The Effects of Emotional Exposure on State Anxiety
Condition: Generalized Anxiety Disorder
MeSH terms: Anxiety Disorders
Study type: Interventional

Summary: 
      A randomized repeated-measures crossover clinical trial was performed. Forty healthy, female
      college students completed a 30 min session of YogaFit and a time-matched seated rest
      condition on separate days. After each condition, participants viewed 30 min of emotional
      picture stimuli. State anxiety, heart rate and time-domain and frequency-domain measures of
      HRV were assessed baseline, post- condition, and post-exposure to emotional stimuli. Data
      were analysed using a condition x time (2 × 3) repeated-measures ANOVA.
    

Detailed description: 
      The design was a repeated-measures randomized crossover trial. Each study participant
      completed 4 different sessions on 4 different days: (day 1) participant screening; (day 2 or
      3) study condition A (seated, quiet rest); (alternate day 2 or 3) study condition B
      (moderate-intensity YogaFit); and (day 4) a session to rate IAPS pictures (14) and undergo a
      single DEXA scan [Prodigy/301776R. G.E. Medical Systems-Lunar DEXA Scanner, Fairfield, CT,
      USA]. Utilizing a simple randomization process, participants were randomized in a 1:1 ratio
      to participate in either the YogaFit condition or the quiet rest condition. The study
      conditions were counterbalanced and alternated using odd and even numbers to begin the
      sequence. Participants were not informed if the first condition was A or B. Self-reported
      anxiety levels and 10 min of continuous physiological data were collected: (a) baseline; (b)
      post-condition; and (c) post-exposure for both condition A and B. All participants completed
      both the psychological and physiological assessments. Both experimental conditions A and B
      were completed in 90 min. To ensure compliance, participants were observed through a glass
      window every 10 min during study conditions. Testing time and procedures were identical with
      the exception of the experimental condition on days two and three.

      All participants were familiarized with the videotaped YogaFit session before participating
      in the study. Participants were instructed to arrive for all visits dressed in loose fitting
      athletic wear and were asked to refrain from all food, alcohol, caffeine, gum chewing or the
      use of tobacco products 3 h before their scheduled meeting in the laboratory.

      During pre-screening, participants completed: (a) a standard health history questionnaire;
      (b) the STAI-Y2; (c) the BDI and (d) a custom DEXA safety questionnaire. Qualified
      participants were then asked to track their menstrual cycle using a menstrual log and e-mail
      the primary investigator on day 1 of the follicular phase of their menstrual cycle, thus
      using the first day of the women's menstrual cycle to generate an unpredictable random
      sequence and to eliminate any sequence bias. The participant was then scheduled for condition
      A first or condition B first. The conditions were counterbalanced to control for order
      effects, with odd numbers beginning condition A first and even numbers beginning condition B
      first. To control for the effects of the menstrual cycle on anxiety, participants completed
      condition A and condition B within a 7-day period during the follicular phase of their
      menstrual cycle (specifically days 1-10). Participants were also asked to maintain pre-study
      physical activity levels during the 7-day period. All testing was completed by day 10 of
      their menstrual cycle. State anxiety was psychologically quantified using a reliable and
      validated assessment of anxiety, Spielberger's State-Trait Anxiety Inventory (STAI-YI).

      Instruments for testing all physiological variables were calibrated and used by the same
      investigator in order to control possible inter-tester variation. During both condition A and
      B, a ProComp Infiniti System with Biograph software version 6.0 was used to measure HR and
      indices of HRV at a sampling rate of 2048 cycles per sec at the 3 different time points.
      Three electrodes were placed on the participants to monitor HR as specified by the ProComp
      Infiniti System. The negative electrode was placed in the right shoulder fossa below the
      clavicle, the positive electrode was placed medially on the thorax below the sternum, and the
      ground electrode was placed in the left shoulder fossa below the clavicle. Indices of HRV
      included the time-domain variable, root mean square of successive differences (RMSSD) and two
      frequency-domains: the low frequency power bands and the high frequency power bands in
      normalized units (LFNU and HFNU, respectively).

      Measures of HR and HRV were analysed using CardioPro Infinity-HRV Analysis Software
      Module-SA7J90 [ProComp Infiniti System, Montreal, Quebec, Canada: Cimetra LLC]. An
      accelerometer using the ActiLife 6 Software and a Polar Heart Rate Sensor were strapped to
      the participant and used to monitor the intensity level of both study conditions A and B. The
      accelerometer was used only to record HR data and no other accelerometer data were analysed.
      Participants were then informed of the experimental condition. For study condition A (quiet,
      seated rest), participants sat on a yoga mat in a cross-legged position for 30 min in a quiet
      laboratory setting. For study condition B [YogaFit Vinyasa Flow (referred to as YogaFit in
      this manuscript)], participants followed, via digital versatile disc, a standardized YogaFit
      format choreographed by a certified American Council of Exercise Instructor and Registered
      Yoga Alliance Teacher. Yoga- Fit was performed in the same laboratory setting and lasted 30
      min. There are 7 principles of alignment that are applied in every YogaFit session: (1)
      establish a base and dynamic tension; (2) create core stability; (3) align the spine; (4)
      soften and align the knees; (5) relax shoulders back and down; (6) hinge at the hips; and (7)
      shorten the lever. The YogaFit essence is based on: Breathing, Feeling, Listening to the
      Body, Letting Go of Competition, Judgement, Expectations, and Staying in the Present Moment.
      The movements included in each specific phase were chosen from Beth Shaw's YogaFit Vinyasa
      Flow Series. To measure intensity of theYogaFit routine, ratings of perceived exertion (RPE)
      [24] were recorded following both condition A and B. The accelerometer and heart rate sensor
      were removed after the study condition. After both study conditions, participants again
      completed STAI-Y1 and 10 min of post-condition data were collected. Participants then viewed
      90 emotionally arousing pictures from the IAPS after both study conditions A and B. Pictures
      were viewed on a 70" × 70"portable projection screen. The 90 pictures were arranged in 3
      blocks of 30; each block contained 10 pictures from each valence category. Among the 90
      pictures used, 30 were pleasant (15 erotica and 15 babies, families, and cute animals); 30
      were neutral (15 neutral people and 15 neutral objects and scenes); and 30 were unpleasant
      (15 threat and 15 mutilation) based on normative ratings of valence [5]. No more than two
      pictures from the same category appeared consecutively. Two different picture orders were
      constructed and counterbalanced across testing day and experimental condition. Each picture
      was shown for 4-s, followed by a 12-, 14-, or 16-s inter-picture interval, which consisted of
      a centrally located fixation cross. The total picture-viewing time, including brief breaks
      between each picture block, was approximately 30 min. Participants were instructed to look at
      each picture the entire time it was on the monitor and to subjectively categorize each
      picture as pleasant, neutral, or unpleasant using a response pad [E-Prime 2.0, Psychology
      Software Tools, Inc., Pittsburgh, PA, USA] resting on their lap. These ratings were not used
      to compare to the normative ratings, but rather, the purpose of categorizing the pictures was
      to ensure that participants concentrated on the pictures. Immediately after viewing the
      pictures, participants again completed STAI-Y1 and 10 min post-exposure data were collected.
      In accordance with the Center for the Study of Emotion and Attention, participants were also
      asked to rate the IAPS images in order to further image standardization. Participants rated
      each of the 90 pictures (hard copy, one picture per page in a standard, self-paced order)
      using the Self-Assessment Manikin (SAM) during visit 4 to the laboratory. Additionally,
      participants underwent a single DEXA scan for body composition assessment.
    

Intervention name(s): YogaFit; Quiet Rest
Intervention type(s): Behavioral; Behavioral
Intervention description(s): For YogaFit Vinyasa Flow (referred to as YogaFit in this manuscript)], participants followed, via digital versatile disc, a standardized YogaFit format choreographed by an American Council of Exercise Certified and Registered Yoga Teacher (RYT). YogaFit was performed in the same laboratory setting and lasted 30 min. YogaFit is a westernized version of yoga that does not use Sanskrit terms (Shaw 2009). Breath was an integral part of every movement with specific breath rates for each phase of the session. The objective was to move the body with intention and purpose and be present in the body.; Participants completed 30 min of quiet rest
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Methods: A randomized repeated-measures crossover clinical trial was performed. Forty healthy, female college students completed a 30 min session of YogaFit and a time-matched seated rest condition on separate days. After each condition, participants viewed 30 min of emotional picture stimuli. State anxiety, heart rate and time-domain and frequency-domain measures of HRV were assessed baseline, post- condition, and post-exposure to emotional stimuli.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: autonomic function; emotion; heart rate variability