01
Pick one job
IHHT for empty-lung capacity, Box for control under load, 4–6 to downshift after training. One protocol per session — no guesswork.
The Gap
You Measure Everything
Downstream Of Your Breathing.
Heart rate to the beat. Splits to the second. Sleep staged, macros weighed, HRV trended for two years. Then the system running underneath all of it — the one that decides whether you hold pace or fold in the transition — has no number at all.
Not because it can't be measured. Because nothing was measuring it.
Where you'd land
Here Is The Scale.
See Where You Land.
- 0:20Untrained
- 0:45Occasional practice
- 1:30Trains this specifically
- 3:00Competitive freediver
- —:—Never measured
Empty lungs, not full. The four-minute breath-holds you've seen online start with a full inhale and measure something else entirely. Exhale first and the numbers get small, honest, and trainable.
Five Minutes. Seated.
No Equipment.
02
Just breathe
No feed, no guru, no soundtrack standing in for the work. The LED counts every second and stops when you stop.
03
Watch it climb
Every rep is written to the second against the date — the line a stopwatch and a good memory can never give you.
IHHT Session
Ready
3 Rounds30 Breaths
Halo1:08
Hold
Start IHHT
ResetBest Hold2:15
Breaths540
Sessions18
BreatheLogProgressProfile
Your History
Breath Hold Log
AllWeekMonthYear
BreatheLogProgressProfile
Your Numbers
Progress
Best Hold
2:15Average Hold
1:42Breaths
540Sessions
18Total Time
24:36Jun 4Aug 20
Aug 20Hold Times 2:15Average 2:15
4 Sessions This Week
BreatheLogProgressProfile
Built for the transitions
The Race Is Decided
In The Roxzone.
Not the sled. Not the wall balls. The ninety seconds between them, when your breathing decides whether you start the next run on pace or twenty seconds down.
Coaches in this sport already prescribe breath-hold work to raise CO₂ tolerance. What none of them have is the instrument — a number for where you started, and a line showing where it went.
8
stations, one engine
1km
between each of them
0
of it spent at rest
The science
Your Body Adapts
To Less Oxygen.
Empty-lung breath holds are intermittent hypoxia — a real, trainable stimulus. When oxygen drops, HIF-1α switches on the genes behind EPO and VEGF: more oxygen-carrying capacity, more blood flow. It's the same adaptation altitude athletes chase — and you get it in a chair.
In a controlled study, trained men doing this saw growth hormone climb 1.5 to 5.6 times baseline. We time every hold to the second and write it down, so over ninety days you watch your own line climb.
Practice seated or lying down — never in water or a car.
The record
One Hold Is A Number.
Ninety Days Is A Line.
A single time tells you almost nothing. Sleep, caffeine, altitude and stress all move it. What means something is the shape of two hundred of them.
That's the part that can't be rebuilt. Delete the app after a year and you're not losing a timer — you're losing the only record of what your breathing actually did.
Seven Days Of Everything.
Then Decide.
No card to start. Every protocol, every hold written, the full history and the stats. On day seven you either keep the record or you don't.
Yearly
Most take this$49
per year · 7-day trial
- • Every hold written, forever
- • Full history, stats and filters
- • 7-day trial, no card
- • One bill. A year of the record.
Lifetime
$99
once · no trial
- • Everything, no renewals
- • No trial — you already know
- • Only 70 left at this price
Web first today — install the PWA on your phone for full-screen sessions.
Who trains this
Freedivers Have Done This For Decades.
Everyone Else Is Late.
Apnea athletes, altitude climbers and tactical teams have trained CO₂ tolerance for years, because in their work the ceiling is obvious. Hybrid racing found it about ten minutes ago. Every breath-hold app on the store is still built for the pool.
Endurance · Hyrox · CrossFit · Combat sports · First responders · Pilots · Freedivers
Before you ask
The Four Questions
Everyone Has.
Isn't this just holding my breath with a stopwatch?
For one rep, yes. The product is the two hundredth rep and the line connecting them — plus a protocol that makes the reps comparable to each other.
I can hold my breath for three minutes.
On a full inhale, probably. Exhale everything first and most people who say that land under fifty seconds. Different test, different scale.
Is this safe?
Seated, on land, at rest — yes. Never in or near water, never in a car. Shallow-water blackout is the real hazard in this category and it gives no warning.
What happens on day seven?
You're asked for a card. Decline and nothing is deleted — the log goes read-only and your history stays.
Find out where you land