When we talk about cortisol, most of us immediately think of sugar, carbs and stress; we should probably stop pretending they don’t count. But the truth is, your cortisol levels are influenced by far more than what’s on your plate.
Sleep, stress, hydration, caffeine habits even how long you sit at your desk, all play a role in how efficiently your body manages glucose. And the tricky part? Many of these habits feel completely harmless, even healthy, on the surface.
Here are eight everyday behaviours that may be subtly affecting your cortisol balance, and what you can do about them.
1. Not getting enough sleep
A poor night’s sleep doesn’t just leave you groggy; it also affects how your body handles sugar. Research shows that even one night of insufficient sleep can reduce insulin sensitivity, meaning glucose stays in the bloodstream longer instead of being used for energy. When you’re tired, your metabolism simply doesn’t work as efficiently.
2. Being dehydrated
Water plays a surprisingly big role in blood sugar regulation. When you’re dehydrated, glucose becomes more concentrated in the bloodstream. On top of that, dehydration triggers stress hormones like cortisol and vasopressin, which can further elevate blood sugar. Consistently drinking too little water has been linked to a higher risk of chronically high glucose levels.
3. Sitting for most of the day
The human body wasn’t designed for back-to-back Zoom calls and eight-hour sitting marathons. Long periods of inactivity interfere with how the body regulates blood sugar, blood pressure and fat metabolism. Studies suggest that sitting for prolonged hours increases diabetes risk, even among people who exercise regularly. Short movement breaks, like a couple of minutes of walking every 20 minutes, can significantly reduce post-meal glucose spikes.
4. Overdoing caffeine
That morning coffee may feel non-negotiable, but excessive caffeine can temporarily reduce insulin sensitivity. This means sugar is cleared from the bloodstream more slowly. The impact is often amplified when coffee is paired with sugary baked goods. The good news? Having caffeine with or after meals, especially those containing fibre or protein, can soften the effect.
5. Chronic stress
Stress hormones exist to help us respond to danger, but modern stress rarely involves running from predators. When cortisol and adrenaline rise, blood sugar levels increase to supply quick energy. Even everyday stressors like deadlines, arguments or presentations can trigger spikes. Breathing exercises, gentle movement and short mental breaks can help lower stress-related glucose surges.