The goal of this clinical trial is to examine the effects of slow breathing breathing on markers of stress in healthy college aged individuals. The breathing intervention is performed for five minutes pre and post a virtual reality active shooter drill.

The main question to answer is:

1) what is the impact of a controlled breathing intervention and virtual reality active shooter drill on markers of subjective and biological stress?

For this study participants will be randomly assigned either slow breathing 1 [(SB1); four second inhale, two second pause, four second exhale, two second pause, repeat for five minutes] or slow breathing 2 [(SB2); four second inhale, two second exhale, repeat for five minutes]. The breathing intervention will take place five minutes prior to the start of the virtual reality based active shooter drill. Researchers will compare the two groups in terms of change in heart rate (HR), blood pressure (BP) subjective stress [(SAI); state-trait anxiety inventory], and salivary markers of stress before and after the breathing intervention and virtual reality active shooter drill (VR-ASD).

All procedures were reviewed and approved by the University Institutional Review Board.

Experimental procedures upon arrival to the testing site, subjects will be instructed to rinse their mouth with water and rest in a quiet room for 10 minutes. Immediately after the 10 minutes of rest period, an initial saliva sample, HR & BP (Suntech, Hauppauge, NY, USA) and SAI measures were collected (30 min prior to VR-ASD). Throughout the experimental session HR, BP, SAI, and saliva samples will be collected a total of four times : 1) 30 minutes prior to start of the VR-ASD, 2) 5 minutes prior to the start of the VR-ASD (immediately before the breathing intervention) 3) 5 minutes post VR-ASD (immediately post breathing intervention), and 4) 30 minutes post VR-ASD.

Virtual Reality- Active Shooter Drill (VR-ASD):

This is a virtually reality simulation, the participant will put on the VR headset and carry a Glock 17 training pistol, they will be able to physically move through the entire ASD without interruption. The VR lab is larger than the virtual environment (~35 x 20 ft). The participant will physically walk down a ~10-foot-long virtual hallway where they will encounter 2 simulated wounded victims. One will be on the ground with traumatic injuries and the second victim will 'run' out of the attack room with gunshot wounds to his/her left arm and leg. Once at the threshold of to the attack room, they will observe one victim on the ground with a traumatic head injury and the shooter firing his handgun at the last victim. If the subject hadn't fired his/her weapon yet, the shooter would turn toward the participant to elicit a response, the participant will " fire" a shot if needed. The shooter will fall after being shot.

Slow breathing 1 ("Box" breathing/slow breathing): Four second inhale through the nasal + hold two seconds + four second exhale through the mouth + hold for two seconds, repeat (~25 breath cycles within the 5 min intervention) Slow breathing 2: Four second inhale through the nose into the diaphragm followed by a two second exhale, repeat (~50 breath cycles within the 5 min intervention)

Breathing Instructional video The lead researcher will provide a 5- minute instructional video over randomly assigned breathing method to the participant prior to starting the breathing intervention. The instructional video will include a visual of the researcher performing the breathing intervention alongside a voice over with a countdown on the screen to go-along with the breathing tempo. A researcher will be in the room with the participant counting their breaths per minute to make sure they are keeping up with the breathing tempo and ending at the appropriate time. If the participant is unable to keep up with the breathing tempo they will be asked to discontinue.

Inclusion Criteria:

• apparently healthy, aged 18-39
• free from any known cardiovascular or metabolic diseases,
• free from any major stressors within the last 30 days such as birth of a child, abortion, or divorce.

Exclusion Criteria:

• subjects are required to not have a history of motion sickness, or vertigo
• not previously diagnosed with a brain injury or epilepsy, asthma, or currently taking psychological medication