4 reasons for a wall, or BONK: Electrolytes, Hydration, Heart Rate, Calories

Dallas Rock ‘n Roll Half- PR 1.57

I set a PR this weekend in my half.  Also, set personal best for my 10k, 53m. I still pooped out at about 11 miles.  This keeps happening in my training, so I sent my brother an email and here is the interaction.  Hopefully it will give you some help for your training as well. 

See you at OKC, April 24.

What do you do when you keep hitting a wall at 11 miles?

4 reasons for a wall, or BONK:  Electrolytes, Hydration, Heart Rate, Calories


Electrolyte replacement.

Electrolytes consist of Sodium, potassium, Chloride, and Bicarbonate.


In marathons drinking too much water without electrolyte is a risk of a problem called Hyponetremia, people die of drinking too much water without electrolytes. 


Your body can only hold enough electrolytes to go for 90 minutes.  Period.  That is just the science of it.  So if you do not replace the electrolytes you will crash out, “Bonk”.  As it gets hotter you will find that wall gets harder and harder to get through.  It becomes a “bonk” or physical shutdown of your body.    


1 gel pack for every hour or every 45 minutes from the time you start.  Over 85 degrees I use the 45 minutes.  It keeps you from running out of electrolytes at 90 minutes. 


Additionally, With my sweat rate, I have to drink Gatorade instead of water, for at least half of my fluid intake.  Typically I take a bottle of Gatorade and split it into 2 and put water in the other half so it is not as strong.   I carry the single serve packets, G2 has lower calories, and is less sweet, easier on your stomach at mile 56 of a bike ride, or 16 of a run, but you probably need the calories in G.


On workouts over 4 hours in temperature over 80 degrees, I will also drink about 1 ounce of pickle juice for every hour, typically, 2 ounces per hour starting at 3 hours.


Electrolytes are also why a person cramps, not enough potassium, eat bananas.



Typically, if you are not taking in enough fluid you body does not have the ability to supply your body’s cells with needed items.  Most people lose about 1 liter (yes 32 ounces) per hour, and so should replace at about that same level, or at a rate of at least .5 liters per hour minimum (16 ounces).  This needs to be tested and adjusted with your bathroom needs, and will vary greatly due to heat.   My sweat rate on days above 80 degrees is about 2 liters per hour.  So I have to replace at about 1.5 liters per hour.  Also, if you feel thirsty it is too late, you are already dehydrated, and when you try to catch up on fluid you will get the sloshy stomach.



Slow your pace, especially on distance days…  I know that is not what you want to hear but you heart rate should not exceed 80% of max during the entire exercise. Over 80% = time in the red. The trick to going long is to be able to go faster with a lower heart rate.  For every 10 seconds you spend over 80% you take about a minute off of the total time you will be able to go.  Not exact but a rough estimate.  So 1 minute in the red = 6 minutes closer your “bonk” moves.  10 minutes in the red 1 hour closer to bonk.  Now the trick is “what is someone’s total exercise time.”   That is a factor of overall endurance built in a season.   You must build your race pace over time.  That is why your speed workout should only be your midrange workout during the week.  You build your time in the red the same as you build your distance, but you typically do not build them on the same day.  Typically in a 20 week training program you would do a distance, and red zone workout together at the most every 4th week but probably better every 8th week.  Just before your taper week.  Just as an example, not from an actual program, So say you do 10, 12, 13, 12 race pace,  9, 12, 14, 16, then 10, 13, 18, 16 race pace.   But even that is extreme. 


Caloric intake

A higher heart rate burns calories first and then burns fat.  The trick is to stay below the anabolic threshold so that you burn half fat and half calories.   It takes 2 times as much energy to burn fat alone as it does to burn Calories alone.   When you run out of calories you expend twice the effort to go the same speed.  That is why your breathing gets heavier and you feel more sluggish.


The concept of Carb loading works for some and not for others.  But there is some science to the process. 

Typical male will burn around 2,2200 calories per day. 

Typically an additional 800- 1000 calories per hour on a run. 

Doctors recommend for weight loss at a rate of 1-2 pounds per week or 3,500-7,000 calories.  I have found this to be the recommended level of weight loss because you do not feel a caloric deficit in your life.  Extreme fatigue inability to function, and you body consumes muscle.  To avoid the negative they recommend no more than a deficit of approximately 1,000 calories per day maximum.    So in a run if you hit that 1,000 calorie deficit you will feel negative effects, 2,000 calorie deficit and you will want to cut off your legs.


You may not need to necessarily carb load the day before a race, but you do need to make sure that you were not at a caloric deficit from a workout the day before.


Typically they say that you can only retain an additional 2,500-3,500 calories from a meal the night before the event.   That will give you approximately 4 hours of energy at an 800 calorie per hour rate.   But if you started at a deficit you will run out sooner.


I typically do better with Protein than carbs, I usually try to have about 1,500 calories in the meal the night before an event with about 600 coming from protein.   And the other from pasta.


1.5 to Two hours before starting an event I will eat a bagel with peanut butter on both halves.   You have to time this right or you will be looking for a bathroom 15 minutes into the run.   My eat half a banana also.

Then starting at 1.5 hours I eat a 100 calorie granola bar every hour.   Basically I alternate granola with gel packs every 30 minutes.   This gives me 200 calories per hour taken in, plus typically about 100 calories of Gatorade.  It prolongs the bonk.


At the end of a race the quickest way to ensure recovery is to replace the calories before your body realizes it is in a deficit and starts eating muscle.  Replace with a 100 calorie protein drink, or a slimfast meal replacement shake, and a lunch of protein and a beer.




Happy running,




Tim Avance


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