His feet are a bit sore and he could do with a good night's sleep, but David Lake is still enjoying his six-week trek around London.
The army officer from Swansea is now 10 days in to the six-week Flora 1,000 Mile Challenge, which will see him and five others walk - or run - a mile every hour for 1,000 miles.
The 25-year-old from Skewen knows there is still a long way to go, but as of 1300GMT on Thursday the record shows he had completed 262 miles.
At the end, on Sunday 13 April, they will have completed the London marathon circuit 38 times.
The group of two women and four men will be paid £6 for every mile completed and a further £1,000 for finishing 1,000 miles.
This is our 10th time up and down and we've started to find nice little places to stop and eat
The first man and woman challenger will also get £3,000.
"It's going very well so far," he said.
"I had a few minor problems towards the start with tendonitis in the achilles and blisters, but apart from a few aches and pains I'm feeling pretty good.
"I've been getting about five-and-a-half hours sleep at night and I've got quite used to that, but I have just started sleeping a little in the day.
"It's not as bad as I thought it would be."
The challenge is taking place on the London marathon circuit.
"This is our 10th time up and down and we've started to find nice little places to stop and eat," he added.
"Because it is the marathon route, there are a lot of people out running and they know about what we are doing and they are wishing us good luck."
Money raised by Mr Lake will go to charity
The group has been advised to walk or run two back-to-back miles so they can make the most of their rest time.
Their mammoth test is a re-enactment of a challenge undertaken by Royal Welch Fusilier Captain Robert Barclay in 1809.
Mr Lake is a serving member of the regiment.
Mr Lake's fundraising will go to the Army Benevolent Fund.
Despite individuals thinking ahead of tactics, the group of six has remained together for most of the 262 miles completed so far.
"Everyone has their one way of doing things but we chat among ourselves and the group dynamics are going well," he added.
One of the other challengers is Lloyd Scott who set the slowest London marathon record of five days, eight hours, 29 minutes and 46 seconds when he walked the course dressed as a Deep Sea Diver.
He later repeated the feat at the New York Marathon.