I have owned many stethoscopes in my practice. They can be purchased in Canada at Shopper's Home Health. I lend them out to families and group homes to reinforce how breathing can slow your heart rate down.
When our bodies move to fight/flight/freeze-
there are hormones that are released by your sympathetic nervous system. Hormones like adrenaline. They help you to combat the threat or perceived threat in your environment. It is beneficial to help trauma survivors increase oxygen levels when they feel the symptoms they experience after they are flooded with stress hormones. Symptoms can include a dry throat, sore tummy, instant headache and fast heart beat. Helping them to recognize how fast their heart beats both when feeling threatened and also when in a "resting state" is the first step to helping them feel more empowered. They can manage these hormones by slowing that heart beat down- Just by breathing!
Sesame Street: Common and Colbie Caillat - "Belly Breathe" with Elmo (Sesame Street (c)).
Another strategy to help people feel more relaxed in their body is Progressive Muscle Relaxation.
Progressive muscle relaxation can and should be practiced daily. Parents - we need to teach our children as well as practice this ourselves. This guided relaxation was posted on You Tube by Johns Hopkins All Children's Hospital and was published on Apr 15, 2016.
Play Therapy training offered by Maritime Play Therapy Institute includes integrating neurodevelopmental interventions.