Keto Marathons Logo

Marathon 4 Penrith, NSW


Marathon 4: The Final ‘Warm Up’ Marathon

Sleep last night was an absolute disaster. I woke at 12am and struggled to sleep the rest of the night. Not a great way to recover in time for marathon number four! During the night I felt light headed and it clicked that I’d overhydrated the day prior. I took a bunch of salt tablets throughout the night (eight in total) and by 5am I felt better but far from my best. The one hour trip from home to the marathon route allowed the salt to do its thing and I felt back to baseline for the start of marathon four.

Again the forecast was over 30C heat so the early start was crucial to try and get ahead of it. The course changed today as the Sydney Regatta Centre were hosting a triathalon hence it was out of action. Instead I ran a continuous loop around the Nepean River in Penrith that equated to approximately 6km each time. An additional challenge was the smell of BBQ meats cooking at the festival being held riverside! Basically my route involved me running around a giant bbq! Not quite what I’d have planned for day four of my fast. Fortunately it wasn’t an issue and hunger was again minimal.

Pace per km

Yesterday I’d worn compression pants to try and assist with the pain in my legs. My rookie error was failing to accompany the pants with compression socks and thus my ankles were left exposed during yesterday’s marathon. The result was seeing my entire lower body was compressed into my ankles! This was extremely painful and each step felt pretty excruciating all day. It was daunting to think I had close to seven hours ahead of me. The first 10km was reasonably cruisy as the plan was to simply repeat the pace from yesterday. I started the run without the compression pants but the ankle swelling soon started rising up my shins (very painfully) so again I donned the compression pants and the issues didn’t escalate.

Calls from friends and family broke up the monotony nicely and was a fantastic distraction from the pain in my ankles. My hip caused me grief again but only for the first 2 hours. I had to stop a number of times to stretch it out when the pain became too intense.

The final 10km was a breeze as my friend Harry joined me and we completed the final leg in comfortable time. It was a huge boost to have someone with me to close out my 4th marathon.


I’d handled some heat during the first few marathons but today really dialled up the difficulty a notch. My poor recovery last night resulted in me starting a little later than originally planned and I knew I’d have a significant part of this marathon in some extreme temperatures.

I’d only made it to 16km before the mercury broke through 30C. It continued to escalate and the last two hours it was consistently above 37C!

My hydration and salt intake were both really high today but my thirst did feel quite insatiable. After last night’s episode I was conscious of not overdoing it but in that level of heat it’s really hard not to drink. Little did I know at the time that all of this water was something I’d pay for later.

Active Pace

This was my slowest marathon which I completed in 6 hours 46 minutes. It was only 20 minutes slower than my previous marathons which actually was a pretty good result given the pain in my ankles and the extreme heat.

Marathon 4 Statistics

All done! I finished my fourth marathon in 6 hours 46 minutes (average pace 9:36 min/km).

Heart Rate

My heart rate appeared to have two phases today. Iniitially it stayed really low which I’m sure is due to my slow pace in attempting to manage the ankle pain. My heart rate then stepped up considerably at the 16km mark which coincided with the temperature breaking above 30C.

I did manage to maintiain a heart rate in zone 2 and zone 1 for the entire marathon which was the objective.

Continuous Blood Glucose

Testing was done at 5.00am this morning and I did not feel great due to my overhydration.

My blood sugar remained at normal levels above 4mmol/L and by the evening was back up at 5.6 mmol/L.

My CGM indicated that my blood sugar did drop low during the night. I’m sure my body was battling wars on a few fronts during my sleep. My blood sugar didn’t fall to any levels that would be of concern and the regular 6am spike still appeared as expected.

Throughout today’s marathon, my blood sugar was again quite stable. It dipped a little below 4 for the last 90 minutes of the run which was also the most extreme heat of the day.

24 Hour CGM

Blood Ketones

My ketones have ramped right up now and are well north of 2.0 mmol/L. I was expecting this towards the back end of my fast and the data clearly supports a profound increase in ketone production.

Fasting and Hunger

My hunger has completely disappeared again. I’m really not interested in eating and there isn’t even the slightest urge or craving for food. Today’s run involved me running around a giant BBQ (a riverside festival) for close to 7 hours and even that didn’t stir the hunger demons. I genuinely still feel satiated. I will point out that it’s a little difficult to completely ignore the thought of food when you are actively asking yourself if you are hungry. It’s much like not picturing an elephant when you tell yourself ‘don’t think of an elephant’.

Post Marathon measures:

  • Hunger: 1/10

Sleep and Mood

My sleep last night was simply a disaster from 12am onwards. The data indicates that there were significant periods of me being awake. Mentally it was difficult to try and force myself to sleep knowing how much I needed it to maximise recovery. Staying awake the night before just one marathon is poor preparation let alone not sleeping before marathon number four!

Surprisingly my sleep statistics indicate some pretty good metrics. This provided some reassurance that whilst I may have had a lot of periods awake, the sleep I did get was reasonable quality.

My mood this morning was the lowest it had been. The thought of running another marathon was rather daunting. This isn’t surprising given it is 5am, I’m experiencing symptoms of overhydration, dealing with ligament pain and still needing to complete a 6 hour run! My determination really kicked in and the entire objective today was to just ‘get to the start line tomorrow!’. I must say that once I started the marathon today my mood lifted immensely as it was now clear that this really was the home stretch!


  • Pre Marathon: 3/10
  • Post Marathon: 8/10


Four days in now and my weight has ticked down to 74.0kg. This equates to a total loss of 1.7kg after four days of fasting and four marathons.

Post Marathon

The afternoon involved some recovery work at that physio and a very long epson bath at home. Post marathon my mood was again at an all time high as it was clear that the finish line was in sight.

Tomorrow is the final day and it will be the official Sydney Marathon. I’m very pumped to get this done and really hope the crowd and excitement of the event make it an enjoyable day. A personal goal will be to finish inside the marathon cut off time of seven hours but it will be what it is. I won’t be breaking any speed records and really just want to take it all in. Bring on marathon number five!

For now, it’s marathon number four done!!!

Related Posts