Early August 2021

What’s on my mind lately:

• Running shoes - is squishier better? And for whom? Anyone who has ever tuned the suspension on a mountain bike knows that stiffness, damping, mass and speed all play into how the system works. But you’ve probably bought shoes based on your foot size and how they “feel”, without quantifying beyond that. I’ve been looking at data on running shoe stiffness and impact forces and it’s pretty interesting. Yeah, the Hoka’s are one of the reasons I got curious about this. For me, I love adidas adizero’s which are not quite minimalist but definitely on the less cushioned end of the spectrum. Maybe I’ll share some data from my Garmin running dynamics next newsletter.

• Stanley Druckenmiller is a legend in investing, and he’s been spewing common sense about the economy, investing, and entitlements for a long time. He spoke recently about the risk that the dollar may end its time as the world’s reserve currency. Few people understand or contemplate the meaning of this.

• This Led Zeppelin tribute album is awesome. Four Non-Blondes covering Misty Mountain Hop is especially good. I hope my neighbors like it, they sometimes get to hear it.

• More on running - yes I know the Olympics are underway and Sara Hall is not there but this video of her training, narrated by her husband Ryan Hall, is super interesting. I love seeing how the best train and even more, how they build a mental model for analyzing their training. Ryan has a great discussion of this at the start of the video.

• I’m super interested in continuous glucose monitoring and the expansion of medical sensors into the consumer performance and wellness space. This recent development, in which the FDA allows Dexcom to share their data out to other app developers, is big news. Garmin is one of the first developers on the list to get access to Dexcom device data, via their Application Programming Interface (API). As you may know I’m also a hard core Garmin user. Happily I’m also a shareholder in both Dexcom and Garmin, both big winners in my portfolio this year. All that said, the science is still very immature on how to best use CGM data in healthy people. So if you try it, you need to have the mind of an explorer.