I run on Zürisee almost every day and have always wanted to run around it. Today I finally did it.
Information
- Date: 06 September 2025
- Start time: ~6:15
- Weather: 11°C (52 °F) to 19°C (66 °F), sunny
- Total time: 4:57:47
Background
- Age: 38 years
- Weight: 66 kg (145 pounds)
- Height: 175 cm (5' 9'')
- Equipment: Nike Vaporfly 3, Salomon S|Lab vest
- Nutrition & hydration: started with 500 mL flask of water and 500 mL flask of sports drink, 9 Powerbar gels (67 mL, 23 g carbs), and a Bärli cookie (47 g carbs, 31 g fat, 8.1 g protein)
Preparation
My training was about 10 weeks peaking at 100 km/week. Not a great training cycle but pretty consistent. I made sure to run most of the route to scout out where there is construction, which in Zürich in the summer is pretty common. My goal was to complete the route in under 5 hours unsupported and I did lots of training at that pace to get comfortable. My longest long run was 35 km (22 mi).
The attempt
I started the attempt around 6:15 AM to take advantage of the cool weather. I set out going counter-clockwise from Bürkliplatz at a <7:10/mi pace, which I knew was faster than necessary, but I also expected a major collapse in the final miles. The first 32 km (20 mi) were uneventful. I filled one of my empty flasks at the Wädenswil public fountain and I rewarded myself at mile 20 with a Bärli. This was probably a bad idea but I was worried about having only liquid carbs for 5 hours.
Going across the bridge and through Rapperswil was tricky. I don't know the area very well and had to retrace my path once but only lost maybe 20 seconds. I did fill another water flask at a public fountain in Rapperswil. Once I was through Rapperswil, my legs started to slow down and I found myself doing "runner's math" for the entire last 32 km (20 mi) to try to figure out how to stay under 5 hours.
Final thoughts
Aside from the Bärli cookie, I think I nailed the water and nutrition. If you have a similar body-composition you might find this helpful. I would also recommend going counter-clockwise like I did because the West side of the lake is significantly more annoying with lots of street crossings, and I think it's better to deal with those early on.
Thank you to the FKT community, particularly Jonathan Dack who made this a really tough challenge for me.