Substrate Utilization and Hormonal Status in Women

Women sexual hormones (i.e. estrogen) are involved in the regulation of substrate utilization and storage. Being under oral contraception (OC) may conduct to metabolic and hormonal modifications, but results are confused regarding the impact on substrate utilization. In the present study, the aim is then to explore the effect of hormonal status on substrate utilization during sous-maximal exercise, comparing women with and without OC.

We hypothesised that women under OC have a lower Respiratory Exchange Ratio (RER) at exercise than women without contraception underlying a greater reliance on fat oxidation.

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Key information

Conditions

Substrate Utilization Behavior Motor Activity

Age range

19 year–30 year

Sex eligibility

Female

Study type

Observational

Primary location

CHU Clermont-Ferrand

Clermont-Ferrand, 63003, France

About this study

24 healthy young women (12 with OC and 12 without any contraception) will complete a maximal test on an ergometer cycle to obtain their maximal oxygen consumption (VO2max).Their body composition will be assessed by DXA. They will be asked to complete 3 experimental sessions.

During a first session the volunteers will remain inactive, and only a breakfast will be offered. During the second session, a breakfast will be offered and they will have to complete a sub-maximal exercise set at 60% of their VO2max 3 hours after breakfast. And the third session will consist in the realisation of exercise on fast state. Those three sessions will be realized in a randomized order. Several blood (catheter) and salivary samples will be collected during the three sessions, throughout the experimental day.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Female
Adults between 19 to 30 years old
Body mass index between 20 and 25 kg.m-²
Oral contraception (half of the sample) : mini-dosed, and mono-phasic, ethinyl estradiol ≤ 30 µg
Without contraception (half of the sample)
Affiliated to National Health Insurance
Subject giving her written informed consent
Subject considered as normal after clinical examination and medical questionnaire.

Exclusion criteria

Chronic pathologies : cardiovascular diseases, cancer, chronic inflammation diseases, renal, intestinal impairments
Refusal to be registered on the National Volunteers Data file
Being in exclusion on the National Volunteers Data file
Practising intensive physical exercise
Heavy consumer of alcohol or/and tobacco
Previous medical and/or surgery judged by the investigator as incompatible with this study
Pregnancy

Treatment and study plan

Primary outcomes

Substrate utilization will be the main outcome under study.For each volunteer, it will be assessed during exercise (between 12h and 12h45) for the 2 experimental conditions with exercise

Time frame: during exercise (between 12h and 12h45)

Substrate utilization:

The Respiratory Exchange Ratio (RER) that corresponds to carbon dioxide production divided by oxygen consumption (VCO2/VO2) will be used to determine the energetic substrate used during exercise. This RER will be obtained, in continuous, thanks to an indirect calorimetric system composed of a breath by breath gas analyzer. A RER closed to 0.7 illustrates lipid utilization while carbohydrate use will correspond to a RER that reached 1.

Secondary outcomes

The hormonal regulation involved in substrate utilization. It will be assessed during the 3 experimental conditions during all the experimental day: - Breakfast + exercise - Exercise alone - Breakfast alone

Time frame: before (8h, 8h45), during (12h, 12h20, 12h30, 12h45) and after exercise (13h15, 13h45; 14h45)

The hormonal regulations involved in the substrate utilization will be assessed thanks to blood samples collected before, during and after exercise.

At each blood collection, the nurses will collect a EDTA tube (5ml) used to assess free fatty acid and glycerol; and 2 heparin ones (2*5ml) to assess 17β-œstradiol, progesterone, triglycerides, cholesterol, HDL-C, LDL-C, glucose, insulin, growth hormone, IGF-I, IGFBP-1, IGFBP-3, adrenaline, noradrenaline, Atrial Natriuretic Peptide, and C-Reactive Protein.

Sponsors and collaborators

Lead sponsor

University Hospital, Clermont-Ferrand

Other

Collaborators

French Federation of Physical Education and Gymnastic (EPGV)

Registry information

Official study title

Impact of Women Hormonal Status (Oral Contraception vs no Contraception) on Substrate Utilization During Exercise

Important dates

Study start: 2010
Primary completion: 2010
Study completion: 2010
First posted: Mar 30, 2010
Registry last updated: Jan 19, 2011

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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Completed