Three Breathing Techniques for Heart Rate Variability, Attention, Reaction Time, and Anxiety

Comparative Effects of Three Breathing Techniques on Heart Rate Variability, Attention, Reaction Time, and Anxiety in Healthy Adults: A Randomized Controlled Trial

This randomized controlled trial compared the effects of Mindfulness Breathing, Box Breathing, and Nadi Shodhana Pranayama on heart rate variability, attention performance, reaction time, and anxiety in healthy adults aged 18-40 years. Participants were randomly assigned to one of three breathing intervention groups and practiced their assigned technique daily for six weeks. Primary outcomes included resting heart rate, RMSSD, and respiratory rate derived from 5-minute heart rate variability recordings. Secondary outcomes included attention performance assessed by the Digit Cancellation Test, reaction time assessed using the BlazePod system, and state and trait anxiety assessed using the State-Trait Anxiety Inventory. Participants received standardized face-to-face instruction, home practice videos, and daily WhatsApp reminders throughout the intervention.

Healthy adults aged 18-40 years were recruited using convenience sampling and randomly assigned in a 1:1:1 ratio to Mindfulness Breathing, Box Breathing, or Nadi Shodhana Pranayama. Participants received an individual face-to-face training session delivered by the same physiotherapist, practiced their assigned breathing technique under supervision until correct performance was confirmed, and subsequently performed daily home-based practice for six weeks using standardized instructional videos. Daily WhatsApp reminders containing the appropriate video link were sent to support adherence.

Heart rate variability was assessed using a Polar H10 heart rate monitor with 5-minute resting recordings analyzed using Kubios HRV software. Attention performance was measured using the Digit Cancellation Test, reaction time was assessed using the BlazePod wireless reaction system, and anxiety outcomes were evaluated using the State-Trait Anxiety Inventory. Assessments were performed at baseline and after six weeks.

Inclusion Criteria:

• Healthy adults aged 18 to 40 years.
• Ability to provide written informed consent.
• Ownership of a smartphone with internet access.
• Willingness to participate in daily breathing practice for six weeks.

Exclusion Criteria:

• Respiratory disease.
• History of lung transplantation.
• Pregnancy or suspected pregnancy.
• Previous experience with yoga, Qigong, breath therapy, or other structured breathing practices.