A gradient sky during sunset with hues of orange, pink, purple, and blue.
Close-up of the word 'Sisy' in white text on a black background.
Get early access 🔒
Get early access 🔒

Beat stress.
Stay sharp.
Live better.

SISU uses your body’s data to keep your mind performing under pressure. Understand your stress, act with personalised protocols, and prevent burnout before it hits.

FOR MINDS THAT WON’T SWITCH OFF

Detect stress early.
Know what to do.

SISU reads your data, identifies early shifts in stress and recovery, and translates them into precise actions you can easily follow—so your mind performs at its best, every day.

Get early access 🔒
Get early access 🔒

Your stress response,
finally measured.

The Resilience Score™

A single score built from your stress signals, recovery, and sleep—measuring how you are handling pressure, so you know when to push and when to reset.

iPhone screen showing a resilience score of 97 with an optimal rating on a blue background.
iPhone screen showing a resilience score of 97 with an optimal rating on a blue background.
A young man with curly brown hair, glasses, and a beard, smiling while looking into the distance, with a colorful sunset sky in the background.

Your mind, understood through your data.

SISU connects to your wearables, calendar, and glucose monitor to track stress and recovery as they change — translating your own data into a clearer understanding of your mind.

A woman with brown hair and freckles smiling against a sunset sky.
Close-up of a digital device displaying five circular icons with logos of Garmin, Apple, Voyage, and two others, arranged in a grid.

INSIDE SISU

Sisu is your mind,
at its best.

A hand holding a smartphone displaying a mental health app with a message about stress load trending up this week, against a sunset sky background.

Resilience Score
Your capacity, in real time.

Drift Detection
Identify early signals of stress.

Phase Tracking
Baseline, overload, or recovery.

Personalized Protocols
Improve sleep, recovery and focus.

Weekly Reports
Clear trends, not just daily scans.

Based on a real case —
detectable 12 months earlier.

Close-up portrait of a middle-aged woman with short blonde hair, blue eyes, and a gentle smile, resting her chin on her clasped hands against a dark background.

Camila Tomás
‍ Sisu Co-founder

“I burned out without seeing it coming. Looking back at my data, the patterns were clear—stress rising, recovery declining. The signals were there 12 months before. I just didn’t know how to read them.

SISU was built to make your signals visible—and actionable.”

Designed for performance.
Grounded in physiology.

SISU uses established signals like HRV, resting heart rate, and sleep—anchored to your personal baseline, not population averages.

A man with wavy dark hair, wearing glasses and a black shirt, sitting indoors with a bright background.

“What impressed me most is how actionable the insights are. No wellness fluff — just precision.”

— Marcus 
Private Equity Investor
A woman with dark curly hair smiling and resting her face on her hand, wearing a white shirt.

“I’ve spent years tracking performance metrics. This was the missing layer.”

— Olivia 
Olympic Performance Specialist
Black and white portrait of a smiling man with short dark hair and a beard, wearing a long-sleeve black shirt and a wristwatch, standing against a plain light-colored wall.

“I didn’t realize how exhausted I was until Sisu showed me the trend.”

— Alex
Founder
A colorful sky during sunset with a gradient of orange, pink, purple, and blue hues.

Sisu
/ˈsiːsu/ (noun, Finnish)

Sisu is a Finnish word that represents inner strength, determination, and resilience. The SISU app translates this philosophy into data, helping you understand your stress, act with precision, and sustain peak mental performance.

SISU is your mind, at its best. Every day.

The word 'Sisy' written in large, white, stylized text on a black background.
Get early access 🔒
Get early access 🔒

Sisu 2026 ®

Legal notice