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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: 26 year-old female Cold water = 45º F Warm water = 95º F Duration of immersion (M = 35 sec.) Snake phobia 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. Mean heart rate mean per interval 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 Subject 1010: 27 year-old female Cold water = 50º F Warm water = 80º F Duration of immersion (M = 24 sec.) Spider phobia Subject # 1006 Mean heart rate mean per interval 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). Mean Heart Rate During Water Immersion 130 Mean Heart Rate During Water Immersion Start of first dunk 120 110 70 100 90 • For Subject 1006, heart rate got as low as 60 bmp • For Subject 1010, heart rate got as low as 45 bmp 60 stimulus 80 50 cold water 70 Subject 1006 Subject 1010 Start of 2nd dunk 60 19 21 23 25 27 29 31 33 35 37 39 41 43 45 47 49 40 36 38 40 42 44 46 warm water 48 50 52 54 56 58 60 62 64 10 second intervals 10 second intervals The dunks begin at 230 and 330 seconds The dunks begin at 460 and 560 seconds Mean Heart Rate after Water Immersion Mean Heart Rate after Water Immersion 130 ● 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. 90 120 80 110 70 100 90 60 stimulus 80 50 70 Subject 1010 40 60 0 4 2 8 6 12 10 16 14 20 18 24 22 28 26 32 30 34 warm water 0 36 4 2 38 8 12 6 10 16 14 20 18 24 22 28 26 32 30 36 34 40 38 42 10 second intervals 10 second intervals The post-water period (after the second dunk) begins at 40 seconds The post-water period (after the second dunk) begins at 30 seconds % 30 30 The following sequence of events occurred: 20 • 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. Mean Parasympathetic Response after Water % ● Parasympathetic responses were stronger following cold water immersion than following warm water (during the 5 minutes intervals of exposure to the snake or spider). cold water Subject 1006 40 Mean Normalized High Frequency Start of 2nd dunk 80 40 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) • Heart rate reduced by an extra 10 beats per minute during cold water immersion (compared to warm water). Start of first dunk Procedures: The procedures 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. Wherein: • Breath holding and immersion in water (cold or warm) led to a 10-30 beats per min reduction in heart rate. 90 Mean Parasympathetic Response after Water 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) ● The dive response occurred for both participants as evidenced by the greater decrease in heart rate during cold water immersion. Subject # 1010 This current study uses a ABABAB single-subject design Method Results • Parasympathetic response was 50-100% stronger following cold water immersion than following warm water Conclusions stimulus 20 cold water Subject 1010 Subject 1006 10 10 0 4 2 8 6 12 10 16 14 20 18 24 22 28 26 32 30 0 36 34 warm water 38 4 2 8 6 12 10 16 14 20 18 24 22 28 26 32 30 36 34 40 38 42 10 second intervals 10 second intervals The post-water period (after the second dunk) begins at 40 seconds The post-water period (after the second dunk) begins at 30 seconds Heart Rate Variability Following Immersion for Four 5-minute Exposure Periods Subject: 1006 SdNN (ms) Subject: 1010 SdNN (ms) Warm Water 54 52 60 72 Warm Water 70 145 109 153 Cold Water 99 88 139 137 Cold Water 138 142 168 155 Subject 1006 SdHR (beats per minute) Subject: 1010 SdHR (beats per minute) Warm Water 11 10 10 11 Warm water 5 15 7 12 Cold Water 14 13 18 15 Cold water 8 19 16 15 ● 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 Using the Human Dive Reflex to Promote Emotion Regulation Via Conditioned Bradycardia Milton Brown, Abigail Burt, and Megan Thompson Alliant International University 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. Results 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 ● Conditioned responses (CR) were observed after the temporal pairing of cold water (UCS) and conditioned stimuli (CS) Subject 1009: Female, 26 years old Cold water = 52º F Warm water = 98º F ● Opposite anticipatory responses (heart rate increases) occurred immediately prior to cold water immersion In summary, the sequence of blocks was: ● Opposite parasympathetic responses (decreased occurred when cold water CS (CS-C) were presented. 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 Start of first dunk Subject #1003 Subject #1009 Conditioning Phases Conditioning Phases Start of first dunk Start of 2nd dunk SSDN) ● 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. Start of 2nd dunk Conclusions The procedures 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: ● The dive response occurred for both participants as evidenced by the greater decrease in heart rate during cold water immersion (unconditioned response). Subject #2003 Subject #2009 Conditioning Phase Conditioning Phase Subject #1003 Subject #1009 Conditioning Test Phases Conditioning Test Phases Before Conditioning ● 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. Before Conditioning ● Further studies are needed to clarify the variables that moderate the direction and magnitude of conditioning effects. 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” no CS Participants remained seated throughout the trials. CS no CS no CS After Conditioning CS no CS After Conditioning ● 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 no CS CS no CS no CS CS no CS • • participant #1003 reported a strong aversion to cold temperatures Many individuals report that water below 50 degrees causes facial pain during immersion