Q&A: With Trent Stellingwerff, Top Canadian Sports Physiologist

Canadian Sport Institute’s Sport Scientist Trent Stellingwerff got his start majoring in in sports nutrition at Cornell University.  But he didn’t just study , he also was on the varsity track team at Cornell and co-captain his senior year. During that senior year  he got involved in sport nutrition research. That carried over to eventually doing a PhD  in exercise physiology and nutrition at the University of Guelph, near Toronto.

 

Now Stellingwerff is the Lead of Physiology Innovation and Research at the  Canadian Sport Institute - Pacific, located in Victoria, British Columbia. He is involved heavily with Rowing Canada, Athletics Canada (which deals with Track and Field) and Triathlon and works with many of the the most elites athletes in the world.

 

We often hear stories about pro athletes that kept competing despite broken ribs, fractured collar bones, etc. This seems unfathomable, and superhuman. Most amateur athletes just cannot put themselves in such great pain, why is this?

Interesting question, without a clear answer. It may come down to nature vs. nurture.  Do elite athletes adapt and harden, or callus, themselves to the hard training, and indirectly, the pain?  Or are they already born with the ability to tolerate pain?  Certainly, some of the research by Prof. Samuel Marcora’s work on training the brain, and mental fatigue and positive self-talk (read more here) shows that pain tolerance can certainly be trained.  But, I think in the future, through modern functional magnetic resonance imaging (fMRI) of the brain, we are also going to find out more about what makes the elite athlete tick, which series of genes are expressed so they can tolerate more pain.  For example we already know that redheads experience pain differently, potentially via mutations to the gene MCR 1 (seen here) causing them to have increased sensitivity to thermal discomfort.    As with everything, you cannot separate out nature and nurture – they are intimately linked.

 

Where do you think most athletes make the most nutrition mistakes?

Perfect nutrition is never going to make an average, but well-disciplined, athlete into an Olympic champion.  But, I’ve seen very poor nutrition and hydration choices certain change the outcomes of major global championships.  Most times it is the extreme decisions that are the largest mistakes.  For example, eating nothing the morning of a marathon because of nerves and butterflies in the stomach versus eating way, way too much too close to the marathon for fear of running out of fuel can both be disastrous.  Or, undertaking a brand new meal, or fueling protocol, in a race for the first time.   Or other mistakes just include the under-appreciation for nutrition.  We need to remember, elite athletes might train 300 to 500 times per year, but they might eat 1200 to 1500 times per year!  Certainly, training is the most important, but the recovery aspects and the adaptive aspect of nutrition, over that many training bouts, certainly adds up over the year.  Finally, some people are constantly searching for the magic bullet diet, and chasing some elusive supplement or approach – this is also a mistake.

 

How does eating better and exercising change your appetite as a whole? Why does this change happen?

Appetite regulation is a very complex area of scientific research, which involves both feed forward and feedback mechanisms which are both physiologically and psychologically and environmentally based.  This is not my area of expertise at all, so you should really get the best opinion on someone who does research here.  But, certainly, epi-genetic and genetic environmental factors are all starting to emerge as confounding factors in food selection and appetite regulation (e.g. who you eat with, the environment, the size of your plate (concept of volumetrics of eating) etc. etc).

 

We understand that the body has an immense amount of fat storage that it can use as energy, what's the best way to increase the % of fat burned while reducing the body's reliance on burning carbs?

Endurance training is the #1 way to increase fat oxidation at a given speed or power output.  The primary adaptive mechanisms of endurance training (e.g. increased mitochondria, increased capiliarization, increased fat transporters and enzymes (and CHO transporters and enzymes) and even increased fat stored in an athlete’s muscles (intermuscular triglyceride) all serve to increase the percent of fat oxidation post-training.

Recently, there has been some emerging research showing that periodic low carbohydrate availability training may be able to further those increases in fat metabolism.  I put the word periodic in the last sentence on purpose.

 

For endurance athletes, it seems that recovery should be view in two phases: immediate glycogen replenishment within 30 minutes of exercise, and then a meal within 2 hours of exercise. Can you elaborate on this? Should your "recovery" after exercise be largely carbohydrate?

Recovery, first and foremost, depends on long and hard your training bout was, how much you train throughout a week and when you have to train or compete next.  If you are working out 3 or 4 times per week, with workouts less than 60 min, and you eat regularly, than you don’t have to worry too much about optimizing recovery -- eating normally and getting good rest will take care of it.  But, if you have a huge training load, train every day of the week, and  doubles or triples, than optimizing recovery becomes exponentially more important.

In these cases, immediate recovery should feature carbohydrate for glycogen re-synthesis (~1 to 1.5 g CHO per kg BW = ~ 60 to 100g of carbohydrate), protein for muscle protein synthesis (~0.3g PRO per kg BW = ~15-20g of protein) and fluid intake (1.5 x the amount of body weight lost in sweat from training).

 

If caffeine itself is not a diuretic, is there another mechanism or hormone in the body that is brought out by caffeine that enables or  exasperates dehydration?

In terms of hormones – no.  It is thought that caffeine might increase urinary sodium exertion, which might cause it to be a very mild diuretic –but no worse than water intake (which also causes urination).  A great overview by Prof. Lawrence Armstrong outlined and summarized that consuming a moderate level of caffeine results in a mild increase of urine production. Although this diuresis may not be significantly greater than a control fluid and there is no evidence to suggest that moderate caffeine intake induces chronic dehydration or negatively affects exercise performance, temperature regulation, and circulatory strain in a hot environment.

 

Should athletes be focused on hydration away from food consumption? EG, would hydration be more effective if consumed on an empty stomach?

Hydration requirements really depend on whole body fluid balance requirements, which are primarily dependent upon exercise sweat rates and environmental conditions (temperature/humidity).  Whole-body hydration is improved when there are “solutes” in the drink (e.g. carbohydrate, protein, electrolytes) as a lot of these are transported from the intestine into the blood stream with water.  So, drinking fluids with food would actually help to retain the water over the same amount of water consumed alone.

(note: Dr. Stellingwerff worked with 27-time world record holder Hailie Gebrselassie, one of the athletes with the highest recorded sweat rates in the world)

 

Extreme temperatures drastically change dietary needs during exercise. Do you have any examples of athletes you’ve worked with in extreme heat? extreme cold? What is the number one thing to pay attention to?

The biggest change in extreme temperature is fluid requirements.  Secondary to that are nutritional requirements, and primarily changes in muscle glycogen utilization increase in both very cold (Shivering) and very hot conditions – so CHO intake needs to be increased relatively to more thermo-neutral conditions.

 

What are you opinions about the beets “craze”?

For me, a “craze” is something which proliferates the market or alters behaviour without any, or very little, scientific peer-reviewed evidence.  For example, 3 or 4 years ago the PowerBalance bracelets were everywhere, but without any scientific evidence.

So  I wouldn’t call beetroot a craze, as there is zero doubt that nitrate precursors, such as beets, certainly cause robust changes to metabolism and blood pressure.  These changes include decreased VO2 demand at a given power-output (e.g. increased economy) and, potentially, increased endurance performance.  There are at least 20+ studies in humans confirming some of these varying physiological changes.  As always, the performance data is somewhat mixed (either improvement in performance or no change), but more studies have been favourable, than no change.  There are some studies suggesting that the very elite endurance athletes may not benefit from beetroot supplementation.  But, in my opinion, a lot more research needs to be done before final performance outcomes can be clearly made.