Humans: Extreme Adaption

One of the amazing capacities of the human being, is it’s ability to adapt to its surroundings and extreme stress placed upon it.  The human being can transform itself to improve it’s chances of survival against extreme stressors, like starvation, heat, cold and sleep deprivation.  Through real-time aggregation and analysis of nervous, hormonal, chemical, psychological  and conscious information inputs – the human body dynamically shifts and learns to accommodate new stressors placed upon it.

Extreme Endurance exercise stress is no different, where a cascade of physical, physiological, enzymatic, hormonal, neuro-transmitting and bio-chemicals shift – resulting in a body that is tuned to go longer.

In my Naturopathic medicine under-grad studies we were educated on the holistic integrated nature of the human body and it’s systems.  However, we need to keep grounded in the the realization that the human body isn’t one system, but it’s one body of many integrated systems.

This is important, as it helps us understand how to manage  the fine line of extreme endurance exercise, diet and lifestyle being ‘health-giving’, versus ‘exhaustive’, versus it being down-right ‘abusive’. I’ve experienced each of these three outcomes several times over, in living the ultra endurance lifestyle for the past 30 plus years.

Now, generally speaking the medical and scientific community collectively agree that the stress of aerobic endurance exercise is a good thing, making the species stronger and holistically healthier…but is it that simple, are we endurance athlete types super human – immune to all disease?   Not so fast.

Rapid Intensity Change: Training Stress

Maybe a simple example of understanding these integrated discreet systems – would be how endurance exercise trains the body systems, at different rates and speeds.  Most endurance athletes (particularly seasonal racing athletes) would know, that cardio-respiratory fitness returns faster after restarting training (new season), than does musculo-skeletal strength.  The same stress (aerobic exercise) can trigger quiet rapid changes to the efficiency of how blood-oxygen is delivered to cells, carbon-dioxide is removed, lactic acid is handled.  Yet over the same period, under the same stress, in the same person, the adaptions in strength made in joints and soft-tissues typically takes longer.  And it’s precisely in this difference of ‘adaption-speed’ that the ‘heart and mind’ want to train more and train faster…yet the joints and soft tissues aren’t ready for it.   It is here that many repetitive soft-tissues injuries are born – where the body crosses the line between well-being, ‘exhaustion’ … and if continued, ‘abuse’.

Lifelong Endurance Exercise: Heart Stress

At the turn of the century, studies were beginning to be published, suggesting that life-long endurance exercise (repeated extended stress) raised the risk of atrial fibrillation (AF).  Just this month, in an article titled “State of the Art Review: Atrial Fibrillation in Athletes”, researchers point out that  the type, intensity and amount of the sport being causative to influencing the risk of developing AF. How much endurance exercise is done over ones lifetime is a risk-factor, where as a female-gender seems to have  lesser risk.  Over time the study highlights, various remodeling of the heart, plus inflammation and changes to vagal-nervous tone.  Interestingly, we are seeing studies going deeper into AF, like diet, and specific foods like chocolate consumed – and how they may reduce the risk…but clearly more research is needed here.

Repeated Sugar Spiking: Metabolic Stress

Prediabetes and Type 2 Diabetes (T2D) continues to grow in prevalence with now 86 million  Americans believed to have prediabeties, based on a CDC report.  90% of prediabetics don’t know they have it, and upto 30% of them will develop type 2 diabetics within 5 years – if no weight loss or moderate physical activities are adopted.

However, while exercise improves fat oxidation and insulin sensitivity (lowering T2D risk), research is showing that in 15-20% of people, glucose tolerance and insulin sensitivity does NOT change following exercise training intervention.  In a more recent study published late last year, researchers again found a wide variance, in exercise intervention improving insulin sensitivity, and calling out a significant proportion of people being ‘non-responders’ to exercise.

This is a red-flag for endurance athletes, with a false sense of security, blinding the athlete to believe they are immune to the diabetic risk.  This concern, in our view, is further compounded when the simple-sugar-consumption volume of endurance athletes are considered.  In our report, we think a significant number of endurance athletes could be spiking their blood-sugars several times daily, and it not inconceivable that they could be consuming the equivalent of over 100 teaspoons of simple-sugars per week.

Then to make this risky metabolic stress even worse, two irresponsible studies have been published just this year, focused on training the gut to accommodate more sugar loads (and spikes) for endurance sport training-racing.  Physiology and consumption methods are explored in a forced attempt to help the body ignore the clearly natural repulsive reaction of the gut to high dose simple sugar/carbs. Gut symptoms and reactions in endurance sport, is still the number 1 reason for not finishing an endurance race – our report on this is here.

But again, this is not simply about transient sugar gut symptoms stopping an athlete completing their race (hospitalisations are not uncommon, by the way).  There is something far more sinister at work here.   This is about potentially heightening the risk and predisposition to become a victim, to possibly the largest epidemic of the 21st century – diabetes.  A condition where high sugar in the blood increases the risk of blindness, kidney failure, heart disease, stroke and loss of limbs.

Endurance athletes only have to pick-up their preferred magazine, search google or facebook groups to find increasing frequency of published articles, or athlete groups talking through a lower-carb higher fat based approach to fueling, in training, racing and their diet lifestyle.

A Final Enduring Word…

There are some aspects of endurance exercise – that we put up with, like training load, and over-use injuries. We train, we get the balance wrong and we course-correct….for most of us – this is not a problem.  

Then there is this emerging data suggesting life-long endurance sport may heighten the risk of conditions like atrial fibrillation – and clearly we need more data and research done on why this is, and what to do about it.

Finally, we have a sea of data on the risks of high sugar consumption, type 2 Diabetes and chronic disease risk.  And furthermore, new emerging research that shows us, that exercise alone may not make all of us immune to the metabolic stress of prediabetes and diabetes proper. Safest bet, reduce/minimise the sugar.

Thanks for reading.