In-person baseline surveys using the web-based data collection platform, Research Electronic Data Capture before the random assignment to HRVB+DS arm. This group will receive a standardized HeartMath© Inner balance device and HRV biofeedback training session at the start of the two-week intervention period. They will be asked to attend either a group or one-on-one 30-minute HRVB training session and asked to practice their HRV biofeedback skills at home for 10 minutes each day for a two-week period. Participants will also be asked to watch four digital stories of other HCT patients (2 videos per week) with a weekly email notification and reminder phone call. Each story was made with voice, images, and sound (3-5 minutes each).

In-person baseline surveys using the web-based data collection platform, Research Electronic Data Capture (REDCap) before the random assignment to HRVB waitlist +DS control arm. After the baseline data collection, during two weeks, they will be provided four digital stories of other HCT patients sharing their experiences (challenges, feelings, strategies, coping, each 2-3 minutes long). At the end of the two-week period, participants will be scheduled for a final in-person session including T2 survey and HRV assessment. They will be also provided HRVB training session at T2.

Baseline surveys contained a series of scaled questions, including sociodemographic variables (age, sex, cancer type, and etc), profile of mood states, social well-being, emotional processing and acceptance.

The Emwave Pro Plus device from HeartMath will be used to collect HRV data and heart rate using a 3-minutes "neutral" protocol (we call "waiting at the bus stop" implying that no particular intent for breath or mindful state is to be evoked) to understand the benefits of DS+ HRVB. In addition, HRV measures will be obtained for the 1-minute paced breathing period to understand the effects of paced breathing on HRV. The following precautions will be provided as instructions to participants prior to data collection: no coffee, tea, or caffeinated drinks such as energizing drinks in the 2 hours before the data collection, and no alcohol consumption during 24 hours prior to the data collection.

Psychological distress will be measured using the Profile of Mood States (POMS) short version (15 items, 5-point Likert scale; 0=not at all, 4=extremely). The POMS is one of the most frequently used and validated scales in studies of psychosocial interventions for cancer patients. The POMS Total Mood Disturbance (TMD) score has been shown to be most sensitive to interventions designed to facilitate emotional expression. The POMS consists of the TMD dimensions (tension-anxiety; depression-dejection; anger-hostility; and confusion-bewilderment) (Cronbach's a = .93) to be used in the current study as the primary outcome measure; and two others (fatigue-inertia; vigor-activity) will be documented. Total of Mood Disturbance= (anxious+depression+anger+fatigue)- vigor (Range from 12 to 48). The higher values represent a worse emotional well-being.

Depression will be measured using the Center for Epidemiological Studies Depression Scale Revised (CESD-R-10) scale (10 items, 4-point Likert scale (0 = rarely or none of the time, 3= all of the times, Cronbach's a = .86). The higher values represent a worse depression.