Friday thoughts: measuring VO2 max (a reader question) and my personal supplement stack

The post I published in November on VO₂ max, grip strength & balance training for non-athletes was popular then and, apparently, remains so now, because it raised a very good, very detailed reader question from Robyn E. just this week:

Reader Q&A re VO₂ max

ROBYN E.: “How to measure VO2MAX? Apple watch is useless. At 70 I have become a devotee of strict Z2 HR training rather than the Z2 Peloton Output Training and while I prioritise strength training for my osteoporosis. I am using average output watts/average HR as my proxy for VO2MAX. What are your thoughts?”

Great question, Robyn! My thoughts:

First, let us agree that when it comes to VO₂ max, Apple Watch is, indeed, useless.

Second, let’s define what we’re talking about here. VO₂ max is the maximum amount of oxygen your body can take in and use during hard exercise. Think of it as the size of your engine: the amount of air your lungs can pull in, the amount of oxygen your heart can pump to your muscles and how efficiently those muscles can burn that O₂ for energy. VO₂ max (the V stands for volume) is expressed in milliliters of oxygen per kilogram of body weight per minute, which is why it's a fitness measure and a body-weight measure at the same time. The higher the number, the harder and longer you can go—and the lower your statistical risk of dying early¹.

The only real measurement of actual VO₂ max comes from a lab test—the mask-and-treadmill/bike protocol, typically available only at a university exercise physiology lab or sports medicine clinic. (In my case, there’s one waiting for me at Dr. Renee Young’s naturopathic center, near Santa Cruz, Calif.) Everything else, including your smartwatch, is an estimate. Needless to say, some are better than others.

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In case you missed it….

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That said, Robyn’s watts-per-heartbeat proxy is a solid way to track the thing that matters most, which is the direction of your VO₂ max. If your average output at the same average heart rate rises over months, your aerobic engine is improving; if it falls, it isn’t. You won’t get an absolute VO₂ max number out of it, but for training purposes do you really need one, other than post-Peloton bragging rights (not an insignificant reason, I would add)?

So my bottom line thought is: You’ve got a good system. Just keep the test conditions honest: same bike, similar ride length. Or, if you’re more like me: same jump rope workout duration, location (indoor/outdoor), interval/rest time and pre-workout nutrition plan. And remember that heat, sleep and caffeine all move heart rate.

If you ever want the real number, do a lab test once and use it to calibrate everything else. Otherwise, keep doing what you’re doing, Robyn. Strict Z2 by heart rate, plus strength work for the osteoporosis, seems like a sensible program at any age.

My supplement stack (including one moonshot & one guaranteed result)

AGING with STRENGTH has a foundational thesis that durable longevity comes not from supplements but from doing the work: Moving like it’s 1899; eating whole foods; knowing who you really are; taking sleep seriously²; mattering; and spiritual strength (ie, resilience and personal belief systems).

But it’s Friday afternoon and, after 47 years of weight training, 7 orthopedic surgeries and two weeks shy of my 60th birthday—and maintaining ~17% body fat for the last 10-15 years—I figured it’s time to share the supplements I take to augment my fitness, strength and sleep quality.

And below the supplements rundown, my verdict after two years of using a $400 red-light therapy device from a Norwegian manufacturer.

Here are my current supplements, in short order. For the clinical background on most of them, check out my rundown of the “top 12” longevity supplements. NOTE: What follows is not a recommendation or endorsement of any supplement; rather, it’s a de facto list of what I’m currently taking and the benefits, if any, each may have on me.

Magnesium. For sleep quality and to keep your digestive tract moving right along. There are several different forms of magnesium, each with different targeted effects. I take two 500-mg magnesium oxide tablets, Walgreens brand, at night before bed. They seem to have a positive impact on sleep quality and, along with espresso-based caffeine, keeping the GI tract operationally predictable (was that subtle enough?).

Zinc. My data is strictly n of 1 and anecdotal: Since I started taking zinc and magnesium together before bed each night two years ago (thanks for the tip, mom), I haven’t gotten sick once. No colds, no nothing in two full years and counting. That is a remarkable achievement for someone with poorly draining sinuses who grew up suffering through a couple grueling respiratory infections per year.

Can I prove the daily Walgreens zinc tablet is the reason? Not at all. But if this is what a placebo effect looks like, sign me up for 30 years of it, please.

Alpha-ketoglutarate (AKG). To boost athletic performance, I decided to start taking a couple tablets every morning. There’s no significant downside, though the upside is