Boost Your Health and Lifespan: Part 3 of VO2 Max

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6 min read

Boost Your Health and Lifespan: Part 3 of VO2 Max

By

Hillary Lin, MD

Published

Apr 30, 2024

I just returned from a snowboarding trip where I suffered many painful but thankfully quickly recovering injuries (I can now sit on my bottom with only minimal pain). My physical pains include my sleep deficit going up by about 8 hours over the weekend. A future post will definitely that flavor of damage.

This post follows Part 1 of VO2 max, where we learned why this measurement is so valuable for one’s healthspan and longevity, and Part 2, where we learned how to easily measure a VO2 max for as little as no money (!). Did you check your VO2 max yet?

Theoretically, you are now intrigued and motivated to improve your VO2 max. If not, at least maybe this post will be the first step in inspiring you down the road. 😂

In this post:

Hormesis and its value to health
HIIT exercises definition and benefits
Best practices for HIIT

This post has a few studies, but if you’re allergic to scientific explanations you can just take away this tldr…

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tldr; Just 6 min of HIIT exercise 3x a week can significantly improve your VO2 max!

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Hormesis — A Greek Word

I’m spending a paragraph describing hormesis because this rather common-sense practice will come up over and again in DH3 as relevant to health and longevity.

Hormesis defines low-dose stresses, experiences, stimulatory effects, and so on that essentially expose an organism to something toxic or detrimental at a much higher dose. Typical examples are vaccines for infections, exercise for strength and endurance building, and meditation for focus and calm.

Another key piece of effective hormesis is it require some threshold to be crossed before the benefits are realized. For example, simply getting out of bed and walking to your desk and couch will set you up well to do these activities in the future. But to achieve marathon-level running fitness, you’ll need to walk, then run, then run harder and faster with an intentional upward training curve to succeed without collapsing at the end of mile 1.

^{The area under the curve but above the control line represents the “hormetic zone.” Dosing for optimal hormesis is tricky to get entirely correct for anything other than drugs and toxins (where there’s a similar concept called the “therapeutic window”). Still, you can conceptually understand that you need to push a limit to about 150% of your current comfortable baseline and keep doing so to move the curve to the right without overdoing it with any single exposure. NOEL = no observed effect level.}

Endurance Training for Health

It probably comes as no surprise that the way to improve your VO2 max, or cardiorespiratory fitness, is to, well, exercise.

Specifically, you’ll want to do cardio in some form, such as running, cycling, rowing, swimming, or a circuit of activities to get your heart rate up. Running is most common for endurance training because it’s easy to titrate your pace to increase your heart rate (AKA your cardiac load). I find it extremely hard to get my heart going with rowing — probably because I’m doing it wrong. 😂

^{This is failing at rowing (but may still be effective at cardiac training?).}

HIIT

HIIT, or High Interval Intensity Training, is an umbrella term for group classes where you do floor acrobatics to a shouty instructor. JKJK it’s a highly effective form of exercise that has been shown to be the most efficient way to improve your VO2 max!

HIIT is a descriptive term, but to break it down, it includes intervals (from 30 seconds to 4 min typically) of high intensity exercise alternating with lower intensity activity. The simplest version of this is alternating running at a high pace and low pace.

^{HIIT has been studied in children, middle-aged, elderly people, healthy weight subjects, overweight subjects, heart attack survivors, cancer patients and survivors, and more. (There are over eight studies on lung cancer and HIIT alone!) I encourage you to read these, but the overall summary is HIIT is best for cardiorespiratory training for nearly every population, with the proper medical supervision, of course. Also, look at the upper left graph of 2004–2024 number of papers each year and see how HIIT has captured the scientific world in the last few years!}

For those wondering, you can achieve similar results in VO2 max and muscular endurance with any modality of HIIT. This is one study (a small but randomized controlled trial) that studied running vs. functional activity (what you see on YouTube or many fitness apps with exercises like burpees, jumping jacks, and so on). The results showed improvement for both groups, with just 3–4 sets of low-volume HIIT (20 seconds on, 10 seconds rest, 8x, and a 5-minute rest in the middle), 3–4 times a week for 4 weeks.

That’s just 10 min of HIIT 3x a week for substantial heart benefits.

Do you have 10 min on half the days each week to push forward your health and lifespan? I think we all do!

More on efficiency

A 2020 Canadian study showed something else interesting — apparently in a fairly unfit population (low-active individuals with overweight/obesity), a year of either HIIT (75 min a week split over 3 sessions as 10-min high intensity x 1-min rest) or MICT (moderate-intensity continuous training as 150 min split over 3 sessions) showed similar improvements in cardiorespiratory fitness.

^{For data nerds out there, you can see a significant and growing improvement of the VO2 relative (the same as VO2 max) in both groups and no significant difference between the groups.}

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So you can spend half the time and gain similar benefits if you do alternating intervals!

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What about resistance training for VO2 max?

A brief note for those relying mainly on resistance training: High-intensity resistance exercise is likely less effective than traditional high-intensity interval exercise for VO2 max training in most people. A 2022 Swedish study showed that even resistance training designed to increase heart rate and VO2 was less effective than HIIT at challenging the cardiorespiratory system.

However, a 2022 British systematic review and meta-analysis did show that resistance exercise is effective in improving VO2 max in adults age 60+, so the difference may only matter if you’re focused on optimization.

How to HIIT?

Now let’s bring this home — you only need to decide 3 things.

Type of activity: running, rowing, cycling, functional, etc.
Any activity works! Just make sure you can get the intensity up to 80% or higher of your maximum heart rate, the definition of high intensity in this context.
Frequency of HIIT sessions
3 sessions a week of HIIT is recommended in most studies, although any frequency will likely improve your VO2 max as long as you are consistent.
Length of intervals and sessions
The truth is, basically any interval or session length has been shown to be effective, with one meta-analysis confirming that even 6-min HIIT protocols are as effective as longer ones.

Notably, one study in adolescents saw diminishing returns beyond 20 minutes of vigorous physical activity (note they did not specifically test HIIT), so you might draw some loose conclusions about session length based on those results.

And that’s it!

Tackle health from many angles

Today’s post is hyper-focused on the most optimal way to improve your VO2 max with the smallest amount of effective effort, but don’t forget that many aspects of health and longevity require other interventions. I’ve been diving deep into everything from resistance training to micronutrients to even your personal practice around content consumption for healthier and happier living.

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More soon! Until then…

Cheers to your health,

Hillary Lin, MD

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