30 minutes of aerobic activity before cognitive behavioral therapy, while watching the same nature documentary the CalmCBT group watches.

The C-SSRS will be used to assess and monitor suicide ideation and behavior. The severity of the ideation subscale is rated on a 5-point ordinal scale: 1 = wish to be dead, 2 = nonspecific active suicidal thoughts, 3 = suicidal thoughts with methods, 4 = suicidal intent, and 5 = suicidal intent with plan. Suicide behaviors are rated on a nominal scale that includes actual, aborted, and interrupted attempts; preparatory behavior; and non-suicidal, self-injurious behavior.

The DARS is a self-report measure that assesses state anhedonia across multiple domains. DARS is a 17-item survey on state anhedonia divided into four domains: hobbies, food/drink, social activities, and sensory experiences. Participants must list two activities within each of these categories that they consider their favorite and then respond to questions regarding their interest in/enjoyment of those activities on a 5-point Likert scale from "Not at all" to "Very much." During pre/post-administration, participants will be asked to respond to how they are feeling "right now."

An anhedonia Visual Analog Scale [VAS] with 0 indicating 'No pleasure at all' and 100 indicating 'Greatest pleasure imaginable' will be used to measure anhedonia. In past research by the PI, correlations between the DARS and VAS were 0.49-0.69 indicating a moderate-to-strong agreement between the measures. The VAS will be used to provide a supplementary assessment of anhedonia.

Serum BDNF will be quantified from a standard blood draw. Blood samples collected during Visits 1, 4, and 8 will be allowed to clot for 30 minutes and then centrifuged for ten minutes at 5500 RPM and 4 ◦C. Following centrifugation, blood serum will be extracted with samples stored at -80 ◦C until BDNF analysis. Enzyme-linked immunosorbent assay (ELISA) kits will measure the concentration of total BDNF in the serum according to the manufacturer's instructions. Each blood sample will be run in duplicate and averaged.

Participants will place an activPAL on the midline of the thigh on either leg and wear the monitor during all waking hours, removing it only for water-based activities (e.g., swimming). For data to be valid, the monitor must have been worn for 20 hours on at least 4 days, including a minimum of 3 weekdays and 1 weekend day. Sleep time will be parsed out from each day's sitting/lying time automatically using PALanalysis. From these data, average minutes of sitting per day will be used to assess total sedentary time, minutes of stepping time with a cadence greater than or equal to 75 and less than 100 will be used to assess minutes of light-intensity physical activity and minutes of stepping time with a cadence greater than or equal to 100 will be used to assess minutes of moderate to vigorous physical activity (MVPA).

Sedentary time, physical activity time and sleep time will all be recorded in minutes per day.

Participants will place an activPAL on the midline of the thigh on either leg and wear the monitor during all waking hours, removing it only for water-based activities (e.g., swimming). For data to be valid, the monitor must have been worn for 20 hours on at least 4 days, including a minimum of 3 weekdays and 1 weekend day.

Steps are recorded as cumulative number of steps per day as measured by the activPAL device.

The IPAQ is a physical activity questionnaire that inquires about average amounts of walking, moderate physical activity, vigorous physical activity, and sitting time per week. Walking and physical activity are reported in minutes per day of activity, sitting time is reported in hours per day.

The SF-36 assesses health-related quality of life. It consists of eight scaled scores (including vitality, physical functioning, bodily pain, general health perceptions, physical role functioning, emotional role functioning, social role functioning, and mental health), which are the weighted sums of the questions in their section. Each scale is directly transformed into a 0-100 scale on the assumption that each question carries equal weight. The higher the score the less disability (i.e., a score of zero is equivalent to maximum disability and a score of 100 is equivalent to no disability).

Generalized Anxiety Disorder 7 (GAD-7) is a self-reported questionnaire for measuring generalized anxiety disorder. GAD-7 has seven items, which measure the severity of various signs of GAD according to reported response categories of: Not at all (0 points), Several days (1 point), More than half the days (2 points), and Nearly every day (3 points), with scores of 5, 10, and 15 as cut-off points for mild, moderate and severe anxiety, respectively.

The ATQ is a 30-item instrument that measures the frequency of automatic negative statements about the self. Each item is rated on the frequency of an occurrence from "not at all" to "all the time". Total scores are the sum of all 30 items, with higher totals indicating a higher level of automatic negative self-statements.

Session Evaluation Questionnaire (SEQ) will be used to evaluate session effectiveness. This includes responses to twenty-one items in a 7-point bipolar adjective format questionnaire to assess how the client feels about each CBT session. The questionnaire assesses session depth, smoothness, positivity, and arousal. An overall score of the average of the values across each subscale will be used in this study.

Lyssn is an AI-powered assessment platform for recording and managing session files, and all clinical interviews and therapy sessions will be recorded on the Lyssn platform. Lyssn will process the audio files from therapy sessions to generate session-level data.

Lyssn generates metrics related to therapy effectiveness and fidelity, with individual metric scores (e.g., empathy, collaboration) ranging from 0 to 5 with higher scores indicated greater levels of the metric.

The LEAPS is a 10-item self-report scale that provides a measure of productivity in the workplace. Scores range from 0 to 28, with higher scores indicating higher impairment in work productivity.

The Patient Global Impression of Change scale is a single, self-administered question asking respondents to rate how their condition has changed since a certain point in time. Participants respond to the prompt "Since the start of the study, my overall status is: [1] 'Very Much Improved', [2] 'Much Improved', [3] 'Minimally Improved', [4] 'No Change', [5] 'Minimally Worse', [6] 'Much Worse', or [7] 'Very Much Worse'.

The REST-Q is a 9-item questionnaire assessing the extent to which the participants' last night of sleep was restful or restorative. Scores range from 0-36, with higher scores indicating more restful sleep.

The ERQ is a 10-item scale measuring emotional regulation on a 7-point scale for each question (total range: 7-70). Higher scores indicate increased use of emotion regulation strategies.

The RRQ is a 24-item questionnaire assessing levels of rumination. Each item is scored 1-5 (total scores ranging 24-120). Higher scores indicate higher levels of rumination.

The WAI scores 12 items from 1-7 in 3 domains: Tasks (4-28), Goals (4-28), Bond (4-28). Total possible range of scores from 12-84. In all domains higher scores are stronger perceived working alliance. The Bond subscale is a primary outcome measure. The total score and the two other subscales, Tasks and Goals, will be analyzed as secondary outcomes.

The ACES consists of 16 questions pertaining to the respondents' first 18 years of life. Participants respond with yes or no regarding if a childhood adverse event occurred. Adverse events questions are grouped by categories. Participants are scored for each event category they are exposed to with scores ranging from 0 (unexposed) to 7 (exposed to all categories).

A 12-item subscale of the WHODAS is used at baseline to record any difficulties due to health conditions. Each item is scored 0-4, with higher scores indicate higher level of disability.