Diaphragmatic and Box Breathing on Heart Rate Variability and Perceived Stress

Inclusion Criteria:

* Academic Status: Currently enrolled, full-time undergraduate Physical Therapy students
* Age Range: 18-25 years
* Health Status: Generally healthy individuals with no known chronic respiratory or cardiovascular diseases.
* Informed Consent: Ability and willingness to provide written informed consent and commit to the 4-week protocol (6 sessions/week).
* Stress Level: A baseline score on the Perceived Stress Scale (PSS) indicating at least moderate stress.

Exclusion Criteria:

* Pre-existing Breathing Expertise: Individuals with professional training in yoga (Pranayama), formal meditation, or advanced breath work that might bias the baseline results.
* Medical Conditions: Diagnosed respiratory conditions (e.g., Asthma, COPD).
* Cardiovascular issues (e.g., Arrhythmias, Hypertension).
* Clinical psychological disorders (e.g., Generalized Anxiety Disorder or Panic Disorder) that may require medication.
* Pharmacological Factors: Use of medications that influence the Autonomic Nervous System (e.g., Beta-blockers, antidepressants, or heavy use of stimulants/sedatives).
* Substance Use: Smokers/Vapers
* Excessive Caffeine "Participants consuming more than 400 mg of caffeine per day (equivalent to approximately 4 standard cups of brewed coffee) will be excluded.
* Recent Acute Illness: Any respiratory tract infection or fever within two weeks prior to the start of the study