On early contractions

Kelly Starrett talks about the difference between pain and discomfort in movement training. Pain signals damage-you stop immediately. Discomfort signals adaptation-you breathe through it and keep working. Most athletes learn this distinction through experience.

Freedivers face the same challenge, but underwater. When contractions start earlier than expected, your nervous system sends one clear message: something’s wrong, breathe now. The question is whether you’re dealing with a real problem or just training noise.

Most freedivers can’t tell the difference. So they surface early, frustrated, convinced their CO2 tolerance is regressing. They’re not wrong about the early contractions. They’re just misreading what they mean.

Why contractions start early (and it’s not always bad)

Your diaphragm contracts when CO2 levels trigger chemoreceptors in your brainstem. That much is basic physiology. But the timing of that trigger depends on factors you probably aren’t tracking:

Sleep quality from the last 72 hours. Not just last night. Accumulated sleep debt affects nervous system sensitivity. Poor sleep = earlier contractions, even when your actual CO2 tolerance hasn’t changed.

Stress from work, relationships, or life. Cortisol affects chemoreceptor sensitivity. High baseline stress means your body interprets CO2 buildup as more threatening than it actually is. (This is exactly why Keep Training (Even When You Don’t Feel Like It) matters-consistency builds resilience through all states.)

Training load from the previous week. If you’ve been pushing hard, your nervous system might be hypervigilant. Early contractions could be a sign you need recovery, not that your fitness is declining.

Hydration and electrolyte balance. Even mild dehydration affects blood chemistry, which affects how your body processes CO2. Most freedivers underestimate this completely.

The mental game when contractions start early

Here’s what usually happens: contractions start at 2:00 instead of your usual 2:30. Your brain immediately goes to I’m having a bad day, my training isn’t working, maybe I should stop. That mental spiral creates more stress, which makes the contractions feel stronger, which reinforces the panic.

Trevor Moawad calls this “negative thinking.” Not just pessimism, but factually inaccurate self-talk that creates worse outcomes. The truth is simpler: early contractions are information, not verdict.

Reframe the narrative. Instead of “my CO2 tolerance is shot,” try “my nervous system is sensitive today, let me work with that.” Same physical sensation, completely different mental response.

Use it as technical practice. Early contractions give you more time to practice relaxation techniques while under stress. That’s actually valuable training. You’re not failing-you’re getting extra reps on the mental game.

Track patterns, not individual sessions. One session with early contractions means nothing. Three sessions in a row? That’s data worth investigating. (This is where consistent logging in Appneist helps-you can see patterns instead of getting lost in daily fluctuations.)

What to actually do when it happens

Focus on technique, not time. Use the session to practice breath-up protocols, body positioning, or mental relaxation techniques. You’re still training, just emphasizing different aspects.

Adjust your targets. If contractions usually start at 2:30 and today they’re starting at 2:00, adjust your session plan accordingly. Do shorter holds with perfect form rather than forcing your usual times with terrible technique.

Look for systemic factors. Review sleep, stress, training load, and recovery. Early contractions are often your body’s way of saying “something’s off in the bigger picture.”

Where this connects to real training

The ability to work calmly through early contractions transfers directly to performance. When you’re at 25 meters and contractions start earlier than expected, you need the mental training to assess whether it’s real danger or just nervous system sensitivity.

Freedivers who panic at early contractions in the pool will panic at early contractions at depth. Those who learn to work through them with good technique and clear thinking develop the mental resilience that keeps them safe when conditions aren’t perfect.

This is exactly why structured training matters. Volume matters. Appneist’s session tracking helps you see the patterns, so you’re making decisions based on data, not daily fluctuations.

Early contractions aren’t failure. They’re practice. Use them.