“Exercise…I consider to be by far the most potent domain in terms of its impact on both lifespan and health-span.”  Dr. Peter Attia

The CrossFit methodology has evolved over the past 13 years since I first took the Level 1 exam. The experience we offer in the gym I believe has grown to include the lifespan and health-span long view. The old CrossFit mantra of “Go Hard, Go Heavy or Go Home” we have finally accepted is not a way to help our members and a sure way to send many down the path of injury and sickness. What has not changed is the theory on energy systems (what CrossFit calls metabolic pathways).

Let’s start by relabeling “exercise” with a term that better captures the purpose behind our programming here at Iron & Grit — TRAINING. Why training? Our goal is to train the metabolic pathways that maintain our metabolic health. In CrossFit we define our 3 systems as Phosphagen (anaerobic), Glycolytic (moderate output) and oxidative (Zone 2/Aerobic). We want to train these systems to work together and to operate more efficiently. There are 4 areas in training that require focus on a weekly basis: Zone 2 Training (oxidative/aerobic), Anaerobic, Strength and Stability. Our chosen methodology is CrossFit, and throughout our weekly program we vary the workouts to have components of all four. Today we will be unpacking Zone 2 training.

My son Lukas and I 10 years ago. I had just started CrossFit and dragged him along on the fun journey.


This is your cardiovascular systems best friend. Most people would call this aerobic training and to get the most benefit from Zone 2 training it is necessary to train in this system 2-4 times a week. Dr. Attia the author of OUTLIVE recommends that four times a week is optimal. A 30–45-minute jog at an easy pace builds your base of fitness. If you are not a runner, Zone 2 can be achieved on a rower, bike, swimming, or an elliptical machine. To get the most benefit from Zone 2 it is best to sustain effort for the duration of time you are targeting. The continuous effort is what is needed to get the benefit, in fact, Zone 2 is best achieved by continuous effort where you can still have a conversation. However, it is not a walk in the park, EFFORT needs to be exerted. It takes a little practice to establish your Zone 2 pace.

As with any micro habit, developing Zone 2 into your week is best done with manageable, achievable, and sustainable effort.

Good: 2 Times A Week

Better: 3 Times A Week

Optimal: 4 Times A Week

In addition, the amount of time you spend in Zone 2 can start with your current fitness level. The beginner is going to have to build in smaller increments of 15 minutes while the advanced athlete can keep a longer sustained time in Zone 2. Here is a good road map to follow:

Beginner (just starting a fitness program): 15 Minutes of light jog, row, stationary bike, or swim 2-4 times a week. Over a 4-week period build to 30 minutes by adding 5 minutes each week.

Intermediate (have trained but have gotten out of shape or lost motivation): 30 minutes of light jog, row, bike, or swim 3-4 times a week. Build over a 4-6 week period by adding 5 minutes a week until you are able to sustain 45 minutes.

Advanced (train consistently for the past 10 years—3-6 days a week is what we would consider consistent): 45 minutes of light jog, row, bike or swim 4 days a week minimum is the base we are building towards. This does not include stability, strength and anaerobic training.

The benefits of consistently training at the Zone 2 level 2-4 times a week cannot be understated. Most obvious is the benefits to your cardiovascular system. Your body’s ability to intake oxygen and utilize it becomes more efficient as you increase your aerobic system. Simply put, it is the base of your fitness. Not only because it burns excess calories, but Zone 2 training is like banking years to your life. To live a sedentary life is to put yourself into sickness or as Dr. Attia puts it: “Poor cardiorespiratory fitness carries a greater relative risk of death than smoking.” That is a bold statement indeed and one I hope will motivate you to get off the couch and get started!

Zone 2 training requires a little planning if you are not a conditioned athlete. It is possible to add Zone 2 training into your weekly training cycle with a few adjustments. If you need help planning out your week let me know. I am happy to sit with you for a GOAL REVIEW and help you find a plan that fits your busy life. The important thing to know is that if you go consistently to our CrossFit classes you are getting a combination of all 4 training domains: Zone 2, Anaerobic, Strength and Stability.

Join us on Wednesday and Friday mornings for Zone 2 running in the Arnold Arboretum. We meet at the entrance of Fairview and Mendum Street in Roslindale at 6 am. This is a free running group and all levels are welcome.