How to Calibrate Your Hilo Core: Four-Day Setup and Monthly Recalibration

Set aside a few quiet minutes each day. Wear the band on the same wrist, place the cuff on the opposite bare upper arm, rest for five minutes, and remain still until the app accepts the session. The included upper-arm cuff provides the system’s point-in-time reference reading. The cuffless band-and-app experience adds a longer record of wellness trends across days and weeks. The current Hilo app and user manual take priority over older instructions. Explore Hilo Core.

Key Facts

• Calibration takes four separate days: Complete one app-guided cuff session — three consecutive inflations — on each of four different days. Sessions done on the same day do not count as separate days.
• The included cuff does the work: No separate device is needed. The Hilo Cuff provides the reference readings that personalize the band to your physiology.
• Recalibrate every 30 days: After the initial setup, the app will prompt a monthly refresh. Complete it as soon as practical when the prompt appears.
• Calibration does not make the band a clinical measurement device: The cuff supplies point-in-time reference readings. The band and app support awareness of longer-term wellness trends.

The Four-Day Hilo Calibration at a Glance

• Days 1–4: Complete one guided cuff session on each day.
• Each session: Let the cuff complete all three inflations.
• After day 4: Keep wearing the band and review the cuffless trends in the app.
• Every 30 days: Complete the recalibration when the app prompts you.

Why Hilo Calibration Takes Four Days

Blood pressure changes over the course of a day and from one day to the next. Sleep, recent activity, stress, meals, caffeine, bladder fullness, posture, medication timing, and the time of measurement can all affect a cuff reading. Collecting the starting reference sessions on separate days reduces the influence of any one day’s circumstances.

Hilo’s four-day schedule is product-specific. The measurement method behind it follows the same discipline emphasized in the 2025 AHA/ACC High Blood Pressure Guideline: use a validated upper-arm device, standardize preparation and body position, take repeated readings, and base decisions on averages instead of a single number.

The AHA scientific statement on cuffless blood pressure devices describes calibration as a critical part of cuffless systems. The quality of the cuff reading, the user’s technique, and the timing of recalibration all affect the reference supplied to the device. Hilo includes the reference cuff and guides the process in the same app.

The upper-arm cuff platform was evaluated in a peer-reviewed study under its earlier Aktiia device name. The study included 85 adults and 255 paired comparisons with reference double auscultation under the ANSI/AAMI/ISO 81060-2:2013 protocol. Mean test-reference differences were 1.3 mm Hg for systolic pressure and -0.2 mm Hg for diastolic pressure. See the cuff validation study.

Before Day 1: Prepare for a Reliable Cuff Reading

Choose a chair, a table, and a time when you can sit without interruption. Then work through the following steps.

1. Charge and connect both devices

Fully charge the Hilo Core and Hilo Cuff. Install or update the Hilo app, pair both devices, and keep Bluetooth enabled. A reliable internet connection may be needed while the app completes setup.

2. Choose one wrist and keep using it

Place the band on the top, or outside, of your chosen wrist above the wrist bone. The optical sensor should sit directly against your skin. Adjust the strap until it is snug and comfortable. Keep the band on this wrist throughout the four-day setup and the following 30-day interval.

3. Place the cuff on the opposite bare upper arm

Use the cuff on the arm opposite the band. Position it directly on bare skin, about 2 to 3 cm above the bend of the elbow. The solid section with the logo should sit on the inside of the arm, with the logo and blue light facing toward the elbow. The cuff should be secure while still allowing two fingers underneath it.

4. Prepare as you would for a careful home reading

For at least 30 minutes beforehand, avoid exercise, caffeine, smoking, alcohol, eating, and stressful activity. Empty your bladder. Sit quietly for at least five minutes with your back supported, feet flat, and legs uncrossed. Rest the cuffed arm on a table so the cuff is at heart level.

For more detail on upper-arm cuff technique, read how to measure blood pressure correctly at home.

5. Stay still until the app confirms the session

Do not talk, use your phone, move, or tense the cuffed arm during the inflations. Keep the forearm supported. Once the app accepts a session, leave it in place. Repeating an accepted session to obtain a different number adds unnecessary variation to the setup.

Complete One Session on Each of Four Days

Each session follows the same routine: band on your chosen wrist, cuff on the opposite bare upper arm, five-minute rest, three guided inflations, confirmation in the app. Work through the steps below once per day on four separate days.

Day 1: Start the guided calibration

Open the Hilo app, put the band on your chosen wrist, and place the cuff on the opposite upper arm. After the five-minute rest, start the session and remain still through all three inflations. Wait for confirmation in the app before removing the cuff.

If the app rejects the session, check the band fit, cuff position, posture, Bluetooth connection, and internet connection. Follow the message shown in the app. Hilo Support advises waiting at least two hours before another attempt. Contact Support after three failed attempts made at different times of day.

Days 2 and 3: Return once each day

Repeat the same routine on the next two days. Use the same wrist, keep the cuff on the opposite arm, rest for five minutes, and complete one guided session. The numbers may differ from one day to another. Consistent preparation and positioning are more useful than trying to reproduce the previous day’s result.

Day 4: Finish the initial setup

Complete the fourth guided session and wait for the app to confirm that calibration is complete. Keep wearing the band as instructed. The next scheduled calibration is due 30 days later.

What Happens After the Initial Hilo Calibration

The band uses photoplethysmography, or PPG, to record optical pulse-wave information at the wrist during suitable low-motion periods. Signal-quality checks determine which optical segments can contribute to the cuffless trend experience. A loose strap, poor skin contact, cold skin, or movement may reduce the amount of usable data.

The app displays cuff readings separately from cuffless trends. A cuff reading records blood pressure at a specific moment. The band-and-app view shows longer-term changes across days and weeks within Hilo’s wellness experience. Use the Hilo Cuff whenever you need a point-in-time reading.

Explore how blood-pressure patterns change over time.

Recalibrate Every 30 Days

When the monthly prompt appears, repeat the same setup. Wear the band on the established wrist, place the cuff on the opposite bare upper arm, rest for five minutes, support the arm at heart level, and remain quiet and still during the guided sequence. Wait until the app confirms that the refresh is complete.

Complete a missed calibration prompt as soon as practical. Extra sessions are usually unnecessary between prompts unless the app or Hilo Support asks for one. You can continue to use the upper-arm cuff for point-in-time readings at any time.

Common Hilo Calibration Problems

If a session fails or the setup does not advance, check for these common causes:

• Completing more than one of the four starting sessions on the same day.
• Putting the cuff over clothing or on the same side as the band.
• Wearing the band loosely or allowing the sensor to lose skin contact.
• Switching wrists during the four-day setup or the monthly interval.
• Skipping the five-minute rest or calibrating soon after activity, caffeine, smoking, alcohol, food, or stress.
• Talking, moving, using a phone, or leaving the cuffed arm unsupported.
• Retrying too soon after a failed calibration or repeating a session the app already accepted.
• Starting with a low device charge, disabled Bluetooth, or an unstable internet connection.

Correct the setup, rest again, and follow the retry timing shown in the app. Contact Hilo Support if calibration fails three times at different times of day or the app does not let you continue.

WHEN A VERY HIGH READING NEEDS URGENT ACTION

If your upper-arm cuff shows a reading higher than 180 systolic and/or 120 diastolic, wait at least one minute and measure again.

If the second reading is just as high and you have chest pain, shortness of breath, back pain, numbness, weakness, a change in vision, difficulty speaking, or another new concerning symptom, call 911.

If you do not have symptoms but the reading remains that high, contact your health care professional promptly.

Follow the American Heart Association severe-hypertension guidance.

Do not change medication based on a single reading unless a qualified clinician tells you to.

Disclaimer: Hilo Core is a wellness product. It is not intended to diagnose, treat, cure, or prevent any disease. It is not intended to measure blood pressure for medical purposes. This article is for general informational purposes only and does not constitute medical advice. Individual health decisions should be made in consultation with a qualified healthcare professional. Hilo Core is not recommended during pregnancy or for individuals with certain cardiac implants or pre-existing conditions. Please consult your healthcare provider before use.

Frequently Asked Questions About Hilo Calibration

How long does Hilo Core calibration take?

Initial calibration takes four calendar days. Each day includes one short app-guided session with three cuff inflations. The monthly recalibration is a single session.

Can I complete all four starting sessions in one day?

No. The app expects one session on each of four separate days. Several sessions completed back-to-back do not follow the intended setup and will not be accepted as four separate calibration days.

What should I do if I miss the 30-day calibration?

Complete the prompt as soon as practical. Use the upper-arm cuff when you need a point-in-time reading until the app confirms the monthly refresh is complete.

Does calibration make the band a clinical blood pressure device?

No. The included upper-arm cuff provides the point-in-time reference reading in Hilo Core. The cuffless band-and-app experience supports awareness of longer-term wellness trends. It is not intended for diagnosis, treatment decisions, or medication changes.

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Sources

1. Jones DW, Ferdinand KC, Taler SJ, et al. 2025 AHA/ACC/AANP/AAPA/ABC/ACCP/ACPM/AGS/AMA/ASPC/NMA/PCNA/SGIM guideline for the prevention, detection, evaluation, and management of high blood pressure in adults. Circulation. 2025;152:e114–e218. doi:10.1161/CIR.0000000000001356. Primary current U.S. guideline for validated devices, cuff size, standardized technique, and repeated readings. 2025 AHA/ACC High Blood Pressure Guideline
2. Cohen JB, Byfield RL, Hardy ST, et al. Cuffless devices for the measurement of blood pressure: a scientific statement from the American Heart Association. Hypertension. 2026;83:876–886. doi:10.1161/HYP.0000000000000254. Identifies calibration as a critical component of cuffless systems; reviews evidence gaps for cuffless devices in clinical contexts — the Hilo Core band operates within the U.S. wellness framework. AHA scientific statement on cuffless blood pressure devices
3. Alexandre J, Tan K, Almeida TP, Sola J, Alpert BS, Shah J. Validation of the Aktiia blood pressure cuff for clinical use according to the ANSI/AAMI/ISO 81060-2:2013 protocol. Blood Press Monit. 2023;28(2):109–112. doi:10.1097/MBP.0000000000000639. Peer-reviewed validation of the upper-arm cuff used in Hilo’s product lineage. Cuff validation study
4. American Heart Association. When to Call 911 About High Blood Pressure. Last reviewed August 14, 2025. AHA severe-hypertension guidance