A global sleep study reveals that 62% of people wake up feeling tired at least three times a week, even after getting the recommended 7 to 8 hours of sleep. While stress and screen time are often seen as the culprits, the true cause might be more elusive.
There are hidden, science-backed factors that could be quietly disrupting your rest, and most people aren’t even aware of them. Here are five surprising culprits, supported by research and expert insights.
1. Your Alarm Sound Is Triggering a Stress Response
The cheerful jingle or default ringtone on your alarm might seem harmless, but research reveals that sudden, high-pitched tones can trigger a spike in cortisol levels, instantly activating your body’s fight-or-flight response. On the other hand, melodic sounds or alarms that gradually increase in volume help reduce sleep inertia, creating a smoother, more gentle transition to wakefulness.
“Ditch the panic tones. Go for a slow-build chime or sunrise alarm to ease your brain into the day.”, – says Dylan Tollemache, co-founder and CEO at Onebed.
2. Mild Dehydration – While You Sleep
Even a 1% drop in hydration levels during sleep can impact energy and cognition upon waking. During the night, your body continues metabolic processes and breathes out moisture, meaning you wake up slightly dehydrated, even if you felt fine before bed.
“Try a small glass of water before bed—just not right before lights out unless you love 2am bathroom runs,” suggests Dylan.
3. Your Mattress Is Amplifying Micro Movements
Certain mattresses, especially memory foam or hybrid models, can trap heat and amplify micro-wakenings caused by temperature shifts or minor discomfort. These awakenings might last just seconds, but they fragment your sleep cycle and leave you feeling groggy.
“A mattress that traps heat will wreck your rest,” according to Dylan. “If you’re tossing, turning, or waking up damp, it’s time to rethink your setup.”
4. Pre-Sleep Overthinking Isn’t Just Mental – It’s Chemical
Running through your to-do list before bed doesn’t just make you feel anxious – it triggers a release of norepinephrine, a brain chemical that keeps your nervous system alert into the night. Even if you fall asleep, this hormone can keep your brain from entering deeper, restorative sleep stages.
“If your thoughts won’t quit, don’t fight them – write them. Jotting things down before bed gives your mind permission to shut off,” says Dylan.
5. You’re Breathing Through Your Mouth All Night
Studies show that mouth breathing during sleep leads to lower oxygen absorption and higher fatigue levels in the morning. It also increases the chance of waking up with a dry mouth, sore throat, or brain fog. Many don’t realize they mouth-breathe until symptoms start stacking.
According to Dylan, “Dry mouth in the morning is a red flag. Mouth taping sounds strange, but it’s a legit and safe fix if done right.”
Getting enough sleep isn’t always enough to wake up feeling refreshed. It’s the way your body moves through the night that truly matters. Small habits, like your choice of alarm sound or even how you breathe, can disrupt your entire sleep cycle. If mornings feel tough, it might not be about how many hours you’re sleeping, but the small details you’ve been overlooking.
