Recently, I spoke with a physician as passionate about sleep as I am. We were discussing the common advice everyone hears, "keep your bedroom cool," or "don't eat too close to bed", when he highlighted the questions his patients always end up asking:
What temperature is actually best for me? Exactly how long before bed should I finish my last meal?
His answer was simple and honest: "It depends." There is no single number that works for everyone.
Why "One-Size" Tips Aren't Enough
General guidance is a useful starting point, but your body isn’t general.
Take temperature. Most sleep resources recommend a cooler room, roughly 65°F (around 15–19°C), to support the natural drop in your core body temperature at night. Yet, separate research suggests older adults may sleep best in a slightly warmer environment, often around 68–77°F (20–25°C). Both of these findings can be true, because the “right” setting ultimately comes down to you.
The same pattern applies to meal timing. While heavy meals right before bed can disrupt sleep, a light snack can be helpful for some. A common guideline is to finish dinner 2–3 hours before sleep, but again, your optimal window is individual.
Your Hidden Blueprint: Why Your Chronotype Matters
One of the biggest variables in sleep is your chronotype, your body's natural tendency toward being a morning person or a night owl. This isn't just a preference; it's rooted in genetics. For example, variations in genes like PER3 have been linked to whether someone is a natural "early bird" or "night owl."
While not clinical labels, popular shorthand helps illustrate this:
- Lions (Early Types) often thrive with earlier bed and wake times.
- Wolves (Later Types) may feel their best by shifting their entire schedule later.
- Bears (Middle Types) tend to do well following the sun’s cycle.
Helpful? Yes, but only as a sketch. Some Lions can’t fall asleep before 1 a.m. (early rise, late fade). Some Wolves manage fine on an early-shift job after strategic habit tweaks. Chronotype is a spectrum, not a cage.
When your daily schedule fights your internal clock, you feel social jetlag, that persistent, "off" feeling you can't shake, even when you "do everything right".
The Goal: Stop Collecting Rules, Start Finding Your Formula
Better sleep isn’t about collecting more rules. It's about learning how your personal inputs connect to your outcomes. It requires shifting from asking "What's the best practice?" to "What works best for my body?"
- Do you sleep best at 66°F, or is 70°F your sweet spot?
- Does a 2-hour gap after dinner work, or do you feel better with three?
This is where you have to separate correlation from causation. Remember the umbrella analogy from our previous piece: umbrellas and wet streets always appear together when it rains, but umbrellas don't cause rain. Just because streets are wet when people carry umbrellas doesn't mean umbrellas cause rain. Similarly, two things in your life can be linked without one driving the other. The goal is to discover what actually moves the needle for you. Finding causation beats guessing at correlations.
How Trillies+ Helps You Connect the Dots
Trillies+ is built to find the drivers in your existing data. Our system goes beyond simple correlation to test if X is likely causing Y for you. It looks at key relationships:
- Direction & Timing: Did a stress spike come before a restless night, or was it the other way around?
- Amplifiers: Do two small factors, like a late meeting plus a later dinner, disrupt your sleep more together than either one does alone?
- “What-If” Scenarios: When you consistently shift dinner earlier or wind down after evening emails, what tends to happen next?
The aim isn’t absolute certainty, biology is far too complex for that. The aim is to give you higher-confidence, personal starting points so you can focus your effort where it's most likely to matter.
What This Looks Like in Real Life
With this clarity, you can make small, targeted adjustments that add up:
- You learn that keeping the room slightly cooler than you thought helps you fall asleep faster, without waking up cold at 3 a.m.
- You discover the timing of your last meeting influences your sleep quality more than your step count that day.
- You notice that a consistent schedule is more powerful than an extra hour in bed when your week gets busy.
The Bottom Line
There is no single right answer for everyone. There is a right answer for you.
Finding it means listening to your body, understanding your patterns, and acting with data-backed confidence.
Curious about your personal sleep drivers? Trillies+ turns everyday data into your ideal bedtime formula, so you can stop guessing and start sleeping.
About the Author
Darren S. is the founder of Trillie Inc., bringing over 20 years of experience in technology and product management. He is passionate about advancing causal AI and building sustainable solutions that make practical, affordable technology accessible to people and communities everywhere. Connect on LinkedIn