What This Timer Is Doing
Why a square, and what the counting is for
Equal counts hold your breathing at 3.75 breaths a minute, against a resting rate of twelve to sixteen. That slowdown is the mechanism. Slow exhalation raises vagal tone, which shows up as a measurable increase in heart rate variability, and the two holds mostly serve to stretch the cycle out and give you something to count.
The reason it gets taught to people under pressure — it is also called tactical breathing, or four-square — is not that it beats other paced patterns. It is that four, four, four, four survives a bad moment. A ratio you have to think about does not.
What the research supports is slow paced breathing in general: controlled trials find acute reductions in self-reported stress and small drops in heart rate and blood pressure. Very little of it isolates this pattern specifically. Treat the box as a delivery mechanism for slow breathing rather than as the active ingredient, and the claim stays honest.
Questions
How long should I do it for?
Six cycles is about a minute and a half, and that is a sensible first session. Longer is fine but longer is not what makes it work — doing it on the days you do not feel like it is.
Why do the holds feel harder than the breathing?
The hold after the exhale is the unfamiliar one. Most people have never deliberately paused with empty lungs, and the first few attempts feel like being underwater. Set Hold empty to 0 and you get four in, four held, four out — still useful, and the timer switches to a circle because three phases on a four-sided shape would leave a dead side.
Should I breathe through my nose?
In through the nose if you can. Out through either. Nasal breathing warms and humidifies the air and slows it down on its own, which helps, but a blocked nose is not a reason to skip the session.
Does this work offline?
Yes. Once the page has loaded it runs entirely in your browser — no requests, no server, no account. Put your phone in airplane mode and it keeps working.