Monday, October 9, 2023

Mindfulness meditation at the bottom.

 Let's be honest, we all reach the end of our rope at times.  Options like nihilism ("I just don't care"), or alcoholism ("all I need is a drink"), or binge eating, or even, perish the thought, suicidality -- all of these can creep into our lives if pushed hard enough.

One of the ways that I think about mindfulness meditation comes from the term "zero cultures". Sam Harris uses it to describe cultures that, unlike our American puritanism, are cultures where nothing, as manifest by mediation practice, in and of itself is an achievement.

As an alternative to any of the above behaviors, having a practice that allows you to get closer to cessation that is also positive, healthy, forward moving, not to mention addictive, pleasurable -- being able to say to yourself, "rather than doing something I would regret later (if I lived to tell the tale), let me do something in the present that is both positive but also offers some sense of relief." That is a useful tool to have in the toolkit.

The one caveat I have to say here though is that just meditating in times of crisis hasn't worked for me in the past.  It's not enough to just sit when I really need to.  For me it requires an actual, regular, meditation practice for it to be deployable as a technique in crisis.

Sunday, October 8, 2023

Tuesday, October 3, 2023

What actually is V̇O2max, and why is it an indicator of fitness?

V̇O2max is the maximum rate of oxygen consumption that the body's cardiovascular system can maintain.  Let's break that down:

When a muscle contracts, oxygen is required in the reaction that provides the energy.  If we jump on a treadmill, and increase the speed or incline every couple of minutes, we will see the rate of oxygen uptake also increase -- to a point.  

Oxygen is provided by the "cardiovascular" system, meaning the heart and blood vessels.  There is an upper limit to what the heart can provide.  At V̇O2max, we might increase the speed or incline of that treadmill, but the heart and blood vessels can no longer provide any more oxygen.

Why does this provide a measure of fitness?  

The point of exercise (or one of the points including mental health...etc) is to stress the body in such a way that in the process of trying to maintain homeostasis (I will get to that in a second), the system adapts in such a way that it can provide more capacity in the future.  Think muscles getting bigger due to weight lifting, or brisk walks / runs getting easier over time.

A key to understanding adaptation is the idea that the body has systems that keep its systems 'in working parameters' for safety, like the systems in a Tesla that keep the battery from dangerously overheating.  For example when the muscles demand more oxygen due to increased effort, the body works to maintain the level of oxygen in the blood by increasing heart and respiratory rate (probably chiefly in order to protect the brain if I had to guess.). This puts a stress on the heart, to which it adapts over time.

Locally, Rutgers will test V̇O2max in a lab for less than $200.  Fitness watches also have a test that uses heart rate variability, a subject for a future discussion, once I understand it, as a proxy for maximum oxygen uptake.

--edit: One potentially useful note is that V̇O2max occurs at max heart rate, so if something is calling for exercise (as in a stepped test) at 85% of V̇O2, this is the same as 85% MHR.

-- Note to self: The dot above the V in V̇O2max reflects the fact that it is a rate, and is typed by using the extended US keyboard on a mac and the key combination opt-shift-w after the letter.

Monday, October 2, 2023

I think if I wanted accurate body fat data I would go for hydrostatic weighing or Bod Pod over DEXA.


Google result for "is there any cancer risk with DEXA scans?"

DEXA scans provide some pretty interesting information about bone density and body fat.  My question though is about the radiation risk, particularly if you are going to do any kind of regular testing.  A surface-level Google search yields a pretty definitive clip from CDC.  I think if I wanted body fat data, and particularly wanted to test it multiple times, I'd try to find someone that does hydrostatic weighing.


I'm not as familiar with Bod Pod, but I gather that it uses air volume instead of displaced water volume.  This also seems like a good option.

Sunday, October 1, 2023

I got some pretty bad advice on alcohol on low carb diets, which I think I have figured out.

 The bad advice I got was to drink spirits instead of beer or wine, because spirits don't have carbs.  The problem with that approach is that even a single whiskey a couple of nights a week was enough to completely torque my sleep schedule and my mood.  Hard liquor just has a much more dramatic effect than other drinks.

What I discovered over the last couple of days is the polar opposite of whiskey.  That is, the ultra-low carb, and consequently fairly low-alcohol beer.  The beer I had with dinner tonight had 2.5g of carbs per bottle!

If a drink in hand is a social requirement, or if you just enjoy it, I'd suggest a Michelob Ultra (or another low-carb / low alcohol option) rather than a Buffalo Trace.

My formative years (photo tour) elite junior rowing, circa 1995

Even though it was a very long time ago, I don't feel like my current fitness interest would exist without this formative experience. Even if it were just participation trophies for 5k or marathin walk, I would like to get some more current competitive experience.  

Are optical heart rate sensors universally inaccurate?

 TLDR: For weight lifting, yes.  They are universally inaccurate when compared with a chest EEG strap.

TLDR: For aerobic activities like spinning, the answer is mixed.  If you want the best data, use an EEG chest strap like the Polar H10.

In the following graph, a weight lifting session done by Rob ter Horst, a postdoc at the CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, Vienna, Austria, aka The Quantified Scientist.  While his conclusion was that the heart rate tracking on a popular optical watch was generally good, during this session the agreement between an H10 and the watch wasn't that great.  Anecdotally, I think this is representative of the type (optical watch), not the model (Polar Vantage).

Also in this spinning test, one of a few, the concordance was again not that great.  Rob doesn't go into why this test is this way compared to other similar tests, and again, his conclusion is that the tracking is pretty good.  

Same video as above.

My intuition is that the wrist-worn optical sensor (watch) is not as accurate as the forearm, or upper-arm worn optical sensor (Verity Sense), which is not as accurate as the EEG strap (H10).  I'm not all that interested in getting even marginally bad data, and I already have a Fitbit to wear as a fashion accessory, so I think I'll be sticking with my Verity Sense, worn on the forearm, for the time being.