We call it Zone 2.
If you’re my age or older, you probably have been taught to do “cardio” as a way of losing weight, being healthy, and burning fat.
In the 1980s, popular exercise regimens (Richard Simmons comes to mind) focused on “aerobics” and high heart rate activities. I do recall jumping around to a Richard Simmons VHS tape at about the age of five.
For me even as an adolescent and young adult, doing “cardio” meant training myself to run. I played sports as a kid and adolescent which involved running but outside of that I didn’t consider myself an avid runner. I tried anyway because I thought that was the ticket to health and, more importantly to a teenager, looking awesome.
We were also culturally conditioned to the appearance of “skinny”. These exercises would make you thin. Thin makes you healthy, so we were taught.
As the decades have gone on, we’ve needed more and more help with the truly basic things of life: eating, drinking, and moving. As Casey Means points out in her book Good Energy, fitness memberships are at an all-time high. As of 2024, the global fitness industry is worth $244 Billion and growing over 5% each year.
We’re trying to insert movement back into our lives because it’s been all but plucked out entirely.
Now trying to reinsert movement is confusing and complicated, which usually makes us give it up altogether.
What is Zone 2?
Zone 2 is just one of several zones that delineates different activity intensities, their associated target heart rates, and physiologic result.
Zone 2 is considered “moderate” activity. You may find that it’s easier than you thought. Zone 2 is not out of reach for most ordinary people which is great news for us.
Below is a chart (from Cleveland Clinic informational website) showing zones and their corresponding heart rate measurements plus the type of fuel our body uses in each.
If you don’t have a wearable device that tracks your heart rate, I would suggest getting one. We are in a great time of biometrics and personalized health. I wanted a watch that looked like a regular watch and not like something Dick Tracy would have worn, so I wear this Garmin Lily 2.
If you either don’t want a wearable device or want another way to gauge whether you’re in zone 2, you can use the “talk test”. Your ability to speak during the exercise activity should be slightly compromised, but you can still speak in short sentences. If you are casually able to speak in full sentences, you’re like not intense enough. If you are so winded that you can’t speak two words, you are too intense.
How Do I Know My Zone 2?
To calculate your Zones, first subtract your age from the number 220. This is your maximum heart rate, a ceiling that you should not be crossing in any activity.
Maximum heart rate = 220 - age
Zone 2 is calculated between 60% and 70% of that maximum heart rate, so we can multiple our number above by 0.6 up to 0.7 to find our zone.
If you’re beginning an exercise regimen (good for you!), you may want to start at the 60% end or even lower at 50% (Zone 1) and work your way up.
If you are doing the same activity you’ve been doing but your heart rate is not reaching as high as it was when you first started, that means you are gaining fitness and you can increase your activity. That’s called progression! That is a result!
Why is Zone 2 Important?
As we saw in the chart above, fat is the fuel source our body uses in zone 2 (and zone 1). This means you are literally burning (oxidizing) fat.
One of the most common things I hear from midlife women is that they notice their body changing. Even for active women, they’re performing their same activities but their mid-section is expanding.
For midlife women, fat accumulation speeds up with hormonal changes and loss of estrogen. It also accelerates the breakdown of our muscles. This means we are in an uphill battle to build muscle and burn fat.
We need to be strategic. Biometrics like target heart rate is one way to guide precise movements of your body.
Can I Use Zone 1 Instead?
Fat is the primary fuel source for activity in zone 1 as well as zone 2 but the target heart rate is lower. This may lead to the idea that we can do less and still burn fat. While that isn’t incorrect, there’s a catch.
To burn calories (also important though not the complete story when it comes to body composition), the activities need to be done for long enough to put us into a deficit (burning more calories than consuming).
While fat is the source in zone 1, it will take longer to burn the calories. Zone 2 will burn calories faster and while still using fat as the source of fuel.
I use zone 1 on my “recovery” days, which is what I do on days between harder work outs - either zone 2 or muscle building activities.
Whether you still call it cardio or now zone 2, the activity matters more than the term. This is incredibly important for a midlife woman for both internal and external benefits, though isn’t the only exercise strategy to optimize our health (see here for my discussion of muscle building).
Resources:
Some of the information contained in this article is the result of my training, medical knowledge, and personal experience without a specific source to be cited.
This is not medical advice.
https://www.signos.com/blog/fat-burning-heart-rate-zone
https://www.fitnessondemand247.com/news/gym-membership-statistics-you-should-know-in-2024
https://www.heart.org/en/healthy-living/fitness/fitness-basics/target-heart-rates
https://health.clevelandclinic.org/exercise-heart-rate-zones-explained
