Using the Human Dive Reflex to Promote Emotion Regulation and Fear Counter-Conditioning

1. Using the Human Dive Reflex to Promote Emotion Regulation and Fear Counter-Conditioning Milton Brown, Megan Thompson, and Abigail Burt Alliant International University Subject 1006: Subject 1010: 26 year-old female 27 year-old female Cold water = 45º F Cold water = 50º F Warm water = 95º F Warm water = 80º F Duration of immersion (M = 35 sec.) Duration of immersion (M = 24 sec.) Snake phobia Spider phobia • Results • ● The dive response occurred for both participants as evidenced by the greater decrease in heart rate during cold water immersion. • Breath holding and immersion in water (cold or warm) led to a 10-30 beats per min reduction in heart rate. • Heart rate reduced by an extra 10 beats per minute during cold water immersion (compared to warm water). • For Subject 1006, heart rate got as low as 60 bmp • For Subject 1010, heart rate got as low as 45 bmp • ● There was no difference in the rate of decrease of subjective fear in the 5 minutes of exposure to the snake or spider following cold vs. warm water immersion. • DSQ scores were not lower following cold water. • SUDS ratings were not lower following cold water. • ● There was no difference in heart rate during the 5 minute intervals of exposure to the snake or spider following cold vs. warm water immersion. • ● Parasympathetic responses were stronger following cold water immersion than following warm water (during the 5 minutes intervals of exposure to the snake or spider). • Heart rate variability (SDNN) was higher following cold water immersion than following warm water. • Normalized high frequency values were higher following cold water immersion than following warm water. • Parasympathetic response was 50-100% stronger following cold water immersion than following warm water • Conclusions • ● The human dive response is a robust finding; there is a reliable and large decrease in heart rate when the face is immersed in cold water. • ● There are enduring increases in parasympathetic activity following immersion of face in cold water during therapeutic exposure to feared stimuli • The dive response is a promising method to promote emotion regulation. • ● Further studies need to test the dive response with psychiatric patients • There is strong evidence for a human dive reflex. • 1) Holding the breath and immersing the face in cold water leads to bradycardia, a reduction in heart rate below resting heart rate. • 2) Bradycardia is the result of increased parasympathetic activation. • Hypotheses: • 1) Eliciting the dive reflex will effectively regulate emotional arousal. • Following cold-water immersion: • 1a) Heart rate will decrease • 1b) Parasympathetic activity will increase • 1c) Self-reported arousal will decrease • 2) Eliciting the dive reflex will accelerate fear reduction during in vivo exposure therapy. • Following cold-water immersion: • 2a) Heart rate will decrease more quickly • 2b) Self-reported arousal will decrease more quickly • This current study uses a ABABAB single-subject design • Method • Participants: • ■ 2 graduate student volunteers • ■ Excluded if: • 1) heart arrhythmia disorder • 2) current psychotropic medication use • 3) recent use of tobacco, caffeine, or other stimulants • Measures: • Subjective Units of Distress Scale (SUDS) ratings were reported before and after each water immersion • Diagnostic Symptom Questionnaire (DSQ) was used as a self-report method of anxiety and panic symptoms • Heart rate (HR) and other heart data was measured continuously. • Normalized High Frequency (100 x HF/HF+LF). Higher values indicate increased parasympathetic influence on HR. • Heart Rate Variability (HRV). We measured HRV during 5 minute intervals of exposure to snake/spider (between water immersions). • Standard Deviation of the Normal to Normal Inter-beat Intervals (SDNN). • Standard Deviation of Heart Rate (SDHR in beats per min). Procedures: • Theprocedures comprised a ABABAB design. • Participants alternated between in vivo exposure periods and pairs of cold water or warm water dunks. • Participants remained seated throughout the trials. • The following sequence of events occurred: • 1. Exposure 1 (2 min), WW, WW, Exposure 1 (5 min) • 2. Exposure 2 (2 min), WW, WW, Exposure 2 (5 min), CW, CW, Exposure 2 (5 min) • 3. Exposure 3 (2 min), CW, CW, Exposure 3 (5 min), WW, WW, Exposure 3 (5 min) • 4. Exposure 4 (2 min), WW, WW, Exposure 4 (5 min), CW, CW, Exposure 4 (5 min) • 5. Exposure 5 (2 min), CW, CW, Exposure 5 (5 min) • Wherein: • WW = face immersed in Warm Water • CW = face immersed in Cold Water • Exposure 1 = least-feared stimulus (e.g., seeing snake/spider 10 ft away) • Exposure 5 = most-feared stimulus (e.g., holding snake or spider) Subject # 1006 Subject # 1010 Start of first dunk Start of first dunk Start of 2nd dunk Subject 1006 Subject 1010 Start of 2nd dunk Subject 1010 Subject 1006 % % Subject 1010 Subject 1006 Heart Rate Variability Following Immersion for Four 5-minute Exposure Periods

2. Using the Human Dive Reflex to Promote Emotion Regulation Via Conditioned Bradycardia Milton Brown, Abigail Burt, and Megan Thompson Alliant International University • Results • ● The dive response occurred for both participants as evidenced by the greater decrease in heart rate during cold water immersion (unconditioned response). • ● Conditioned responses (CR) were observed after the temporal pairing of cold water (UCS) and conditioned stimuli (CS) • ● Opposite anticipatory responses (heart rate increases) occurred immediately prior to cold water immersion • ● Opposite parasympathetic responses (decreased SSDN) occurred when cold water CS (CS-C) were presented. • ● Interoceptive, auditory, and tactile stimuli that were paired with cold water immersion did not elicit consistent conditioned responses. • conditioned stimuli increased heart rate for subject #1003 • conditioned stimuli decreased heart rate for subject #1009 • ● Conditioned stimuli that were paired with termination of cold water immersion did alter heart rate. • Conclusions • ● The human dive response is a robust finding; there is a reliable and large decrease in heart rate when the face is immersed in cold water. • ● Conditioning of the dive response holds promise as a method to improve psychophysiological responses even when no cold water is available. • Cue controlled bradycardia and relaxation (based on the human dive response) may be able to develop as a portable emotion regulation skill. • ● Further studies are needed to clarify the variables that moderate the direction and magnitude of conditioning effects. • ● Conditioning effects may be a function of: • The water temperature • The nature of the conditioned stimuli • sensory modality • internal versus external • The response channel measured • sympathetic responses • parasympathetic responses • subjective states of arousal • The frequency of conditioning trials • Sensitivity to cold or pain • participant #1003 reported a strong aversion to cold temperatures • Many individuals report that water below 50 degrees causes facial pain during immersion • There is strong evidence for a human dive reflex. • 1) Holding the breath and immersing the face in cold water leads to bradycardia, a reduction in heart rate below resting heart rate. • 2) Bradycardia is the result of increased parasympathetic activation. • This current study uses an ABABAB single-subject design with several participants to determine if conditioned stimuli can be paired with cold water facial immersion to later elicit (without water immersion) conditioned bradycardia and the subjective experience of relaxation versus an opposite rebound effect. This study has implications for use of cue controlled bradycardia and relaxation (based on the human dive response) as a portable emotion regulation skill. • Method • Participants: • ■ 2 graduate student volunteers • ■ Excluded if: • 1) heart arrhythmia disorder • 2) current psychotropic medication use • 3) recent use of tobacco, caffeine, or other stimulants • Assessment Instruments: • Subjective Units of Distress Scale (SUDS) ratings were reported before and after each water immersion • Heart rate (HR) and heart rate variability (HRV) was measured continuously throughout. HRV will be measured as the standard deviation of the normal to normal inter-beat intervals (SDNN). • Skin conductance (SC) was continuously measured throughout participation. • Theprocedures comprised a single-subject ABABAB design. 1. Pre-Conditioning Test Phase • Repeated conditioning test blocks (CTB), which test the response to the conditioned stimuli (CS) 2. Conditioning Phase • Repeated conditioning blocks (CB), with CS (CS-C) paired with cold water (UCS-C), other CS (CS-OC) paired with termination of cold water, and (for comparison) other CS (CS-W) paired with “warm” water (UCS-W) 3. Post-Conditioning Test Phase • Repeated conditioning test blocks (CTB), which test the response to the conditioned stimuli (CS) CS were: 1) imagining putting one’s face in cold water, in warm water, or taking one’s face out of cold water 2) recorded water sounds 3) silently repeated the words “so cold,” “so warm,” or “no more cold” • Participants remained seated throughout the trials. • Subject 1003: Female, 24 years old • Cold water = 45º F • Warm water = 70º F • The sequence of blocks was: • CTB, CTB, CTB, CTB, CTB, CB, CB, CB, CB, CB, CB, CTB, CTB, CTB, CTB, CTB • Wherein blocks were: • CTB = CS-C (15 sec), 45 sec, CS-W (15 sec), 45 sec • CB = (CS-C)+(UCS-C), (CS-C)+(UCS-C), 2 min, (CS-W)+(UCS-W), (CS-W)+(UCS-W), 2 min • Subject 1009: Female, 26 years old • Cold water = 52º F • Warm water = 98º F • In summary, the sequence of blocks was: • CTB, CTB, CTB, CB, CB, CB, CB, CTB, CTB, CTB • Wherein blocks were: • CTB = CS-C (30 sec), 30 sec, CS-OC (30 sec), 30sec, CC-W (30 sec), 30 sec • CB = (CS-C)+(UCS-C), CS-OC, (CS-C)+(UCS-C), CS-OC, 2 min, (CS-W)+(UCS-W), (CS-W)+(UCS-W), 2 min Subject #1003 Conditioning Phases Subject #1009 Conditioning Phases Start of first dunk Start of first dunk Start of 2nd dunk Start of 2nd dunk Subject #2003 Conditioning Phase Subject #2009 Conditioning Phase Subject #1003 Conditioning Test Phases Subject #1009 Conditioning Test Phases Before Conditioning Before Conditioning no CS CS no CS no CS CS no CS After Conditioning After Conditioning no CS CS no CS no CS CS no CS