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Fitness
In the latest fitness trends, you may have come across the "Zone 2" training promoted by the well-known doctors Huberman and Peter Attia. Easy, but not too easy, exercises can improve your fitness and metabolic health. Here's how to do it.
You've probably heard of high-intensity interval training (HIIT), where bursts of near-maximum effort are alternated with low-intensity exercise sessions. HIIT is more efficient than slow, steady workouts for fat loss and conditioning.
In the last decade, scientists, physiologists and trainers have once again embraced the benefits of slow and steady "Zone 2" cardiovascular exercise - exercise that keeps your heart rate in a zone between 60 and 70 percent of your overall maximum heart rate.
Some new and unique benefits have also been observed with this workout. In 2014, for example, scientists demonstrated that endurance athletes had greater gains in VO2 Max (a fitness marker that measures the maximum amount of oxygen your body can use at one time) when they incorporated Zone 2 compared to those who only practiced HIIT and sprint training.
Since then, similar benefits have been found for recreational ultra-endurance runners, where slow training helped aerobic performance and body composition, but also for high-intensity exercisers such as mountain bikers and soccer players. Experts say that most of your exercise regime should fall into this Zone 2 range.
The mechanisms behind this type of training
The demanding level of physical exercise is often divided into five approximate "zones" of intensity, marked by a percentage range of maximum heart rate.
Although trainers often have their own system, Zone 5 is usually 90-100 percent of your maximum heart rate (achieved with intense exercise, such as all-out running), while Zone 1 is 50-60 percent of your maximum (a brisk walk).
At lower intensities, from rest to Zone 2, the body relies mainly on fat for energy. Fat is an efficient fuel source, but it requires a lot of oxygen to be metabolized.
As the intensity increases, carbohydrates, in the form of stored glycogen, become the body's main source of fuel. Zone 2 is the space where you are doing the maximum level of effort without crossing the "crossover point" from aerobic ("with oxygen") to anaerobic ("without oxygen") where carbohydrates start to become the preferred fuel source. Fat and lactate (a by-product of glucose metabolism) begin to accumulate.
The zones are not clearly delineated, they are percentage ranges of maximum heart rate, with "soft borders" between the zones. There's no magic that happens if you're a few beats above 70% of your maximum heart rate range.
But prolonged efforts in Zone 2 seem to have some unique characteristics that help improve overall fitness.
Almost three decades ago, exercise physiologist and professor at the University of Colorado School of Medicine, Iñigo San Millán, interested in mitochondrial function as "the epicenter of performance" and a former competitive cyclist, he wanted to find an exercise intensity that improved mitochondrial function.
By measuring an athlete's lactate through blood samples, he discovered that training in Zone 2 is the best way to stimulate mitochondrial function and cultivate a cardiovascular base from which both professional cyclists and weekend 5km athletes can benefit.
The many benefits of Zone 2 training
Doing 150 minutes a week of moderate, Zone 2 activity is associated with reduced risks of heart disease, diabetes and certain types of cancer, according to the CDC.
It also does wonders for your metabolic health, especially when it comes to your body's ability to break down energy substrates (glucose and fat) and achieve metabolic flexibility. Here's an overview of the different ways in which Zone 2 training optimizes metabolism and your overall health:
In this training zone, we stimulate Type 1 muscle fibers. Type I muscle fibers are dominant at low exercise intensities. These fibers have many mitochondria that produce energy aerobically and use fat as fuel.
Therefore, we stimulate mitochondrial growth and function, which will improve fat utilization capacity. This is fundamental for athletic performance, because by improving fat utilization, we preserve glycogen utilization throughout the competition.
These mitochondria generate energy aerobically, using fat and lactate as fuel. As a result, an improvement in mitochondrial function increases the ability to burn fat and eliminate lactate.
The "pain point" for those interested in Zone 2 resistance work is that it requires a relatively long time: 1 hour of exercise, 3-4 times a week, for 12 weeks - the time needed to change exercise behavior. Patience is therefore required
How to tell if I'm in training zone 2
Through a metabolic test
With lactate samples
Using the conversation test
Even if you're not taking blood during your workouts to measure lactate like professional athletes do, there is a non-invasive way to get a closer look at whether you're training in Zone 2: the "talk test".
Zone 2 is a little harder than an easy run or a relaxed bike ride, although this varies from athlete to athlete.
While you're training try talking, you should be able to talk, but it should be a bit of a struggle.
But you should be able to speak complete sentences at this pace. This zone, which represents around 70% of maximum heart rate, should be achievable for almost everyone,
Despite all the attention Zone 2 training has received, it's important to remember that it's just one slice of a larger fitness pie. More specifically, it should represent around 80% of that pie, with the remaining 20% done at high intensity.
Instead of thinking of Zone 2 as a tool for losing weight, it's more accurate to think of it as a way of making your internal engine more efficient.
Instead of imagining a six-pack, imagine beautiful mitochondria inside the cell, operating at maximum efficiency.
Disclaimer: This content, including advice, provides generic information only. Do not replace a medical opinion in any way.