Slow Diaphragmatic Breathing

The diaphragm is a dome-shaped muscle that sits beneath your lungs, a bit like an upturned bowl. When you breathe in, it flattens and draws down, making room for your lungs to fill. That’s why your belly gently moves out. When you breathe out, it relaxes back up.

Your heart is listening the whole time. Heart rate naturally rises a little as you breathe in and slows as you breathe out. Slow the breath and lengthen the exhale, and you spend more time in that slowing phase.

This is thought to strengthen the calming side of the nervous system, the parasympathetic system, which is linked with rest, digestion and recovery. Practise often enough, and your body begins to remember the way.

Slow breathing is one of the simplest tools in the Toolkit. Research has found benefits you can measure, like changes in heart rate variability, and benefits you can feel, like less stress.

Heart rate and nervous system regulation. A review of 223 studies found that slow breathing increased a type of heart rate variability (HRV) linked to the parasympathetic nervous system, which helps the body settle. The change was measurable during breathing practice, immediately afterwards and after programs of repeated sessions [1].

Stress, anxiety and low mood. A 2023 review of 12 randomised trials involving 785 adults found that people who practised breathwork reported less stress than those in control groups. The improvements were small to moderate, with similar benefits for anxiety and depressive symptoms across the broader review [2].

Cortisol and focus. In a study of 40 healthy adults, those who practised diaphragmatic breathing over eight weeks had lower levels of the stress hormone cortisol, were better able to sustain their attention and reported fewer unpleasant emotions after the programme [3].

You can practise slow belly breathing anywhere, sitting at your desk or lying in bed. It’s free, needs no equipment and gives you something simple to do when you feel wound up.