Clinical trial NCT00915642: Overnight Weight Loss and Sleep Structure
Official title: Overnight Weight Loss, Sleep Structure and the Endocrine System
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Obesity
Healthy
Keywords: Obesity
Weight loss rate
Sleep
Vigil
Metabolism
Actigraphy
Normal
Lead sponsor: Associacao Fundo de Incentivo a Psicofarmcologia
Sponsor class: OTHER
Collaborators: name: Fundação de Amparo à Pesquisa do Estado de São Paulo
First posted: 2009-06-08
Enrollment: 60
Sex: MALE
Minimum age (years): 21
Maximum age (years): 35
Standard ages: ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Normal and obese volunteers

Brief summary: The objectives of the present study are:

1. to evaluate if overnight weight loss is dependent on sleep structure assessed by polysomnography;
2. to compare weight loss rate during sleep and awake rest;
3. to compare night weight loss profile of normal and obese volunteers.

Detailed description: Weight loss can be caused by loss of body mass due to metabolism and by water loss as insensible water loss, sweating, or excretion in feces and urine. Eighty-three percent of the total weight loss is due to insensible water loss from airways and skin. Water loss rate varies according to changes in activity and ambient temperature and humidity. Although weight loss during sleep is a well-known phenomenon, there are no studies relating it to sleep structure or any other functions during the distinct sleep stages, particularly SWS and REM sleep. There is evidence suggesting a homeostatic mechanism for weight control in animal models and humans. This mechanism is thought to be dependent on energy intake, energy expenditure, and environmental conditions. The literature suggests that sleep is important for weight homeostasis on a long term since sleep shortage is associated with overweight status, but overnight weight variation had not yet been studied. Considering these facts, we hypothesized that the overnight weight loss rate is not uniform throughout the sleep period. We also intend to compare weight loss rate during sleep and awake rest.

Intervention: Normal and obese volunteers will undergo whole night polysomnography with continuous body weight and temperature register after an adaptation night. After that, volunteers will remain awake resting in bed during the following day for continuous weight and temperature register.

Eligibility criteria: Inclusion Criteria:

* normal and obese volunteers

Exclusion Criteria:

* serious medical or neurological condition

Primary outcomes:
measure: Adaptation polysomnography (first night) followed by experimental polysomnography with continuous body weight register (second night)
timeFrame: 8 hours (first night), 8 hours (second night)
Secondary outcomes:
measure: Pletysmography
timeFrame: 1 hour (before second night), 1 hour (after second night), 1 hour (after daytime)
measure: Actigraphy (nighttime, daytime)
timeFrame: 24 hours (second night, daytime following second night)
measure: Skin temperature plot
timeFrame: 8 hours (second night), 8 hours (daytime following second night)
measure: Daytime continuous weight register
timeFrame: 8 hours (daytime period following second night)
Other outcomes:
Locations:
city: Sao Paulo
country: Brazil
facility: Instituto do Sono / Associacao Fundo de Incentivo a Psicofarmacologia
Study officials:
affiliation: AFIP / UNIFESP
name: Walter Moraes, MD PhD
role: PRINCIPAL_INVESTIGATOR
affiliation: AFIP / UNIFESP
name: Marco Tulio Mello, PhD
role: STUDY_DIRECTOR
affiliation: AFIP/ UNIFESP
name: Sergio Tufik, MD, PhD
role: STUDY_CHAIR
References: