Dry-land breath-hold training: a structured approach to CO2 tolerance tables

[DryDive]

Hey everyone,
I've been freediving for a few years now and one thing that made the biggest difference in my progress wasn't pool sessions or depth days — it was consistent dry-land breath-hold training. Figured I'd share some of what's worked for me in case it helps anyone else who's plateauing.
Why train on dry land?
Most of us can't get to the pool every day. But you can run a CO2 tolerance table from your couch in 20 minutes. The idea is simple: repeated breath holds with decreasing rest intervals. Over time your body adapts to higher CO2 levels, which directly translates to longer, more comfortable dives. The diaphragm contractions come later, and when they do come, you handle them better.
A basic CO2 table structure:

• Start with a hold at ~50% of your max static
• Rest for 2 minutes before the first hold, then reduce rest by 15 seconds each round
• 8 rounds total
• By the final round you're resting maybe 30-45 seconds between holds

The key is consistency over intensity. 4-5 sessions per week at moderate effort beats one max-effort session. You're training your chemoreceptor response, not trying to set a PB every time.
What I track:

• Hold times across each round
• Time to first contraction
• Subjective comfort level (1-5 scale)
• How the numbers trend week over week

I recently started using a free app called DryDive (drydive.app) that structures these tables automatically and tracks your progress over time. It handles CO2 and O2 table generation based on your current max hold, and you can see your tolerance improving session by session. Saves me from doing the math or using a spreadsheet. Worth checking out if you want something purpose-built for dry training.
A few tips from experience:

• Always train lying down or seated — never in water alone, never while driving, etc.
• Don't train on a full stomach
• If you feel dizzy or get tingling, stop the session. Dry training should never be pushed to blackout territory.
• Pair breath-hold work with diaphragm stretching (full lung stretches, exhale holds) for better results

Curious what routines others here are using for dry training. Anyone doing exhale-hold tables or mixing in Wim Hof-style breathing before their CO2 work? Would love to compare notes.
Dive safe

 

[Parables]

this is great
what is the link to the drydive app. i asked the app creator for the link but it seems to have expired.
i am searching for it on my computer so maybe it's mobile phone only
please advise
thank you