Slow breathing

Heart rhythm, CO₂ and the long exhale, explained with the research.

Turban Sauna // Journal

When the heat rises during a round, most people start breathing faster and higher up in the chest. The gusmaster guides you towards the opposite: slow breaths with a long exhale. Here is what happens in the body when you breathe that way, and what research knows about it.

The heart follows the breath

Your pulse changes a little with every breath. It speeds up slightly when you breathe in and slows down when you breathe out. This is called respiratory sinus arrhythmia, and it is a sign of a healthy, flexible nervous system. The exhale is linked to the vagus nerve, the main nerve of the parasympathetic nervous system, which helps the body settle.

At rest, adults breathe around 12 to 20 times a minute. Research defines slow breathing as fewer than 10 breaths a minute. At around six breaths a minute, the rhythm of the breath and the rhythm of the heart line up, and the variation in pulse becomes larger. Researchers call this resonance, and it is the basis of a method called heart rate variability biofeedback.

CO₂ keeps the balance

Fast breathing in the heat lowers the level of carbon dioxide in the blood. Low CO₂ narrows the blood vessels in the brain and can give dizziness, tingling in the fingers and a restless feeling. Slow, calm breaths keep CO₂ steady. That is one reason the breath feels like an anchor when the steam comes in waves.

What research shows

A systematic review of 15 studies in healthy adults found that slow breathing increased heart rate variability and alpha activity in the brain, a pattern associated with calm alertness. Participants reported more comfort, relaxation and energy, and less anxiety and anger.

A randomised study from Stanford compared three five-minute breathing exercises with mindfulness meditation over one month. The exercise with the longest exhale, called cyclic sighing, gave the greatest improvement in mood and the largest drop in resting breathing rate. The studies are small and short, and most were done outside the sauna, so the research is still at an early stage.

Why the gusmaster guides your breath

Heat, steam and the towel waves all push the body towards alert mode. The gusmaster counts the breath with you, so the room breathes in the same rhythm. Breathe in through the nose, let the exhale be longer than the inhale, and follow your own pace. If the breathing feels hard, move to a lower bench where the air is cooler, or step out after the round.

Sources

Zaccaro et al. (2018): How breath-control can change your life. A systematic review on slow breathing

Russo et al. (2017): The physiological effects of slow breathing in the healthy human

Lehrer & Gevirtz (2014): Heart rate variability biofeedback: how and why does it work?

Balban et al. (2023): Brief structured respiration practices enhance mood and reduce physiological arousal