Book Now!We all know what it feels like to be tired. But there’s a special kind of exhaustion — the one that leaves you not just sleepy, but queasy. It sneaks up on you after long days, heavy workloads, or intense emotional stress. You feel nauseous, a little shaky, maybe even dizzy.
It’s not just in your head. Here’s what’s really happening in your body when you’re so tired you feel like you might throw up.
When you miss out on sleep, your body moves into survival mode. Hormones like cortisol (your stress hormone) surge to keep you functioning, but they come at a cost. Cortisol messes with your digestive system, leading to stomach discomfort and nausea.
Your nervous system also takes a hit. Sleep deprivation keeps your sympathetic nervous system (aka "fight or flight") switched on, instead of letting you drop into the restful parasympathetic state ("rest and digest"). When that happens, digestion slows way down, or even stalls completely, which can make you feel sick to your stomach.
Plus, sleep loss throws off your hunger hormones — ghrelin and leptin — confusing your brain about whether you’re hungry or full, and that mismatch can trigger nausea.
So if you’ve been skimping on sleep and suddenly feel nauseous, it’s not random. It’s your body’s way of waving a big red flag: "Please let me rest"
Here’s the part most people don’t realize: even if you’ve technically been sleeping, *your brain can still be so overworked that it makes you feel physically ill.
Mental fatigue — from decision overload, emotional stress, endless multitasking, or high-stakes thinking — uses an enormous amount of energy. Your brain might only make up about 2% of your body weight, but it burns roughly 20% of your daily energy. When you push it too hard for too long, it sends distress signals that feel physical.
Brain Drain: Long periods of concentration deplete your mental energy reserves. When that happens, your brain struggles to regulate basic functions, like digestion. Nausea can be an unfortunate side effect.
Stress Chemistry: Mental overload can elevate stress hormones just like physical exhaustion does. Even without running a marathon, you’re pumping out adrenaline and cortisol as if you are — which upsets your stomach.
Vagus Nerve Connection: The vagus nerve links your brain to your gut. When you’re mentally fried, it overstimulates, which can cause that sick, uneasy feeling in your stomach.
Hyperarousal: Mentally, you’re still in high gear, even if you’re sitting still. That hyper-alert state keeps your nervous system revving, making you feel wired *and* nauseous at the same time.
So if you’ve been deep in emotional processing, big decisions, or creative problem-solving and suddenly feel sick — know this: it’s not weakness, and it’s not random. Your brain and body are begging for a reset.
The antidote is simple, but not always easy: rest!
Not just sleep (though that helps a lot). True rest. Step away from screens, give your brain some quiet time, breathe deeply to activate your parasympathetic system, and hydrate. As my therapist always tells me, there's a difference between being unproductive, and resting. After pushing back on that sentence for many years, it’s now something I repeat to my clients almost weekly, because it appears the truth is relentless ;)
Even short, intentional pauses in your day can stop this nausea spiral before it takes hold.
Next time you’re overwhelmed and start feeling physically off, try not to push through it blindly. That nauseous, exhausted feeling is your body’s way of saying: *“Enough. I need to recover.”* Listen to it. You’ll bounce back stronger.
