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Aug 20

I will be on the road for the 2 or so weeks, with limited or no net access (off the beaten path) so I will not be posting. Hopefully, I will be back with more to say when I get back to civilization.

Take care.

Aug 18
Jeannie Longo is shown here about 1 km below t...Jeannie Longo, Image via Wikipedia

The Olympics is a gathering of the world’s greatest athletes, but does it have something to tell us regarding general trends?

Sure, two 21 year olds from Jamaica won the men and women 100 meter sprints (traditionally sprinters peak at around 25): youth was served, but is there any hope for older athletes?

List:

38 year old Constantina Tomescu from Romania won the women’s marathon. The previous oldest women to win the Olympic marathon was 30 (oldest man to win was 37).

33 year old Oksana Chusovitina won the silver medal in women’s vault in gymnastics. Gymnastics is dominated by women in their teens, if you in your early 20s you are considered old. For a 33 year old to compete at the Olympic level, not to mention win a silver is stunning. There is also a heart warming story regarding her son’s leukemia (they moved to Germany so her son could be treated, and she now competes for Germany).

41 year old Dara Torres in her 5th Olympics is swimming faster than she ever has (the new suits help a bit) and won a silver in the 50 m freestyle sprint in Beijing. She lost by 1/100 of a second and the silver she won is her best ever showing in an individual event at the Olympics. She won another silver in a relay event.

49 year old Jeannie Longo from France is a bicycling legend and competed in her 7th Olympics in which she finished 4th in the time trial event only 2 seconds out of the bronze (in an event that took 34 minutes – so 2 seconds is a very small margin). She also placed 24th in the road race bicycling event.

Beyond athletes excelling at their chosen sport, hopefully us mere mortals can gain a greater perspective of the possibilities. If these mature athletes can compete at the the highest world class levels then surely we have no excuse for not indulging in bodily pursuits because we think we are too old.

This is also a wake up call for the ‘younger’ crowd. I have heard late 20 year olds saying they are too old to run, hike up a mountain, sprint – or whatever. You need to keep moving for if you stop you will pay a cost (see my linked pieces below).

As I previously covered, exercise into your old age has many benefits including greater survival rate and more functional ability (see here and here).

Don’t use age as an excuse – get out there.

Aug 14
Marine of the United States Marine Corps runs ...Image via Wikipedia

Yesterday, I wrote a piece about a recent paper that found that runners had a higher survival rate and a lower rate of disability as they aged compared to non-runners. While I had a few problems with the study in the end I agreed with the authors conclusions (mainly a problem of running long term longitudinal studies).

But I want to go back to one important point:

How much did they exercise:

In 1984 the completers in the runners group were running 4 hours per week, while the community control group averaged 25 minutes (not yet separated into ever-runners and never runners), but the total aerobic exercise for the two groups were: 5 hrs and 7 min. versus 1 hour and 40 minutes. If we break them into ever-runners and never runners: running 3 hrs 21 min. vs 0 hours 2 min. and for total aerobic exercise: 4 hrs 32 min. vs 1 hr 7 min.

Now if you look at 21 years later (2005) (so talking about average age of 78-81) the ever-runner group was down to running only 1 hr 1 min per week while the never-runners was at 0, and for total aerobic exercise the ever-runners were at 4 hrs 29 min, and the never-runners at 1 hr and 27 min.

Basically, the running groups performed 3-4 more times aerobic exercise per week compared to the non-runners. Simplifying things, the runner group was doing 4 hours of aerobic exercise while control were getting 1 hour per week. What appeared to happen was as the running group aged they switched from running to other forms of aerobic exercise, but despite being in their 70s still put in 4.5 hours of aerobic exercise each week (they stayed very active).

Now it is easy to take in the hours of exercise abstractly 4.5 to 5 hours of weekly exercise. But in reality us humans think mostly at the daily level. So what does 4.5 hours of exercise mean? It equates to 45 minutes of exercise 6 days a week.

Now this is just one way to break it down, of course you could run 30 minutes a day 3 times a week then on the weekend go for a longer run of 3 hours (marathon training). You can obviously combine different types of exercises. But still 45 minutes a day, 6 days a week gives you a pretty good idea of the dedication involved. And this is the average for all year. Now many of you during the summer may reach these goals when you add up the weekend hikes, those family bike rides etc. But the problem is many of you have a fair bit of drop off when the bad weather comes. You figure that you are still getting plenty of exercise but I suggest you track it and see if it adds up to 4.5 hours per week and averaged over the complete year.

Bottom line:

If you want to increase your chance of surviving to an older age and have reduced disability so you can continue to enjoy life make sure you get plenty of vigorous exercise.

45 minutes a day of vigorous exercise 6 days a week should be your goal 52 weeks a year (or at least average this).

Break it up over the week any way you see fit in whatever form of exercises you like – but make sure you do it.

Aug 13

How many of hours of aerobic exercise are you doing each week? How much should you be doing?


50+ year olds that run were less likely to die and had lower disability scores as they aged compared to non-runners. The new research paper was published by Chakravarty et al., 2008 a group from Stanford University in Archives of Internal Medicine.

Now most of you would say of course – that is obvious, and I would agree with you, but now there is evidence that our common sense is backed up by scientific testing – which might provide further impetus for people to exercise.

However, despite me being a big proponent of exercise, including running (at the endurance and sprint level), there are potentially a number of problems with this study that we should look more closely at before we accept the results at face value.

For further background check out this piece at Ouroboros about exercise mimetics, and the comment sections. Animal studies show examining exercise show modest effects on mean lifespan (usually in the 8-12%) and no effect on maximum lifespan. But what we want to know is can exercise help human longevity (and other parameters) – and while not perfect this paper at least tries to answer this question

Methods and problems:

In this study they took two groups at age 50+, runners (average age 58) versus non-runners (average age 62) in 1984, and what is most interesting about this study followed these same subjects for the next 21 years. The subjects are now in their late 70 early 80s.

The runners were chosen from a 50+ runners association and the controls were chosen from permanent staff and faculty from Standford university and the demographics matched between the two groups. They ended up with 538 runners and 423 controls. Each year the participants filled out extensive questionnaires (medical history, exercise habits, and the health assessment questionnaire disability index (HAQ-DI) – there main outcome measurement. In 2005, there was 284 runners and 156 control members that continued to participate (obviously there were a number of dropouts over the 21 years but also some had died). The attrition rate for the runner group was 3% per year, while it was 6% for the control group.

Now as the authors point out at baseline (1984) the runner’s group was younger (58 vs 62), leaner (BMI 22.9 vs 24.4), and less likely to smoke (1.9% vs 9.5%) compared to the community control group (the overall results are similar for the all subjects enrolled and completers – so I only report one of these). Additionally, a far greater percentage of the runners were male (84%) while the control population consisted of 56% males. Now I don’t think the BMI (leanest) is too much of a concern because both groups are fairly lean compared to the general population, and the larger proportion of females should actually help the control group regarding lifespan (women live on average longer then men). But females might be less mobile as measured by HAQ-DI as they age compared to males. To the authors credit they do later on in their paper break down the groups into females and males and in both sexes runners have a lower disability score than non-runners. So the differential proportion of sexes in the two groups can be eliminated. The large difference in smoking at the beginning of the study is still troublesome though. (other measurements were consistent between the two groups: education level, alcohol intake). But maybe most importantly, their main outcome score (other than lifespan) the HAQ-DI score (which from now on I will refer to as disability score) was already lower in the runners group (86.6% of runners scored 0 (no disability) while in the controls only 61% of this group scored 0).

Later on they further broke up the groups into ever runners and never runners (for obviously some of the staff and faculty from Stanford university could be runners). Subjects were considered ever runners if they said yes to: “Have you ever run for exercise for a period of greater than 1 month?” So the ever run groups includes members who currently run but are not members of the running association, but also runners who no longer run.

Now even after they break all subjects into ever-runners and never-runners many of the same problems exist. Differences in age (58.4 vs 63.1) and smoking prevalence (2.1% vs 12.9%). For the disability score 82% of the ever-runners had a 0 disability score, while only 58.6% of the never-runners scored a 0 disability score.

So when the authors give the results they openly admit the differential scores between the groups (no matter how they break them up) and no great surprise throughout the next 21 years the runner groups continue to have a lower disability score than the community control group or never-runners. The authors main point that seem to support their conclusions is that the rate of disability is different between groups, with the controls and never-runners having a faster rate of increasing disability. And I would agree with this part of the paper – but there could still be a threshold effect.

How much did they exercise:

In 1984 the completers in the runners group were running 4 hours per week, while the community control group averaged 25 minutes (not yet separated into ever-runners and never runners), but the total aerobic exercise for the two groups were: 5 hrs and 7 min. versus 1 hour and 40 minutes. If we break them into ever-runners and never runners: running 3 hrs 21 min. vs 0 hours 2 min. and for total aerobic exercise: 4 hrs 32 min. vs 1 hr 7 min.

Now if you look at 21 years later (2005) (so talking about average age of 78-81) the ever-runner group was down to running only 1 hr 1 min per week while the never-runners was at 0, and for total aerobic exercise the ever-runners were at 4 hrs 29 min, and the never-runners at 1 hr and 27 min.

Basically, the running groups performed 3-4 more times aerobic exercise per week compared to the non-runners. Simplifying things, the runner group was doing 4 hours of aerobic exercise while control were getting 1 hour per week. What appeared to happen was as the running group aged they switched from running to other forms of aerobic exercise, but despite being in their 70s still put in 4.5 hours of aerobic exercise each week (they stayed very active).

To be more precise he paper actually uses the term: ‘vigorous’ exercise, but when you refer to the method section regarding the questionnaire it says, “exercise habits (running and other vigorous exercise including biking, aerobic dance, and swimming)”. So to me that sounds like aerobic exercises (this doesn’t mean appropriate level of weightlifting or other forms of exercises not mentioned would not also have the same potential benefits, assuming done at the appropriate intensity and you are not just standing around most of the time).

Now I wish the authors had included the amount of running and other aerobic exercise was performed though-out the different time periods (though this might have been covered in earlier papers when they reported earlier results of this same study). But also I wish they had broken the running groups into those that continued to exercise and those that didn’t.

Lifespan effect:

At the end of 2003 15% of the runners had died and 34% of the controls (but remember there were difference in starting age and smoking prevalence). But even after adjusting for a number of variables at baseline the authors report a significant survival advantage. Bottom line runners had a greater survival rate.

Runners not only had a reduction in death from cardiovascular disease, but also interestingly cancer and neurological disorders.

(as expected initial age, sex, and initial disability score was associated with survival rates: surprising to me smoking did not reach statistical significance).

Conclusion:

Despite some problems with this study that centers around different starting points for the two groups (which can be a problem with long term longitudinal studies) the rate of increase of disability as they aged was lower in runners compared to non-runners. Additionally, runners also had a higher survival rate. What more could a person ask for, better survival rate and more functional ability?

Now with these type of studies there is always a problem of self-selection. Are people that decide to run more concerned about their health, do they eat better, and do other things in their life that give them advantages over non-runners. An open question. But at least the two groups were comparably at the socioeconomic level (based on education levels).

Also I would have liked to know how much running did the runners do before they reached their 50s. Were the ones that gained the biggest advantage running for 40-50 years when they reached their late 70s? How many years do you need to run to see these effects? There is always more questions. I am sure we will here more in the future.

Take home message:

Hopefully this data either gives you further impetus to continue to exercise program, or for you to start your exercise program today. But also remember the running group was putting in 5 hours of aerobic exercise per week (4 hours of running) in their late 50s, and in their late 70s still put in 4.5 hours of aerobic exercise per week (1 hour of running). That is impressive!

Now it is easy to take in the hours of exercise abstractly 4.5 to 5 hours of weekly exercise. But in reality humans think mostly at the daily level. So what does 4.5 hours of exercise mean? It equates to 45 minutes of exercise 6 days a week.

Now this is just one way to break it down, of course you could run 30 minutes a day 3 times a week then on the weekend go for a longer run of 3 hours (marathon training). You can obviously combine different types of exercises. But still 45 minutes a day, 6 days a week gives you a pretty good idea of the dedication involved. And this is the average for all year. Now many of you during the summer may reach these goals when you add up the weekend hikes, those family bike rides etc. But the problem is many of you have a fair bit of drop off when the bad weather comes depending on where you live). You figure that you are still getting plenty of exercise but I suggest you track it and see if it adds up to 4.5 hours per week and averaged over the complete year.

Bottom line:

If you want to decrease your chance of surviving to an older age (though it might not increase maximum lifespan) and have reduced disability so you can continue to enjoy life make sure you get plenty of vigorous exercise.

45 minutes a day of vigorous exercise 6 days a week should be your goal 52 weeks a year (or at least average this).

Break it up over the week any way you see fit in whatever form of exercises you like – but make sure you do it.

How many hours of aerobic exercise are you doing each week? And I bet most of you are not in your late 70s – something to think about. Keep moving, and keep moving a lot.

Aug 12

Chris Patil from Ouroboros has done another great job of hosting, and writing up the connections between the various blog pieces on the biology of aging (Hourglass). Go check it out the 2nd installment of the Hourglass.

From Chris:

“Hourglass III will be hosted on September 9th by Alvaro at SharpBrains, and Hourglass IV on October 14th by Anne at Existence is Wonderful. We’ll set up a standalone email address and archive page for the carnival at some point — but for now, if you have submissions (or want to volunteer to host the carnival), please email me and I will forward them to the current host.”

Aug 11

Can we look at the history of some leading diseases to get an indication of the potential breakthroughs in longevity research?

Research in the longevity field has dramatically grown in the last 3-4 years, and many are claiming we will realize great breakthroughs resulting in longer lives and more healthier years. And I for one hope that these breakthroughs do occur so there is reduced suffering, and enable people to live more healthier years, along with longer lives.

Aubrey de Grey, one of the leading drivers of longevity research, approach to longevity will be discussed in the concluding section of this piece in reference to the rest of this blog piece.

We could examine how are we doing in some of the leading causes of death over the last 50 years to maybe get some clues. The leading causes of death are led by the big 3, with the percentage of total deaths listed after the particular disease.

Heart diseases: 26.6%

Cancer: 22.8%

Cerebrovascular diseases (stroke): 5.9%

(all data is from the American Cancer Society and/or National Cancer Institute unless otherwise specified). Additionally, all data presented below in this piece is age adjusted rates, meaning we can compare across time despite different demographics from different eras.)

I am going to pick cancer to examine in more detail.  Cancer not only is the second leading cause of death, but also males have a 1 in 2 probability of developing cancer in their lifetime, while women are 1 in 3. So this disease affects most of us or someone we love. I have done a little bit of a background check to see how science has fared in treating this terrible disease over the last 50 years, or so.

(I am also reporting the cancer results of America, which according to recent data has the best cancer survival rates in the world, which means the conclusion might be worse for the rest of the world).

Now every week we are told of a new cure for cancer, a new breakthrough in cancer research that is going to save millions of lives. And we are also told that the survival rate of cancer X has improved ‘X’ percent in the last 10 years. Therefore, we must have huge decreases in cancer death rates over more than the last 50 years. In 1950 we hadn’t yet discovered DNA, not to mention sequenced the entire human genome, and started the whole biology revolution in research.

The cancer death rate (age adjusted) per 100,000 was:

In 1950: 193.9

In 2005: 183.8 (the most recent data set).

I am not even sure if this is a statistical difference? A 5.2% improvement in cancer death rate over the time of 55 years.

And possibly even more interesting if you look at the 2002 data and compare with 1950.

1950: 193.9

2002: 193.4

The cancer death rates are virtually the same for 1950 and 2002. How can there be no difference from 1950 to 2002? Is this not shocking to you – it is to me? What about all those new cures for cancer I have been reading about the last 30 years. And even the difference between 1950 and 2005 seem frighteningly small (5.2%).

So even if you skip all the basic advances we have made in molecular cancer research over the last 50 years, all the new treatments, etc, then just think of all our new advance screenings that we perform now, that we certainly did not do in 1950: pap test (papanicolaou test), PSA testing for prostate cancer, breast mammograms. Just the advanced screening should make a huge difference because all the cancer experts agree that the main key to treating cancer is catching it early. It could be argued that the small improvements we do see is all due to early diagnoses (screening and awareness), and nothing to do with actual better medical treatments, more research, new treatments, etc. Then why with the access of these new early screening tools, and far better public awareness why aren’t we seeing huge reductions in cancer death rates?

First we need to examine the leading types of cancers and which are the deadliest cancers. All the cancer groups when reporting this data put in the caveat of excluding non-melanoma skin cancers ( which is roughly 5 to 6 times higher incidence than breast or prostate, but very low death rate) so if we exclude then the leading new cases of cancer types are (again listing the big 3):

Males: ——————————————————–Females:

Prostate: 25%                                                                                    Breast: 26%

Lung and bronchus: 15%                                                                  Lung and bronchus: 14%

Colon and rectum (colorectal): 10%                                                  Colon and rectum: 10%

And the big 3 are also among the most deadliest, as I list the percentage of total cancer deaths by these three below.

Males: ——————————————————–Females:

Lung and bronchus: 31%                                                                   Lung and bronchus: 26%

Prostate: 10%                                                                                     Breast: 15%

Colon and rectum: 8%                                                                       Colon and rectum: 9%

A NY times graph probably gives you a more intuitive image of cancer types and deadliness (click on any of the graphs for a higher resolution image).

So to address cancer death rates one has to take into consideration the big 3, and in particular lung cancer because it has nearly 2 -3 times higher death rate than prostate or breast cancer.

One argument for the lack of large drops in the cancer death rate is a small but continuous increase in cancer incidence as depicted in the graph below (from 1975 onward).

The blue line is for male cancer incidence (per 100,000 age adjusted), the gray bottom line is female rate, and the red line represents both sexes. You see a general increase, but with a unusual blip in the male and combined sex lines between 1990 and 1993.

So let us look at individual trends in males and females as depicted below.

Males:

The red line represents prostate cancer incidence rate (per 100,000), while the blue and green are lung and colorectal respectively, which are decreasing.

You can see a large increase in prostate (red) cancer incidence, which then then falls back down before remaining relatively constant. The prostate cancer incidence mirror the overall cancer rates in males (blue line) in the previous graph. This suggest that new technology such as PSA screening and doctor and public awareness was catching more cancers that previously determined. A newscientist article reports that in 2002 1/3 of PSA detection of cancer in older males would not actually  cause symptoms in their lifetime, while the majority of these subjects would still  undergo cancer therapy. And there is an ongoing debate on the accuracy and usefulness of PSA testing.

Females:

The purple color represents breast cancer which is increasing slightly, along with the blue line – lung cancer, while the colon and rectum cancer (green line) incidences are trending downwards.

Therefore, it appears that the overall increase of cancer incidence over the years is largely attributed to the rise of prostate and breast cancer in the respective sexes. There is an open argument, particularly for prostate cancer, that some of this increase might be false positives. Either way the increase is not that large and mainly centered around prostate and breast cancer (there is also an increase in lung cancer in females – see below).

(I am leaving out discussion on possible environmental causes of the increased incidences of cancers for this blog piece).

But since lung cancer has a relatively high incidence and the most deadly of the most prominent cancers it plays a large role in the overall cancer statistics so we should examine this form of cancer in more detail.

For this I offer these graphs that go far back as 1930 and report cancer death rates for multiple cancers.

Males:

Females:

What these graphs displays in an increase in lung cancer for males until around 1993 then a decline, while female lung cancer rates rise about the same year then levels off. Therefore, behavioral trends in humans, such as smoking might be playing an important role and we should explore this possibility.

Tobacco use:

The black is the tobacco use, and the blue depicts cancer death rates from lung cancer for males, with the red representing the same for females. Tobacco use peaks about 1962 and the lung cancer death rate for males peak in 1990. So we can see a 25-30 year delay in tobacco use and death by lung cancer, especially for males.

Now we know that females in general took up smoking at a later time period than males and the death rate from lung cancer are offset in the sexes so we should look at the sexes separately. And if we look at data for the separate the sexes for smoking prevalence since 1965 as depicted below we can learn a few more things.

From this graph we can see that since 1965 there is a decrease in smoking prevalence in both sexes. Therefore, given the 25-30 year delay from smoking behavior changes and cancer death rates from lung cancer we would expect to see a drop in both sexes starting at say 1995 onwards. We do see this for males but have yet to see it in the female population.

But overall from 1992 we see a drop from 90 to 70 (rate per 100,000 age adjusted) in males and steady rate of around 40 for females in death rate from lung cancers. And since lung cancer has such a large influence on the overall cancer death rates (due to high incidence and high death rate) that this overall (combined sexes) drop in lung cancer death rates could largely account for the small overall drop we see in cancer death rates.

An equal argument can be made that the 1950 death rates are relatively low because the 25-30 year lag had not shown up in the rising rate of smoking that occurred from 1925 to 1950. And the 1950 cancer rates are largely determined from the level of smoking in 1920-25. And this is a valid argument, but it also points to the fact that behavioral changes have far larger influence on cancer death rates than our medical advances.

So one way to approach the potential confounding variable of tobacco use is to eliminate it from our analysis.

Now if you go back to the most telling graph of cancer death rates starting from 1930 and examine all the other cancers we see that for males a large decrease in stomach cancer death rate (most likely due to changes in diet in food preservation) and a smaller decrease for liver cancer, no real changes in prostate or colorectal cancer death rates (using the eyeball test) and an increase in death rate for leukemia and pancreas cancers. The news is better for females as we observe a decrease in stomach, uterus, colorectal and a smaller decrease in breast cancer death rates, and a increase in ovary and pancreas cancer.

But the bottom line is over 70 years it is hard to argue we are not much further ahead in overall cancer death rates that seem disproportional to the advances we have made in biological science and more specially cancer research.

Conclusion:

Cancer is the second leading cause of death in humans, so it appears to me that if we are going to make any significant improvement in longevity and/or more healthy years we would have to make large strides in reducing cancer death rates (but see below).

However, despite all the vast sums of money and time spent on the fundamental basic biology of cancer, and all the clinical studies we have made very little, if any, real progress in cancer death rates over the last 50-70 years. Additionally, think of all the advances we have made in screening, awareness and early diagnoses of cancer over the last 50 years. They could easily account for the little improvements we might observe, but then again you would ask why not better? Then you have the weekly announcements of new cancer treatments that we have seen for the last 30 odd years – where are the results?
It is actually hard to believe the lack of results.

(I am sure cancer researchers and lobbyist could sell a far brighter picture that I have just presented – but I have just presented their own data at face value – though they might to do a better job at interpretation.)

Now, with this all said we have made some progress in heart disease from 1950 to the current time, though if you look at the limited amount of research from 1900 we might have not had any improvements from 1900 to  the year 2000 (suggesting lifestyle and environmental factors). But there is no argument that we have a longer lifespan now compared to 1950, but this is largely due to reduction in death during childbirth (for both child and mother) and reduction in death in childhood. Vaccination for common childhood diseases and antibiotics have probably had the biggest contribution to the increase in lifespan, and it is open to debate if we have made any gains on the other end of the lifespan spectrum.

Aubrey de Grey, also points out the lack of success of the single disease paradigm (discussed in these video links: via PIMM , TED talk, and this google talk). His argument is we have to get at the core of the problem, but isn’t this similar to the molecular cancer researchers approach? Specifically, Aubrey argues that the gerontology approach that tries to stop the damage, by usually altering the metabolism, or the geriatric approach which tries to reduce or halt the pathology that results from the initial damage might not be the best approach. He believes an engineering approach concentrating on the damage might be a better approach (see his video lectures).

I think Aubrey would argue that the cancer results over the last 50 – 70 years can not tell us much about the possibilities of his approach to longevity. But I still think that if we are going to have fundamental advances in longevity we are still going to have an appropriate level of molecular biological manipulation that is similar in principle as treating cancer (to the point that we reduce cancer death rates).

I wonder if we can not made huge strides in cancer death rates then what are the hopes for meaningful progress in longevity research?

Now the argument that usually occurs at this point is that only now do we know enough at the biological level to come up with real breakthroughs. But this is the exact same line we have been told for at least the 30 years of my memories. The new breakthrough, the new cure is heralded yesterday, today, tomorrow – but then 1, 5, or 10 years later nothing has changed (based on the cancer results).

I hope that this time we really are at the threshold of fundamental breakthroughs that result in reduced death rates from cancer, but also all other diseases. But if you want me to believe you that this time is different from all the other times – show me the results.

Aug 7

Low heart rate variability (HRV) s associated with reduced lifespan, cardiovascular diseases (CVD), diabetes, several mental health diseases and a growing list of other conditions I will cover in this post. For a more thorough background check out my two previous posts: heart measurements for your health , what heart rate measurements can tell you about your brain.

Heart rate variability can be broken into time and frequency. Regarding time, though there are still many measurements of this, you can think of one as the standard deviation between interbeat intervals (IBI). As for frequency: both low frequency and high frequency spectral power have been used an indices of vagal activity.

Another way to look at these two measurement of variability is that frequency domains are an attempt to try to dissect out the excitatory (sympathetic) and inhibitory (parasympathetic) components/contributions, while the time series measurements are seeking to measure the overall chaos or complexity in the system.

As for the general take home message, people with a higher rate of variability are considered healthier and less likely to die. So at first this might sound somewhat counterintuitive for those not familiar to the heart field or chaos theory. But think of it as the more dynamic the system the better it can react to external changes.

Overall: low heart rate variability is bad and related to several diseases and predictive of a shorter lifespan. The other thing to keep in mind is that the higher the sympathetic drive the lower the HRV (sympathetic is one component of the autonomic nervous system – the other being the parasympathetic). Enough of the background (for more check my previous post listed above).

What are some of the other conditions that are related to decreased HRV? One could guess any overall negative health condition may lower HRV. Obesity would be one example and research has found that these individuals do have a lower HRV (Piestrzeniewicz et al., 2008). Subjects with a BMI of over 30 had lower HRV (many measurements) than lower BMI subjects, and waist circumference was better correlated with lower HRV than body mass index (BMI). Syme et. al., 2008 had an interesting related study as they were investigating the relationship between intra-abdominal fat (IAF) (simplified: another name for visceral fat) and metabolic syndrome (MS) in 12 to 18 year old. MS was completely absent in subjects with low IAF, but 8.3% of females and 13.8% of males with high IAF had MS. Additionally, high IAF subjects had altered autonomic nervous system response with higher sympathetic responses, associated with lower HRV. Erectile dysfunction was recently found to be related to higher sympathetic activity (Dogru et. al., 2008). I guess if I wanted to increase my googleness and reading rate I should have written a seperate blog piece on this subject with appropriately intriguing title.

Okay, those are only a few examples of recent papers finding more health conditions associated with higher sympathetic activity and lower HRV. But then the question becomes what can you do to increase your HRV. Probably the most well studied is appropriate exercise can increase HRV (I will go into more detail later), but for now see my previous piece. There is also a very recent paper that is freely available that examined exercise and HRV published in Plos ONE (Earnest et. al., 2008). But what about other options to increase HRV?

Researchers have found that a vegan diet increased HRV, which was related to LDL cholesterol levels (Fu et. al., 2008). Now a vegan diet might be considered too extreme by the average population, what about other dietary manipulations (another extreme diet: every other day fasting (EODF) has been shown to increase HRV, Mager et al., 2006) ? Fish consumption is linked with increases in several measurements of HRV and in a study of over 1,000 subjects that had a follow-up period of 10.8 years found that some of these HRV indicies related with fish consumption (short term fractal scaling exponent) had up to 8.9% differences in relative risk of cardiac death (Mozaffarian et. al., 2008). As most of you know there has been several studies showing wide health benefits of fish consumption (but apparently don’t fry your fish) including for heart health.

Can your general disposition affect HRV? During high stress conditions, be it giving a speech,or exercising, there is a decrease in HRV, but interestingly people with higher self-esteem display less of a HRV decrease during a speech task (O’Donnell et al., 2008). Now at first glance this makes perfect sense, the people with higher self-esteem feel less stress under this task because of their confidence. At a second level it suggest that more self-confident people (high self-esteem) would undergo less stress in their overall life and have higher HRV (over their lifetime) and is this predictive of a longer lifespan? Now you might argue that you do not have much direct control over your self-esteem, but I guess at least try, and try hard not to have low self-esteem (easier said than done).

So the point of this piece was to update you with some of the latest research in HRV. Obesity, and more specifically waist circumference, visceral fat, is associated with lower HRV. Additionally, erectile dysfunction (ED) is also related with high sympathetic drive (lower HRV). Obviously, the increase of abdominal fat (visceral) could be related to the ED. Either way I don’t think anybody particularly wants to either to be fat or have ED.

Now I think people should be forward thinking, sure they might not be too overweight, or have ED currently. But could HRV give us a concrete measurement prior to these more severe health conditions (diabetes, ED, depression, CVD, …. death) that we can monitor on a daily, weekly, monthly basis. Of course one must take the next step and do the best they can to either maintain your current level of HRV (HRV decreases with age) or increase HRV with various lifestyle changes (better diet – fish, fasting, vegan, etc and exercise).

Tomorrow, I will give you more detail on how the average person can actually monitor their HRV without reliance on the health care system (they probably wouldn’t give you monthly readings or it would come at a relatively high cost).

Aug 6
An embedded hard drive-based player (Creative ...Image via Wikipedia

Most of us live a busy life. Never enough time in a day to do all what you want. What we need are brain/life hacks to increase our time, productivity, and pleasure. One simple solution I have found is the use of audiobooks. I have a last generation nano ipod, while not fancy is nice and small, which makes it perfect for my daily runs. I have listened to several very good books this summer while listening to them exclusively during my runs. The history of economics, neuroeconomics – irrational human behavior, the political brain, and a very good near future sci-fi thriller.

I am reasonably sure I would not have made time to ‘read’ all these books since I am already reading a 1,000 page novel this summer not to mention the many hours of daily internet reading I do on science and too many other topics to mention here.

My point is that audiobooks is a convenient form of information consumption. A good audiobook can be both relaxing and engaging, as I learned listening to some of the books this summer.

Listening to my audiobooks only during my runs actually was another incentive to run, I wanted to know about the next chapter on economic history, or wanted to know what was going to happen next in the novel. I made a point of not listening to my audiobooks during the rest of the day, which I think increased the incentive to get out and run in the evening. I would recommend trying this same incentive trick of listening to your audiobook during whatever form of exercise you are doing.

If you want to increase your productivity and pleasure try out audiobooks on whatever form of player you have (mp3 player, cell phone, etc). It might save you some time, or at least maximize your time not to mention potentially increasing your incentive to get your daily exercise.

Aug 4
WASHINGTON - NOVEMBER 05:  U.S. President Geor...Image by Getty Images via Daylife

Francis Collins, the outgoing director of the National Human Genome Research Institute, has chosen currently not to get his personal genome scanned  – why ?

If you want a overview of current genome knowledge and personal genome research, take a look at this video. Charlie Rose is interviewing Francis Collins from July 29 2008. Francis Collins is the director of the National Human Genome Research Institute (NHGRI) and is stepping down as director as of August 1st.

Load up the video and continue your daily computer work (you don’t have to actually ‘watch’ the video just listen).

Interestingly, Dr. Collins has chosen not to obtain his personal genome profile, even though it would be easy and probably free for him. The reason of why he has not is because he thinks the lifestyle interventions that increase your overall health outcome is dependent on your personal genome profile – but we don’t know which profile will benefit from lifestyle change X. So while he knows there is a great deal of information to be obtained from getting your own personal genome scan he doesn’t think the science has advanced far enough to deliver ‘identifiable actions’ based on the personal information.

Aug 1
The Thinking Man sculpture at Musée Rodin in ParisImage via Wikipedia

I figure that anything that increases empathy (‘capacity to recognize or understand another’s state of mind or emotions’) in our world must be a good thing. Yesterday, I wrote about how new research indicates that meditation can alter gene expression of whole blood, and that as little as 8 weeks can have an effect.

The paper I will discuss today is also fairly recent (March 2008) authored by Lutz et. al., (freely available) from the University of Wisconsin.

Traditionally such mental training comprises years of scholastic study and meditative practice. The long-term goal of meditators undergoing such training is to weaken egocentric traits so that altruistic behaviors might arise more frequently and spontaneously. The purpose of this study is to examine the brain circuitry engaged by the generation of a state of compassion (short for ‘‘compassion and loving-kindness meditation state’’) in long-term Buddhist meditators and novice meditators.

The world needs more compassion in my humble estimation.

Like the study I covered yesterday the researchers had expert meditators (10,000+ hours), but also novice meditators then tested them while in a meditative state and at rest. There is a big open ended question of what they didn’t have a control group that did not meditate, unless you can argue that the ‘rest’ state represents that control, but still it would have been nice for a control group that was just asked to think emphatically (with no fancy meditation).

The instruction for the novice meditators was:

One week before the actual fMRI scan session, novices were given written instructions on how to perform the meditative practices, written by Dr. Ricard, following which they practiced this compassion meditation and two other meditations for one hour a day for a week (20 minutes per meditation). As described in Dr. Ricard’s instructions for novices: ‘‘During the training session, the subject will think about someone he cares about, such as his parents, sibling or beloved, and will let his mind be invaded by a feeling of altruistic love (wishing well-being) or of compassion (wishing freedom from suffering) toward these persons. After some training the subject will generate such feeling toward all beings and without thinking specifically about someone. While in the scanner, the subject will try to generate this state of loving kindness and compassion.’’

They scanned the brains of the two groups during three different conditions: positive sound (baby laughing), negative (sound of a distressed woman), neutral (background noise in a restaurant).

The researchers predictions were:

We predicted that participants would feel more moved by the
emotional sounds during compassion meditation than when at
rest. Thus, the brain regions underlying emotions and feelings
(insula, anterior cingulate cortex (ACC), and possibly somatosensory
areas, for review see [12,13,14]) would be more activated in
response to emotional sounds during compassion meditation than
during the resting state. As this meditation is said to enhance
loving-kindness when the joy of others is perceived or compassion
when the suffering of others is perceived, this effect was predicted
to be stronger for the negative sounds (sounds of a distressed
woman) and positive sounds (a baby laughing) than for neutral
sounds (background noise in a restaurant).

What they found was that in both meditative groups (expert and novice) there was a greater activation of limbic regions of the brain (Insula and cingulate cortices), which had previously been related in other studies with an empathetic response, in the meditative state compared to the rest state.

In the meditative state there was greater activation of the insula for the negative sound compared to either the positive or neutral sounds. Additionally, the strength of insula activation correlated with the self-reported intensity of meditation in both groups. Now many of you, even you biologist, might not be too familiar with the insula (insular cortex). But I have read quite extensively about the surprising importance of the insula in decision making, which I will report about at another time.

No great surprise that the expert meditators had greater activation of the ‘emphatic brain circuitry’ than the novice group.

The authors concluded:

Together these data indicate that the mental expertise to cultivate positive emotion alters the activation of circuitries previously linked to empathy and theory of mind in response to emotional stimuli.

I think there are several questions that need to be addressed in further research (a sign of good research): 1 – the need of a real control group; 2 – do you have to be in a meditative state to gain the benefits of the growth of empathetic feelings (you would hope it would translate into your ‘normal’ state): 3 – is there a difference between experts, novice, and a real control in the ‘rest’ state for negative and positive sounds for limbic (emphatic circuitry) activation (to me this is the most important test).

Far as I could tell there were no differences between the novice and expert meditators in the rest state for any of the three sounds.

I think this paper is a very good start, and I look forward to further research. They would also have to ask themselves if the people that choose to become expert mediators and even the ‘novice’ volunteers who are  “specifically recruited participants who had an interest in meditation, but who had had no prior meditative training” are a priori different than the average population? It is not unreasonable to suggest that these groups of people might have a different capacity for empathy than the general population. One could ask for 40 volunteers then put half of them into the meditative group and the other half to serve as the real control group.

The other question that comes to mind is what would happen if without meditation a person just sat down for 20 minutes per day and thought about other people, individuals and groups that are in many cases less fortunate than ourselves? What about just taking some time on a daily level to put ourselves in other peoples shoes – would this produce a change in our empathy (be it analyzed by brain scans or in our everyday lives)? The problem is we don’t take those precious moments on a near daily level to ‘train’ or remind ourselves (sounds just like the problem with physical exercise).

So maybe think of taking a few moments each day (be it specific meditation or just plain thinking) and think of others (exercise your insula), and not just yourself.

(ps I will explain how this might help you at many other levels other than developing your empathy in a future piece)