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If you’ve spent any time in wellness spaces lately, you’ve probably heard a version of this message: “HIIT is wrecking your hormones.”
Like most things in health and fitness, the truth is far more nuanced.
Short answer: HIIT is not inherently bad for your hormones, but it has the potential to become a problem in certain contexts. The issue isn’t just intensity, but rather whether your body has the resources to recover from that intensity.
Why Has HIIT Developed a Bad Reputation?
HIIT often gets blamed because it can;
● Increase cortisol
● Feels physically demanding
● Is commonly overused
● Gets layered on top of already stressful lives
Cortisol, however, is not the villain it’s often made out to be. It’s a normal and necessary hormone that helps us respond to stress, including exercise. The problem isn’t acute cortisol spikes, but rather the chronic overload without adequate recovery.
Your body doesn’t distinguish between stressors, but tallies the total load.
Think of Stress Like a Bathtub
● Training stress, work stress, sleep deprivation over time and under-fueling turn the faucet on and fill the tub.
● Recovery (sleep, nutrition, rest days, parasympathetic balance) is the drain.
● If the faucets are on full blast and the drain is clogged, the tub overflows. That overflow looks like fatigue, plateaued performance, disrupted cycles, increased soreness, poor sleep, or feeling “wired but tired.”
HIIT isn’t the problem if the drain is open.
It becomes a problem when the tub is already full.
What the Research Shows
When properly programmed, high-intensity interval training has been shown to:
● Improve insulin sensitivity
● Increase cardiovascular fitness
● Improve metabolic health
● Support performance adaptations
Short, intentional bouts of intensity are not the same as daily, unstructured exhaustion.
HIIT becomes problematic when:
● Training stress is already relatively high
● Nutrition is insufficient
● Sleep is compromised
● Life stress is elevated
What about HIIT in Postpartum & Perimenopause?
Postpartum is one of the most misunderstood training phases. Exercise postpartum has been shown to improve mood, physical function, and cardiometabolic health. HIIT is not inherently harmful after having a baby, but context matters.
Early postpartum recovery involves:
● Healing connective tissue
● Rebuilding pelvic floor integrity
● Managing significant sleep disruption
● Often under-fueling (especially while breastfeeding)
High-impact or high-intensity training too early, particularly without pelvic floor rehabilitation, may increase risk of symptoms, however, systematic reviews suggest progressive exercise postpartum is beneficial, especially when pelvic floor muscle training is included.
Perimenopause is another phase where nuance is critical. Contrary to social media narratives, HIIT can be very beneficial during perimenopause and postmenopause, particularly to improve insulin sensitivity, reduce abdominal fat mass and improve VO2max and vascular function.
Research shows that cardiovascular disease risk increases during and after the menopause transition due to declining estrogen, which is associated with changes in lipid profiles, increases in visceral fat, reduced insulin sensitivity, and altered vascular function.
However, perimenopause often includes:
● Increased sleep disruption
● Heightened stress sensitivity
● Recovery variability
● Hormonal fluctuations that change perceived effort
In this context, it’s not about eliminating intensity, it’s about managing total load. HIIT can be a powerful tool when properly fueled, programmed, and balanced with recovery.
Can Wearables Help You Decide?
Devices like Oura, WHOOP, Garmin, and Morpheus attempt to estimate recovery through metrics such as:
● Heart rate variability (HRV)
● Resting heart rate
● Sleep duration
● Strain/load scores
HRV is a validated marker of autonomic nervous system balance, and wearable devices show moderate accuracy compared to gold-standard measurements when looking at trends. The key word here is trends.
These tools are most useful when:
● HRV is suppressed for several days in a row
● Resting heart rate remains elevated
● Sleep debt accumulates
● Performance feels flat
It’s important to remember that these are not diagnostic tools. They should help to inform curiosity. Looking at energy, mood, performance, and menstrual cycle patterns matter just as much (if not more!)
The Bottom Line
If your training helps you sleep better, feel stronger, and be better at life outside the gym, it’s probably working!
If it leaves you depleted, inflamed, or stuck, you might need to evaluate your stress to training balance. Health and performance don’t come from avoiding stress entirely, but from matching stress with recovery.
Want to learn how working with an LVLTN coach can help you reach your goals—and stay there? Start with a free LVLTN Blueprint Session.
It’s your personalized roadmap to clarity, consistency, and real results. You just need to fill out a quick application, then our team will review it and reach out with a link to schedule your session within 24 hours. Get started by clicking here!
References
- El Khoudary SR et al. (2020). Menopause Transition and Cardiovascular Disease Risk: Implications for Timing of Early Prevention. Circulation.
- Maillard F. et al. (2018). High-intensity interval training reduces abdominal fat mass in postmenopausal women: A systematic review and meta-analysis. Obesity Reviews.
- Weston KS et al. (2014). Effects of high-intensity interval training on cardiometabolic health: A systematic review and meta-analysis. British Journal of Sports Medicine.
- Mountjoy M. et al. (2018). IOC consensus statement on Relative Energy Deficiency in Sport (RED-S). Br J Sports Med.
- Hernando D. et al. (2018). Validation of heart rate variability measurement from wearable devices. JMIR.
- Davenport MH et al. (2018). Canadian guideline for physical activity throughout pregnancy and postpartum. Br J Sports Med.
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