Human Limits

Last Fall I reviewed some of the risk factors, including inactivity, for Alzheimer’s disease and cognitive decline with aging.   In this short post I want turn the discussion around and highlight a couple of things related to cognitive or even school performance and physical activity in kids.  My interest in this topic was stimulated by a news report of a study in Denmark showing that kids who walk or ride their bikes to school concentrate better.  This stimulated me to look a little more about what research tells us about physical activity and school performance.

Study 1:  Walk and read better.

A single 20 minute session of brisk treadmill walking improves academic performance in pre-adolescent children especially reading comprehension.   Here is a figure from that study.  The filled bars are the scores after walking and the open bars are the control scores.

The authors concluded that:

“Collectively, these findings indicate that single, acute bouts of moderately-intense aerobic exercise (i.e. walking) may improve the cognitive control of attention in preadolescent children, and further support the use of moderate acute exercise as a contributing factor for increasing attention and academic performance. These data suggest that single bouts of exercise affect specific underlying processes that support cognitive health and may be necessary for effective functioning across the lifespan.”

Study 2:  A review of physical activity and academic achievement.

This paper is a review of ideas about the so-called academic achievement gap in school performance by some ethnic and socioeconomic groups.   Based on the data surveyed the following conclusions emerged:

“Physical inactivity is highly and disproportionately prevalent among school-aged urban minority youth, has a negative impact on academic achievement through its effects on cognition, and effective practices are available for schools to address this problem. Increasing students’ physical activity and physical fitness can best be achieved through a comprehensive approach that includes physical education, wise use of recess and after-school times, co-curricular physical activity opportunities, and bicycling or walking to and from school.”

Study 3:  Exercise helps kids with ADHD focus. 

This study used a walking protocol similar to study one highlighted above in 20 children (8-10 years old) with ADHD and found:

“Following a single 20-minute bout of exercise, both children with ADHD and healthy control children exhibited greater response accuracy and stimulus-related processing, with the children with ADHD also exhibiting selective enhancements in regulatory processes, compared with after a similar duration of seated reading. In addition, greater performance in the areas of reading and arithmetic were observed following exercise in both groups. These findings indicate that single bouts of moderately intense aerobic exercise may have positive implications for aspects of neurocognitive function and inhibitory control in children with ADHD.”

Summary:  Physical activity is emerging as a key modulator of academic performance and learning among children of all sorts.   It also appears to be a gift that will keep giving.  In a study from Scotland, 11 year old children studied in 1933 and also studied again 68 years later at age 79 showed that physical fitness early in life was associated with successful cognitive aging.   The policy implications of the findings highlighted above for things like physical education in school, recess and public policies aimed at getting kids moving are pretty striking.   If we want a smarter world we need a fitter world.

In a post last September colleagues from the University of Kansas highlighted a free exercise program in Lawrence, Kansas known as “Red Dog’s Dog Days”.   I have been studying exercise in the lab since I was 19 years old, and that got me thinking that it was time to get out of the Ivory Tower and try something similar in Rochester, Minnesota during 2013.     My wife Teri was enthusiastic and so was Wes Emmert, an experienced strength and conditioning expert.  Wes has forgotten more types of calisthenics, body weight strength exercises, and agility drills than most of us have ever heard of.    He also knows how to stop people mid position during push-ups for a 5 second hold to make things more “enjoyable”!

The initial plan was to pilot the program on Saturday mornings with friends this winter and then open things up to the community in April.   However, the local paper reported on one of our earliest sessions and things have accelerated from there.   We now have a Facebook page and during the first month more than 50 different people have participated in our Saturday morning workout –10:30 at Soldiers Field track, EVERYONE IS WELCOME!  The youngest participant has been less than 10 and the oldest around 70.  Most people seem pretty fit to start with but it is also clear we have some beginners and folks perhaps looking to lose a little weight or get back in shape.  The goal is to make the program welcoming to people of all ages and fitness levels and provide everyone a workout they can calibrate to meet their own goals.

All of this has happened outdoors which makes it even more impressive considering how cold and windy it is in January in Minnesota.   Here is a sample of what we did a couple of weeks ago:

•  Stationary Warm-up  (neck circles, jumping jacks, etc)
• Moving Warm-up (over/under hurdles, knee to chest walk)
• Push ups for 60 seconds – lunge to first pole and jog back
• Mountain climbers for 60 seconds – high knees to second pole and walk back
• Squats for 60 seconds – butt kicks to third pole and walk back
• Planks for 60 seconds – skip to fourth pole and walk back
• Sit ups for 60 seconds – run to fifth pole and walk back
• Split squats for 60 seconds – jog to fourth and walk back
• Abs of choice for 60 seconds – side shuffle to third pole and walk back
• Back extensions for 60 seconds –  grapevine to second pole and walk back
• Burpees for 60 seconds – walk to first pole and back
• Cool down – (yoga)
• Optional 2 mile run

So, what have I learned so far?   I have learned that burpees (squat thrusts), planks, lunges, and mountain climbers are much harder than I remember them being in about 1975.   I have been sore for a couple of days after doing them on Saturdays and am now incorporating these movements into my training during the week.  I have also learned that it is pretty easy to stick with what you know and what you are good at.  Endurance sports have always come easy to me and my approach has typically been when in doubt go for a run, get on the bike or hit the pool.   The data shows that as we get older staying strong is really important and my struggles with these simple body weight maneuvers has been an eye opener.  Our ability to literally get up off the floor as we age is a pretty good predictor of healthy aging and even longevity.  Doing challenging old-school calisthenics would seem like an easy way to address this issue.  I am also thinking about starting to jump rope again (remember high school basketball practice?) to improve my footwork and general coordination.

The other thing I have re-learned is that working out with a group is fun and so is using a bull horn and a coach’s whistle.   If the program grows, we may have to invest in an air horn!

I got an e-mail a couple of weeks ago from a reader about when to start training again after a marathon.   That is a pretty broad based question and the answer depends on all sorts of things including the training background and goals of the athlete, the course he or she just ran, and just how sore and tired the runner was after the race.   Here are a few things to think about.

Delayed Muscle Soreness

After a period of exercise, especially trying something new, people frequently experience so-called delayed muscle soreness  that usually peaks about 48-72 hours after the bout of exercise.   This can also happen after something like a marathon and downhill running is a notorious way to generate delayed muscle soreness.  The idea is that microdamage to muscle and inflammation lead to the soreness and pain.   Going down stairs is particularly uncomfortable but going downstairs backwards typically is much easier.   What is interesting is that things like stretching and cold water immersion post-exercise don’t seem to help that much.  Drugs like ibuprofen can help with the soreness but may not improve muscle function either.   The best way to avoid delayed muscle soreness is to start a new program slowly.  One key for running races with a lot of downhill is to actually do some training going downhill.

Training After a Marathon

The rule of thumb is that it takes about 1 day per mile to recover from a race.   So 6 days for a 10k and 20 plus days for a marathon.   I am not sure where these rules of thumb came from and again they would depend on how trained the runner is and a lot of the individual factors mentioned at the start of this post.   However, there is some research on what happens when people do run in the days right after a marathon and whether it speeds recovery.   In a classic study from the 1980s, scientists at Ball State University studied 10 young male runners who ran a marathon on average in less than 3 hours.   Half of the runners ran for 30-45 minutes per day the next week, and half rested.   The authors concluded that:

“Seven days rest postmarathon did not allow complete recovery of maximum peak torque (MPT) nor did exercise facilitate recovery of work capacity. To prevent impairment of the normal course of recovery postmarathon, exercise intensity and duration must be judiciously selected.”

Active Rest

So what to do?  After something like a marathon give yourself at least a week or two to recover.  One idea is to use something called active rest.   This might include things like cycling, swimming, or deep water running for a few days at 50% effort for about 30 minutes until the delayed muscle soreness has passed.   Then slowly add a bit of running.  Daily training is a part of the routine for most people who do marathons so there is no need to get out of your routine.  However, there is nothing magical about “running the next day”, so give it some time and substitute other activities.  One of the nice things about both biking and swimming is that they seem to generate much less of the soreness associated with running.

There was a lot of attention in the press last week about a new report in the Journal of the American Medical Association (JAMA) showing that BMIs in the “overweight” category (25-30) are associated with lower overall mortality rates.   This was accompanied by editorial comments about the need for people to calm down about the fact that U.S. in specific and the world in general is getting fatter.    Before taking a deeper dive into the BMI vs. mortality argument here is a link to a post on BMI, and recent overweight/obesity trends in the U.S.

What is the relationship between BMI and mortality? 

The figure below is from a study of almost 1.5 million whites between the ages of 19 and 84 with a median age of 58.   This study has a couple of advantages over the JAMA study especially because it was prospective as opposed to a meta-analysis of prior studies.   However, it is restricted to only one racial group.  The study also shows that the relationship between mortality and BMI does not really “take off” until people get into the obese (BMI > 30) range.  However it is not as reassuring as the JAMA study and mortality does start to creep up in the overweight (BMI 25-30) range.  The study concludes that:

“In this large, pooled analysis of prospective studies, both overweight and obesity (and possibly underweight) were associated with increased all-cause mortality in analyses restricted to participants who never smoked and did not have diagnosed cancer or heart disease. Thus, analyses of this subgroup should be minimally confounded by smoking or prevalent illness. The associations were strongest among participants whose BMI was ascertained before the age of 50 years. The lowest all-cause mortality was generally observed in the BMI range of 20.0 to 24.9. Longer follow-up attenuated the associations with lower BMI levels.”

BMI Caveats

The small increases in mortality for the overweight and mildly obese are somewhat reassuring; but the whole relationship between BMI and health is tricky.  There are high BMI people who have a lot of muscle mass and not much body fat, and there are low BMI people with a lot of fat who have poor health and increased mortality.  This has been termed normal weight obesity, and suggests that low muscle mass can also be a problem.  Low muscle mass might also explain some of the mortality issues in people with very low BMIs (<20).  There are also high BMI people with plenty of body fat who have normal cholesterol and glucose who are “metabolically healthy”.   Thus, there are several patterns of body composition and BMI does is not that predictive on an individual basis.     In general abdominal obesity tends to be a bigger problem than fat other places.   Here is a link to a Wiki site on abdominal obesity that is informative. Finally, exercise can also modify the relationships between BMI and metabolic health in people in the overweight and obese categories.   This is the whole “fit vs. fat debate”.

Mortality vs. Health?

The BMI mortality data does not tell us much about overweight/obesity and health, and this data is hard to come by.   However, there is good evidence that so-called biomarkers of disease risk show a more linear vs. U-shaped relationship between BMI and the marker of interest than between BMI and mortality.   The figure below shows this for men with data from a large national survey.  CRP is a marker of inflammation related to heart disease risk, HBA1c is a marker related to diabetes, and HDL is so-called “good” cholesterol.   The panels on the left were statistically adjusted for age and the panels on the right for age and smoking.   In the long run the increased risk factors associated with higher BMIs will likely translate into poorer overall health for many people.   The authors conclude that:

”These findings imply that obesity researchers should exercise caution when interpreting mortality findings in broader health terms. From a public health perspective, the findings suggest that even moderate levels of overweight may indicate worse health risk profiles than lower body weights, with potentially important implications for chronic disease and health-related quality of life……”

Summary

The relationships between BMI, mortality and health are complicated.  Based on the data above we probably should take the “don’t worry” interpretation of the findings in the JAMA paper promoted in the mass media with more than a grain of salt.  We also need to think about overweight and obesity using more sophisticated measures of body composition, and a one size fits all BMI based approach to these issues leaves a lot to be desired.   The data from the “normal weight obese” and “fit vs. fat” studies along with the very low BMI subgroups in the big population studies suggest that the role of active muscle mass in our overall health is underappreciated.   Finally, people tend to gain weight over the years and many of the overweight of today are likely to be the obese of tomorrow.

This is the time of year where people in colder climates do more indoor exercise.   People also make New Year’s resolutions to get in shape.   Some serious athletes use indoor training year round because it is possible to better control the exercise intensity and the overall effort of the training session on a treadmill or bicycle ergometer.   All of this is easier now than it was 20-30 years ago before the widespread availability of well-equipped fitness centers.

However, indoor exercise can be boring and it is easy to lose fitness this time of the year.   Getting to the gym can be a hassle and short days along with the urge to sort of hibernate during the winter can make finding time to train a bit harder.   So the question is how to get the most bang for your training buck until it gets warmer and the days get longer?

One thing I do is interval train on the Treadmill 2-3 times per week.   I start slowly about 6.1 miles per hour (mph) and then use a saw tooth pattern of increasing speed.   I go up 0.5 mph on the even numbered minutes and down 0.2 mph on the odd numbered minutes.  After about 10 minutes I get to a pace of around 7.7 mph and then do 10 repeats of 1 min at 7.7 mph followed by two minutes of running in the 8.5-9.5 mph range.    The goal is for each of the two minute repeats to be at a faster speed.   In interval training lingo that is known as “descending” the workout.  A Lot of times I increase my pace by 0.1 mph every 10 breaths, so I pick it up during the fast part of the cycle.   Counting your breaths is also a good way to learn to relax while you are running fast.  Using this pattern, the first mile is almost exactly 9 minutes and then I try to do a bit over 4 miles in the next 31 minutes.  The total session takes 40 minutes.

Along these lines there is an excellent recent paper from colleagues in Denmark on the efficacy and efficiency of this type of training strategy.   They asked moderately fit people in their 30s who had been running about 15-20 miles per week to either keep doing more or less the same thing or do three sessions a week of interval training for seven weeks.  The intervals consisted of three or four 5 minute intervals with two minutes of jogging in between.  However, during the fast part of the intervals low-, moderate-, and high-speed running (<30%, <60%, and >90% of max) for 30, 20, and 10 seconds was used each minute.   This is pretty complicated to describe but the figure below shows a typical heart rate pattern for such a training session.  The heart rate shown with dashed lines is higher during 5 minute intervals and lower during the recovery period than during a steady state training session shown with the solid line.  The slight variations in heart rate during the intervals are due to the 30-20-10 changes in running speed.

Key findings included:

• The interval training group reduced training volume by 54% (14 vs. 30 km/wk about 9 vs 18 miles/wk) while CON continued the normal training.
• After seven weeks VO₂max (a key marker of fitness), and performance in a 1,500-m and a 5-km run improved by 21 and 48 s, respectively.
• Blood pressure and cholesterol values also improved more in the interval training group.

The authors concluded that:

“The present study shows that interval training with short 10-s near-maximal bouts can improve performance and V̇O₂max despite a ∼50% reduction in training volume. In addition, the interval training regime lowers resting systolic blood pressure and blood cholesterol, suggesting a beneficial effect on the health profile of already trained individuals.”

Summary

Relatively brief but high intensity interval training is a great way to maintain and even improve your fitness in the winter.  For people with competitive goals it means that you will be ready for more and harder training as the days get longer and warmer and you head outside in March or April.   There is also a growing body data about the value of higher intensity exercise for people of every ability level and age group.    A New Year’s resolution that includes interval training might be a good way to start.

Why there is so much political gridlock in Washington related to the country’s finances?

It is pretty clear that there are plenty of policy solutions out there.   Here is information from the Peter G. Peterson Foundation Solutions Initiative.   This comes from a program in 2011 that asked six think tanks across the political spectrum to suggest approaches to the long term financial challenges facing the United States.   So, the first thing everyone needs to recognize is that there are plenty of ideas out there.

Then why are our political leaders having so much trouble finding middle ground, compromising and “cutting a deal”?   The standard arguments go something like this:

• The country is more polarized than ever so there is little middle ground.
• There are not enough moderates in either party who can cross party lines to make a deal happen.
• There is a media echo chamber so that each side has their position constantly reinforced.
• The current political leaders lack the political and negotiating skills that were once common in Washington that made deals possible.

I have another take and it comes from brain scanning studies and what parts of the brain are activated in people who are interested in politics.   A technique called functional MRI is used in these studies.  Here is a summary of the results from one such study:

“Using functional magnetic resonance imaging (fMRI), we scanned individuals (either interested or uninterested in politics based on a self-report questionnaire) while they were expressing their agreement or disagreement with political opinions….Behavioral results showed that those political opinions participants agreed with were perceived as more emotionally intense and more positive by individuals interested in politics relative to individuals uninterested in politics. In addition, individuals interested in politics showed greater activation in the amygdala and the ventral striatum (ventral putamen) relative to individuals uninterested in politics when reading political opinions in accordance with their own views. This study shows that having an interest in politics elicits activations in emotion- and reward-related brain areas even when simply agreeing with written political opinions.”

The take home message for the authors was that:

“…..increased amygdala activity in individuals interested in politics for political opinions in accordance with their views may be related to an increased emotional intensity associated with the sense of belonging to a social group and/or the importance of their beliefs to constructing a positive sense of self.”

If you think about these results and the explanation above, perhaps they explain why it is so hard to compromise and negotiate.   Activation of emotional parts of the brain might make it hard to get past your own world view.  There are other interesting findings about how brain structure differs in conservative vs. liberals and how they process political information differently.

Finally, motivated reasoning is a term used to describe biased information processing when people have an emotional stake in the outcome.  It is interesting to note that there is also brain imaging evidence to suggest that political thinking activates specific areas of the brain involved in motivated reasoning distinct from the areas involved in cold or unbiased reasoning.

Based on the ideas presented above it seems to me the issue in Washington is Brainlock and not Gridlock.   I wonder if there are training programs or other techniques that politicians and pundits on both sides could use to increase their mental flexibility.

The obesity epidemic and what to do about it has been a major focus of this blog.   Plug in OBESTIY to the key word search tool and a large number of links show up on many elements of the obesity problem.  Except for the ideas that exercise can modulate the negative health consequences of obesity, limit the impact of obesogenic genes, and play a key role in helping real biggest losers, there is not a lot of good news on the obesity front.

However, there were reports earlier this week that childhood obesity is dropping in some cities in response to comprehensive nutrition and physical activity programs.   Here is a link to a longer report from the Robert Wood Johnson Foundation.   The report concludes:

“Growing evidence suggests that strong, far-reaching changes—those that make healthy foods available in schools and communities and integrate physical activity into people’s daily lives—are working to reduce childhood obesity rates. More efforts are needed to implement these types of sweeping changes nationwide and to address the health disparities gap that exists among underserved communities and populations.”

There are also new ideas about how social media might be able to help fight childhood obesity.  This is an important idea because evidence from the Framingham Study shows that weight gain in our friends is a critical risk factor for weight gain in us!   They followed social connections between and among about 12,000 people for over 30 years and found that:

“Discernible clusters of obese persons (BMI>30) were present in the network at all time points, and the clusters extended to three degrees of separation. These clusters did not appear to be solely attributable to the selective formation of social ties among obese persons. A person’s chances of becoming obese increased by 57% if he or she had a friend who became obese in a given interval.”

The idea is that the same social forces that make obesity “contagious” might also be used to make healthy choices and behaviors contagious.   There is also increasing evidence that food pricing strategies (e.g. sugar and fat taxes) will work to improve nutrition and combat obesity especially in low socio-economic groups.  This is important because these groups have been relatively resistant to other public health efforts directed at obesity.

When you look at the data and ideas described above and discussed previously, it seems to me we need to do the following to turn the obesity epidemic around:

• Adopt the strategies outlined in the Robert Wood Johnson Report nationally.  Like smoking, if we stop obesity early in life it will pay off in middle age.
• Develop comprehensive programs to promote physical activity.  Some of this is about urging people to exercise more.  Some of this is about urban design and planning to make the world friendlier to physical activity.   Most of us live in places that are car friendly but not walking or biking friendly.  This is critical because weight loss is hard and physical activity can prevent weight gain, help with weight loss, and blunt the negative health consequences of obesity.
• Increased public education programs.
• Interventions that increase the cost and/or reduce the portion size of obesogenic foods like sweetened beverages.   This would include so-called sin taxes.
• Use social networking tools to define what is normal and reduce the “contagious” elements of obesity.  They could also be used to increase the contagious elements of fitness and normal body weights.

Summary:  the news on obesity is not all bad and strategies that work are beginning to emerge.   If they are applied widely over the next 20 or 30 years perhaps the obesity epidemic can be stopped.   It is a matter of both our individual and collective cultural will power.

The recent deaths of the legendary jazz musician Dave Brubeck just short of his 92nd birthday, and the great Brazilian architect Oscar Niemeyer at 104 got me thinking about the relationship between creativity and longevity.   These men were among the most creative people of the last 100 years and they remained productive and engaged into old age.   Was there a connection?

In a U.S. Veterans administration study on personality traits, aging and mortality in 1349 men, a 1 standard deviation increase in markers of creativity was associated with a 12% reduction in mortality risk.   The figure below is from a study on personality traits and all-cause mortality in the Edinburgh Artery Study which included 1035 subjects in their 60s or older who took a personality survey in the middle 1990s.  It shows that the subjects who scored highest on markers of openness to new experiences, which is one element of creativity, had much higher survival rates than people who scored lower.

 The authors of conclude:

“During follow-up, 242 (37.1%) men and 165 (24.6%) women died. For the whole sample, there was a 28% lower rate of all-cause mortality for each 1 standard deviation increase in openness and an 18% lower rate of all-cause mortality for each 1 standard deviation increase in conscientiousness. In men, the risk of all-cause mortality was 0.63 for a 1 standard deviation increase in openness and 0.75 for a 1 standard deviation increase in conscientiousness. In women, none of the personality domains were significantly associated with all-cause mortality. Well fitting structural equation models in men (n = 652) showed that the relationships between conscientiousness and openness and all-cause mortality were not substantially explained by smoking, or other variables in the models.”

These observations are certainly consistent with life stories of Brubeck and Niemeyer.   It is also interesting to note that the protective effects of openness and creativity seem to be more pronounced in men.  They also seem to interact with conscientiousness which can be seen as an ability to take good care of yourself by paying attention to your health.  As more research on personality and healthy aging emerges it will be interesting to see if these divergent results for men and women are confirmed.   It will also be interesting to learn if we can train people to be more open and creative to promote healthy aging.   Last week I reviewed the data on what happens when elite endurance athletes remain highly active into their 80s, and in earlier posts I have reviewed the positive effects of physical activity and exercise on longevity.   Maybe fitness and exercise interact with openness and creativity because older fit people are able to try new things and live in what might described as a bigger and more stimulating world.

Enjoy the classic video clip below from the 1960s showing the Brubeck and band playing his signature composition “Take Five”.   Brubeck is on piano and Paul Desmond is playing the sax.

click here if needed for video