For years, the sleep advice has been remarkably consistent: keep your bedroom cold. Somewhere around 65 to 68°F, if the wellness magazines are to be believed. Crack a window, buy a cooling mattress topper, invest in those sheets that supposedly wick heat from your body like a high-end thermos.

Then a new study comes along and quietly suggests the opposite.

Researchers tracking adults with type 2 diabetes across more than 1,300 nights found that on the warmer-than-usual evenings, participants actually slept a little better — fewer wake-ups, higher sleep efficiency, less time staring at the ceiling at 3 a.m. It's a small study, and the findings don't exactly demolish the cool-bedroom orthodoxy. But it does raise a question worth sitting with: what if the ideal sleep temperature is a lot more personal than the internet makes it sound?

What the researchers actually did

The setup was fairly straightforward. A team followed 108 adults with type 2 diabetes and collected data across 1,307 nights — a decent sample for a sleep study of this kind. Participants wore wrist-based activity trackers, the sort that measure movement patterns to estimate when you're asleep, when you're drifting, and when you're wide awake at some ungodly hour wondering why you can't just rest like a normal person.

Separately, small temperature loggers recorded the indoor climate of each participant's bedroom through the night. These little devices sit quietly in the corner and log readings over time, which researchers then averaged across each person's sleep window.

They tracked four specific measures: sleep efficiency (the percentage of time in bed actually spent asleep), how long people stayed awake after first falling asleep, total sleep duration, and how often they woke up during the night. Crucially, they compared each person's warmer and cooler nights against their own typical nighttime temperature — rather than lumping everyone together and comparing cold-house dwellers to warm-house dwellers.

The surprising finding about warmer nights

Here's the headline: on nights that ran warmer than a participant's personal average, sleep efficiency went up and awakenings went down. Not dramatically, but measurably.

Total sleep time didn't shift much, which is interesting. And when researchers compared different participants' average bedroom temperatures against one another, the picture dissolved entirely — no meaningful link between absolute room temperature and sleep quality across the group.

The relationship also wasn't linear. Across moderate temperatures, sleep stayed roughly the same. But once rooms climbed above about 80.6°F (27°C), sleep efficiency climbed and wake-ups dropped. There's a catch, though: relatively few nights in the study hit that temperature, and when those outlier nights were removed, the pattern softened considerably. So take the specific 80°F figure with a generous pinch of salt.

So should you crank the thermostat up?

Probably not. At least not based on this one study.

The research doesn't establish an ideal bedroom temperature, and it doesn't prove that deliberately sleeping in a warmer room will improve anyone's rest. Other research — a pile of it — has pointed to cooler rooms around 65-68°F as better for most sleepers. Core body temperature naturally drops as you move into deeper sleep stages, and a cooler room supports that drop. That physiology hasn't changed.

What this new study does suggest is that the standard advice may be less universal than it sounds. People with type 2 diabetes, for instance, often have different thermoregulation patterns than the general population. And within any group, individual variation is enormous. Your partner might sleep like a log under a duvet in July while you're kicking off every sheet in reach. Neither of you is broken.

How to find your own sleep temperature

Instead of chasing a single magic number, pay attention to the signals your own body throws at you each night. The data is already there — you just have to notice it.

• Watch the nighttime disruptions. Waking up sweaty, flinging the covers off, or curling into a ball from cold are all your body telling you something's off. Note which happens more often.
• Try bedding changes before thermostat changes. A lighter duvet in summer, a wool blanket layer in winter, breathable sleepwear instead of fleece — these can shift your personal microclimate without touching the HVAC bill.
• Look at the whole picture. Temperature is one variable. Light leaking through the blinds, a partner snoring, a late caffeine, a phone buzzing at midnight — any of these can tank your sleep regardless of how perfect the room temp is.
• Give it two weeks. One restless night doesn't mean your room is too warm or too cold. Patterns matter more than individual nights.
• Consider humidity too. A 72°F room at 70% humidity feels nothing like a 72°F room at 35%. Dry air tends to feel cooler; damp air feels stifling.

Why any of this matters for the bigger picture

Sleep is one of those boring, unglamorous foundations that affects almost everything else — mood, cognition, appetite, blood sugar, immune function, how you handle stress, how you process emotional material. People who come to plant-medicine retreats to work on depression, addiction, or trauma almost always discover, somewhere along the way, that their sleep had been garbage for years and they'd normalised it.

Chronic poor sleep doesn't just make you tired. It wears down the nervous system's capacity to regulate itself, which makes everything else harder — therapy, integration work, breathwork, daily life. If you're the kind of person researching deeper healing modalities, getting the basics sorted first is rarely a waste of time. A properly rested nervous system is better equipped for anything heavier you want to do with it later.

And the lesson from this study is a useful one even outside the specific temperature question: a lot of health advice comes packaged as universal truth when it's actually a reasonable starting point that needs personal calibration. Your sleep, your body, your room. Experiment, notice, adjust.

The takeaway

One study doesn't rewrite the sleep rulebook. The weight of evidence still leans toward cooler rooms for most people most of the time. But the finding that warmer-than-usual nights sometimes improved sleep for this group of participants is a useful reminder that the ideal thermostat setting isn't printed on a stone tablet somewhere — it's the one that lets you fall asleep, stay asleep, and wake up feeling like yourself.

If you're the type working on deeper healing — through therapy, breathwork, meditation, or plant medicine — rest is the ground everything else grows out of. For readers curious about that broader territory, a range of plant-medicine and wellness retreats can be browsed on our marketplace here. In the meantime, maybe try nudging your thermostat a couple of degrees this week and see what your body has to say about it.