Let’s Bring Back Cardio For Women (+ FREE Guided Workout!)
Here’s a better way to enjoy cardiovascular conditioning in each phase.
Cardio has become something of a four-letter word in the world of women’s fitness and while I am totally on board with ditching marathon sessions on human hamster wheels, I do believe that cardiovascular conditioning has a place in any balanced movement practice.
To optimize cardio workouts in each phase, aim to work in the heart rate zones that mirror your cyclical metabolic shifts. In other words, adjust the intensity of your effort to leverage what is already happening physiologically.
Benefits of Cardiovascular Training
Cardio is essentially any activity that increases your heart rate and breathing. Though typically an aerobic exercise performed at low-to-moderate intensities, I also consider higher intensity conditioning work to be in this category.
So why has cardio been able to stand the test of time? Just take a look at some of the benefits…
supports healthy body composition and weight loss
improves sleep at moderate intensities
lowers stress and improves resilience
supplies endorphins and elevates mood
improves heart health and circulation
reduces risk of metabolic disease
…the list goes on!
This is why you’ll regularly find cardio and conditioning workouts in the lunae roadmap of exercise. I’m proposing that we bring back cardio in a cycle-informed way!
Cycle-Friendly Cardio & Conditioning
If you’re a cycle-syncing enthusiast, you may see cardio as a luteal faux pas or maybe it’s the last thing you want to do on your period. Before you rule it out though, I encourage you to try this body weight practice and explore the different cardio zones in each phase. When you understand how different intensities feel in your body, you can adapt any style of exercise to support your unique hormone rhythm.
Calculating Max Heart Rate & Intensity
As the intensity of a workout changes, you’ll enter different training modes depending on how your body supplies energy during your session. The level of intensity can be approximated using a percentage of your max heart rate (HR).
Note: This is different from perceived exertion which will vary throughout your cycle. For instance, hitting 65% of your max HR might feel harder in your luteal phase than your follicular phase as a result of your phasic physiology.
For simplicity, we’ll use HR as a universal indicator. The simplest approach is to estimate your max HR and set your target HR zone as a percentage of this number.
Max Heart Rate Formula
There are a few different ways to calculate your max HR, but my preferred formula for women is from Dr. Stacy T. Sims.
Example: max heart rate = 211 – .64 x age → at 39, my max HR is 186
If I want to hit an intensity level of 65%, I would take 186 x .65 = 121 → This is my target HR!
Heart Rate Reserve Formula
To get an even more personalized number, you can use your heart rate reserve (HRR) which takes your cardiovascular fitness into account.
HRR is the difference between your resting and maximum HRs.
Example: max HR– resting HR = HRR → mine is 186 – 64 = 122
Then, to calculate your target HR zone, add the desired intensity as a percentage of HRR to your resting HR.
Example: (HRR x .65) + resting HR = target HR
For 65% intensity I would take (122 x .65) + 64 = 143 → This is my target HR!
You’ll notice that the target HR using the second method is higher for me which means the max heart rate calculation alone may not be sufficient. However, I can safely assume that my 65% HR zone will fall somewhere between 121 and 143 and this is a good range to shoot for!
Phasic Cardio Overview
To optimize cardio workouts in each phase, aim to work in the heart rate zones that mirror your cyclical metabolic shifts. In other words, adjust the intensity of your effort to leverage what is already happening physiologically.
Push yourself in the first half of your cycle when you're metabolizing carbs well. You’ll rely on this substrate for energy at higher intensities.
Hit your highest intensities just prior to ovulation when estrogen levels are on the rise.
Stay in a lower intensity zone during the second half of your cycle to leverage fatty acid utilization. During the high-hormone phase, your metabolism is more likely to spare carbs making high intensities feel harder.
Keep it chill during your transition phases—ovulation and menstruation—when you’re less resilient to stress and metabolism is shifting.
Heart Rate Zones For Each Phase
These heart rate zones are approximated to target different metabolic thresholds as described above. In the anaerobic heart rate zones (HR >80%), you’re relying more heavily on carbohydrates to provide energy whereas in the lower aerobic zones (HR<80%), your body is able to burn fat in the presence of oxygen.
Premenstrual & Bleed | Zone 1 | < 50% | low intensity, recovery
Heart rate is slow and easy, you can carry on a conversation effortlessly. The intensity is low and muscles are getting enough oxygen to utilize fat-burning metabolic pathways.
In practice → Move slowly and take breaks as needed to keep your breath under control.
Follicular PHASE | Zone 2, 3 | 50–70%, 70–85% | moderate to high intensity
In zone 2, you notice the first signs of labored breathing, but the effort is sustainable. You can carry on a conversation, but you’ll have to pause occasionally to catch your breath. Metabolism is using both carbs and fats as fuel.
In Zone 3, you’re working and breathing much harder and you can only speak a few words at a time. Metabolism is relying more heavily on carbohydrates.
In practice → Push your intensity threshold and hover above the point where your breathing becomes labored. Enter occasional periods of intense effort that require a shift in intensity to recover.
Ovulatory PHASE | Zone 3, 4 | 70–85%, 85–95% | high intensity to max effort
Similar to the follicular phase, you’ll spend most of your time working at a challenging pace in zone 3 with the occasional push into your highest level of intensity in zone 4. You can only sustain this max intensity effort for a few seconds and your metabolism is only able to use carbohydrates.
In practice → Enter this mode in the few days leading up to ovulation, but make the shift to luteal mode before you ovulate or when the intensity is harder to maintain for the full session.
Luteal PHASE | Zone 1 & 2 | 50–70% | low to moderate intensity
This is the endurance zone where you’re making expert use of aerobic fat-burning metabolism. You’ll want to hover right around the point where breathing starts to change.
In practice → Stay on the high end of this range in the early luteal phase before tapering down to the low end during the last 3-5 days of your cycle.
Note: With conditioning work, it’s always helpful to have a heart rate monitor for direct biometric feedback, but if you don’t have one, you can come pretty close using your breathing to identify different HR thresholds.
Less Is More
Don’t get me wrong, strength training continues to be my preferred workout style because it gives you the most bang for your buck. If you have limited time and can only choose one thing, I say lift weights! Not to mention that your strength sessions can be cardio sessions and the same heart rate zone approach still applies.
However, if you’re looking for something to do between strength training days or are interested in using conditioning workouts to improve body composition and overall health, consider adding the workout below to your weekly rotation.
In practice → Try to incorporate 1-2 conditioning sessions per week either as part of a strength workout or on their own.
Body Weight Cardio Workout
As you explore the workout below, aim to stay in the appropriate working zone for each phase. You can do this by choosing a higher/lower intensity movement option, increasing/decreasing the pace, or reducing/adding more recovery time.
Workout Details
After warming up, complete the circuit below using the interval structure indicated for your cycle phase. Finish with a brief cool-down until heart rate returns to baseline.
Premenstrual/Flow | 60s continuous intervals *low intensity, no explosive
Follicular | 40/20 intervals *moderate intensity, optional explosive
Ovulatory | 30/30 intervals *high to max intensity, optional explosive
Luteal | 60s continuous intervals *low to moderate intensity, no explosive
jumping jacks
walk out side plank
alt drop taps
launch to push up
lunge hop switch
push-up plank tuck
reverse lunge jump (left)
reverse lunge jump (right)
around the world lunge (left)
around the world lunge (right)
rev lunge twist to knee cross (left)
rev lunge twist to knee cross (right)
kick through
forward lunge clap to overhead reach
burpee
squat to heel or toe tap
hinge jump *chair squat to toes
plank jacks
alt reverse lunge hip circle
plank shoulder taps/knee taps
