Zone 2 - A Love Letter

Why is everyone talking about "Zone 2 Cardio"?

Likely because Zone 2 training could be one of the most effective tools for health, cognitive performance, and disease prevention.

Those of us in the human performance world talk a lot about the value of high intensity training, strength training, mobility, etc.

If you're even remotely interested in health, you may have heard of Zone 2.

For those that haven't, here's a quick overview.

In terms of understanding the workload on the heart during exercise, one common method is to categorize HR into a percentage of Maximal Heart Rate, which fit into Zones 1-5.

Zones 1-2

• 60% - 70% HR max

Zone 3 -4

• 70% - 90% HR max

Zone 4-5

• 90% -100%

Zone 2 training means exercising for an extended period (30+ mins) at 60-70% of your Max HR.

Why does 60-70% Max HR matter? Can't I just take a jog or bike ride?

This boils down to your body's energy systems and when/how they kick in during exercise.

When exercising, the rule of specificity is crucial. How you apply stress to the system (exercise) determines how the system will adapt.

Simply put, 70% of your Max HR is the highest point at which your body is leveraging the aerobic energy system and free fatty acids as a fuel source, something that is incredibly important in our modern times. The more you exercise at this end range, the more your system will adapt.

Here's why this is important.

Diabetes, heart disease, cancer, alzheimers, dementia. All of these are closely tied to metabolic health (the way our body uses the food we eat to give us energy).

Our modern diet and lifestyles are wreaking havoc on our energy systems. Most people don't seem to be exercising in a way that challenges the cardiovascular and metabolic systems enough to maintain a basic level of function with age.

Think of your car not having an oil change, sitting with dirty, old gasoline for 5 years and then going on a cross country road trip.

Would you expect to arrive at your destination without any issues along the way?

This is basically our modern diet and lifestyle. Highly processed carbs (junk fuel) and little to no exercise (rotting drive train, tires, transmission - you get the point).

To Recap - some of the benefits of Zone 2:

Zone 2 builds mitochondrial density - you want this

• Training in Zone 2 leverages the aerobic energy system
• Increasing demands of aerobic work results in increasing mitochondria number and efficiency

Zone 2 establishes a healthier energy system - train variety in the fuel used to live

• Mitochondria use free fatty acids (FFAs) as energy rather than jumping straight into glucose
• The better your aerobic capacity, the better your mitochondria are at utilizing FFAs
• In other words, Zone 2 training improves your fat metabolism
• Improved mitochondrial function reduces risk of Type 2 diabetes, cancer, and heart disease
• Healthy metabolic system is essential to preserve health in the long-run

Zone 2 improves stress resilience, recovery, sleep, and heart health

• Decreases parasympathetic response (fight/flight/freeze)
• Increases sympathetic activation (rest/digest/recover)
• Improves resting heart rate, blood flow, heart function
• Due to improvement in sympathetic tone, HR, blood flow, and heart function, sleep quality goes up

Zone 2 allows you to train harder with more volume, higher intensities

• Increase work capacity before switching from aerobic to anaerobic energy systems (reduce lactate production)
• More mitochondria means better lactate elimination/processing, less build up in the blood
• Improved recovery rates of phosphocreatine stores, leading to faster recovery between sets/workouts
• Increased capillary density and blood flow

More Zone 2? Yes indeed.

• Zone 2 means cardio at 60-70% of your Max Heart Rate
• Target 3-4 Zone 2 sessions per week, for about an hour
• This can be daily walks with the dog or more formal jogs/bike rides
• Make sure you're working a little - not too light, not to intense.

No HR monitor? No problem.

• HR monitors are the best and most consistent way to track, but you don't have to have one
• Use the talk test - move as quickly as you can but still be able to speak a 10-15 word sentence unbroken
• Closed mouth cardio - quick and sustainable pace while keeping your mouth closed, breathing through your nose only

Why this matters: The principle of specificity

• Your body is fine tuned to adapt to specific stressors placed upon it (strength, endurance, power, etc.)
• If you're only form of exercise is "walking" and weight training, you could be neglecting an important part of your metabolic system

Already establish a decent aerobic base?

• Once I started, my base came along fairly quickly
• Slightly increase speed or add incline, maybe a weight vest to your daily walks

Using Zone 2 to manage stress and build resilience, improve longevity

• Mind/body connection - Zone 2 improves the tone of the sympathetic nervous system
• Research is uncovering strong links between heart and brain health - i.e. better cardio health means lower risk of dementia and stroke.
• During my bout with burnout, I stopped true Zone 2 training, making things much worse.
• I walked but that wasn't quite enough - I needed a HR strap and light jogs to get my HR to the right zone
• Once I focused on Zone 2 again, things got better. Fast.

For the last few years, I had adopted a mentality that HIIT, strength, and mobility training was all I needed for a complete movement practice.

Between my dance with burnout and my diving back into the research on exercise physiology, strength and conditioning, human performance and longevity, I'm learning all over again just how magical those short jogs really are.

Happy moving.

Peace,

Geoff