Now recruiting · Greenwater Scientific

ReBreathe: does better air make you recover better?

A five-week study on indoor air and human recovery. You keep wearing the band you already wear. We install a greenwaterHOME air unit in your space for four of those weeks, and compare your own readings across phases. Nobody's data is compared to anybody else's — yours is compared to yours.

Apply to join Takes about 4 minutes · 75 places
Duration
5 weeks
Daily effort
Under a minute
Wearable
Whoop or Watch
Places
75
The structure

Five weeks, two phases

A study coordinator handles every phase change in person. You never have to switch anything on, off, or over.

Week 1
Baseline
No unit in your home. You go about your normal week while we record how you sleep and recover as you already are.
Weeks 2 – 5
Active
A coordinator installs a greenwaterHOME unit in your space and it runs continuously. You don't operate it. One extra daily question appears: hours spent in that room.
What you actually do

Set up once. Then answer one short question a day.

After the first evening, ReBreathe runs almost entirely in the background. Your wearable syncs on its own.

1
Install the app
ReBreathe arrives by email invite through TestFlight. Free, and takes a few minutes on your iPhone.
2
Read and sign consent
The full consent form lives in the app. Read it properly — you can withdraw at any point afterwards.
3
Connect your wearable once
Link your Whoop or Apple Watch a single time. From then on your measurements sync on their own.
4
Check in each day
One short screen about yesterday: alcohol, training intensity, stress, illness, anything unusual. Under a minute.
What you get

Compensation for your time

You're giving us five weeks of daily attention. Here's what comes back.

A participant discount on a greenwaterHOME
If you'd like to keep a unit after the study ends, you get it at a participant rate. No obligation either way.
Your choice of thank-you
A box of protein powder, or a recovery basket — magnesium, ashwagandha and similar. You pick when you apply.
All of your own data, grouped by phase
See your readings in the app whenever you like, split by baseline and active weeks, so you can read your own five weeks.
What we are not promising
We are not promising that your sleep or recovery will improve. Whether cleaner indoor air changes anything measurable is the exact question this study exists to answer — and a genuine answer requires that we don't assume it in advance. If the data shows no effect, that is a real and publishable result. Please apply because you find the question interesting, not because you expect a health outcome.
Before you apply

Three things you'll need

You're 18 or older Required to give informed consent
You own an iPhone ReBreathe is iOS only for now
You own a Whoop band or Apple Watch And you already wear it most days
All three are checked at the start of the application. If something doesn't line up, you'll know in under a minute rather than at the end of a long form.
Apply to join
Application

Apply to join ReBreathe

Six short screens, about four minutes. Your answers save as you go, so you can close this and come back.

Eligibility
Step 1 of 6

First, a few checks

These take about thirty seconds. If something doesn't line up you'll find out right here rather than at the end of a long form.

You need to be 18 or older to give informed consent for a research study.
Please enter your age.
Do you own an iPhone?
The ReBreathe app is iOS only for now. An iPad or Mac won't work — it has to be an iPhone you carry.
Please pick one.
Which of these do you own?
The study reads recovery and sleep from your own device — we don't lend hardware.
Please pick one.
How often do you actually wear it?
Daily wear — especially overnight — is what makes the sleep and recovery comparison work. You can still apply, but do let us know in the last step if you'd be able to wear it consistently for five weeks.
Please pick one.
So we can plan the install visit.
Please select where you live.

How we reach you

A coordinator will call to arrange the install window, so a working number matters as much as an email address.

Please enter your name.
Where we send study updates. This can be different from your Apple ID — we ask for that separately on the next screen.
Please enter a valid email address.
+91
Please enter a valid 10-digit mobile number.
Is that number on WhatsApp?
Coordination is usually quickest there. Entirely optional.
Please pick one.
On a normal weekday, where are you?
This shapes how many hours you'd spend near the unit, which is one of the things we measure.
Please pick one.

The one field people get wrong

ReBreathe isn't on the App Store — it's distributed through TestFlight. Your invite has to go to the email address attached to your Apple ID, and nowhere else.

Why this matters
TestFlight will only accept an invite sent to your Apple ID address. If you give us your work address but your iPhone is signed in with an old personal one, the invite simply won't open — this is the single most common reason someone can't install the app. Please check rather than guess.
How to find your Apple ID address on your iPhone
  1. Open Settings.
  2. Tap your name at the very top of the screen.
  3. The email shown under your name is your Apple ID address.
  4. If it reads something like xyz@privaterelay.appleid.com, tap through to Sign-In & Security and use the real address listed there instead.
Please enter a valid email address.
Paste-blocked on purpose — retyping catches the typos that cost people a week.
The two addresses don't match.

The room the unit would live in

The greenwaterHOME goes into one room. Knowing what that room is like helps us read your numbers properly — and helps the coordinator arrive with the right kit.

What kind of home is it?
Please pick one.
Which room would it go in?
Pick the room where you spend the most waking and sleeping hours.
Please pick one.
Do you sleep in that room?
Please pick one.
Please pick one.
Hours a day you're at home, all in
Please pick one.
Is there already an air purifier in your home?
Not a problem either way — we just need to know, because it changes your baseline.
Please pick one.
How often is the AC running in that room?
Please pick one.
And the windows in that room?
Please pick one.
Do any of these describe your home? — tick all that apply

How you sleep and train right now

Your five weeks are only ever compared to your own five weeks. These answers help us group applicants sensibly and spot what else might be moving your numbers.

How long have you had it?
Please pick one.
Nights a week you sleep with it on
Please pick one.
Typical hours of sleep on a weeknight
Please pick one.
How would you rate your sleep at the moment?
1 — poor5 — excellent
Please pick a rating.
Do you work night or rotating shifts?
Please pick one.
Days a week you train
Please pick one.
What sort of training? — tick all that apply
How often do you drink alcohol?
You'll be asked this daily during the study too. There's no right answer — we just need to account for it.
Please pick one.
Will you be away from home for more than three nights in the next two months?
Long trips break the phase structure, so it helps to know now.
Please pick one.
Does anything here apply to you? — tick all that apply
None of these rule you out on their own. They simply need to be on record before we assign phases.

Last bit — what you're agreeing to

This isn't the consent form; that lives in the app and you'll read it properly before anything starts. This is just so we both know what five weeks looks like.

Please tick every box above — each one is a requirement of taking part.
If you complete the study, which would you rather have?
Alongside the participant discount on a greenwaterHOME unit, which everyone who completes receives.
Please pick one.
How soon could you start?
Please pick one.
Please pick one.
Your exact locality, an unusual schedule, a question about the unit — anything at all.
Both consents are required before we can accept an application.
We couldn't send your application just then. Please check your connection and try again — or email it to rebreathe@greenwater.in and we'll enter it manually.

This one isn't a fit — and that's genuinely fine

ReBreathe has a narrow set of requirements, not because of anything about you, but because the measurement only works if everyone's data comes from the same kind of setup.

Thank you for the time you've already given this. We'd genuinely like to have you in a later round.

Want us to get in touch about future studies?
We'll only email you when we open recruitment for something you'd actually qualify for.
Done — you're on the list. We'll be in touch when the next study opens.

Application received

That's everything we need from you for now. Your answers are with the ReBreathe team and nothing further is required until you hear from us.

Your reference —
What happens next
1
We read your application
Within five working days. We're selecting 75 people, so we do read every one properly rather than filtering automatically. You'll hear from us either way.
2
A TestFlight invite arrives by email
If you're selected, the invite goes to your Apple ID address. Install the free TestFlight app from the App Store first, then open ReBreathe through it.
3
A coordinator calls to book your install
Your baseline week starts as soon as you've signed consent in the app and connected your wearable. The unit arrives at the end of that week.
One thing worth double-checking
You told us your Apple ID email is: — If that isn't the address your iPhone is signed in with, the TestFlight invite won't open — and it's the most common reason someone can't get started. Open Settings and tap your name to check. If it's wrong, email us at rebreathe@greenwater.in with your reference number and we'll correct it before the invites go out.