Key Takeaways

Every stressful work thought triggers a cortisol release in your body — and cortisol at night is exactly what blocks the sleep signals your body needs to fall and stay asleep.
Addressing work stress alongside physical root causes — like gut health, hormones, and neurotransmitters — is the fastest path to sleeping well long-term; fixing the body alone isn't enough if work stress is actively breaking it back down.
Three high-impact changes make the biggest difference: setting a hard boundary around work thoughts outside work hours, stopping email after 5pm, and replacing screens after work with a genuine nervous system reset.

You're exhausted. But the second you lie down, work floods in. Emails you didn't send. The conversation that went sideways. Everything sitting in your inbox waiting for tomorrow. Your body registers every single one of those thoughts as a threat — and responds by releasing cortisol.

That's not a metaphor. Your nervous system doesn't distinguish between a stressful work email and a physical threat. Every reactive moment, every anxious thought, every "I forgot to send that" at 11pm is signaling your body to stay alert. And cortisol at night is exactly what prevents you from sleeping.

I've been helping people with chronic sleep issues for seven years, and work stress is one of the most common things I see driving bad sleep. I've also had to figure this out myself — running a business, raising a young son, with a brain that doesn't want to shut off at night.

I mainly talk about physical imbalances that affect sleep: gut pathogens, hormone dysregulation, neurotransmitter deficiencies, heavy metals. But I also help my clients with the stress and mental side of not sleeping, because here's the thing: we can do everything for your gut and your hormones and your neurotransmitters, and if you're still super stressed about work, it may not be enough. The stress is breaking the body down at the same time we're trying to build it back up. Addressing both at the same time is the fastest, most effective way to sleep well — not just for a week, but long-term.

Start with mindset — nothing else works without it

When I started my business, I was also waitressing at night to pay the bills. I'd get home around 10:30pm, wired from the lights and the pace, and sit down in front of the TV to decompress. I loved it. My husband and son were asleep, it was my time. But I was sleeping horribly. I'd still feel wired at midnight, go to bed because I was exhausted, and toss and turn all night.

I finally decided to stop. Even though I loved that TV time, it wasn't working. So I started lying down with my legs up the wall instead — not formal meditation, just lying there, letting my thoughts slow down. Once things calmed enough that I could think about nothing, I'd read a book. Thirty minutes later I was sleepy. I'd go to bed and sleep well. That one change made the biggest difference.

What was also happening during those late-night TV sessions was ruminating about work without resolving anything. I'd loop through the same thoughts, get interrupted, tell myself to stop — and nothing ever got decided. So I set a strict rule: when I'm not working, I'm not thinking about work. When a great idea comes up on a bike ride, I stop and put it in my phone. But if I'm just ruminating? I let it go. The more you practice it, the easier it gets.

The other piece is what you say to yourself. "I'm overwhelmed" and "I have so much to do" aren't neutral descriptions — they create a panicky, rushed feeling that makes you less productive and generates more cortisol. I started telling myself "I always have time" instead. That shift alone helps me slow down and stop making stress-driven mistakes.

During your workday

The calmer your day, the easier it is to wind down at night. A few specific things that help: silence all notifications on your phone and desktop, because every interruption forces your brain to re-engage and fires a small stress response. Remove work email from your phone entirely if you can — checking email outside work hours means one stressful message can hijack your whole evening, even if you have no intention of responding until the next day.

Eating breakfast before coffee also matters more than people realize. Caffeine on an empty stomach triggers a cortisol release and can leave you jittery and anxious. Pairing it with food — especially protein — helps stabilize your blood sugar and keeps you calmer throughout the day.

Blocking time for deep work is both a productivity and a sleep strategy. Multitasking and task-switching are stressful on the body, not just the mind. Having protected focus blocks — even two or three hours — reduces the constant low-level stress of being pulled in every direction.

The calendar hack that changed everything for me

When I'm feeling overwhelmed, I put everything I need to do into Google Calendar with time estimates. Seeing it laid out — here's the podcast episode, here's the client review session, here's the afternoon walk — shows me that there actually is enough time. When I tell myself "I have plenty of time," it's not a lie, because I can see that I do.

If the calendar fills up and there isn't time for everything, at least I know that. Then I can cut or reschedule things deliberately, instead of carrying a vague anxious sense that I'm behind on something I can't even name.

When you're in a busy season or working late

If you're working late or getting home late, this is exactly the wrong time to turn on the TV or scroll your phone. You're already overstimulated. Adding more screen time is just adding more stimulation to an already stimulated mind.

Before you leave work, take two to five minutes to journal: write down everything you need to do tomorrow, anything still sitting in your head. Getting it on paper stops your brain from trying to hold it all night.

And if you can, do a brief breathing practice — I inhale for a count of four and exhale for a count of eight. The extended exhale activates the parasympathetic nervous system. Even a few minutes of this can meaningfully shift the tone of your evening and the quality of your sleep that night.

I also don't work past 8pm. If I'm on screens past that, I don't sleep well. If you know you don't sleep well after working till 11, stopping at 10 and getting better sleep will make you more productive the next day than pushing through. You gain more in the long run.

FAQ

Q: Can work stress actually cause insomnia?

A: Yes, directly. Every time a stressful thought comes in — whether it's an email you forgot to send or anxiety about tomorrow's meeting — your body releases cortisol. Cortisol at night is exactly what suppresses the sleep signals your body needs to fall and stay asleep. It's a physiological response, not just a mindset problem.

Q: I'm exhausted from work but still can't wind down. Why?

A: Exhaustion and being wound up aren't opposites — they happen at the same time when cortisol is elevated. Your body is tired but still in a stress state, which keeps you alert even when you want to sleep. The fix isn't more exhaustion; it's calming the nervous system before bed through breathwork, movement, or a genuine mental break — not TV or phone, which adds stimulation on top of an already stimulated nervous system.

Q: Does checking email at night really affect sleep that much?

A: One stressful message can ruin your entire evening and night of sleep. Even if you have no intention of responding until the next day, your brain will start working on the problem — and that keeps cortisol elevated when it should be dropping. If you're not planning to act on it, you're getting all the stress with none of the productivity.

Q: I've tried to stop thinking about work at night but I can't. What actually helps?

A: Two things from the transcript that work: journaling before you finish work (write down everything you need to do tomorrow so your brain doesn't have to hold it overnight), and the legs-up-the-wall breathing practice instead of screens when you get home. The breathing specifically — inhaling for four, exhaling for eight — activates the parasympathetic nervous system and gives your mind something to do besides loop through work thoughts.

When Work Stress Isn't the Whole Story

If you've genuinely addressed the stress side — the boundaries, the breathwork, the workday habits — and you're still not sleeping, that means something deeper is going on in your body. That's what functional lab testing is for.

The Complete Sleep Solution program investigates the physical root causes that keep people awake even when their stress is managed: gut pathogens, hormone imbalances, neurotransmitter deficiencies, and toxin burden. Stress and physical imbalance work against each other — solving both at the same time is what creates lasting change, not just a temporary improvement.

→ Learn how the Complete Sleep Solution program works

To take the first step, book a free Sleep Better Consultation so we can talk through what's going on with your sleep and whether the program is the right fit.

→ Book a free Sleep Better Consultation

About Martha Lewis

Martha Lewis is a certified Functional Diagnostic Nutrition practitioner and founder of The Sleep Detective™. Since 2019, she has helped 300+ clients identify the root causes of their insomnia using functional lab testing — including gut analysis, hormone panels, neurotransmitter testing, and toxin screening. She discovered her own root causes (hormone imbalances, heavy metals, and a parasite) after years of trying conventional sleep solutions, and now uses the same investigative approach with her clients.

Learn more about Martha →