Zone 2 cardio has been the latest fitness buzz word around gyms for the past year but is it really that revolutionary and it is right for everyone?
This moderate-intensity level of cardiovascular exercise, where the heart rate is elevated to around 60-70% of a person’s maximum heart rate, can be achieved during a brisk walk by the average individual. For more serious athletes and the super fit amongst us, something more athletic may be required. For example elite runners will be able to hold this heart rate zone whilst jogging.
This zone is typically characterised by sustained efforts that can be maintained for longer durations whilst still being able to hold a conversation. Zone 2 cardio has been a foundational component of endurance training programs for decades and offers numerous benefits for overall health and athletic performance. So why in recent years has it resurfaced as a new magic bullet for taking your stamina to the next level? After all, for the non-athletes, this is just going for a walk.
In a small 2022 study published in PLoS One, researchers found that zone 2 cardio was the right effort level to increase blood flow and improve recovery rates of muscle tissue without being so strenuous that it would cause addition inflammation and damage to the muscles. It also helps flush out metabolic byproducts accumulated during intense workouts.
Zone 2 cardio helps strengthen the heart muscle, improve cardiac output, and enhance the efficiency of oxygen delivery to tissues. Over time, this can lead to a lower resting heart rate and improved endurance capacity. This also helps build a strong aerobic base, increasing the body’s capacity to utilise oxygen during endurance activities like long-distance running, cycling, or swimming.
The enhanced blood flow and oxygenation of tissues also positively impacts the brain. Recent studies have increasingly focused on the cognitive benefits of physical activity, particularly in enhancing creative thinking, with positive results. I often write these articles whilst gently peddling on a spin bike. Darwin walked laps of his “thinking path” to help develop his theory of evolution and Nietzsche famously said ““Do not believe any idea that was not born in the open air and of free movement.” So next time you are stuck on a problem, get moving! Plus, levels of stress hormones such as cortisol will be reduced and endorphins will be released, promoting mental well-being and stress resilience.
This low level cardio is enough to stimulate mitochondrial biogenesis, leading to greater mitochondrial density within cells. Mitochondria are the powerhouse of the cell, literally making energy from the calories we eat or from our fat stores. This means improved energy production, burning more calories even after we exercise!
Zone 2 can be hugely beneficial for weight management. It does this by improving the body’s ability to utilise fats as a fuel source. This is not only great news for endurance athletes, who rely heavily on fat oxidation for fuel, but also those of you who are trying to loose a few pounds and improve metabolic health. Strength, power and combat athletes, bodybuilders and jockeys, who may need to maintain or achieve a specific body composition or weight for their sport also incorporate zone 2 into their training.
You can have too much of a good thing. Women already have a better ability to utilise fat during prolonged periods of exercise than men. They have greater metabolic flexibility, the ability to switch between fatty acid and glucose use, depending on what nutrients are available. So for female athletes looking to enhance mitochondria function and fatty acid utilisation, adding extra hours of zone 2 training into an already full schedule will only lead to over training. Instead focus on increasing intensity of HIIT training and lifting heavier weight, with with plenty of proper rest. Limit the zone 2 to a bit of active recovery to get the blood flowing and make sure it is no more intense than zone 2. A very common mistake is to get carried away and spend hours in zones 3 or 4, exhausting the body without the benefits of true intensity or true recovery.
The best news about zone 2 is that you don’t even need to formally schedule it into a training regime. Active recovery classes, such as gentle yoga or pilates will get you in this zone. Increasing the amount of brisk walking and taking the stairs instead of a lift will help you hit the recommended minimum duration of 150 minutes per week. Do this and you will be reaping the benefits in no time!
