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Marathon 5 Sydney, NSW

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Marathon 5: The Official Sydney Marathon

A call with my advising doctor last night made it clear that I was suffering some symptoms of ‘overhydration’ and that an excess of water retention the cause of the swelling in my legs. This all stemmed from the anti inflammatory I took between marathons two to four. Some of the side effects include increased thirst, poor sleep, and water retention. I’d ticked the box for all of these. The other concern was that my weight last night was identical to my starting weight despite being four days fasted and running four marathons.  It appears that the anti inflammatory I took to reduce joint inflammation is the likely cause of the excessive swelling in my legs. The remedy was to avoid all anti inflammatory going forward and sleep with elevated legs in an attempt to drain the fluid.

I took this picture at 1.30am and this was how I spent the majority of the night ‘sleeping’.

It wasn’t a position conducive to a good nights rest but the non-negotiable was the swelling for tomorrow. I did feel a bit like one of those Chuck Norris jokes simply ‘waiting’ for dawn.

It did the trick! The swelling slowly subsided throughout the night and my body was able to clear the fluid. In the morning I was now 2kg lighter than the night before!

Fortunately my accomodation was directly above the start line of the Sydney marathon and hence I enjoyed a ‘sleep in’ until 5.30am when the shorter distance events commenced. Start time was scheduled for 7.15am.

Prepped and ready to go I headed to the start line excited about starting the final marathon! I’d covered almost 170km just to be able to start this marathon.

Pace per km

The race started at a frantic pace and it was difficult to remain slow. The crowded start felt like a strong current and I was appreciative for it sweeping me along! My pace for the first 15km was close to the fastest of all 5 marathons.

The Sydney Marathon really is a spectacularly beautiful event. Running across the Sydney Harbour Bridge is a unique experience and I really enjoyed taking it all in.

A surprising number of people wanted to chat to me once the race kicked off and it was some thoroughly enjoyable conversation even though we were all moving rather quickly. The momentum of the crowd really carried me along for the first hour or so.

As I approached the 15km mark the pain in my ankles and hip ramped up and some strategisation was required. My two options were either dropping back to a brisk walk or maintaining a light run. Unfortunately both were just two different flavours of pain. There simply wasn’t a pain free alternative but at least being able to switch it up kept things interesting! In the end I chose the run option in order to at least benefit from the reduction in time on the feet.

The quicker speed resulted in an elevated heart rate which I was concerned would severely hamper my ability to even complete the race. Hence by 26km I defaulted back to the excruciating walking pace with the sole intention of ensuring that I finish the race.

Active Pace

Considering that this was now my 5th marathon in five days, my pace for the first 21km was much faster than I anticipated. After a significant uphill portion of the course and the mercury steadily rising I dropped the speed back quite a lot so as to minimise the possibility of not finishing.


Today was predicted to be a scorcher and the event organisers were quick to put out warnings the day before to ensure that all runners were prepared. The prediction was correct as temperatures approached record highs for this time of  year and stayed above 30c for the last three hours (26 people were hospitalized on the day).

Maximum temperature during my run was 35C.

Fortunately drink stations were a plenty but after my overhydration incidents over the two days prior, it was barely a sip from me and rather a dousing over the head to stay cool. I didn’t touch a drink during the first two hours and only drank just enough water to be able to consume a salt tablet at the majority of water stations thereafter. I did treat myself to a couple of waters late in the run but given the severe consequences of overhydration (hyponatremia), the least risky strategy was to finish the race partially dehydrated.

Only 21km To Go!

The buzz of the day was a godsend and really helped to make the time pass more quickly. A few fun chats ensued with participants querying my keto marathons attire just to check I was serious about completing five fasted marathons. Friends and family cheering me on throughout the course was also hugely appreciated.

With the finish line less than 2km’s away, one of the on course race announcers surprised me with a quick spiel about Keto Marathons courtesy of being prepped of my arrival by a close friend. It gave me a huge lift coming into the final stretch assiting me to finish strong with plenty of energy.

I crossed the finish line to my friends and family cheering me home and it was a tremendous feeling to finally have achieved my goal. My energy levels remained high all the way to the finish and it took a while for it to set in that I was done!

I was interviewed immediately upon finishing by the race announcer and publicly celebrated the achievement of completing five fasted marathons in five days! What a way to complete my five fasted marathons!

Marathon 5 Statistics

All done! I finished my fifth marathon in 6 hours 24 minutes (average pace 8:57 min/km). This was my second fastest marathon out of all five! This was an extremely satisfying result. I’d fasted for four days and run four marathons prior to the start line and I still had enough energy to achieve this.

Heart Rate

My heart rate was considerably higher today thanks to the faster pace. It was around the 23km mark that it started to get to levels north of 175bpm. Due to the combination of a faster pace and soaring temperatures I consciously dropped back my exertion to bring the heart rate back into a more manageable zone. By this stage of the race there were a very large number of people dropping out and lying on stretchers in the first aid stations. After five days of effort, I was determined not to finish the day in the back of an ambulance and I don’t regret sacrificing a better time to achieve my ultimate goal of completing the distance.

Continuous Blood Glucose

Testing was done at 5.30am this morning.

My blood sugar via my finger prick test was still comfortably within range at 4.3 mmol/L. Interestingly it did spike quite a lot post marathon and into the evening. The most suprising part of this was that I’d still not consumed any glucose or carbohydrates that day. My focus post run was to maximise the efficiency of my recovery and the inflammatory nature of carbohydrates remained a strong reason for me to continue to avoid them today. My only meals included a slice of ham around 5pm and a hamburger pattie with some eggs at 7pm.

My CGM data showed a tough night and was also accompanied by the usual 6am spike.

Throughout today’s marathon, my blood sugar was again quite stable. It very briefly dipped below 4 around 11am which was approximately two-thirds through the marathon and about the time when the heat started to become a factor.

24 Hour CGM

Blood Ketones

My ketones pre marathon were the highest they’d been all week at 3.3mmol/L. These elevated levels were to be expected by this stage of the challenge and I welcomed them. Post marathon saw the peak in my ketones at 4.3mmol/L. The breaking of my fast in the evening post marathon saw a significant reduction in ketones back to 1.9mmol/L.

Fasting and Hunger

Fasting and hunger really didn’t play a role in today’s marathon. Prior to this challenge I’d expected that there would be some mental element of picturing a meal post marathon to help get me to the finish line but honestly the thought of eating wasn’t even a priority. My marathon finished around 1.30pm and it wasn’t until almost 5 hours later that I actually broke my fast with a couple of slices of ham. Even at that point I wasn’t really hungry. Dinner involved a hamburger pattie and a few eggs but I couldn’t quite finish the serving. I’m sure my hunger will return once my digestive system starts to fire up again.

Post Marathon measures:

  • Hunger: 1/10


My sleep last night was very ordinary to say the least. The data illustrates just how much time I spent lying awake and my focus was entirely on alleviating the swelling in my legs rather than sleeping. The elevated feet actually felt fantastic as I could feel every bit of the swelling draining away. I expected that I’d be sleeping soundly the night prior to my fifth marathon but the reality was very different!

It was quite a tough night but the excitement of starting the final marathon the following day was enough for me to not stress too much about it.


My mood this morning was really high and I scored it as a 9 out of 10. I’d made it through four fasted marathons and today was going to be the finish. The thought of only running one more marathon was beautiful. It was empowering to think that I’d already completed over 170km (105 miles) just to get to the start line today. I was still aware that there would be a significant amount of pain today in my ligaments and tendons but the excitement of having a crowd and some fellow runners outweighed any apprehension.


  • Pre Marathon: 9/10
  • Post Marathon: 10/10


By the morning of day five of fasting and my weight was now down to 73.3kg. This equates to a total loss of 3.4kg over since commencing my fasting 5 nights earlier.

The excessive water in my system the night before had added a staggering 2kg to my weight and the scale indicated I weighed almost what I did prior to starting my fast five days ago! It was pleasing to see my weight come back down to expected levels the morning prior to my final marathon. To be clear, I wasn’t excited to have lost weight, I was excited to know that the potential hyponatremia issue (excessive hydration and low sodium) had significantly improved. The overnight loss in weight was a great indicator of a reduction in my water retention.

Post Marathon

Post race involved some quick blood tests and the start of the recovery phase. I’m genuinely not hungry but am obviously looking forward to my first meal. I decided to keep the meal light in order to be sensible in commencing refeeding. It wasn’t until about 7pm that I actually ate. It was delicious and surprisingly filling. I couldn’t quite finish the serving which would be less than a quarter the size of a normal meal for me! Tomorrow, I expect to get back to feast mode and can’t wait to get started!

I’m also looking forward to attaining more data via blood work and dexa scans the week following.

Can you believe it! I got there! Marathon number five is done!!!

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