Don’t Call it a Comeback!

MY PERSONAL EXPERIMENT + RE-IMMERSION IN THE WORLD OF IRONMAN TRIATHLON

Advanced warning : This is a long read ;)
I like to convey key relevant points from people and then one can choose whether to dig into the detail.

  • Knowing Thyself Matters.

  • I’m “Data-Driven” and have benefitted on a physical and psychological level from getting to know my biochemistry, and using that to inform specific supplement use, dietary changes and natural hormonal support.

  • The reason I am so passionate about this is that I myself spent many years pushing through running a tank 1/2 empty because my mental tenacity over-rode the physical signals and standard NHS blood tests & medical advice gave me little insight into why I was feeling so blah.
    And since I established Curoseven, now Fibr Health, I have tested circa 1000 athletes and all have derived some benefit from “knowing their numbers” and being told what to do with them.

  • For me, this means was a series of blood tests over a time (I can take my own blood so I’ve done a few interesting experiments!) perhaps a “DUTCH” hormonal and adrenal test, 3 Gut Health Tests, Genetic Analysis - 23andMe + Strategene.

  • PLUS numerous hours studying learning and immersing in the field to become an ‘expert’ in performance-orientated integrated medicine. Which essentially means putting all that data in the context of your life and informing day-day nutrition, exercise and lifestyle habits.

  • Think of it as “Strava Medical.” (And watch this space ;)

  • I was initially inspired by Ben Greenfield’s “beyond training” book and since Alex Hutchinson’s book. Very different viewpoints but both insightful and Ben’s with some practical - if not slightly eccentric tips.

Tamsin Lewis Triathlon 70.3 Mallorca.png

For many people, they exercise for the pure joy - perceived health benefits and the euphoria of the finish line. But for those who like to push hard, challenge perceived limits and still live a full life, I do believe you can achieve more for less if you take a data-informed (at least initially) approach with the guidance of a skilled health-coach/practitioner.

In the context of looking at developing an intuitive awareness about how you adapt to training, it’s about what makes you feel good and what doesn’t.

Spend less time training alone & more time with your tribe & the training hours fly by and your stress hormone levels will be lower if you train with a crew. (Well if you like the crew! Think mine were substantially higher training with Bella Bayliss back in the day - #justdothework ;)

Back to the Story!

“You can do it Tam, but at what metabolic cost”…. The words of PhD metabolism expert Alessandro Ferretti. Who knows me and my health data well! He also knows that my ‘training in the past 2 years is largely a 20k round cycle commute & a splattering of ad-hoc runs, swims and impromptu squats.

Just Because We Can: Doesn’t mean we should.

THAT rabbit hole.

I’m drawn back to triathlon because I spent 6+ years (yep I was late to triathlon) swimming, biking and/or running most days. I got quite good at it.

However, there’s very little balance though in the tri-world if you want to compete at the pointy end and that is what drives my now cognitive dissonance about returning to the sport.

It is all-consuming.

Which is the point: physical exhaustion silences that monkey mind - but when unable to exhaust oneself the monkey just pops back up, unless of course we get a few more “legs under the table” i.e. other strategies to deal with our overthinking.

Triathlon came into my life and saved me from a series of destructive behaviours which consume many of us - borderline multiple mini-addictions, none of which on their own meet criteria for a systematic diagnosis but when you try to stop them you realise how strong is their hold.

And of course, one of the most accepted addictions is that of exercise addiction - because of its perceived associated with health. And the more you do - the more you are championed by your peers and society.

Because wow, not just anyone can swim/bike run 20+ hr weeks.

Now, in retrospect, the people I admire most in sport are those who are not performing at all costs - but who give time to the community, inspire others and give insight to a wider audience about how to excel not just at sport but at life.

I also think those who maintain longevity in the sport practice the following:

  • Retreat to their Cave and Recuperate

  • Don’t follow the crowd or the latest fad

  • Know Thyself

  • Have other “legs under the table” - classic examples are Nicola Spirig and Lucy Gossage, Jessie Thomas. (Lawyer, Doctor, Entrepreneur = Passion, Joie De Vivre, Bigger Picture)

  • Experiment and track systemically objective and subjective markers under the guidance of a trusted coach/mentor/scientist.

  • Don’t repeatedly beat themselves up when they don’t meet targets. Reframe, Re-adjust, Re-Set, Go again.

  • Have a sensible - non-orthorexic approach to eating and food. Focusing on nutrient density and caloric sufficiency. Strategic supplements which are targeted at specific concerns/outcomes.

So Fast Forward from winning Ironman UK in 2014 my last triathlon - April 2018.

Look, Feel, Do.

Look: On Holiday April in Alcudia with family.

Met my former coach & tri-legend Brett Sutton, saw signs for the race, became nostalgic.

Sun loungers have only ever been attractive to me when physically exhausted. And my ADHD needs a bit of a firehouse approach (much better now).

Hired a bike - rode the race climb - multiple times — seemed to get faster each time as muscle memory cogs slowly re-oiled.

Summiting the climb full of endorphins memories of being in the lead on the bike on the climb in 2014 engulfed me.

Looked at Strava times - waaaay off.

Mind willing, the body didn’t know what had hit it - but it alighted a spark.

The race is sold out so I assumed entry would not be possible - but a friend of the race organiser - managed to squeeze me a last minute entry as a F35-39 category.

Surely, I could get around.

I genuinely did not think about the logistics until the 4 days before the race.

The wetsuit was mouldy, friends borrowed bike didn’t fit, no aero shoes or helmet.

Quite refreshing though.

No pressure, just an underlying anxiety of “can I really do this” with no formal training.

To clarify so people don’t think I am a goofball.

I am active. But other than the London Marathon in 2016 & a few 1/2 mara’s, I’ve not competed.

Multiple reasons - a bit of context given at the start of this blog wider audience so will touch on them later, but boils down to an evolving hypothesis that training for endurance events in the context of a busy mum/work/entrepreneurial life was detrimental to my long-term health - which I increasingly had evidence in my medical tests & health tracking data to support.

I cycle to work and around London (which my former coach actually used to refer to as anti-training - as the low-level physical stimulus + pollution exposure was tiring me rather than triggering any desired adaptation to my fitness).

But needs must - it’s the quickest way to get around & I feel free. The caged animal look on public transport kills a small piece of my soul.

Running - ironically - had been the first thing to go. Bizarrely, I felt it inflamed rather than invigorated me. So I went for many months with no running at all with the odd 10k at the weekend in Richmond Park.

Swimming - which used to be a grind - the chlorine exposure, the nose to the black line - the sets - those 30 x 100’s - the squeals from Brett Sutton of “you only THINK you’re fucking tired”…. Actually became a love, but mostly because I moved back to Barnes (SW London) where over the bridge they have a 25m outdoor pool which is generally quiet, heated year round & low on chlorine.

The immersion in water has immense healing effects on one’s nervous system which has long been dialled towards fight or flight…

So I would swim - incorporating some hypoxic breathing work (breath holding) as I listened to pal, Ben Greenfield (who’s every living moment is biohacked - for better or for worse), talk about the benefits to the brain - BDNF stimulation via Noradrenaline release.

Certainly, a pseudo-euphoric effect, once you push through initial discomfort & it prob makes you fitter for less overall work. As we think all hypoxic and blood flow restricted training does.

On this note - saw a chap in Richmond Park running in an altitude mask this weekend - a bit of a change from the Rapha-Clad MAMILS - Performance Hacks for the masses is seeping into our culture! (Even if Richmond Park is a rather unique upper middle-class SW London demographic).

Rewind: Bolton, UK 2014

The last triathlon event I competed in was Ironman UK 2014 as a pro athlete.

This was my first attempt at the full Ironman distance & unbeknownst to me at the time I was approximately 12 hours pregnant when I won.

As highlighted upon recently and explored humorously with TV presenter Tim Lovejoy.

I’ve written about my roller coaster ride as a pro which thankfully had a euphoric ending when I crossed the line in Bolton that day. Genuinely brings tears to my eyes remembering the crowds that day.

Fast forward 4 years.

Ironman 70.3 Mallorca.

I’ve competed in this race 3 times. And each time a different experience.

An enlivening battle for the podium with Dr Lucy Gossage, some uncomfortable conversations with former doped athlete & last time in 2014 - the fittest I’d ever been (still hold some proud Strava QOMs from this time) - my race was swallowed by “goat gate” which still gets a comedic but cautionary mention at the race briefing.

The motto of THAT story is predicting the behaviour of goats is not reliable. Unless - I assume - one is a goat boy.

The day before the race I met with a friend and pro triathlete Caroline Livesey - we had a mutually un-satisfying lunch - my chicken was off & her salad was full of beastly onions despite requests to the waiter for onion-free cuisine.

She helped me cobble together transition bags where I had a mini panic that I had no race laces in my shoes or indeed any race shoes.

The morning of the event - the calm before the storm. Genuinely no nerves - so refreshing. Donned wetsuit for the first time - had a quick dip - lined up for my first rolling start & away we went.

The dulcet tones of a voice now synonymous with Ironman - Paul Kaye - prepping the competitors for the challenge of the day ahead.

“Feel the Fear but do it anyway” has always been a motto of mine - but for the first time in my life - I did not think about the day ahead - just stayed in the moment.

First buoy - turn around point - a few unaccustomed cramps in my calves and toes - probably as not used to being squeezed by tight wetsuit… swim exit... crowds … SMILE. ….transition… A u t o p i l o t

Enjoy the ride … no pressure.

Ironman70.3 Mallorca Bike Lead

And there I was on a road-bike - no TT bars, with Giro road shoes trotting along the pollenca waterfront with swathes of TT bikes passing me.

I was out of the water towards the front of the field which surprised me given I felt I floated through it - with an average HR of 127. I generally - like many of you - have one set gear in the swim & in the sea in a wetsuit find it difficult to kick to accelerate - so any acceleration would have to come from arm speed and hip ‘thrust’. (Thanks Tom)

I thought - this might be the longest time I have ridden a bike without either talking to someone via a handsfree or listening to some educational podcast. Which in itself was revealing - the essence of being mindful.

Now Focus:

Breathing, cadence, aero as possible. Alone with thoughts. Control them. This is emotional.

I often count when I want to quieten my mind and get stuff done as I am prone to distractibility with my adult ADHD diagnosis (post head injury - attributable to brain inflammation) “One, Two, Three … moving forward but in the moment” (n.b I do not take medication)

Bit of an achy chest - sharpish pains which I had to convince myself were muscular - as a result of the restrictive nature of swimming in a wetsuit not cardiac.

I did a mental check on breathing… normal….

Heart rate - through the wonderfully inaccurate iWatch - was teetering at 135-140. Not in Atrial fibrillation (abnormal heart rhythm common in (cough) ageing athletes) then… phew - the perils of being a doc & knowing what can go wrong.

Especially when exposed to an ‘unaccustomed stressor” Air Hunger can occur when your fight/flight system - sympathetic nervous system - is on overdrive.

The Vagus (Parasympathetic nerve) is under-firing. Practice activating it, Belly Breathing. Heart Math. (Inner Balance) - as heard in Tools of Titans.

Climbing is where I come alive.

The enforced effort with gradient alongside my natural aptitude and body composition feeds my soul.

Riding a road bike in this race - a decision made because I haven’t ridden a TT in 4 years plus to me, it took the pressure off.

Hitting the bottom of the Lluc climb I started to reel in the TTers and the competitive voice whispered… wouldn’t it be cool if you were first over the climb. And at that moment James Mitchell - in his role as race photographer - pulled up alongside me on a motorbike and said I was the first woman.

Now in hindsight, having not started in a rolling start before there could have been some super fast people behind me.

I started with some women - not at the front - but perhaps a few minutes in. In hindsight, it would have been better to start further back and have more of a legal draft on the bike - but as said - this was an outing, not a competition.

Up and over the climb - ticked off the goal of summiting first - gave myself a pat on the back…a little bit of an effort - but careful not to get too trigger happy. Then clear roads for the descent and the awesomely slick cornering of the Pinarello Dogma made for a joyful ride.

The back 1/2 of the bike course is mostly flat which on a road bike, on your own in the wind, is fairly demanding on the physiology in comparison to the seemingly restful position of a TT.

There is a tension in your triceps and shoulders which goes under appreciated, from an overall metabolic cost perspective as in how much energy you are burning through.

I tried to emanate Froome with elbows on the drop handlebars until my hands started to tingle.

I was out on my own for a fair portion of this part of the bike course with the odd Uber-biker steaming past in aero tuck.

I’m OK with being alone - but actually the more time I spend away from competitive sport - the more I realise that I gain energy from people - being with them - learning from them, bantering with them, encouraging them.

I’ve spent many hours looking at the long winding road which brings clarity but also perspective on personal desires.

The Monkey Mind.

Legs started to ache a bit in last 10k on the marshes road back towards Alcudia - riding into a headwind on the drops.

Still staying in the moment.. not thinking about the run, other than to tell myself that I didn’t HAVE to run.

At this point, it was becoming clear - that I would be first off the bike and THAT was enough… I would have surpassed my expectations, having been years since I’ve done a sustained effort on the bike.

This felt fairly awesome, but my monkey mind kicked me, reminding me that this was an age-group only race, that I HAD been a pro and with this thinking, I began to feel a bit embarrassed and that took me to a place of mental conflict.

I knew I had not prepared for this race, was not what I considered ‘fit’ & genuinely wanted to do the race as a personal challenge just to see what was possible.

But would others not simply see this as sandbagging?

My physique is often commented on - as I am lean - which automatically people equate with fitness. Actually to me - being uber lean is not a healthy state & is associated with a host of negative hormonal perturbations which definitely aren’t supporting healthy longevity.

High-Stress Hormones = breakdown & I’ve had high cortisol levels are long as I’ve been measuring them (>10yrs). Explain more later.

Cortisol is anabolic (builds) to belly Fat and catabolic (breakdown) muscle. To put this in context for you. When Cyclists are caught taking Triamcinolone (Kenalog) for “allergies” it is used a performance enhancer for one reason that it can strip weight - and it also is essentially hormone replacement therapy (HRT) for the adrenal glands.

The Adrenal Glands are certainly worked hard as athletes - esp. endurance athletes - and we run high cortisol levels consistently for years - more so if you are under-fuelled calories wise and nutrient density wise (Zinc, Magnesium, B Vits - Quality, Dose, Timing, Matters!) having irregular periods (women) and low sex drive in men.

Note: Keto/High Fat.

Low Carb diets in athletes raise cortisol levels reflecting metabolic stress. I am not anti-strategic Keto - LCHF diets - BUT they are difficult to get right for athletes - ESPECIALLY women.

Nourish Balance Thrive have talked about this on their podcasts - as have I on Endurance Planet.

Nutrition.

In my medical consultancy work with performance athletes, a key piece of (now very common) advice is always practice the nutrition strategy ahead of the race in race simulated sessions.

This is especially important if you have a sensitive gut - and increasingly I am finding (through testing/treating the gut) that most athletes have dysfunction therein.

My mentor and Performance MD Dr Tommy Wood, coined it the ‘chronic hypoxic gut of the endurance athlete’ - which essentially means we spend long periods of time with compromised blood supply to the gut - its busy in the muscles fuelling and shuttling away by-products of exercise.

This can result in impaired gut resilience, immunity, inflammation and absorption ‘issues’.

For some, they get away with it - for others, you may have a predisposition to tummy troubles - perhaps from overzealous use of antibiotics, lack of breastfeeding, a poor diet, or like me years of abuse as a medical student - booze/bulimia/bagels!

I have always been a ‘wing-it’...if you live life on the edge you’ve got to be prepared to fall off from time to time…

I’ve always been prone to under-fuelling given my history with ED - non-intentional but the mitochondrial efficiency means you CAN burn fat for fuel to a relatively high heart rate hence reducing reliance on carbs.

However, this does not mean one cannot benefit from consuming carbohydrate especially if heart rate nears threshold and carb intake has been shown to reduced perception of effort - EVEN as a mouth rinse (spit don’t swallow) - tricks the brain into thinking you have carb intake - I’m now visualising mice pressing on levers in cages to get more sugar delivered - dopamine drive - mainlining into the feel-good centres of the brain.

I should have thought about this pre-race, as an effective strategy would have been to suck on sour haribos - or at the very least shot blocks.

Instead, I ate a banana, washed down with a couple of charcoal capsules (helps settle the stomach) with the carb drink handed out on the course.

My previous nutrition strategy was 4-5 gels (2 with caffeine) in one 750ml bottle diluted with water & the other bottle dilute electrolyte drink sipped over the bike leg. 4 Charcoal capsules.

Off the bike into T2 First Lady - this was fun! Had no idea how legs would feel … but they just went into autopilot.

I had no race laces so sat and tied my shoelaces - it was somewhat refreshing not rushing... which was the theme for the run.

Immediately I felt my stomach knot & felt crampy a situation which resonates highly with many triathletes. Practising running off a well-fuelled bike is essential race prep and having not done this & having a less than robust gut I paid the price.

For the first time ever in a race, I visited a portaloo and had a proper pee. It felt indulgent!

Rather revolting when one thinks about it but many pro’s just pee in their shorts in short bursts which makes for a fragrant after-race massage experience.

That monkey-mind again.

Running past the finish line on the first lap, the voice of Ironman welcoming me back to the sport…leading the race...I felt a little embarrassed.

I had honestly thought I would be trotting around mid-pack and be relatively incognito in the crowds & the dissonance between wanting to be invisible and wanting to re-immerse in the pointy end of the sport became very tangible.

It was at that point, I decided I would just run 10k and then pull aside… it had been a good day.

At 8k with my stomach in knots, I walked and saw Caroline on the side of the road. I’m not easy to challenge once I had made up my mind, but Caroline presented me a no-nonsense northern stoicism commentary on my decision to call it a day. I listened.

For want of a better word - and how I felt in hindsight - I was being a bit of a dick. I asked how long she thought it would take to walk 11k “a long fecking time Tam”! - “drink some water … if you feel sick, be sick… and carry on”.

Aah ok then. Let's try that.

Not the most pleasant spectator viewing - having a “mom” down a drain on the side of the road - I tried to sneak somewhere out of eyesight. Incognito. Failed. On the second lap, this is easier as the course is busier.

The Glamour of triathlon.

Ironman 70.3 Mallorca Run

Thought of the time… What the heck was I doing eating pineapple 2 hours before race start given its fibrous consistency. Full of digestive enzymes and that bromelain may help muscle inflammation … ok, stop it… pineapple pre-race not a good idea for anyone, ever.

Walked for about 10 minutes - spoke to people - I have never done this in a race - on the times I have DNF’d it's either due to accident or injury. But I remember thinking about Lucy Gossage’s long walk in Kona and was full of admiration.

Let's try it. I’m open to new experiences. Walk for a bit - take in the people, ask how their day is going.

I went along in this vein until I realised I had better things to be doing with my time and should stop being a bit of a dick. So picked up to a jog and started to see the blue arches of the finish line getting closer.

I was “running’ at a pace where I could comfortably talk - which was strange in an event as usually at this point on a 70.3 I’d not manage more than a grunt.

Legs definitely a bit “throbby” at this point - I started to think about how high my CK level would be if I did a blood test - an enzyme released when muscle is damaged - which is higher when exercise is “unaccustomed”.

I’ve had the lab call me on a number of occasions reporting high CK (>1000’s) values in athletes - the worry is - if its coming from a cardiac source…which can indicate a heart attack.

A standard test won’t differentiate, so I call the patient and they are fine “just a bit sore” from a 10k at the weekend, if I’m unsure and perhaps you’re in the “at risk” category, I’ll add a CK-MB to look at the source of the muscle damage. The heart is a muscle after all.

Love THAT Finish Line at races. YOU ARE AN IRONMAN. The pull of THAT sentence.

The IMUK finish line pic that Getty captured evokes an emotional response still.

And the fact there is a tangible finish line. Done. Complete. Tangible. Hold that feeling.

One of the reasons for the huge boom in endurance sports events is due to this very reason.

Frustrations with the lack of control, lack of fulfilment, influence of social media about “How to be”.

Get back to our primal instinct to suffer, and to suffer harder if the reason for the suffering is clearly defined.

Go to War. Find your Tribe.

Did you fight harder this time?

I’ve struggled with the transition from professional athleticism where that tangibility of the finish line does not translate. In business, life, entrepreneurship there is no finish line. I thought there was at least I convinced myself intellectually of this.

I kept pushing towards it, then it would shift, the course diverted, unfamiliar territory, other people influencing the course - reactive…….but I would keep going, obviating the need to take on appropriate support and nourishment, because that’s what an endurance athlete does - especially when the psychological drive is strong.

That competitive, Yoda. `do or not do …there is no try…”

It took an astute, in fact, exceptional friend, to point this out to me.

And it took a series of physical health setbacks to make me listen.

Stress is Stress. Exercise, Psychological, Relationships, Work, Excess. The physiological response is the same.

“Why Zebras don’t get ulcers” …Transformed my thinking on this. How your body REACTS to the stress determines its impact on your health.

Dear Zebra,
Please can we figure out a sympathetic nervous system transplant?

Danger > May get eaten - die > Run >>> Ran fast enough, Lion couldn’t keep up. Ha - Silly Lion, must do some more HIT work. But in the meantime lets enjoy being alive and chew some grass. This is great grass. It may even taste sweeter than yesterday. I’ll enjoy this grass for what it is today.

So there we have it.

A Comeback…

Not Yet.

But to the community of triathlon from which I have been mostly absent for the last 4 years - on purpose as life outside the bubble grew and I couldn’t make the two stick - a rediscovery of the tribe and the reasoning.

I may dip my feet in again. But only if I learn something new. :)

Exercise & Leaky Gut: What Every Athlete Should Know

When it comes to exercise, there is definitely a happy medium that provides health benefits. Too little activity is associated with detrimental health effects, including a compromised immune system, decreased resistance to stress, and decreased resilience to circadian rhythms.

However, too much (too strenuous, too intense) activity also negatively impacts health, causing dysregulated cortisol, increased susceptibility to immune-related diseases and infection, and a leaky gut.

Leaky Gut

It actually shouldn’t come as a surprise that intense and strenuous activities cause gut problems. Up to half of all long-distance runners experience something called runner’s diarrhea (colloquially referred to as “runner’s runs,” “runner’s trots,” or “the gingerbread man”).

The symptoms include dizziness, nausea, stomach or intestinal cramps, vomiting, and diarrhea, which occur mainly while running. All these are symptoms of something more insidious happening in the gut.

gut issues

While not all endurance athletes suffer overt symptoms, strenuous exercise does appear to increase intestinal permeability in everyone who indulges in exhaustive exercise, albeit to varying degrees. A variety of studies have documented increased intestinal permeability in athletes who reported no gastrointestinal symptoms. And one study showed that well-trained athletes who suffered from exercise-induced gastrointestinal symptoms experienced significantly more intestinal permeability after exercise than asymptomatic athletes.

Cortisol (Oh and CRH too) & Gut Health

The way that exercise increases intestinal permeability is multi-faceted. First, intense activity is a stress on the body and activates the Hypothalamus-Pituitary-Adrenal (HPA) Axis, i.e., the Stress Axis or the Fight-or-Flight Response. This causes the release of two important hormones that directly affect gut health.

The better known of these hormones is cortisol, the master stress hormone. This secretion of cortisol is largely responsible for the negative impact of intense activity on the immune system, however it can also directly affect the integrity of the gut barrier as well. Very high cortisol alters tight junction assembly, making the gut more permeable to low molecular weight substances and less permeable to high molecular weight substances. High cortisol further, decreases gut motility, decreases mucus production in the gut (by goblet cells), inhibits digestion (by reducing pancreatic enzyme secretion and gallbladder function), decreases intestinal blood flow and may even directly alter the gut microbiome.

Yep, cortisol is not your gut’s friend. But when it comes to activating the HPA Axis, there’s another upstream hormone that has an even more profound impact on the health of the gut: corticotropin-releasing hormone, or CRH. CRH is released by the hypothalamus in response to stress (regardless of whether the stress is a lion chasing you, a traffic jam when you’re late for an important meeting, or a 3-hour long marathon training run).

CRH signals to the pituitary gland to release another hormone which then signals to the adrenal glands to release everything they release, including cortisol. CRH not only increases the permeability of the intestinal barrier (which causes a leaky gut), but it also increases permeability of the lung barrier, the skin barrier, and the blood-brain barrier. It does this two ways:

  1. First, it activates mast cells (an immune system cell type that resides in most tissues and is a major producer of histamine, for example during allergic reactions) which then secrete a variety of substances (histamine, heparin, and cytokines) that trigger the opening of tight junctions.
     
  2. Second, CRH has a direct effect on the tight junctions by increasing the incorporation of a type of protein into the junction that causes those junctions to be more open (the tight junction protein is called claudin-2, and when claudin-2 is incorporated into tight junctions, epithelial barriers are more leaky, or permeable).

However, the stress response isn’t the only way that exercise causes a leaky gut.

Blood Flow & Leaky Gut

Runner

In order to prioritise blood flow to the heart and skeletal muscles during exercise, blood flow is diverted away from the gastrointestinal tract and other visceral organs (like the liver and spleen). This lack of sufficient blood flow results in what is called ischemic injury (injury that results from inadequate blood supply) to the gut, which disrupts the intestinal barrier and thus increases intestinal permeability (aka, the dreaded leaky gut).

Participating in strenuous and exhaustive exercise further stimulates the production of a class of proteins called heat shock proteins (so called because the first of this family of proteins was discovered to be induced by fevers). Heat shock proteins have a direct effect on tight junctions (by affecting the levels of two integral protein families called occludin and claudin), opening them up and causing a leaky gut. In fact, understanding how exercise directly impacts the formation of gut epithelial tight junctions is a robust field of study. If you want to get into geeky details, this review article is a great place to start: http://bit.ly/2zyVCSz.

Perhaps given all this, it’s no surprise that vigorous exercise is also associated with a condition called food-dependent, exercise-induced anaphylaxis, in which the exercise-induced increase in intestinal permeability facilitates the absorption of allergens from the gastrointestinal tract.

Sports Drinks & Ibuprofen Are Not Your Gut’s Friend

Sports Drinks

A few conditions can aggravate the increased intestinal permeability caused by strenuous exercise. One study showed that the use of ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), significantly exacerbated both intestinal permeability and intestinal damage caused by strenuous exercise in well-trained athletes (ironically, popping ibuprofen is a common practice for endurance athletes).

There is also a strong correlation between both food intake and the consumption of carbohydrate-dense, electrolyte-enhanced beverages and gastrointestinal symptoms in endurance athletes. Strenuous exercise inhibits gastric emptying (the movement of food from the stomach to the small intestine), which is then further inhibited as the concentration of carbohydrates and salt in the stomach increases, so sugary sports drinks can actually make the problem worse.

Of course, it goes without saying that dehydration also causes heightened symptoms. It remains unknown whether food and overly concentrated sport drinks actually increase intestinal permeability or simply magnify the symptoms felt by the athlete. Watch this space.

Heat & Exercise = Further Inflammation

Environmental conditions also have an impact. One study showed that a sixty-minute run in both hot (91°F or 33°C) and cool (72°F or 22°C) conditions caused increased intestinal permeability, but that the amount of endotoxin (bacterial protein from Gram-negative bacteria) detectable in the blood was much greater after strenuous exercise performed in hot conditions but not in cool conditions (http://bit.ly/2yxeVI5). This implies that strenuous exercise is more inflammatory if performed in the heat.

Probiotic treatment may also help protect the gut from increased permeability caused by strenuous exercise. One study showed that probiotic supplementation reduced the amount of proinflammatory cytokines in the blood after strenuous exercise in male athletes and decreased the amount of zonulin (a protein that opens up tight junctions between the gut epithelial cells, implicated in a few autoimmune diseases) detectable in the feces (http://bit.ly/2zEINpv).

probiotic supplement

Runners, cyclists, and triathletes have been studied for exercise-induced intestinal-barrier dysfunction. Although there have been no definitive studies on the connection between resistance training and intestinal permeability, it probably depends on the style of workout and the amount of rest time between sets. Certainly, high-intensity, short-rest workouts have been shown to increase cortisol secretion more than traditional resistance training.

Low Intensity V Higher Intensity Exercise

By contrast, regular exercise at a relatively low intensity may protect the gastrointestinal tract from becoming diseased. There is evidence that physical activity reduces the risk of colon cancer, gallstones, diverticulosis, and inflammatory bowel disease, which is yet another argument for increasing physical activity while avoiding strenuous exercise. Again, it’s the happy medium thing.

The Take Aways

So there you have it, it’s not all doom and gloom. Taking the stress out of training will go a long way in protecting the integrity of your mucosal lining and gastrointestinal health in general. This looks different for everybody but too many long and strenuous workouts crammed into an already busy schedule are going to place a strain and likely compromise overall gut health integrity. Limiting the amount of intensive workouts in hot weather, staying away from NSAIDS and ditching those gels and sports drinks will go a long way in protecting you from developing a leaky gut. As will taking a quality probiotic, eating for gut health (fermentable fibres), removing as many toxins as possible from your environment and treating any detected intestinal pathogens.

If you suspect a leaky gut may be the root cause of your digestive issues and performance issues then I thoroughly recommend a Poop test to dig a little deeper ;)