We’ve known this for a while now—that being stressed can lead to high cortisol levels, and high cortisol levels can lead to a plethora of ailments: insomnia, acne flare-ups, unexplainable weight gain and the onset of a fight or flight response. When we put on a face mask, light a candle or try to meditate, it is in hopes of regulating our cortisol levels. Of course, fluctuating cortisol levels are not exactly cause for alarm, but what happens when our bodies hold onto stress for too long?
Enter: autoimmune conditions. Lupus, Graves’ disease, Hashimoto’s thyroiditis—they go by different names and manifest in varying ways, but they often seem to appear after a prolonged period of stress. Reading the symptom list isn’t always helpful—fatigue, low mood and difficulty concentrating can also be signs of burnout or general exhaustion—which makes these conditions harder to detect. Yet, it afflicts more and more of us globally: in a 2026 paper titled ‘Global landscape of autoimmune diseases across different lifespans: A three-decade perspective’, the global prevalence rate of autoimmune diseases nearly doubled from 1990 to 2021. Something is happening in our bodies, and it might have to do with the way we’ve been living our lives.
Understanding the ‘stress hormone’
Dr Ben Ng, senior consultant endocrinologist at Arden Endocrinology Specialist Clinic, understands that cortisol has a bad rep, but points out that it’s one of the most misunderstood hormones. “Cortisol is actually essential for life,” he clarifies. “It helps regulate blood sugar, blood pressure, energy levels, inflammation and how the body responds to illness or danger. In short regulated amounts, the changes in cortisol can be protective. It helps you wake up in the morning, stay alert and respond to challenges.” In fact, functional medicine nutritionist Pratima Nagaraj points out that low cortisol is an equally serious issue, leading to problems like disrupted sleep and other forms of dysregulation in the body. Ultimately, Pratima highlights, “[cortisol] is not just about high or low. It’s about whether the rhythm is right.”
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The immune system under attack
And what disrupts our natural rhythms? Ng cites poor sleep, alongside chronic stress, excessive caffeine, illness and even overtraining in the gym. “The body does not often make the distinction between emotional and physical stress. Modern lifestyles tend to keep people in a constant ‘on’ state, which may chronically activate stress pathways.” And when stress derails cortisol—which normally helps to keep inflammation and immune activity under control—the immune system starts to feel the strain.
Perhaps the scariest part is that the changes can go unnoticed. When it comes to her own clients, Pratima looks at the whole picture: how someone sleeps, how they eat, how they manage their nervous system, and what their stress load actually looks like. “You can do everything right on paper—clean diet, right supplements, right labs—but if the body is living in chronic fight-or-flight mode and does not feel safe, the immune system stays dysregulated.”
It was certainly the case for fashion, wellness and travel creator Clara Hong, who was strength training four to five times a week but felt faint often and took longer to recover. “I had been losing weight unexpectedly, my resting heart rate was constantly high, and workouts that used to feel manageable suddenly became exhausting.” She would find out later that it was because she has Graves’ disease. Reflecting on her lifestyle before the diagnosis, “stress isn’t always obvious,” she notes. “It’s not necessarily about constantly working or having an insanely packed schedule. Stress can live much deeper in the body and nervous system. After a while, your nervous system gets so used to functioning in that heightened way that it becomes your normal.”
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Remedying the cortisol conundrum
There are certainly many possible ways of managing stress and cortisol spikes, but it can be easier knowing what works best for our bodies. If you’ve always prioritised sleep, good news: Ng confirms that “[g]ood sleep hygiene is probably the closest treatment we have for better cortisol regulation.” That looks like sleeping at a consistent time nightly, going screen-free before bedtime, and having a proper wind-down routine. Waking up at the same time every day is equally important—according to Pratima. Having been diagnosed with Hashimoto’s disease herself, she’s made some changes to her own life since.
“The single most game-changing habit I’ve built is getting sunlight within 60 to 90 minutes of waking up. Cortisol is a light-sensitive hormone—morning light exposure is one of the most powerful ways to anchor your cortisol rhythm and set your body up for the day,” she elaborates. Other methods include daily breathwork, meditation and gentle movement like yoga. Pratima also emphasises the importance of gut health and an anti-inflammatory diet. “Digestive overload is a hugely underestimated driver of cortisol dysregulation, especially with autoimmune conditions,” notes Pratima. Supplements—adaptogenic herbs like ashwagandha, holy basil, ginseng—can also support adrenal function and cortisol balance, though she recommends working with a practitioner first before starting anything.
Ng’s advice to patients is to make time for proper rest throughout the day—an approach that Hong is already applying to her own life. “I’ve been scaling back work where I can, creating more space for rest, spending more time offline, and being more mindful of overstimulation and my emotional state overall,” she reflects. The shift has brought about a mindset change, too. “This experience has forced me to stop treating rest as something that needs to be earned. I’m learning to listen to my body earlier instead of pushing through exhaustion or stress just because things ‘look fine’ externally.”
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Regular exercise is also beneficial, though not necessarily in the traditional sense. “High-intensity workouts and too much cardio were actually making things worse, adding more physiological stress on top of an already stressed system,” Pratima clarifies. For her, shifting to gentler workouts like brisk walking, yoga and adding infrared sauna sessions for lymphatic drainage made a real difference. “The answer isn’t to push harder, but to calm the system down first. Then everything else starts to work.”
Above all, it’s also crucial to give yourself grace. “What’s been hardest is accepting that my energy levels can fluctuate a lot depending on my thyroid levels and medication adjustments,” Hong reveals. “Some days I wake up and can function normally, and other days I genuinely can’t do much except stay in bed and let my body rest.” And it’s okay to. Ng echoes the sentiment: “In many cases, cortisol management is really about recovery, rhythm and sustainability rather than quick hacks.”
When to get checked
As much as stress and elevated cortisol levels can lead to autoimmune diseases, Ng highlights that it is not the sole cause. Genetics still play a major role, alongside other factors like infections, smoking habits, gut health, hormonal changes and environmental triggers.
“In many cases, cortisol management is really about recovery, rhythm and sustainability rather than quick hacks.”
While it might be hard to spot signs of autoimmune diseases, it is important to monitor your own body over time. Persistent fatigue, unexplained weight changes, palpitations, hair loss, heat or cold intolerance might be indicators of an autoimmune thyroid condition, but especially so when they persist and do not feel normal to you. The key thing is to be mindful, instead of simply brushing anomalies off. Pratima’s thyroid stimulating hormone levels showed up normal for years—until a complete thyroid panel showed otherwise.
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Autoimmune diseases aside, chronically elevated cortisol can lead to complications like high blood pressure, insulin resistance, poorer metabolic health and increased cardiovascular risk over time, advises Ng. Hong reminds us that just because someone looks okay externally, it doesn’t mean they aren’t struggling behind the scenes. It might indeed be easier to ignore the signs and carry on as before, but convenience can come at the price of our bodies. Take this as your sign to hide the devices, invest in a good pillow and sleep earlier tonight—whatever makes it easier for you to unwind, relax and keep your cortisol levels regulated.
