• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

-Participants imagine themselves improving sleep hygiene

Assesses information comprehension, intentions, perceived risk and severity worry, self- efficacy, response efficacy, affect, race, education, age, numeracy, graph literacy, and exercise and sleep behaviors.

Participants imagine themselves improving exercise

-Reminders to practice mental imagery

-Assesses exercise behavior, intentions, actions plans, self-efficacy, affect, imagery vividness, and practice.

• Recovery Self-efficacy is defined as being sure one can re-engage in physical activity after putting it off
• Measured on a 4 point Likert Scale (range: 1=lower recovery Self-efficacy to 4=higher recovery Self-efficacy)
• Higher recovery self-efficacy is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

• Affective Attitudes to Exercise - Enjoying Behavior is defined as thinking getting regular exercise is enjoyable
• Measured on a 4 point Likert Scale (range: 1=lower Affective Attitudes to Exercise to 4=higher Affective Attitudes to Exercise)
• Higher Affective Attitudes to Exercise - Enjoying Behavior is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

• Affective Attitudes to Exercise - Thinking Behavior is Unpleasant is defined as not thinking getting regular exercise is unpleasant
• Measured on a 4 point Likert Scale (range: 1=lower Affective Attitudes to Exercise to 4=higher Affective Attitudes to Exercise)
• Higher Affective Attitudes to Exercise - Thinking Behavior is Unpleasant is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

• Perceived Vividness of Self-regulatory Imagery is defined as having clear and vivid images of steps towards getting physical activity
• Measured as an average of two variables measured on a 4 point Likert Scale (range: 1=lower Perceived Vividness of Self-regulatory Imagery to 4=higher Perceived Vividness of Self-regulatory Imagery)
• Higher Perceived Vividness of Self-regulatory Imagery is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

• Action planning is defined as having a detailed plan about getting adequate physical activity
• Measured as an average of three variables measured on a 4 point Likert Scale (range: 1=lower action planning to 4=higher action planning)
• Higher action planning is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

• Coping planning is defined as having a detailed plan of solving problems that may prevent getting adequate physical activity
• Measured on a 4 point Likert Scale (range: 1=lower Coping Planning to 4=higher Coping Planning)
• Higher coping planning is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

• Action self-efficacy is defined as having the confidence to engage in physical activity
• Measured on a 4 point Likert Scale (range: 1=lower Action Self-efficacy to 4=higher Action Self-efficacy)
• Higher Action Self-efficacy is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

Total of all reporting groups

-Having a BMI of 30 or greater

-Having a BMI of 25 - less than 30

-Does the participant have one more serious comorbidities (cancer, diabetes, heart disease, stroke)?

-Self-reported health consisted of question asking "In general, would you say that your health is." with choices of Excellent, Very good, Good, Fair, or Poor. Measured on a scale of 1-5, with 5 being higher self-reported health.

• Scale of 0-3; Measured as a sum score of (correct/incorrect) of 3 questions, participant answers each question as fill in the blank.
• "Imagine that we flip a fair coin 1,000 times. What is your best guess about how many times the coin would come up heads in 1,000 flips?"
• "Image that the chance of getting a disease is 1%. If there were 1,000 people, about how many would be expected to get the disease?"
• "Image that the chance of getting an infection is 1 in 1,000. What percent of people would be expected to get the infection?"

• Scale of 1-4; Measured as a sum score of (correct/incorrect) of 4 questions. An example item is:
• "The graph below shows the percentage of people who die from different types of cancer. About what percentage of people who die from cancer die from cancer B, cancer C, and cancer D combined?"

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• Risk display format = risk ladder, table, or text
• Gist comprehension of risk information: being able to extract the bottom-line meaning of information provided by the website (e.g., if exercising decreased heath risk)
• Measured by the sum of (4) questions coded as correctly comprehending risk information (1 point) or incorrectly comprehending risk information (0 points), with a total score range of 0=low comprehension to 4=high comprehension. Higher comprehension is considered a better outcome.
• All comprehension questions have an additional "don't know" option, which is counted as incorrect.
• To limit participant burden, the investigators assessed comprehension for diabetes only, instead of all diseases as planned.
• Comprehension will not be assessed for people who report a history of diabetes because they are not given risk information.

This study was designed as a 3X2 factorial design & only the risk display format intervention (risk ladder, table, or text) was looked at for this outcome, as participants had not yet received the mental imagery intervention, thus it could not affect this outcome.

• Risk communication strategy = risk ladder, table, or text
• Verbatim comprehension of risk information: being able to recall the exact information specific to diabetes risk and hours of recommended weekly physical activity
• Measured by the sum of (3) questions coded as correctly comprehending information (1 point) or incorrectly comprehending information (0 points), with a total score range of 0=low comprehension to 3=high comprehension. Higher comprehension is considered a better outcome.
• All comprehension questions have an additional "don't know" option, which is counted as incorrect.
• To limit participant burden, the investigators assessed comprehension for diabetes only, instead of all diseases as planned.
• Comprehension will not be assessed for people who report a history of diabetes because they are not given risk information.

This study was designed as a 3X2 factorial design & only the risk display format intervention (risk ladder, table, or text) was looked at for this outcome, as participants had not yet received the mental imagery intervention, thus it could not affect this outcome.

• Risk display format = risk ladder, table, or text
• Self-reported physical activity intentions is defined as intentions to engage in physical activity in the next 3 months
• Measured as an average of three variables, each measured on a 5 point Likert Scale (range: 1=lower intentions to 5=higher intentions)
• Higher intentions are considered a better outcome

This study was designed as a 3X2 factorial design & only the risk display format intervention (risk ladder, table, or text) was looked at for this outcome, as participants had not yet received the mental imagery intervention, thus it could not affect this outcome.

• Maintenance Self-efficacy is defined as being sure one can engage in physical activity even when it is hard
• Measured on a 4 point Likert Scale (range: 1=lower Maintenance Self-efficacy to 4=higher Maintenance Self-efficacy)
• Higher maintenance self-efficacy is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection & concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related maintenance self-efficacy among participants who engaged in the exercise-related mental imagery condition.

• Recovery Self-efficacy is defined as being sure one can re-engage in physical activity after putting it off
• Measured on a 4 point Likert Scale (range: 1=lower recovery Self-efficacy to 4=higher recovery Self-efficacy)
• Higher recovery self-efficacy is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection & concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related recovery self-efficacy among participants who engaged in the exercise-related mental imagery condition.

• Affective Attitudes to Exercise - Enjoying Behavior is defined as thinking getting regular exercise is enjoyable
• Measured on a 4 point Likert Scale (range: 1=lower Affective Attitudes to Exercise to 4=higher Affective Attitudes to Exercise)
• Higher Affective Attitudes to Exercise - Enjoying Behavior is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection and concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related affective attitudes among participants who engaged in the exercise-related mental imagery condition.

• Affective Attitudes to Exercise - Thinking Behavior is Unpleasant is defined as not thinking getting regular exercise is unpleasant
• Measured on a 4 point Likert Scale (range: 1=lower Affective Attitudes to Exercise to 4=higher Affective Attitudes to Exercise)
• Higher Affective Attitudes to Exercise - Thinking Behavior is Unpleasant is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection and concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related affective attitudes among participants who engaged in the exercise-related mental imagery condition.

• Perceived Vividness of Self-regulatory Imagery is defined as having clear and vivid images of steps towards getting physical activity
• Measured as an average of two variables measured on a 4 point Likert Scale (range: 1=lower Perceived Vividness of Self-regulatory Imagery to 4=higher Perceived Vividness of Self-regulatory Imagery)
• Higher Perceived Vividness of Self-regulatory Imagery is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection and concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related perceived vividness of self-regulatory imagery among participants who engaged in the exercise-related mental imagery condition.

• Action planning is defined as having a detailed plan about getting adequate physical activity
• Measured as an average of three variables measured on a 4 point Likert Scale (range: 1=lower action planning to 4=higher action planning)
• Higher action planning is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection and concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related action planning among participants who engaged in the exercise-related mental imagery condition.

• Coping planning is defined as having a detailed plan of solving problems that may prevent getting adequate physical activity
• Measured on a 4 point Likert Scale (range: 1=lower Coping Planning to 4=higher Coping Planning)
• Higher coping planning is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection and concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related coping planning among participants who engaged in the exercise-related mental imagery condition.

• Action self-efficacy is defined as having the confidence to engage in physical activity
• Measured on a 4 point Likert Scale (range: 1=lower Action Self-efficacy to 4=higher Action Self-efficacy)
• Higher Action Self-efficacy is considered a better outcome
• Note: to limit participant burden, the investigators used a single item instead of averaging across multiple items

Due to the limitations of data collection and concerns about overburdening participants with too many survey questions, the investigators only assessed exercise-related action self-efficacy among participants who engaged in the exercise-related mental imagery condition.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down an exercise goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.

• With help from a research assistant, participants complete the Risk Assessment App. The App asks demographic & health questions. It then provides personalized risk estimates for participants' current activity level & how it would change with regular exercise.
• Participants take Baseline Survey 1.
• Participants listen to an audio recording that guides them through a mental imagery activity. They write down a sleep goal & are asked to practice the mental imagery twice a day for 3 weeks.
• Participants take Baseline Survey 2.
• Participants receive text messages reminding them to practice the mental imagery twice daily for 5 minutes each time (3 texts a week for 3 weeks).
• Participants take surveys via text at the end of each week for 4 weeks.
• 90 days post-baseline, participants complete a survey sent through the mail.
• Participants may be contacted for another survey 1 year later.