Mechanics & Biology
The autonomic nervous system plays an essential role in breathing. Imagine for a moment when someone tells you they love you – you let out a big sigh, your muscles relax, and you feel happy . That is the work of your parasympathetic nervous system: it slows your heart rate, reserves your energy, and relieves stress . On the other hand, the sympathetic nervous system activates when you experience fear and has the opposite effect. This system is also called the ‘fight-or-flight response’ and, since physical changes characterize it, you can learn breathing techniques to tame that stress response. Mindfulness and yogic breathing are examples of ways to focus on your breathing cycle to manage anxiety and tension.
Moreover, recent studies show how specific breathing rhythms activate particular brain regions that indirectly affect your mood and alertness. One of those regions is the amygdala that subconsciously detects threat-related stimuli and is related to processing fear and negative emotions  . When activity in your amygdala increases and you become fearful, you start to breathe rapidly. Here, studies suggest that fast, shallow breathing may trigger negative emotions such as anxiety. Or the very conditioning can strengthen the association between rapid breathing and stress. Although the connection is complex, more studies find that controlling your breathing is beneficial for your mind and body.
Research from Doll et al., (2016) found that the mindful ‘attention-to-breath’ practice reduced negative emotions associated with amygdala activity . Additional studies added that ‘attention-to-breath’ and other breathing practices strongly influence our emotion, mood, and cognition    . Aside from the emotion-related benefits, your body profits from it too. Mindful breathing lowers your heart rate and blood pressure, decrease cortisol levels, and boost your digestion and sleep cycle   . Overall, it’s safe to say that relaxation through calm breathing offers impressive benefits for us.
Types of breathing
Over the decades, many exercises and ideological movements have practiced ways to control and use it to their advantage. Of those movements, mindfulness and yoga are the best known. Certain types of breathing invoke different states of the mind and body.
- Eupnea is the regular, healthy type of breathing you’re often not even aware of. When focussing on your breath, the familiar rhythm is 4 seconds in and 4 seconds out, where you take 4 to 6 breaths per minute. Paying attention to your regular breathing is a great way to appreciate where you are at that moment.
- Hyperpnea and tachypnea are both faster than usual. Where hyperpnea often results from exercise, tachypnea is quicker and shallower, taking in more oxygen than necessary. This type of breathing is associated with the sympathetic nervous system (‘fight or flight response’) and increases your alertness and tension.
- Diaphragmatic is also called deep breathing and used in mindful and yogic breathing practices. As the air fills your lungs, your lower belly rises, and you become calmer. Although there are different versions, the general rhythm is 4 seconds inhale and 8 seconds exhale. Deep breathing helps you fall asleep and to relax completely.
Mindfulness & Aromatherapy
The essence of mindfulness involves awareness and acceptance of whatever is occurring in the present moment. 
Deep breathing helps you to become more mindful. By paying attention to your surroundings and yourself, you perceive the world with more openness and understanding. Not only does it benefit your state of mind and body, it also creates more empathetic and compassionate behaviour  and social connectedness .
Becoming mindful and aromatherapy go hand-in-hand. Using the healing properties of natural ingredients in oils, the body and mind are relieved of tress and tension. Specific oils promote the opening of the airways, such as eucalyptus, cedar, and peppermint. Other fragrances, like lavender, bergamot, and cinnamon, encourage relaxation during meditation and yoga. Depending on the exercise and moment, aromatherapy can enrich the experience of mindfulness. You can create a pleasant and clean environment with fragrances that match your mood. And after all, don’t forget to take a deep breath once in a while.
-  https://www.yogabody.com/lucas-rockwood/
-  https://books.google.nl/books?hl=en&lr=&id=TMJRynOxsisC&oi=fnd&pg=PA54&dq=parasympathetic+nervous+system+and+breathing&ots=Ka_ipb4LvU&sig=-5oRAJuHVEDrDjbC5XBZ3m4QVs4&redir_esc=y#v=onepage&q=parasympathetic%20nervous%20system%20and%20breathing&f=false
-  https://physoc.onlinelibrary.wiley.com/doi/pdf/10.1113/expphysiol.2008.042424
-  https://www.jneurosci.org/content/jneuro/24/46/10364.full.pdf
-  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6636643/pdf/nihms-1012470.pdf
-  https://www.researchgate.net/profile/Donatella_Di_Corrado/publication/311750288_The_role_of_deep_breathing_on_stress/links/5aaf7a340f7e9b4897c08027/The-role-of-deep-breathing-on-stress.pdf
-  https://journals.physiology.org/doi/pdf/10.1152/jn.00551.2017
-  https://www.researchgate.net/profile/Miguel_Bellosta-Batalla/publication/340291262_Brief_mindfulness_session_improves_mood_and_increases_salivary_oxytocin_in_psychology_students/links/5e86d7544585150839b961ef/Brief-mindfulness-session-improves-mood-and-increases-salivary-oxytocin-in-psychology-students.pdf
-  http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.912.4622&rep=rep1&type=pdf
-  https://journals.sagepub.com/doi/pdf/10.1177/1533210108329862
-  https://self-compassion.org/wp-content/uploads/publications/shapiro.study.pdf
-  https://www.researchgate.net/profile/Cendri_Hutcherson/publication/23302107_Loving-Kindness_Meditation_Increases_Social_Connectedness/links/0912f508e975ee28ce000000.pdf