Heat Stress in Individuals With Schizophrenia

Potential changes in mood (7 subscales of mood: tension, anger, depression, fatigue, confusion, vigor and esteem related affect). The POMS-40 is a validated, self-administered questionnaire that examines seven distinct aspects of mood state across two positive subscales (Esteem-Related Affect, and Vigor) and five negative subscales (Fatigue, Tension, Confusion, Anger, and Depression), which are described across 40 distinct adjectives. For each individual item, participants are asked to describe "how you feel right now" by responding using a 5-point Likert scale (0 = "Not at all", 1 = "A little", 2 = "Moderately", 3 = "Quite a lot", or 4 = "Extremely"). The values of items associated with a specific subscale (e.g., Fatigue) are summed to calculate its score.

Self-reported environmental reactions and medical symptomatology associated with prolonged heat exposure. The ESQ-IV is a validated 68-item, self-administered questionnaire that has been used successfully in identifying symptomatology during exposure to a wide variety of environmental conditions, including heat exposure. Participants are asked to assess and described "how you have been feeling today" by responding to each item using a 6-point Likert scale (0 = "Not at all", 1 = "Slight", 2 = "Somewhat", 3 = "Moderate", 4 = "Quite a bit", or 5 = "Extreme"). Total Symptom Score is calculated from this data by taking the sum of the intensity ratings from all 68 individual items using reverse scores for the three positive items from the list ("I Felt Good", "I Felt Alert", and "I Felt Wide Awake").

Perceived exertional assessed via an ordinal scale ("How hard are you working?") ranging from "no exertional at all" to "maximal exertion"

Activity levels, quantified by number of steps taken per hour and totaled for each 6 hour exposure, assessed via a wearable accelerometer worn on the wrist and hip.

Feel good scale assessed via an ordinal scale (How good do you feel?) ranging from "very good" to "very bad" (midpoint: neutral)

Thirst sensation assessed via an ordinal scale ranging from very, very thirsty to not thirsty at all.

Thermal comfort assessed via an ordinal scale ("How comfortable does your body temperature feel?") ranging from "very uncomfortable" to "comfortable".

Thermal sensation assessed via an ordinal scale ("How do you feel?") ranging from "hot" to "cold" (midpoint: neutral)

Thermal sensation assessed via an ordinal scale (How hot do you feel?) ranging from "extremely hot" to "neutral".

Fluid loss calculated as the change in body mass during each exposure presented as a percentage of baseline body mass (corrected for food consumption).

Average hourly fluid consumption calculated by weighing participant water intake at the start and end of each hour of exposure (normalized to the exposure duration).

Hydration status measured via assessing the urine specific gravity of a urine sample.

To assess postural stability, participants will be asked to stand on a BTracks force plate with their feet spread out to shoulder width, hand on their hips and eyes closed. The assessment will comprise of four trials (one practice trial) lasting 20 seconds in length and 20 seconds between trials. Center of pressure (COP) vector data along vertical (y) and horizontal (x) axes will be summed for the total path excursion length (cm) during each trial

Participants will be provided with a tablet device with the Sway Medical testing platform for the assessment of executive function. Participants will complete the Cued Stroop test, in which they are presented a sequence of congruent, neutral and incongruent color-word tasks.

To assess postural stability, participants hold a tablet to their chest, then auditory cues guide participants through four consecutive stances, feet side by side, instep of one foot touching the big toe of the other foot, tandem stand with one foot in front of the other, heel touching toe, and stand on one foot. The balance assessment will be evaluated based on movement detected by an accelerometer integrated into the hardware of the tablet device (Sway Medical Inc).

Participants will be provided with a tablet device with the Sway Medical testing platform for the assessment of memory recall. Participants complete both a delayed recall test and a working memory test.

Participants will be provided with a tablet device with the Sway Medical testing platform for the assessment of impulse control. Participants will be asked to respond to both "go" and "no-go" visual cues. In response to the "go" cue, participants will initiate a movement of the device.

Participants will be provided with a tablet device with the Sway Medical testing platform for the assessment of reaction time. Participants will be asked to initiate a movement of the device in response to a visual cue.

Diastolic blood pressure measured in triplicate via automated oscillometry (~60 seconds between measures).

Systolic blood pressure measured in triplicate via automated oscillometry (~60 seconds between measures).

Heart rate measured at hour 6 of exposure to indoor overheating (15-min average).

Areas under the curve (AUC) of heart rate during the 6 hour exposure to the simulate indoor overheating.

Peak heart rate (15 min average) during exposure. Heart rate is measured continuously throughout the 6 hour exposure to the simulated indoor overheating.

Mean skin temperature measured over 7 body regions at hour 6 of exposure to indoor overheating (15-min average).

Areas under the curve (AUC) of mean skin temperature as calculated over 7 body regions during the 6 hour exposure to the simulate indoor overheating.

Peak mean skin temperature (15 min average) during exposure. Mean skin temperature as calculated from skin temperature measured across 7 body regions is measured continuously throughout the 6 hour exposure to the simulated indoor overheating.

Visceral temperature measured at hour 6 of exposure to indoor overheating (15-min average).

Areas under the curve (AUC) of visceral temperature during the 6 hour exposure to the simulate indoor overheating.