The StoWicks Conversations
by
Carolyn and Seth Wicks
Today's Key Points:
- Aerobic Capacity Predicts Longevity
- If You Don't Train It, You Lose It
- Consistency Builds The Engine
Carolyn: You hear Seth and I harp on strength training all the time (and for good reason). Lifting protects your joints, preserves lean muscle, supports metabolic health, and heck yes, it changes the way you look. There is nothing shallow about wanting to feel strong and look strong. But one of the most overlooked indicators of long-term health isn’t how much you can squat (although I love a heavy squat day!), it’s your VO₂ max, or your aerobic capacity.
We first understood the magnitude of this after reading Peter Attia’s book Outlive, where he explains that VO₂ max, the maximum amount of oxygen your body can use during intense exercise, is one of the strongest predictors of all-cause mortality. It measures how efficiently your heart, lungs, blood, and muscles work together under stress. The higher your VO₂ max, the lower your risk of cardiovascular disease and early death.
One of the most interesting things we learned is that if you don’t train it, it declines by roughly 10% per decade. That means the capacity you have at 35 is not guaranteed at 55, unless you intentionally build it.
Today we’re diving into what this means for you, how to measure it, and how to train it.
Seth: We’ve been wanting to write about this for a while, but the Olympics pushed it to the front of our minds. I mentioned Johannes Høsflot Klæbo last week and his relentless work ethic, and as of this writing he’s won 6 gold medals in two weeks. He’s now second all time in gold medals behind Michael Phelps!
Perhaps his single greatest asset is his aerobic capacity. We don’t know his exact VO₂ max (it hasn’t been publicly confirmed) but cross-country skiing consistently produces some of the highest VO₂ max athletes in the world. When you watch him sprint uphill at the end of a two-hour race, what you’re seeing is a massive cardiovascular engine at work. What breaks others simply doesn't break him.
Circling this back to what this means for us, having higher aerobic capacity is vital not only for athletic competition but also everyday life. Carrying in the groceries, climbing three flights of stairs, playing with your kids. No matter if you're 25 or 75, if you're out of breath when doing simple tasks, that means your own engine is shrinking.
Your goal should be to increase your VO₂ max so that your healthspan matches your lifespan.
Carolyn: So how do you actually improve your VO₂ max? Two primary ways: Zone 2 training and intervals.
Zone 2 is aerobic work done at a conversational pace, meaning you can speak in full sentences without gasping for air. Think brisk walking, steady jogging, cycling, or incline treadmill work for 30–60 minutes. This intensity builds mitochondrial density (the energy engines inside your cells), improves fat oxidation, strengthens your heart, and does so with relatively low stress on the body. The good thing is, it won’t leave you crushed on the floor totally out of breath. Which is awesome because it still delivers an incredibly high return on investment when done consistently.
Intervals, however, are the opposite end of the spectrum: short, intense bursts of effort followed by recovery. These sessions push you near your limit and raise your VO₂ max ceiling, your body’s maximum oxygen output. They’re efficient and powerful, but more taxing, which is why you don’t need them as often.
Our personal rhythm is simple: 2–4 Zone 2 sessions per week, 1 interval session, and daily walking (non-negotiable). Right now, that looks like two miles around the neighborhood with the stroller, slower than we used to move, but still building our aerobic base while investing in our marriage. Seth prefers running for intervals; I love the stair stepper on interval mode.
The great thing about this is none of this is extreme, and that’s the point.
Seth: Carolyn mentioned something at the beginning of this newsletter that I want to revisit. Your aerobic capacity will decline with age, no matter how rigorous your training is. Even the most elite athletes will slow down. The thing is, if you exercise regularly, that decline will be slowed in half.
Pause for a second and think about that. Instead of a 10-12% decline per decade, it would be closer to 5-6%. So for the younger audience, training your aerobic capacity now will pay massive dividends in the future. If you're on the older side of our audience, this may be even more important for you. If you start training today, you can improve your VO2 max. Even if it's only 15%, that buffer could be the difference between independence and dependence.
No matter your age, your body will always respond to stimulus and adapt accordingly. So while decline may be inevitable, the rate of decline is not.
Carolyn: If you’re wondering where to start, start here: walk 8–10k steps per day, add two steady-state (Zone 2) sessions each week for 30–60 minutes, and include one interval session to push your ceiling. Protect your sleep, because recovery is what allows your heart to adapt, and if you’re able, track your resting heart rate occasionally. Over time, a lower resting heart rate is a simple sign your aerobic system is getting stronger. This does not require fancy gadgets, expensive programs, or marathon training. It requires consistency, so keep the plan simple. Let the compounding effect of daily movement do what it was designed to do.
Seth: Remember: Your health is the ultimate currency. Linking your healthspan to your lifespan is critical to staying capable and independent.
The modern world is full of convenience. It's built to have you sit and stare at screens, to sit on the couch and do nothing with your body. Comfort is the norm in today's society, but that doesn't mean it should be.
To be clear: If you live a sedentary lifestyle, your capacity to do any physical activity will decline. So don't ignore what is plainly obvious. Do a little bit every day and your future self will thank you.
Carolyn: This week, schedule your Zone 2 sessions and one interval workout before Sunday night. Don’t wait for motivation, put it on the calendar and protect it like you would any other important commitment.
Seth: Don’t let this be another newsletter you nod at and forget. Text one person today and commit to the plan Carolyn laid out. Put them on the calendar and send that person a screenshot when it’s done. Accountability will always help turn intention into action.
Both: Reply to this email and tell us: what’s your weekly cardio plan going to look like? We read every response and we’re building this alongside you.
See you next week,
Carolyn & Seth
The StoWicks
Quote of the Week:
"VO₂ max is perhaps the single most powerful predictor of longevity.”
Peter Attia
