Presentation companion notes: Longevity Fireside Chat with Geoff Girvitz (May 16, 2024)
Follow along to see sources and references for the presentation discussion.
This is a companion post to the Fireside Chat we’re hosting with Geoff Girvitz on May 16, 2024. Follow along to see relevant references and diagrams during this presentation and return to them for future use.
Geoff Girvitz: expert in exercise and behavioural change
Geoff has worked in the areas of health and behaviour change for nearly 20 years and an expert in exercise and behaviour change. Geoff founded Bang Personal Training in 2008, where he and his team take a mindfulness-based approach to strength training.
Geoff has worked with Thrive Global, Precision Nutrition, and Dr. BJ Fogg, along with the Behavior Design Lab at Stanford University. He has been featured in in Vice, GQ, and the Globe and Mail.
What is VO2max and why does it matter for human longevity?
The strict definition, from Wikipedia:
VO2 max (also maximal oxygen consumption, maximal oxygen uptake or maximal aerobic capacity) is the maximum rate of oxygen consumption attainable during physical exertion.
VO2max is a measure of cardiorespiratory fitness.
Cardiorespiratory fitness matters because the fitter you are, the lower your risk of dying.1
A landmark JAMA study in 2018 on a similar topic also noted the following:2
Cardiorespiratory fitness is inversely associated with long-term mortality with no observed upper limit of benefit. Extremely high aerobic fitness was associated with the greatest survival and was associated with benefit in older patients and those with hypertension. Cardiorespiratory fitness is a modifiable indicator of long-term mortality, and health care professionals should encourage patients to achieve and maintain high levels of fitness.
What is Zone 2 training and why is everyone so hyped about it?
Zone 2 training consists of aerobic exercise where you train well under your lactate threshold (the level above which lactate is produced faster than it can be cleared). In Zone 2, your primary source of energy is fat metabolism. At this level of exertion, your body is not building up lactic acid and hydrogen ions.
The intensity of exercise required to get you into Zone 2 varies depending on your fitness level. For some individuals, a brisk walk might get them into Zone 2; for those in better condition, Zone 2 means walking uphill or a light jog.
People are increasingly excited about Zone 2 training because it’s gained popularity as a mechanism for boosting VO2max, and people are interested in the longevity benefit of this.
There are multiple ways of checking if you’re in Zone 2. One popular method is the “Talk Test:”
The Talk Test: In Zone 2, you can carry out a conversation but it’s not as comfortable as a regular discussion - i.e., you should be a little more strained. If you can’t maintain a conversation, then that’s too high intensity and you are out of Zone. If you were to have a phone conversation in this state, the person on the other end of your conversation should be able to know that you are exercising based on the way you sound.
What is High-Intensity Interval Training (HIIT) and how is it different than zone 2?
High-Intensity Interval Training (HIIT) consists of alternating between time intervals of higher-intensity and lower-intensity training. Typically this means intervals with >80% of your maximum HR.
Unlike Zone 2, it is not a steady-state exercise where you aim to continuously maintain a certain HR for an extended period of time.
What is an example of a HIIT protocol?
High-intensity interval: A 4 minute-interval with the highest intensity pace you can sustain for the entire 4 minutes (i.e. not "all-out").
Low-intensity interval: Follow the high-intensity interval with a 4 minute-interval at a low-intensity pace such that your heart rate can recover to less than 100 beats per minute.
Repeat the cycle above three more times for a total of four cycles.
For a video overview of different possible HIIT workouts, Rhonda Patrick has a good summary here.
Doesn't HIIT training require less time to boost VO2max than Zone 2 training?
Per unit of time dedicated to exercise, HIIT training can produce improvements in VO2max and cardiorespiratory fitness faster than Zone 2 training.
However, because of the increased intensity, it can be more taxing on the body and more easily lead to over-training.
If HIIT is more time-efficient for boosting VO2max than Zone 2, why do Zone 2 at all? (hint: mitochondria)
We’ve been searching for data and arguments in favour of a regimen that combines Zone + HIIT versus HIIT alone given that HIIT alone does also improve mitochondrial health.
There is some data to suggest that Zone 2 endurance training is better than high-intensity training at producing cardiac remodelling to accommodate greater stroke volume, which is associated with an increased VO2max.3
Here’s an excerpt which goes over the mitochondrial benefits specifically:
Mitochondrial biogenesis—the making of more mitochondria—has been found in studies to be tied to how much total training you do. Because Zone 2 training is more sustainable than more intense exercise, you can do more of it and thus build more mitochondria.
Studies show that moderate exercise like Zone 2 also induces your cells to clear out old, malfunctioning mitochondria through a process called mitophagy. Higher-quality mitochondria have a greater capacity for fat oxidation and oxidative phosphorylation, the final stage of cellular respiration. Lower-quality mitochondria have been associated in studies with insulin-resistant states like Type 2 diabetes and metabolic syndrome. When mitochondria are of higher quality, as they are in elite athletes, research has found that they can switch back and forth between using fat and glucose (aka metabolic flexibility) to create ATP quickly and efficiently. But in people with insulin resistance, the mitochondria are less robust and less efficient at using glucose and fat. Zone 2 increases the quality and number of your mitochondria, improving your ability to fuel your efforts—you’re fitter, so you can stay stronger for longer.
This is still an area that’s more controversial and pragmatic constraints (e.g. risk of over-training and exhaustion) tend to predominate.
In general, evidence has accumulated to demonstrate that boosting mitochondrial health has numerous benefits, including in cardiovascular health.4
Apparently up to 40% of people won't boost VO2max with just zone 2 training. Is this why you want to add HIIT?
There’s concern among experts that moderate intensity, continuous exercise (such as Zone 2) will not produce an effective response in boosting VO2max/cardiorespiratory fitness.5
The solution is to increasing training intensity. Thus, many experts recommend combining Zone 2 training with HIIT.
Can I just do HIIT to boost my VO2max if I don't have the time to do 3+ hours of Zone 2 every week + HIIT?
Yes, but this may be more taxing on your body.
What's an example weekly protocol? e.g. 3 hrs/week of Zone + ~30m of HIIT/week
An example is Dr. Peter Attia’s PROTOCOL: A weekly training schedule with an ~80:20 | Zone 2:HIIT ratio.
3 hours (or more) of Zone 2 training per week split into 2 90 minute sessions OR 3 one-hour sessions OR 4 forty-five minute sessions.
~30 minutes (or more) of HIIT training consisting of 4 minutes of the highest-intensity pace you can.
Maintain an ~80:20 ratio of training time in each of these 2 training modalities.
Note that you can also do your HIIT session immediately after a Zone 2 training session for increased scheduling efficiency.
Coda: Strength and longevity
It’s not just cardiorespiratory fitness that extends human healthspan and longevity.
It’s also strength! Muscle mass, for example, is positively correlated to longevity - so our focus shouldn’t only be on cardiorespiratory health, but building strength, also.6
Consider the following study with 12,000+ participants on the relationship between strength training and cardiovascular mortality:7
Even one time or less than 1 h·wk of RE [resistance exercise], independent of AE, is associated with reduced risks of CVD and all-cause mortality.
Where can people find Geoff?
You can find him at the following links:
Interested in becoming a member of Optimal?
Check out our members-only community here.
You can also read our free performance and longevity wiki docs here.
Lastly, you can follow us on X(Twitter) here.
References:
Kokkinos P, Faselis C, Samuel IBH, Pittaras A, Doumas M, Murphy R, Heimall MS, Sui X, Zhang J, Myers J. Cardiorespiratory Fitness and Mortality Risk Across the Spectra of Age, Race, and Sex. J Am Coll Cardiol. 2022 Aug 9;80(6):598-609. doi: 10.1016/j.jacc.2022.05.031. PMID: 35926933.
Mandsager K, Harb S, Cremer P, Phelan D, Nissen SE, Jaber W. Association of Cardiorespiratory Fitness With Long-term Mortality Among Adults Undergoing Exercise Treadmill Testing. JAMA Netw Open. 2018;1(6):e183605. doi:10.1001/jamanetworkopen.2018.3605
Child JS, Barnard RJ, Taw RL. Cardiac hypertrophy and function in master endurance runners and sprinters. J Appl Physiol Respir Environ Exerc Physiol. 1984 Jul;57(1):176-81. doi: 10.1152/jappl.1984.57.1.176. PMID: 6236190.
Poznyak AV, Ivanova EA, Sobenin IA, Yet SF, Orekhov AN. The Role of Mitochondria in Cardiovascular Diseases. Biology (Basel). 2020 Jun 25;9(6):137. doi: 10.3390/biology9060137. PMID: 32630516; PMCID: PMC7344641.
Bell, L.R.; Gabbett, T.J.; Davis, G.M.; Wallen, M.P.; O’Brien, B.J. Stubborn Exercise Responders–Where to Next? Sports 2022, 10, 95. https://doi.org/10.3390/sports10060095
Srikanthan, Preethi, and Arun S. Karlamangla. 2014. "Muscle Mass Index as a Predictor of Longevity in Older Adults." The American Journal of Medicine 127 (6): 547-553. doi:10.1016/j.amjmed.2014.02.007.
Liu Y, Lee DC, Li Y, Zhu W, Zhang R, Sui X, Lavie CJ, Blair SN. Associations of Resistance Exercise with Cardiovascular Disease Morbidity and Mortality. Med Sci Sports Exerc. 2019 Mar;51(3):499-508. doi: 10.1249/MSS.0000000000001822. PMID: 30376511; PMCID: PMC7385554.