Want a sure fire way to feel old?  Re-do your life insurance!

 

I just went through this painful process with my wife.  We each had to do interviews with the insurance adjustor and were told we were going to have a nurse come to the house to do a mini medical (blood pressure, urine, and bloodwork).  My wife completed hers and in yet another reminder that I ‘married up’ she was informed because of how darn healthy she is, she qualified for the super low risk category reserved for the top 5% or so in terms of health for her age range.

 

I finished my interview and waited for the call to schedule a medical.  I waited.  Then I waited some more.  Crickets.

 

I ended up calling the insurer asking why I hadn’t even had a call to schedule a medical.  After some digging I was informed that a medical wasn’t necessary as no matter what I qualified at a fairly normal category.

 

Well I obviously couldn’t let my wife get away with being deemed the healthiest in the family so I demanded a medical to try and qualify for the lowest premium category too.  It was my spousal duty!

 

I was told that wouldn’t be necessary.  The explanation?  My family medical history.

 

Because my father is a colon cancer survivor and my mother has had lifelong hypertension, and some TIA’s, I couldn’t move up to the lowest premium category no matter how well I scored on a medical.

 

After stewing on this for a while and crowning my wife the Kissel health champion, it got me thinking about the best way to make changes in my life now to ensure my kids have a chance to be more like their mom.

 

Compounding can be a life changing phenomenon, specifically in finance and wealth creation.  But what about the compounding effects on health?  Does lifelong proper sleep habits have a compounding effect to your health later in life, where sleeping well over decades has a compounding effect on your well being?  What about nutrition?  How about cardiorespiratory exercise and strength?  Specifically it got me wondering about how much the choices we make in regards to fitness at a young age affect our health status at a much later age.

 

Lucky for me, an extremely influential paper was just published that answered exactly these questions.  On top of that, it was able to use real life health testing from the 1970’s and 1980’s and see how these people fared decades later in life.  This was a proper cohort study which are considered both extremely high quality and extremely rare due to the obvious difficulties present in following a study population for that long (in this case 40 YEARS!!).  No fancy computer modelling to determine an outcome.  This is straight data.  Measure someone when they are young.  Then measure the same person again when they are old to see what happened.

 

So how did this one come about?  Through war!  In the 1970’s and 1980’s conscription was MANDATORY for the Swedish Military for young men at age 18.  They did all kinds of health testing of Swedish male adolescents at the time of conscription.  In fact, this encompassed between 82-92% OF ALL Swedish men.

 

Then, more recently there has been one of the largest research collaborations ever taking place in Sweden in a joint venture with 6 universities that are aiming to predict AND prevent cardiovascular and pulmonary diseases.  This is called the SCAPIS trials and for this one they have been doing cardiac measures on nearly 10,000 males in Sweden, including Coronary Artery Calcium (CAC) scores and measuring carotid plaquing via advanced imaging.

 

The incredible, but unintended consequence of this trial is that nearly ALL of these men measured for the SCAPIS study had fitness testing and measures done in the 1970’s and 1980’s when they were conscripted into the army!  Voila!  An incredible data set where they could see fitness levels of men aged 18-20 and then see how their cardiovascular health and plaquing ended up 40 or 50 years later!  This is the equivalent of a nerds superbowl!

 

My other random thought in reading this study…….thank goodness that nobody threw all this data out from the 1970’s!!!  Remember this was largely pre-computer.  These would have been hand written fitness measures on the entire Swedish male population for that age cohort.

 

The purpose of the study was to examine the associations between cardiorespiratory fitness and strength as an adolescence and coronary or carotid atherosclerosis in middle age.

 

Now before you read on I will ask you to pause for a moment and make a prediction on the outcome.  Do you think that cardiorespiratory fitness (measured with a maximal bike test) or strength (knee extension machine) was predictive of atherosclerosis later in life?  Is one more predictive then the other?  Neither predictive at all?

 

A little foreshadow….the results are a bit surprising.

 

But first, why is this study so important?

 

Cardiovascular death is still the #1 leading cause of mortality worldwide.  Atherosclerosis (inflammation affecting all arteries) is the principal pathway that cardiovascular death occurs.

 

Atherosclerosis can be subclinical, presenting as plaquing in the walls of arteries, or it can be clinical via TIA’s, strokes and heart attacks.  Plaquing, if caught early, is a marker of future cardiovascular disease and is still the best predictor of cardiovascular events.  That means early prevention and identifying ways to either lessen plaquing or better yet preventing it from beginning are super important.

 

It should be no surprise that cardiorespiratory fitness has a strong link in reducing plaquing.  In fact, the American Heart Association now recognizes cardiorespiratory fitness as a ‘vital clinical sign’ due to just how strong this association is.  That’s great in theory, but when was the last time you did a cardio test at your doctor’s office!  It’s usually saved for a treadmill test once a problem is already found.

 

It’s also been shown in past studies that strength actually has benefits to atherosclerosis, though cardiorespiratory fitness is still thought to be better. (Spoiler alert…..this study may change these thoughts slightly).

 

Again, these are all measures done AT THE SAME TIME.  Meaning let’s test somebody’s cardio and strength.  Then let’s put that person through a Coronary Computed Tomography Angiography (CCTA) test that gives a very comprehensive measure of atherosclerosis throughout your body and establish the relationship.

 

That’s great…..but we has never been studied is how your cardio and strength levels in adolescence are able to predict atherosclerosis later in life.

 

The sample size used in this study was massive.  In fact, they ended up with 14,646 older males in the SCAPIS trial mentioned above, and shockingly they found fitness records from conscription on 8,986 of them.  Better still, the average follow up from data at conscription to the SCAPIS study was a full 38.2 years.  Incredible!

 

The cardiorespiratory test used at conscription was an electrically braked cycle ergometer test that went up 25 watts per minute and you had to go to exhaustion keeping the bike at 60-70 revolutions per minute.  A brutally difficult test that is no longer used regularly.

 

For strength they did knee extension strength, handgrip and elbow flexion.

 

The results:

 

Generally for the SCAPIS participants, the mean age was 56.5 years and 52.6% of participants had definable coronary stenosis (meaning the arteries had smaller diameter) and 58.8% had carotid plaques.

 

They then split the participants fitness levels into 3 groups (tertiles) of fitness meaning low, medium, and high.  They did the same for strength.

 

Cardiorespiratory fitness

 

In general, as you can see from the graph below, there was a trend towards an inverse association between your fitness level and your CAC score where the better your netness, the lower your risk.  In fact, they found that when compared to the lowest 1/3^rd of fitness, those in the medium and highest thirds had 18% and 22% lower odds for severe (>50%) coronary stenosis.  No surprise here.

 

What was surprising (to me anyways) was that there was no clear association between where you ranked in cardio fitness and the amount of stenosis if it was under 50%.  So there did not seem to be an association between your cardio fitness and mild to moderate stenosis.

 

Even more surprising was that for carotid atherosclerosis, those in the middle and higher thirds of fitness actually had 18% and 17% HIGHER odds for unilateral carotid plaques but there was no association for plaquing on both sides.

 

 

Muscular strength:

 

This one had a MORE CLEAR PATTERN where there was a negative association between strength and severe coronary stenosis (>50%). This time however there was no clear association between strength and carotid plaques.  So no worse but also no better.

 

 

 

 

 

What about cardio and strength combined? 

 

The effects were the same, just amplified.  Those in the highest third for strength and cardio had 33% lower odds of severe stenosis and a better CAC score.  But again, they didn’t have a change in odds for carotid plaques.

 

What have we learned?

 

• This was a rare, large population based study that shows an inverse association between cardio fitness in adolescence and coronary atherosclerosis, particularly severe almost 40 years later.
• Strength showed an inverse relationship with severe coronary stenosis but also with high CAC scores in middle age.
• Neither cardio fitness nor strength was robustly associated with the presence of bilateral carotid plaques.
• A combination of both cardio and strength was the best.
• An interesting note was that those in the absolute highest cardio level (95^th percentile and higher) actually had an INCREASED burden of coronary atherosclerosis. This suggests a “U shaped relationship” where having too high and too low are both considered bad.  BUT, one caveat…..when you read the paper you see that the confidence interval for this part of the study was very high (which is bad), meaning you can’t draw such strong conclusions for this finding.  Although it was an interesting finding (having too good cardio predisposed some to atherosclerosis).

 

The overall take home points:

 

This can largely be summarized in 2 statements:

• You do not want to be in the lowest third of cardiovascular fitness early in life to stave off negative effects of stenosis and atherosclerosis later in life.
• Combined cardio and strength seems to be best.

 

I finished reading the study wanting more.  There were a few significant limitations, such as only having males as study subjects, but the authors noted in the 1970’s and 1980’s, only men were forced into conscription in Sweden.

 

It also only points out a single time in life and follows people later.  Ideally, it would have also measured the subjects fitness every 5 years to see how they ended up.  I’m certain in the study population there were people in tip top shape at the age of conscription, then ‘let themselves go’ in the next few decades.  Conversely, someone may have been horribly out of shape at age 18, and then through the army they ‘found their fitness’ and got in great shape.  This study would not have captured these changes.

 

Either way it was a fun study to read, and really shows the concept of ‘compounding your health’.  Being in shape and exercising even at a very young age, pays massive dividends later in life.