stretching and aerobic components. When I inquired further about whether it was Iyengar style or one of those high-energy aerobic practices (like Ashtanga Vinyasa), I realized that our discussion had reached a dead end. He had no idea what I was talking about.

Photo from Yoga: The Poetry of the Body by Yee and Zolotow

So when I ran across another article today on Yoga for Back Pain that was mentioned in the Science Times section of this weeks NY Times (see here), I decided to take a little closer look at what the actual practice was. I also looked back at the Ornish and Blackburn study I discussed a couple weeks ago (see here), as well as a few other studies I had run across. I was interested in seeing how well the practice was described and whether it made in sense.

I was surprised to find that the most high profile of these studies, the 2008 Ornish and Blackburn study (see here), had the least detail. What they described as yoga for stress management consisted of “gentle yoga-based stretching, breathing, meditation, imagery, and progressive relaxation techniques 60 min/day, 6 days/week”. In contrast, a study published this summer by Dr. Fishman on osteoporosis and yoga (see here ) was considerably more comprehensive, listing all 10 yoga poses by both Anglicized and Indian names, e.g., “Upward and Downward Dog poses (Adho Mukha Svanasana and Urdhva Mukha Svanasana),” as well providing an appendix of 13 figures illustrating each poses. It should be pointed out that the lead author of this study was extremely familiar with yoga, having practiced it in India for three before attending medical school.

Another group that was fairly thorough in their description was Sherman et al. which just appeared on-line a couple days ago (see here) in their study of chronic low back pain, where they describe a viniyoga practice consisting of 5-11 poses (with pictorial diagrams referenced from earlier 2005 paper by this same group (see here). Interestingly, these authors also provided the credential for the teachers as “instructors with at least 500 hours of viniyoga training, 5 years of teaching experience, and familiarity with the selected postures and who were briefed by our yoga consultant.” This paper also gave a defense of their yoga style (viniyoga), as “a therapeutically oriented style of yoga that emphasizes safety and is relatively easy to learn.” 

Iyengar-style yoga was used in another study examining stress and inflammation by Kiecolt-Glaser, et al (see here) because it ”emphasizes the use of props to help students achieve precise postures safely and comfortably according to their particular body types and need”. In this latter study, the 12 poses and timing of each were well described and was constant, and apparently selected “based on their purported relationship to immune function and/or restorative effects.”

Obviously not everyone is going to agree with what is a good or best yoga practice for stress, back pain, osteoporosis or whatever. But what is clear is that these studies need to provide a through description of the regimen (time, poses, teacher qualifications) and their overall rationale, so that if someone wanted to reproduce this study or compare it with another, they shouldn’t be in the dark as to what the yoga practice was. In the end, it’s you who is going to have to decide on what to believe, as the standards for comparing these practices, pose sequences, and yoga styles are confusing at best. Maybe Nina and Baxter can comment on this, as I’m not an expert.

FRIDAY Q&A

Q: I'm wondering to what extent, and at what rate, we should expect to be able to increase our flexibility as we continue to age. I've made significant progress over the years, and have generally learned how to be mindful enough not to overdo. However, every so often I overstretch without realizing it - whether it's my back trying to get a fuller forward bend, or my Achilles tendon while pushing the envelope. I'm in my 50s and have been doing regular yoga for about 5 years. It's made an immense difference in my core strength and balance and flexibility and I'm much less injury prone now. And yet, every so often, it's my yoga practice that puts me out of commission.

A: Baxter and I discussed your question, and he agrees with me that there is no fixed extent or rate for increasing flexibility as we age, as this will differ from person to person. His advice is to maximize the effectiveness of your stretches while minimizing potential injury by holding your stretches longer rather than pushing harder. He mentioned that it takes at least 45 seconds to get your muscle to fully release. And my kinesiology teacher taught me that in order to change the resting length of the muscle (the length the muscle returns to after stretching), you need to stretch it for 90 seconds. So I use a timing of 90 seconds for many of my stretches. --Nina

Q: Does yoga have any good stretches for a 60 year old stiff person?

A: Yoga has a very large number of poses that allow you to stretch a very wide variety of muscles, no matter how stiff you are. So the first question to ask yourself is: where exactly am I stiff? Some of us are stiff all over and some of us are flexible all over, but it turns out that many of us are flexible in some areas and stiff in others. Identifying which areas you need to stretch will help you chose the poses that will be most helpful to you. That being said, there are a couple of poses that we highly recommend for their versatility. Downward-Facing Dog pose is especially wonderful because it stretches your legs, hips, shoulders and arms, all at the same time.

If this pose is too demanding, you can do an easy variation, Half Dog pose (also called Right Angle pose). With your hands at shoulder-height on the wall or resting on the surface of a table, walk back so your hips are directly over your feet and your arms are parallel to the floor.

Baxter recommend that you warm up for these poses with some dynamic movement, such as swinging your arms above your head or moving your legs around in your hip joints. --Nina

Q: How would one go about investigating the effects of yoga on aging scientifically?

A: This question is intriguing and so important that Brad will devote an entire post to the subject sometime soon.

Q: Just curious about how autoimmune diseases are related to aging? Some seem to be inflammatory conditions I think, and that makes me wonder about allergies, yoga and aging.

A: This is a very big and complicated question! And there’s no quick, simple answer, as the mechanisms behind many of these diseases (not to mention aging itself) are not fully understood. But Baxter says, “Not all autoimmune diseases are created equal.” Different autoimmune diseases arise at different stages in life, so not all are related to aging. Also, not all are related to inflammatory conditions. So that’s why we’ve decided that on this blog we’ll discuss the autoimmune diseases associated with aging individually, over time. Is there any particular disease that concerns you?

We are going to try to do a Q&A every Friday, so keep the questions coming. You can leave a question in a comment or you can email a comment to us at the address shown under "Contact Us" in the right-hand column.