IRONMAN 70.3 Marbella, Spain. February 23, 2019 ~Bonking~


2:45 hours at 190 Watts + 15 min Run off bike

brick workout is any workout that combines swimming, biking and/or running into a single session. The most common example is the bike to run brick, where you go for a run immediately after finishing a bike ride.

Pre-exercise meal (30 minutes before):
2 bananas + BCAA + Coffee ☕️ (45 carbs 150 calories)


38 g (carbs/hour) x 2.75 (2 hours 45 minutes) = 105 grams of carbs required
2 protein bars + Cliff energy chews = 100 C 21 F 28 P 660 calories


The GOAL: 
prevent loosing more than 2%  (1.5 kg) of body weight in fluids. 

What do I need?
Sweat Rate: 1500 mL x 2.75 = 4125 mL
Sodium: 0.5 x 4125 = 2062 mg
Carbs: (X / 4125) x 100 = 5% -> X=0.05 x 4125= 206 g of carbs!?

What I got:

G2 Gatorade: 6 bottles (591 mL) + own solution (580 mL)= 4126 mL 
Carbs: 12×6 = 72 g
Sodium: 270×6 + 330 = 1970 mg
Additional Sodium: AminoPro 2 scoops 230 mg + Vega hydrator 100 mg = 330 mg in 580 mL of water💦
Calories: 300

Total Calories: 960 calories: 350 calories/hour
Using the Cooling Fan


Pre-weight: 69.3 kg
Post-weight: 69.3 kg
Liquids consumed: 3930 mL
Sweat Rate: 1430 mL/hour (confirmed previous calculations)

Total fluid loss: 3930 kg (2% body weight)

I am satisfied with this numbers and consider my calculations right on point. It’s a win!


What do you know about “bonking”?

The first 40-50 minutes felt strong, pedaling without too much of an effort (RPE 3-4). Wasn’t fueling until 30 minutes into the ride. Approximately at minute 50 my power began going down increasing RPE.

Since then it was a total suffer fest. No matter how much I ate or drank, my power kept going down and down. I hit the wall or how cyclists call it “bonked”. Glycogen in my muscles and liver got depleted making my body fatigue and bonk. It felt incredibly hard to keep pushing 190 watts and I had to slow down multiple times for 10-15 seconds, because I just couldn’t keep going. My mind began playing tricks on me, but no matter what I did, I just couldn’t physically spin my legs. Even knowing my legs were hurting, it wasn’t about pain. I simply couldn’t force my body to push the pedals. Multiple times I had thoughts to quit and stop this suffering as I couldn’t keep up with workout.

Here is how bonking looks like on a graph:

While heart rate is going up, speed and power falls down.


Immediately after the ride I put my running gear on and went out for a 15 minutes run. My legs felt like jelly, running at 5:28 /km pace RPE felt like 6-7. Didn’t try to push, making the emphasis on keeping the form.

Severe diarrhea hit me 5 minutes into the run. I honestly thought I would shit my pants… In addition to that had minor stomach cramps. Had to finish the cool down part short… at the restroom.

Lessons Learned:

  1. 3,000 calories / day with 400 grams of carbohydrates I currently eat on my diet is not enough to fulfill the energy demands. I went glycogen depleted into the training and payed the price.
  2. 100 grams of carbs from pre-meal burned in 40 minutes.
  3. Confirmed my Sweat Rate calculations. Approximately 1500 mL/hour.
  4. Learned what the bonking is and how it feels.
  5. If you drain your glycogen tanks, there is no way to refuel it on the fly, while keeping the power & speed.
  6. Cooling fan didn’t make significant change in my sweat rate.
  7. I don’t like energy chews. They get stuck in teeth.

What will I do different?

  1. Increase my carbohydrate consumption to 600 grams/day. Total daily calorie intake: 3,900 calories
  2. Always have a big, carbohydrate-rich meal at least 90 minutes before workout.
  3. Try consuming liquid calories. See how that feels on stomach and absorption.