By: Ed Lippie
Dr. Peter Attia, found of Early Medical and New York Times best-seller, uses an analogy of building a pyramid when developing your cardiorespiratory fitness. As he puts it, you want the pyramid’s base to be as wide as possible and the peak of the pyramid to be as high as possible. The base represents your endurance, while the height represents your maximum aerobic output, as expressed by your Vo2Max.
The key word in building your pyramid is “AND,” meaning that you need to engage in the types of work that will both widen your base AND increase the height of your pyramid. And as it turns out, those types of workouts are very different.
To achieve a wide base, you will need to do longer bouts of lower-intensity exercise, often referred to as Zone 2 training, which corresponds with an effort level of 60-70% of max heart rate. A couple of good functional ways to measure the appropriate Zone 2 effort level are maintaining the ability to speak in full sentences (but preferring not to) or the ability to breathe through your nose throughout the workout. The improvement in overall endurance from Zone 2 training is a function of enhanced mitochondrial efficiency, which increases fitness levels and improves virtually every bodily process.
A higher peak to your pyramid will be achieved by doing shorter bouts of intense cardiorespiratory exercise, marked by heart rates above 85% of the max heart rate. You will need to breathe through your mouth at that level of intensity, and speaking will be difficult. This work will improve Vo2Max, a validated metric for cardiorespiratory fitness that is highly correlated with improved health span and lower rates of all-cause mortality. Studies have revealed that even modest improvements in Vo2Max decrease the risk of death from all health-related causes.
Practical Takeaways:
For optimal results, engage in 3-4 sessions of 45 minutes of Zone 2 training per week. Don’t let perfection be the enemy of the good. If you can’t commit to that time, start with 2 40-45 minute sessions weekly. I find podcasts or other forms of digital entertainment work well to pass the time while doing Zone 2 work.
It’s easy to get lost in the weeds on what constitutes Zone 2 training; when in doubt, use the practical guides I referenced earlier: Maintain the ability to breathe through your nose and maintain the ability to speak in complete sentences (but you’d prefer not to speak).
Shorter, more intense intervals improve Vo2Max and should be a staple of your workout plan. The most effective length of Vo2Max intervals is between 3 and 8 minutes. Repeated intervals within a workout are most effective. For example, a Four-minute interval followed by a four-minute rest repeated three times for a total of four (4×4) is sufficient to improve Vo2Max. Doing this workout once per week is sufficient to improve Vo2Max.
Combining aerobic exercise and strength training in the same workout works well for doing a shorter period of Zone 2 work or repeated higher-intensity intervals of one minute or shorter. If you are starting to exercise or getting back into exercise after an extended period not exercising, start with 4-6 weeks of only Zone 2 training before challenging yourself with higher intensity intervals.
