Blood Pressure Guidelines in Japan (JSH)

Japan's categories are set by the Japanese Society of Hypertension (日本高血圧学会, JSH). The current guideline is JSH 2025, published in August 2025 — the first revision in six years. Its diagnostic thresholds carried over unchanged from JSH 2019, and uniquely, every category is defined twice: once for readings taken at the clinic (診察室血圧) and once for readings taken at home (家庭血圧), with the home limits set lower.

Hypertension means Grade I or above: 140/90 at the clinic, or a home average of 135/85, on either number. The "Elevated" band (高値血圧) is not yet hypertension, but the JSH's own booklet for the public is blunt about it: elevated blood pressure is a condition that must not be left unattended — and JSH 2025 explicitly extends the guideline's scope down to this band rather than covering only diagnosed hypertensives.

The headline change in JSH 2025 is the treatment target. JSH 2019 had two — a tighter one under 75 and a looser one over — and the new guideline replaces both with one target for all ages: below 130/80 at the clinic, below 125/75 at home. For people 75 and over it applies "if tolerated, judged individually," with explicit caution about lowering blood pressure too far.

Japan's guideline does something few others do: when clinic and home readings disagree, it says to trust the home number. The JSH's reasoning is practical — research has shown 家庭血圧 (home blood pressure) predicts strokes and heart disease better than clinic readings do, so the guideline gives it priority in diagnosing hypertension.

That priority is what catches the two patterns a clinic visit alone misses: white coat hypertension (白衣高血圧 — high at the clinic, normal at home) and its more dangerous mirror image, masked hypertension (仮面高血圧 — normal at the clinic, high at home, with risk similar to sustained hypertension). Home measurement is the tool that tells them apart.

The JSH protocol is specific, and it is worth following exactly:

• Morning: within 1 hour of waking, after urination, before breakfast and before taking any medication.
• Evening: before bed.
• Both times: sit quietly for 1–2 minutes first, cuff at heart height, legs uncrossed, no talking during the measurement.
• Take 2 readings per occasion and record all of them — judge by the average, never by the best one.
• Diagnose on the average of 5–7 days or more, not on any single day.

Our step-by-step measurement guide covers the same setup in detail — arm position, cuff fit, and the mistakes that quietly add 5–10 mmHg to a reading.

The JSH's advice to the public is unambiguous: use a monitor whose cuff wraps around the upper arm (上腕). Wrist-cuff devices, in the booklet's own words, "tend inevitably to give inaccurate values" — the anatomy of the wrist means the artery isn't reliably compressed, and holding the cuff at heart height is hard to get right.

The society goes further than advice: its device working group publishes accuracy-validation results for blood pressure monitors sold in Japan, covering upper-arm devices from the major manufacturers. Only upper-arm models are listed — wrist devices are excluded outright — and the JSH is careful to note the list is a validation record, not an endorsement of any particular device.

If you're weighing cuff styles, connectivity, or what "clinically validated" actually means, our guide to monitor types compares the categories.

Most adults in Japan don't have to seek out a blood pressure check. Under the 特定健診 (tokutei kenshin) system, health insurers are required to offer everyone aged 40–74 an annual health checkup, and blood pressure measurement is one of its basic examination items. Employees are typically measured every year through workplace health checks as well. So for most people, the question isn't getting a reading — it's what to do between the annual ones, which is exactly where the home protocol above comes in.

Japan also has a paper tradition the JSH actively encourages: the 血圧手帳 (blood pressure notebook), a small log of morning and evening readings you bring to checkups and clinic visits. The JSH's booklet tells readers plainly to record every home reading in one and show it to their doctor. If you want a free printable version, Kenporen — the National Federation of Health Insurance Societies — offers free downloadable 血圧手帳 templates in 1-, 3-, and 6-month layouts, plus an Excel version that graphs your entries automatically. The JSH and the Japan Hypertension Association also co-edit an official printed notebook, available to order in several formats.

Whether the notebook is paper or an app, what matters to a doctor is the same thing: a consistent morning-and-evening record with all readings kept, not just the good ones. Our blood pressure log guide covers what to record alongside each number.

Japan diagnoses hypertension from 140/90 at the clinic and 135/85 at home. US guidelines draw the line lower, at 130/80 — so a clinic reading of 134/84 is "Elevated" (高値血圧) in Tokyo and "Stage 1 hypertension" in New York. Neither is wrong; they are different judgments about where treatment starts paying off, applied to different populations.

The two systems are converging, though, and JSH 2025 is the clearest sign of it: Japan's new treatment target — below 130/80 for all ages — lands on exactly the number the US uses as its diagnostic threshold. Diagnosis still starts at 140/90 in Japan, but once you're being treated, both countries now steer you toward the same place.

The Blood Pressure Journal app ships with the US (ACC/AHA) bands by default, so out of the box it flags readings from 130/80 as high. If your doctor in Japan works to the JSH thresholds, the app's classification ranges are customizable — set the hypertension boundary to 140/90 and the categories will match what your 血圧手帳 and your doctor say. Wherever the lines are drawn, the number worth bringing to a doctor in Japan is the same one the JSH names: a home average at or above 135/85 over 5–7 days.

The scale of the issue explains the guideline's reach: by the JSH's own estimate, about 43 million people in Japan have hypertension — the country's most common lifestyle disease.

A single high reading is almost never an emergency on its own. If your monitor shows something alarming, sit quietly for a few minutes and measure again — anxiety about the first number is itself enough to inflate the second.

If a reading stays above 180/120 mmHg and you have symptoms such as chest pain, shortness of breath, weakness, numbness, vision changes, or difficulty speaking, seek emergency care immediately. In Japan, call 119 for an ambulance (救急車). If you're unsure whether the situation needs an ambulance, many regions run the #7119 advice line (救急安心センター), where nurses and doctors assess the situation by phone, direct you to appropriate care, and transfer you straight to 119 if it's urgent — availability and hours vary by region.

Readings above 180/120 without symptoms still warrant contacting a doctor promptly — just not necessarily an ambulance.