CHARGE: Pilot Trial of Self-directed Use of Resources for Physical Activity (CHARGE)

This is a pilot RCT examining physical activity outcomes at 3 months across 3 conditions: use of large language model (LLM) fully self-directed; use of LLM with guidance; and use of online tools to help with sleep.

Study Overview

• Status: Not yet recruiting
• Conditions: Physical Activity
• Intervention / Treatment: Behavioral: LLM alone; Behavioral: LLM enhanced; Behavioral: Sleep promotion

Detailed Description

To prepare for a future fully powered RCT, we are conducting a pilot RCT. The pilot RCT will enroll n=39 insufficiently active primary care patients, and randomize them to one of 3 conditions: LLM alone condition: participants are recommended to use a publicly available, general-purpose LLM for physical activity promotion over the next 3 months (n=13); LLM enhanced condition: participants are recommended to use a publicly available, general-purpose LLM for physical activity promotion over the next 3 months and additionally attend an initial session providing guidance on LLM use and weekly text message with suggestions on using the LLM (n=13); or Control condition: participants are recommended to use publicly available tools to help with sleep (websites with tips for sleep and guided meditation videos) over the next 3 months (n=13). At study onset, all participants will be given basic information about exercise safety. At 3 months, moderate-to-vigorous physical activity will be measured with a validated self-report measure. Feasibility and acceptability outcomes such as recruitment and retention--metrics essential for advancing to a subsequent large-scale trial-will be measured.

• Study Type: Interventional
• Enrollment (Estimated): 39
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Megan A McVay, PhD; Phone Number: (352) 294-1638; Email: megan.mcvay@ufl.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 18-75
• Reports a desire to increase physical activity level
• Not meeting minimum aerobic PA as indicated by L-CAT endorsement indicating level of activity below moderate (moderate defined as >= 5x/week activity or higher)
• Reports willingness to use LLMs to help with exercise goals.
• Access to internet through phone data plan or home Wi-Fi.

Exclusion Criteria:

• Conditions warranting more extensive supervision of physical activity, including:

  • Any history of MI or stroke, arrhythmias, or heart failure
  • Uncontrolled hypertension
  • Type 1 or 2 diabetes
  • COPD or asthma
  • Recent orthopedic surgery or fracture
  • Advanced Parkinson's
  • Pregnant or planning to become pregnant in next 9 months
  • Active cancer undergoing treatment
  • Recent major surgery (<12 weeks)
  • Use of assistive devices for ambulation
  • History of eating disorder diagnosis
• Dementia diagnosis
• Unable to read on own.
• Hospitalization for mental health reasons in past year
• Has used LLM to support physical activity goals in prior 3 months.
• Currently enrolled in a structured program to promote physical activity or weight loss.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: LLM alone; Participants are recommended to use a publicly available, general-purpose LLM for physical activity promotion over the next 3 months	Behavioral: LLM alone; Participants are recommended to use a publicly available, general-purpose LLM for physical activity promotion
Experimental: LLM enhanced; Participants are recommended to use a publicly available, general-purpose LLM for physical activity promotion over the next 3 months and additionally attend an initial session providing guidance on LLM use and weekly text message with suggestions on using the LLM	Behavioral: LLM enhanced; Participants are recommended to use a publicly available, general-purpose LLM for physical activity promotion over the next 3 months and additionally attend an initial session providing guidance on LLM use and weekly text message with suggestions on using the LLM
Active Comparator: Sleep promotion; Participants are recommended to use publicly available tools to help with sleep (websites with tips for sleep and guided meditation videos) over the next 3 months	Behavioral: Sleep promotion; Participants are recommended to use publicly available tools to help with sleep (websites with tips for sleep and guided meditation videos)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Recruitment feasibility	Ability to meet recruitment goal of 39 participants within an acceptable timeframe	6 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Retention	Ability to retain 80% of participants at 3 month assessment	3 month
Physical activity	MET-minutes per week based on international physical activity questionnaire (IPAQ)-short form	3 months

Collaborators and Investigators

• Sponsor: University of Florida

Study record dates

Study Major Dates

• Study Start (Estimated): June 22, 2026
• Primary Completion (Estimated): December 15, 2026
• Study Completion (Estimated): December 15, 2026

Study Registration Dates

• First Submitted: June 12, 2026
• First Submitted That Met QC Criteria: June 12, 2026
• First Posted (Actual): June 17, 2026

Study Record Updates

• Last Update Posted (Actual): June 17, 2026
• Last Update Submitted That Met QC Criteria: June 12, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: physical activity; exercise; artificial intelligence; chatbot; large language model; generative AI
• Additional Relevant MeSH Terms: Behavior; Motor Activity
• Other Study ID Numbers: IRB202600162

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No