Your Polar watch × your AI

Train like you
know something.

Because now you do. Northbeat connects your Polar watch to your AI: every night of sleep, every beat of HRV, every session you have ever logged, remembered forever and read back like advice from a coach who never sleeps.

Join the waitlist Founding-member pricing. No card, just an email.
The conversation

Ask it anything.

Your watch already measures everything. Northbeat gives it a voice: add one URL to Claude, sign in, and your numbers start answering back.

Claude · connected to Northbeat OAuth · revocable
Should I go hard today or is that stupid?
Your HRV is 11% above baseline and last night hit 92% sleep efficiency, your best week this month. Go hard. Save tomorrow for zone 2: your load ratio says two big days back to back is where you usually dig a hole.
Show me.
Today at a glanceReady
HRV
0ms
↑ +11% vs baseline
Sleep score
0
→ +1% vs baseline
Resting HR
0bpm
→ −1% vs baseline
Load ratio
0
↑ +4% vs baseline
HRV is 11% above your 30-day baseline, trending up 7 days
Sleep score in line with baseline (73 vs 72)
Training load ratio 1.04, building steadily inside the safe band
Good day for a hard session. Recovery markers are all green.
85% CONFIDENCE
Keep bedtime consistent to protect the HRV trend.
70% CONFIDENCE

The real product draws this card live inside Claude, from your numbers. Ask a different question, get a different card.

The morning briefing

It works while
you sleep.

You don't open Northbeat. It opens with you. Before you're up, its agents have already read your night, sleep stages, overnight HRV, breathing, skin temperature, against years of your own baselines. You wake to a briefing, not a dashboard. And when something looks like the start of an illness, you hear about it before your throat does.

Northbeat · Morning briefing07:02

Slept 7h 41m at 92% efficiency. HRV 38ms, up 11% on your baseline: best recovery in 12 days.

Today is the day for the intervals you keep postponing. Your last three breakthrough sessions all followed nights like this one.

Skin temp normal. No illness signals. Bedtime drift this week: 12 minutes. Keep it.

The outcomes

Push on the right
days. Rest on purpose.

Run further

Race-day guessing, retired

Months of load, recovery and sleep in one place. Your AI spots the pattern between your easy weeks and your breakthrough sessions, then tells you when the next one is due.

Lift heavier

Strain when it counts

HRV above baseline and sleep in the green is a green light. Northbeat catches the mornings your body is ready before your head is, and the ones where it is the other way round.

Sleep deeper

Your nights, decoded

Hypnograms, overnight HRV, breathing rate and skin temperature, night after night. When something drifts from your normal, you hear about it in plain English.

The longer life, the better everything and the private jet are not medically guaranteed. The part where you finally understand your own body is.

The memory

Polar's API forgets
in 30 days. We don't.

Most of your history is locked inside a one-month window. Northbeat syncs it continuously to your own private store, so your AI reasons over years of you, not last month's snapshot. And your baselines are yours: "is this normal?" means normal for you, never a population average.

SLEEPstages + hypnogram
HRVnightly + samples
ECGfull waveform
SKIN TEMPnightly trend
SPO2overnight
WORKOUTSzones + samples
GPS ROUTESevery session
VO2 MAX+ thresholds
RECHARGEANS + breathing
ALERTNESSthrough the day
CARDIO LOADstrain vs tolerance
BASELINESnormal, for you
The setup

Two minutes.
No server. No Docker.

01

Connect your watch

Sign in with your Polar account. Sync starts immediately and keeps running while you sleep.

02

Add one URL to your AI

Paste the Northbeat connector into Claude and sign in. OAuth, not API keys. Revoke any time.

03

Ask better questions

"How did I sleep this month?" "Am I overreaching?" "What happens to my HRV after late sessions?" Answered from your data.

The waitlist

Be first under
the lights.

Northbeat is being built by the person behind the open-source engine it runs on. Waitlist members get early access and founding-member pricing, locked for life.

One email when it launches. Nothing else, ever.