Should You Stop Running or Lifting? What the Science Says About Cortisol and Exercise

Health & wellness influencers are making bold claims like “stop running or lifting because it’s raising your cortisol and inflaming you.” They blame intense workouts for causing the inability to lose weight, inflammation, and moon face (swelling of the face).

Is this fact or fiction? Let’s see what the science actually says.

Understanding Cortisol

What is Cortisol?

Cortisol is a hormone that helps you stay awake and alert, provides steady energy throughout the day, and keeps your immune system balanced.¹

Your cortisol levels naturally rise and fall throughout the day – highest in the morning (to help you wake up) and lowest at night (to help you sleep).

What Does it Mean to Have High Cortisol?

A healthy individual has a 50-60% increase in cortisol within 30 minutes of waking up and then a gradual decline throughout the day to reach a third to two thirds of morning values by evening.² Normal cortisol varies dramatically throughout the day, but an abnormal pattern would be elevated late-night cortisol or high morning levels.

The most reliable way to detect high cortisol is the dexamethasone suppression test where you take dexamethasone at night and measure your cortisol levels in the morning.³

Symptoms of High Cortisol

Common manifestations include:

Resistant hypertension (high blood pressure) requiring multiple medications⁴
Difficulty losing weight (especially waist/abdominal area) despite appropriate diet and exercise⁵
Swelling and rounding of the face due to fat accumulation (referred to as moon face or cortisol face)⁶
Poor diabetes control despite adequate diet, exercise, and medication⁷
Unexplained bone loss or fractures, especially vertebral (spinal) fractures⁴
Depression that doesn’t respond well to standard treatments⁸

How Common is High Cortisol?

The vast majority of people (>98%) do not have clinically high cortisol.⁷

Severely high cortisol (Overt Cushing’s syndrome) only affects 0.006-0.008% of the population.⁹

Exercise and Cortisol: What the Research Shows

How Exercise Affects Cortisol

Exercise induces cortisol increases that are normal, beneficial, and temporary.¹⁰

Research shows that cortisol only increases if you’re working out at moderate to high intensity (60% VO₂max increases cortisol levels by 39.9% and 80% VO₂max increases cortisol levels by 83.1%).¹¹ Peak cortisol occurs 20-30 minutes after exercise and returns to baseline within 90 minutes.

HIIT (high-intensity interval training) increases cortisol the most and the fastest, but it goes below baseline at 2-3 hours and returns to baseline within 24 hours.¹²

Contrary to the TikToks and IG reels, exercise has actually been shown to improve cortisol patterns and lower cortisol levels overall.¹³

The Real Culprit Behind Symptoms

Potential Causes of Inability to Lose Weight and Inflammation¹⁴ ¹⁵ ¹⁶ ¹⁷:

Poor sleep
Processed food
Alcohol
Hormonal imbalances
Insulin resistance and blood sugar dysregulation
Thyroid dysfunction
Gut health
When people restrict calories, their metabolism naturally slows
People often eat more after exercise (calories consumed > calories burned)
Overtraining without adequate recovery (can cause inflammation through tissue damage, but does not cause chronic cortisol elevation or weight loss resistance)¹⁸ ¹⁹

Potential Causes of Facial Puffiness²⁰ ²¹ ²² ²³ ²⁴

High sodium intake
Poor sleep
Alcohol
Thyroid dysfunction

The Bottom Line

Should you consider lowering your cortisol? Probably not.

Should you stop running, doing HIIT, or lifting weights? Probably not.

References

Medical Disclaimer: This content is for informational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult with qualified healthcare providers before making changes to your health regimen, especially if you have diagnosed medical conditions or take medications. The author is not a licensed medical professional, and this information should not replace professional medical care.