Recruiting

Heat & Mood

Sponsor:

Hartford Hospital

Code:

NCT07903896

Conditions

Depressed Mood

Young Adults

Heat Stress

Sleep

Eligibility Criteria

Sex: All

Age: 18 - 25

Healthy Volunteers: Not accepted

Interventions

Heat/Humidity Exposure Condition

Thermoneutral Condition

Study Details

Brief summary:

The goal of this clinical trial is to learn how hot indoor temperatures affect mood in young adults with depression, with or without anxiety. It will also explore whether the time of day the heat happens matters, and whether changes in sleep, thinking, and daily activity help explain the effect.

The main questions it aims to answer are:

  • Does heat during the day affect mood differently than heat at night?
  • Do changes in sleep, thinking, or activity help explain those effects? Researchers will compare a weekend that is hot during the day to a weekend that is hot at night to see how the timing of heat affects mood.

Participants will take part for about four weeks. During that time, participants will:

  • Stay in a sleep lab for two weekends, two weeks apart. Each stay runs from Friday afternoon to Monday midday.
  • Spend one weekend in rooms that are hot (32°C, or 90°F) from 8 in the morning to 8 at night, and comfortable (22°C, or 72°F) overnight
  • Spend the other weekend in rooms that are comfortable (22°C, or 72°F) during the day and hot (32°C, or 90°F) overnight
  • Be woken up at 2 in the morning on the last night of each lab stay. Participants will answer questions and do short thinking tasks, then go back to sleep.
  • Wear sensors that track their sleep, heart rate, and body temperature, and swallow a small capsule that measures body temperature from the inside
  • Answer questions about their mood and do short thinking tasks, both in the lab and at home
  • Use a phone app for the whole four weeks of the study. The app asks about mood and sleep, and works with the sensors to track sleep, movement, heart rate, temperature, and humidity.

Conditions

Depressed Mood

Young Adults

Heat Stress

Sleep

Study ID

NCT07903896

Start date

Oct, 2026

Status verified date

Oct, 2026

Completion date

Sep, 2030

Anticipated

Primary completion date

Sep, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 25

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • 18 ≥ age ≤ 25 at time of consent
  • has current depression as measured by a PHQ-9 score >9 and corroborated by the DIAMOND Diagnostic Interview
  • resides within 75 mi. of Yale Biobehavioral Laboratory
  • willing/able to travel up to 75 mi. each way by car from their home to the Yale Biobehavioral Laboratory and back to their home
  • speaks/reads English fluently (surveys, interviews, and study measures are only validated in English; translating materials without proper validation could lead to responses that are not truly comparable, threatening reliability; limitations in budget, staffing, and available interpreters prevent the use of translated materials or hiring sufficient bilingual team members)
  • any gender
  • any race/ethnicity
  • able (have capacity)/willing to sign informed consent form (ICF)
  • has reliable access to a smartphone

Exclusion Criteria:

  • age <18 or age ≥26 at time of consent
  • does not have current depression as indicated by a PHQ-9 score <9
  • does not reside within 75 mi. of Yale Biobehavioral Laboratory
  • not willing/able to travel up to 75 mi. each way by car from their home to the Yale Biobehavioral Laboratory and back to their home
  • does not speak/read English fluently
  • unable (not have capacity)/unwilling to sign informed consent form (ICF)
  • has a job that requires rotating shifts and/or works 2nd or 3rd shift (i.e., night shifts) that affect circadian rhythm and sleep architecture
  • planned air travel between time zones during the study period that is likely to affect circadian rhythm
  • does not have reliable access to a smartphone
  • is pregnant or lactating
  • has a recent history (hospital admission within 2 years) of heat-related illness (e.g. heat stroke, heat exhaustion, or rhabdomyolysis)
  • weight < 40 kg (88 lbs) - minimum body weight requirement
  • has a motility disorder of the gastrointestinal tract
  • has undergone surgical procedures in the gastrointestinal tract
  • has known swallowing disorders or dysphagia
  • has any condition that affects normal digestive function (GERD requiring treatment; Barrett's esophagus; achalasia or esophageal stricture; gastroparesis; IBS; inflammatory bowel disease (Crohn's disease or ulcerative colitis); celiac disease; microscopic colitis; chronic constipation or chronic diarrhea; malabsorption syndromes (e.g., pancreatic insufficiency, bile acid malabsorption); chronic liver disease; chronic pancreatitis; symptomatic gallbladder or post-cholecystectomy syndrome; prior bariatric surgery or bowel resection with ongoing effects; ostomy; chronic motility disorders; diabetes with autonomic neuropathy; neurologic or systemic diseases affecting GI function (e.g., Parkinson's disease, multiple sclerosis, scleroderma); chronic medication-induced GI dysfunction; eating disorders affecting digestion or nutrition.
  • has any condition that affects the body's ability to regulate temperature, including, Neurological conditions (such as spinal cord injuries, multiple sclerosis, traumatic brain injury, Guillain-Barré syndrome); Endocrine/metabolic disorders (such as hyperthyroidism/hypothyroidism, Type 1 or 2 diabetes, and anorexia nervosa); Cardiovascular conditions (such as Reynaud's disease, hypertrophic cardiomyopathy, and congenital heart); Dermatological conditions, (such as anhidrosis or hyperhidrosis and extensive burns or scarring associated with trauma).
  • engage in regular alcohol use (>2 drinks per day), daily cannabis use, or any illicit drug use which can affect sleep architecture

Study Design

Enrollment

75 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Sequence A: Cool Days-Hot Nights

Subjects exposed to thermoneutral conditions during the day on Saturday; followed by hot/humid conditions during the night on Saturday night; followed by thermoneutral conditions during the day on Sunday; followed by hot/humid conditions during the night on Sunday night.

experimental: Sequence B: Hot Days-Cool Nights

Subjects exposed to hot/humid conditions during the day on Saturday; followed by thermoneutral conditions during the night on Saturday night; followed by hot/humid conditions during the day on Sunday; followed by thermoneutral conditions during the night on Sunday night.

Interventions

Heat/Humidity Exposure Condition

  • Ambient temperature within the laboratory is set to 32 degrees Celsius (\~90 F)
  • Ambient humidity is set to \~13g/m³

Thermoneutral Condition

  • Ambient temperature within the laboratory is set to 22 degrees Celsius (\~72 F)
  • Ambient humidity is set to maintain \~13g/m³

Primary outcome measure

  • PANAS-10 [ Time Frame: periprocedurally* measures collected during lab weekends (i.e. periprocedurally) ONLY - marked with " * " ]
  • POMS-8 [depression subscale of POMS-60] [ Time Frame: periprocedurally* ]
  • PHQ-9 [ Time Frame: baseline, pre-intervention, periprocedurally ]
  • GAD-7 [ Time Frame: baseline, pre-intervention, periprocedurally ]
  • Qualitative Experience [ Time Frame: immediately after intervention* ]

Central Contacts and Locations

Central contacts

Isaac C McAlister, PhD

860-545-7231Isaac.McAlister@hhchealth.org

Joshua R Wortzel, MD, MPhil, MS(Ed)

860-545-7084Joshua.Wortzel@hhchealth.org

Locations

Yale Biobehavioral and Translational Research Center

Recruiting

Orange, Connecticut, United States, 06477

Contacts

Monica Ordway, PhD, APRN, PPCNP-BC, FAAN

203-737-5354monica.ordway@yale.edu

Sarah Linsky

sarah.linsky@yale.edu

Principal Investigator:

Klar Yaggi, MD, MPH

More Information

Sponsor

Hartford Hospital

Last update posted

Oct 29, 2026

Last verified

Oct, 2026

Keywords

  • heat stress
  • depression
  • sleep
  • young adult
  • mood
  • temperature
  • mental health
  • laboratory
  • EMA
  • summer
  • physical activity
  • cognition

Trial information was received from ClinicalTrials.gov and was last updated on 2026-10-30. This information was provided to ClinicalTrials.gov by Hartford Hospital on 2026-10-29. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.