Breathing exercises and progressive muscle relaxation (PMR) are the two most evidence-based relaxation techniques in clinical psychology, and both effectively reduce stress, anxiety, and improve sleep. The key difference: breathing exercises work primarily through the autonomic nervous system (bottom-up), while PMR works through the muscular system and body awareness (top-down). This difference makes them complementary rather than competing approaches.
For speed of effect, breathing exercises win — you can shift your nervous system state in 30-60 seconds with the right breathing pattern. PMR typically requires 15-20 minutes for a full body scan. For chronic tension and body-held stress, PMR has an advantage because it directly addresses muscular tension that breathing alone may not release. For portability and discreteness, breathing exercises are superior — you can practice anywhere without anyone noticing.
The optimal approach combines both: use breathing exercises as your primary daily practice for autonomic regulation, and add PMR sessions 2-3 times per week to address accumulated physical tension. Many therapists teach this combined approach for anxiety disorders, insomnia, and chronic stress because the two techniques address different layers of the stress response.