Heat Therapy and Cardiometabolic Health in Obese Women

NCT03644524 | Completed

• 1 other identifier: 08282015.026
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

Brief Summary

Traditional medical treatments are often based on research done exclusively in males, and recent research efforts in the physiology community have highlighted critical sex differences in disease presentation and progression. For example, the relative risk of fatal heart disease is 50% greater in obese, diabetic women as compared to their male counterparts, and women appear to respond differently to lifestyle interventions such as exercise compared with men. Chronic passive heat exposure (hot tub use) provides alternative or supplemental therapeutic potential for improving cardiovascular and metabolic health in obese women. In addition, passive heat exposure may offer specific cellular protection from stresses like a lack of blood flow (ischemia), which is the primary cause of fatal coronary heart disease. This study is investigating the possible cardiovascular and metabolic health benefits of chronic passive heat exposure, and whether regular hot tub use (3-4 days per week for 8-10 weeks) may reduce obese womens' cardiometabolic risk. The investigators are examining cardiovascular health through blood pressure, blood vessel stiffness, sympathetic ('fight or flight') activity, and responsiveness to stresses like increased or decreased blood flow. The investigators are also examining metabolic health through an oral glucose tolerance test and a subcutaneous fat biopsy. The goal of this research is to develop a therapy targeted toward the specific health needs and complications of obese women, in an effort to improve cardiovascular and metabolic health and provide therapeutic alternatives in this high-risk population.

Conditions

Obesity; Polycystic Ovary Syndrome; Prehypertension; PreDiabetes; Cardiovascular Risk Factor; Metabolic Syndrome

Keywords

heat therapy; blood pressure; oral glucose tolerance test; adipose tissue; muscle sympathetic nerve activity

Outcome Measures

Primary Outcomes (3)

• systolic blood pressure

  Resting supine blood pressure, measured in triplicate with median recorded

  through study completion, an average of 10 weeks

• diastolic blood pressure

  Resting supine blood pressure, measured in triplicate with median recorded

  through study completion, an average of 10 weeks

• oral glucose tolerance test

  glucose and insulin responses to a 75-g, 2-hr oral glucose tolerance test after a 12+hr fast

  through study completion, an average of 10 weeks

Secondary Outcomes (8)

• muscle sympathetic nerve activity burst frequency

  through study completion, an average of 10 weeks

• arterial wall thickness (carotid)

  through study completion, an average of 10 weeks

• arterial wall thickness (femoral)

  through study completion, an average of 10 weeks

• dynamic arterial compliance (carotid)

  through study completion, an average of 10 weeks

• dynamic arterial compliance (femoral)

  through study completion, an average of 10 weeks

Other Outcomes (2)

• C-reactive protein

  through study completion, an average of 10 weeks

• Cholesterol panel

  through study completion, an average of 10 weeks

Study Arms (2)

Heat Therapy

EXPERIMENTAL

Subjects assigned to heat therapy underwent 30 1-hour hot tub sessions over 8-10 weeks (3-4 per week). The hot tub was set to 40.5 Celsius, and core temperature and heart rate were monitored throughout each session.Subjects were instructed to not make any other dietary or lifestyle changes.Cardiovascular and metabolic health assessments were made Pre (0 heat sessions), mid (after 14-16 heat sessions, \~4-5 weeks), and post (after all 30 heat sessions; \~8-10 weeks).

Behavioral: Heat therapy

Time Control

NO INTERVENTION

Subjects were monitored at matched timepoints (start of study, 4-5 weeks, and 8-10 weeks) but not exposed to any intervention. Subjects were instructed to not make any dietary or lifestyle changes.

Interventions

Heat therapy BEHAVIORAL

Regular hot tub use

Heat Therapy

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: female
• Healthy Volunteers: No
• Age Groups: Adult (18-64)

You may qualify if:

• Age 18-40
• Body mass index (BMI) between 30-45 kg/m2.
• Willing to maintain consistent diet and activity patterns through the study
• Willing to refrain from food, physical activity, supplements, and medications as required before testing days
• Willing to refrain from blood donations over the course of the study

You may not qualify if:

• overt cardiovascular disease or diabetes
• medications that affect blood vessel function (i.e. Spironolactone), insulin sensitivity (Metformin), or blood coagulation (i.e. Warfarin)
• Recent rectal, anal, or vaginal surgery
• pregnant, breastfeeding, or trying to conceive within 6 months.

Sponsors & Collaborators

• University of Oregon: lead
• American Heart Association: collaborator

Study Sites (1)

University of Oregon

Eugene, Oregon, 97403, United States

Location

MeSH Terms

Conditions

Obesity; Polycystic Ovary Syndrome; Prehypertension; Prediabetic State; Metabolic Syndrome; Hyperthermia

Interventions

Diathermy

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Ovarian Cysts; Cysts; Neoplasms; Ovarian Diseases; Adnexal Diseases; Genital Diseases, Female; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Genital Diseases; Gonadal Disorders; Endocrine System Diseases; Vascular Diseases; Cardiovascular Diseases; Diabetes Mellitus; Glucose Metabolism Disorders; Metabolic Diseases; Insulin Resistance; Hyperinsulinism; Body Temperature Changes; Heat Stress Disorders; Wounds and Injuries

Intervention Hierarchy (Ancestors)

Hyperthermia, Induced; Therapeutics

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NON RANDOMIZED
• Masking: SINGLE
• Who Masked: OUTCOMES ASSESSOR
• Masking Details: It was not possible to blind the subject or PI to treatment group, but all measures that were collected were analyzed offline by a blinded investigator.
• Purpose: PREVENTION
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Kenneth & Kenda Singer Endowed Professor

Model Details: Subjects were matched for age and BMI, then assigned to either a heat therapy intervention or time control (no intervention, just outcomes assessment at matched timepoints).

Study Record Dates

• First Submitted: August 20, 2018
• First Posted: August 23, 2018
• Study Start: September 8, 2015
• Primary Completion: April 30, 2018
• Study Completion: July 1, 2018
• Last Updated: August 23, 2018

Record last verified: 2018-08

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)