Are you too old to get fit? Cardio Edition
Building & Maintaining Cardio after 40
In 2023 I had the privilege of sharing an Ironman 70.3 course with a man in his 80s. Being 43 years old myself, I marveled at the man nearly twice my age, and I saw him during the run too. He’d already swum 1.2 miles and cycled 56 miles. And he wasn’t walking! He was still trotting. It was unbelievably motivating. And a visceral reminder that it’s never too late to get fit and always too soon to stop training.
I imagine my reader thinking, that’s all well and good for him, but what about regular HUMANS? What can an average person do? And what does science say about fitness after 40?
Fair enough.
In this blog, I’ll take you on an evidence-based dive into building and maintaining cardio after turning 40. I will show you why cardio matters MORE as you age. It’s the single most potent longevity strategy! I will show why you’re never too old to start getting fit. And I’ll offer my top four tips for crushing cardio after 40.
Here are links to each section.
Why Cardio Matters More After 40
Cardio is EVERYTHING as we age. For one thing, your CardioRespiratory Fitness (CRF) determines what kinds of physical activity you can do. With terrible CRF, you might struggle to climb 5 flights of stairs, play with the kids or tackle a long hike. The worse your CRF gets the harder EVERYTHING becomes.
Alternatively, great CRF opens doors. Want to go for a long bike ride in the Italian countryside? Or tackle an Ironman Triathlon? The better your CRF gets the easier EVERYTHING becomes.
To understand how this works, let’s take a brief look at some exercise science. To perform physical activities you need energy, specifically adenosine triphosphate (ATP). To create energy (ATP), you need oxygen. Different people convert oxygen into ATP at different rates. We can measure this variance by testing a person’s maximum rate of oxygen intake (VO2 max). The higher your VO2 max, the better you are at converting oxygen into energy.
It’s a difference you can feel!
The closer you are to your VO2 max for any given activity, the harder it feels. For example, if an activity pushes you to 80% of your VO2 max, it is going to feel hard! For some people this might be climbing 5 flights of stairs. For others it might be running 10 km in under 50 minutes.
Alternatively, if an activity pushes you to 10% of your VO2 max, it feels inconsequential. You can do it all day without a thought. If you're familiar with lifting weights, you can think of VO2 max as the 1 rep max of your cardiorespiratory system. And just like strength, CRF follows a simple rule: Use it or Lose It
Use it or Lose it
Your VO2 max declines by about 1% per year or 10% per decade. Once you hit 70, it declines sharply at a rate of about 20-25% per decade for men and 15-20% per decade for women. To put this into perspective, the average non-athletic 40 year old has a VO2 max of 27-39. Once your CRF gets below a VO2 max of about 20, you won’t be able to convert enough oxygen into energy to climb 5 flights of stairs. You’ll be forced into a sedentary life with all the negative health and lifestyle factors that it entails. Want to ski in your 70s, travel the world in your 80s, or actively play with your great grandkids? You’ll need to build and maintain as much CRF as possible. Not only does CRF make hiking or SCUBA diving easy, but it makes a MASSIVE difference in longevity outcomes.
Cardiorespiratory Fitness and Longevity
CRF is the most potent longevity intervention science has discovered. There’s nothing you can do that will have a greater impact on the number of healthy, active years you have left to enjoy. We’ve had good reasons to suspect this for decades. For example, studies have shown that CRF reduces your risks of developing cancer, having a stroke, contracting diabetes, and suffering from hypertension.
But then, in 2018, a study in JAMA uncovered a remarkable link between VO2 max and longevity. Researchers conducted VO2 max tests on over a hundred thousand participants, who ran on treadmills while their oxygen consumption was measured. Participants were categorized into five levels of fitness, from 'unfit'—the bottom 25%, to 'elite'—the top 2.3%. For example, for a 43-year-old like me, 'unfit' would be a VO2 max below 32, while 'elite' would be above 56."
After 8.4 years, follow-up data revealed that participants in the elite category were 80% less likely to have died compared to those in the unfit category— a disparity greater than that between smokers and non-smokers. It really matters!
To verify these remarkable results, another study in 2022 involving 750,000 participants confirmed similar outcomes. Elites were still four times less likely to die than those completely unfit. Although this is a slightly more modest effect, it places CRF at the very top of the list of things you can do to improve your health and longevity. If health, longevity and an active lifestyle are the goals, CRF is far and away the number one answer. Everything else comes in a distant second.
Building elite VO2 max levels takes years, not months. For instance, after training for my second full-distance Ironman, my VO2 max peaked at 56—just shy of the elite level. It's taken years of consistent effort to achieve this. However, you don't need to reach elite status to see significant benefits. While more is generally better, the law of diminishing returns applies; moving from untrained to above average can confer most of the benefits, with minimal differences seen between highly trained and elite levels
Next up, I’ll show you why it’s never too late to get started. Even if you’re unfit and in your 50s or even older, you can always get fitter and reap enormous benefits!
Why You’re Never Too Old to Get Fit
Are people in their 50s too old to get fit? In 2018, researchers decided to find out. They enrolled a group of untrained, unfit individuals in their 50s into a two-year randomized controlled trial. One group underwent rigorous training—up to 4-5 sessions per week, including high-intensity workouts—while the control group continued their normal lives
The training was intense! Participants worked up to 4-5 sessions per week for a minimum of 30 minutes per session. They averaged 5-6 hours of training per week. And at least one session per week was a high-intensity session. But all the work paid off BIG!
They raised their VO2 max by an average of 18%. No steady decline for these folks! Not only that, but they significantly changed the structure of their hearts making them less stiff and erasing a couple decades of aging.
Ok, what about people in their 60s, 70s or older? While it's true that fitness gets harder with age, the potential for dramatic results remains, no matter how old you are.
Consider the remarkable Robert Merchand, a French WWII veteran and former POW. At the ripe young age of 101, he set an age group world record in the one-hour cycling event, covering 24.25 km.
Yet, being a member of the greatest generation, he decided he could probably do a bit better. He trained even harder for two years and crushed his own world record, completing 26.92 km in an hour. He had also raised his VO2 max from 31 to 35, putting it above that of an unfit 43-year-old.
While we may not all become legends like Robert, improvement is always there for the taking. Next, I'll share my top four tips for crushing cardio after 40.
My Top 4 Tips for Crushing Cardio After 40
1. Lay a Wide Foundation of Walking
If you’re completely untrained, one of the best ways to get started is walking. It’s low impact, accessible for most age groups, a great weight loss strategy and insanely healthy. The average sedentary American walks just 3,000 to 4,000 steps per day. According to a 2023 study, increasing this to 12,000 steps per day slashes your risk of premature death by a staggering 67%.
12,000 steps is a lot, but don’t worry! You can build up slowly. The same study revealed that adding just 1,000 steps per day can bring a 15% decrease in mortality risk. Thus, I recommend you start by adding 1,000 steps to your daily total, then after a few weeks, try adding another 1,000 steps. For most people, a great goal is 10,000 steps per day.
Establishing a walking habit also makes it much easier to start running. I recommend using Run Walk intervals for the transition from walking to running. For instance, after warming up with 5-10 minutes of brisk walking, you might run one minute and then walk for four minutes and do intervals like that 4-6 times. From there, it’s just a matter of slowly increasing the percentage of running you do. Listen to your body and be patient. It can take some time to build up to full runs.
2. Utilize a Polarized Training Program
Polarized training simply means some of your training is at a slow and easy pace and some of your training is at a really fast and difficult pace. Every plan you’ll find online for everything from half marathon to full Ironman utilizes polarized training. It’s the cornerstone of evidence-based endurance training programs. Moreover, if you want to optimize your fitness for health and longevity, you’ll need both easy and hard sessions to comprehensively train different components of your cardiorespiratory system.
Do you remember the study that trained people in their 50s? Each participant was given an individualized plan that was monitored and continuously adjusted. In other words, they were coached. But we can use this study as a template for building our own polarized training routine.
First, they spent two months working up to 30 minutes of slow and steady cardio 3x per week. In month three they added one hard session per week, a Norwegian 4x4 VO2 max training session.
To perform a Norwegian 4x4, start with a 10-minute warm-up at an easy pace. For each interval, push hard (85-95% max heart rate) for 4 minutes, then recover at a slow pace for three minutes. You repeat the interval four times. Finish with a 5 to 10-minute cool down at an easy pace. For a low impact version, you can perform these on a stationary bike.
Six months into the program, they were training cardio 5-6 hours per week. They had two hard sessions per week and one long (at least 60 minutes) slow session per week.
In many ways their training looked VERY similar to half Ironman training. They were even encouraged to embrace multisport training.
For a more detailed look at Half Ironman Training, check out my blog, What to expect: A first-timer's guide to the Ironman 70.3
3. Embrace Multisport Training
Multisport training involves engaging in two or more sports. In my case, it includes swimming, running, and cycling for Ironman competitions, though you could choose a different combination. In terms of fitness after 40, multisport has three advantages.
First, it reduces your risk of injury by diversifying your activity, preventing overuse of any single muscle group. For instance, to achieve the same level of cardiorespiratory fitness from running alone, I would need to triple my running volume compared to what I do in triathlon training.
Second, cross-training offers tremendous flexibility to prevent overuse injuries. Experiencing knee pain during a run? Simply switch your next few runs to cycling or swimming sessions. If you already feel confident and have the equipment, there’s no barrier to entry.
Finally, training in multiple sports is more fun and interesting. Unlike running several times a week, having three different disciplines keeps training varied and engaging.
4. Avoid Taking Long Breaks
I’ve got good news and bad news here. First the bad news: cardiorespiratory fitness declines swiftly once you stop training. CRF reshapes your body in numerous ways—altering your heart's size and shape, enhancing mitochondrial density and efficiency, and increasing capillary networks in your muscles. Once you cease training, these adaptations begin to reverse. Consequently, research has found that VO2 max declines by 7% after just 21 days of inactivity.
The good news: even after three months of no training, you only lose about 16% of your VO2 max. So, while setbacks occur, they don’t erase all your gains. Given the benefits, the message is clear: don’t stop! Keep going!
Closing Thoughts
My son, who is just 4 years old, loves strength training with me, and we’ve already started biking together. Meanwhile, my daughter joined me for her first run at the age of 7. These moments constantly remind me of the importance of maintaining fitness for as long as possible.
I dream of summiting mountains with my grandkids and cycling through the Italian countryside with my wife after we retire. According to science, it's entirely possible—all you need is to train intelligently and consistently, avoid injuries, and just keep going!
If you enjoyed this article and would like to learn more about training and longevity, check out my article Maximizing Lifespan: The Essential Guide to Exercise for Longevity
