Science-backed · Navy SEALs · Stanford · Sleep Research
Science-backed breathing, one click away
Stillsea is a free collection of guided breathing exercises built on techniques backed by research from Stanford, clinical sleep studies, and high-performance training programs. Each exercise runs as an interactive timer right in your browser — no app to download, no account to create.
Tell us how you feel and we recommend a technique, or explore the exercises below and choose your own.
Breathing Techniques
Box Breathing
4-4-4-4 technique used by Navy SEALs for calm and focus.
Start exercise → Sleep4-7-8 Breathing
Extended exhale pattern designed to help you fall asleep faster.
Start exercise → Balance & HRVCoherence Breathing
Simple 5-5 rhythm to balance your nervous system and boost HRV.
Start exercise →Exercises by Goal
How It Works
- 1
Choose your mood. Pick how you feel — anxious, sleepless, unfocused, low energy, or tense — and Stillsea recommends the right technique.
- 2
Follow the guided timer. An animated visual guides each inhale, hold, and exhale so you can close your eyes and simply breathe.
- 3
Feel the shift. Most people notice a calmer mind and slower heart rate within one to two minutes — about four rounds of breathing.
Frequently Asked Questions
Do breathing exercises really work? +
Yes. Slow, controlled breathing activates the parasympathetic nervous system — the body's "rest and digest" mode — which lowers heart rate, reduces cortisol, and eases the physical symptoms of stress. Research from Stanford, Harvard, and clinical studies consistently shows measurable effects within just a few minutes of practice.
Which breathing technique should I start with? +
If you are new to breathwork, box breathing (4-4-4-4) is the easiest to learn because every phase is the same length. For sleep, try the 4-7-8 technique. For general daily balance, coherence breathing (5-5) is a great choice. You can also let Stillsea recommend one — just pick how you feel on the homepage.
How long do I need to practice? +
Most people feel calmer after just one to two minutes (about four rounds). For deeper relaxation or to build long-term resilience, aim for five to ten minutes daily. Consistency matters more than session length.
Is Stillsea free to use? +
Yes, completely free. All breathing exercises and guided timers on Stillsea are available at no cost with no sign-up required. Open the page and start breathing.
Can I use these exercises if I have a medical condition? +
Breathing exercises are generally safe for most people. However, if you have a respiratory or cardiovascular condition, are pregnant, or experience dizziness during practice, stop and consult a healthcare professional. These exercises are not a substitute for medical advice or treatment.