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Karl Etzel
@karletzel
33
Health & fitness tech, wearables, the occasional random life post.
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Location
Silicon Valley
Website
http://www.system3.co
Created
2016-12-30 02:07
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Wallet
karletzel
habits
7y
Old dogs, new tricks
I've lately been more conscious about the effort required to change deeply held beliefs, in particular the ones you hold about yourself. Being very cerebral I tend to fall back on data and facts in assessing
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karletzel
cycling
7y
The most underrated piece of cycling gear
Cycling pro tip of the day: I just wanted to highlight one of the most useful pieces of gear that I see almost noone else using, and that is the helmet cover: Your mom always told you to wear a hat because
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karletzel
backpacking
7y
Kings Canyon NP, June 2019 trip
Every year I take the boys backpacking at least once, usually the high Sierras. This year we did not get to high (last year we made it to Glenn Pass). With all the snow pack the creeks and rivers are RAGING
karletzel
rogan
8y
Art Imitating / Reflecting Life
Adding a little more random content to my seldom-updated blog for 2019. I've twice had the experience in the last 6 months of seeing something in media or popular culture which really resonates or speaks
karletzel
fasting
8y
Fasting and HRV, part II
Lest you think (as I did) that the first time was an anomaly or random: And with a second system / measurement device (this one more accurate - the Firstbeat Bodyguard used with their Lifestyle Assessment),
karletzel
fasting
8y
Fasting and HRV
Can you guess which night I was 24 hours into a fast? 113 ms might be my highest HRV ever. I have begun extending my weekly fast to 36 hours (IOW I ate dinner Monday night and did not eat again til Wednesday
karletzel
cycling
8y
FTP, Zwift, Shoulder work
Training binge over the holidays worked, did an FTP test on Zwift today (nothing magic to Zwift, it's a standard 20 minute protocol but Zwift has one pre-programmed with a really efficient warm-up effort),
karletzel
sleep
8y
Sleep tracker comparison
Quick note on a comparison I ran over the holidays on 4 (yes, 4 in parallel) sleep trackers: Oura, Firstbeat Lifestyle Assessment, Vital Scout, and the latest entrant, Beddr. Oura is a ring, Vital Scout
karletzel
cycling
8y
Day 1 of a training block
For a variety of reasons I have the week off to get some work done and I'm training a lot, my goal is 3 hours per day. The plan is 4 days doing 3 hour rides and then the other 3 days, ride 90 minutes and
karletzel
cycling
8y
End of year binge
The blog's been quite a while, life has been full. Started a new FT gig in a startup, scaled back a number of things, found some new devices I wanted to test, and working on building up the work capacity
karletzel
hrv
8y
Stress Analytics and Training Load
Been tweaking the training up a bit lately and shortening my weekend rides, just getting too bogged down and tired on my long-ish loop to Page Mill. Rode last weekend with a pretty fast friend who races
karletzel
cycling
8y
Some new carbon goodness, fall riding, prepped for winter
Wow been a long while, been super busy with a new FT gig in a medical device startup and my ex was outa town so I had a long stint in solo dad mode. Anyways...fall riding is gorgeous lately, I've been
karletzel
cycling
8y
Chill day up Hwy 9
Nothing too dramatic today, I had a somewhat rough week in terms of just feeling super fatigued, so I took it a bit easier today: My time up Hwy 9 was about 2:30 slower than my time last week, but still
karletzel
cycling
8y
Nootropics for Athletic Performance - Day 1
Two stories from my day today, one was just an overall very solid ride with a new PR on my local climb: I felt on the climb like I was going well, so I'm not too surprised by this. My Garmin 935 reported
karletzel
testosterone
8y
Testosterone Optimization
Quick post about a very important topic - hormone optimization. You can't optimize what you don't measure. I use InsideTracker for all my blood work. Check them out: One of my projects of the last few
karletzel
cycling
8y
New PRs, and VO2max intervals, and needing a rest
After my backpacking trip I had a super sluggish week, as I indicated last week. Then I did my usual Sunday loop (Highway 9 - Skyline - Page Mill - Foothill home) after a week or so of recovering and turned
karletzel
hrv
8y
HRV Analysis of 6 days Backpacking
For this backpacking trip I wore the Firstbeat Bodyguard and ran the data through our Lifestyle Assessment ( Here are a few notes from the report. First up is the fact that my HR numbers clearly show the
karletzel
cycling
8y
Some Altitude work
Been a hectic start to summer, just back from the Sierras with my boys. Legs have been super sluggish - One of my local warm-up hills, a good 40 Watts less than I had been doing for a while there. I should
karletzel
fitness
8y
Training update, fatigue vs. intensity
Here's yesterday's ride from TrainingPeaks: One thing that I really notice after so many years away from racing is that hard efforts leave me really wasted. I had 3-4 efforts yesterday where I really pushed
karletzel
cycling
8y
VO2max, another small step
Load up the training volume, things improve. Here's some background behind VO2max: If you don't know your score, and you are serious about fitness, you should.
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