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3 reasons to fuel properly during long workouts

Michael Liberzon

Here in the eastern part of the country, the Canadian winter is showing no signs of surrender. Days are still short, roads still sloppy, and the temps below zero. Your training, however, cannot wait till better weather. So regardless of your 2018 racing goals, it is likely that you have already started logging ever-longer bike and run sessions to build that aerobic base.

Several of my athletes have early season long course races, mandating some serious saddle and run time already! As their training sessions grow progressively longer, I am constantly reminding them of the importance of fuelling and hydrating correctly for these efforts.

I won’t get into the ‘how’ in this piece, but rather go through the ‘why’. Here are 3 reasons why you should (almost) always do your best to onboard as much hydration and nutrition as your body will tolerate for long workouts:


  • Controlling intensity


Training dehydrated or with low glycogen levels increases the difficulty of the workout. Dehydration reduces blood plasma volume and increases blood viscosity. That means the heart must work harder to pump the fluid. Likewise, as muscle and liver glycogen stores run low, the body must increasingly rely on fat oxidation. While even the leanest athlete has abundant fat stores to fuel a workout, its utilization for fuel is more metabolically costly. That again means an increase in the rate of work that the body must perform for the same mechanical work output.


  • Facilitating recovery


Dehydration and glycogen depletion delays recovery. While it is not possible to replace all the fluid and carbohydrate lost during a workout. Consuming as much as your body can handle will help reduce the difference between its depleted state at the end of a long session and its homeostatic baseline. That means less time is required in getting back to its pre-workout fluid and fuel levels, and therefore, a more rapid recovery.


  • Fuel absorption and utilization training


A coach I know calls an Ironman race a ‘managed bankruptcy’. That is to say that often the greatest obstacle to optimal performance is fuel. So it makes every bit of sense to maximize your body’s ability to ingest, digest, and absorb as much carbohydrate and water as possible. Just like you train your muscles and your mind to tolerate race-day stressors, so too should you train your gastrointestinal system. This process takes time, but is well worth the investment. Come race day, an inability to fuel optimally may be the may be the game changer!

One last point. Why did I say that maximal fuelling and hydrating is almost always the way to do it? There is some evidence that infrequent depleted training can improve the rate of fat metabolism. In my experience, however, athletes overestimate this effect and underestimate the costs of training low. So the most simple solution is to stick with ‘always’.