Substrate Utilization and Hormonal Status in Women

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

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.

Study Overview

• Status: Completed
• Conditions: Substrate Utilization

Detailed Description

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.

• Study Type: Observational
• Enrollment (Anticipated): 24

Contacts and Locations

Study Locations

• France
  • Clermont-Ferrand, France, 63003
    • Chu Clermont-Ferrand

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 19 years to 30 years (Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: Female

• Sampling Method: Probability Sample

Study Population

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

Description

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

Study Plan

How is the study designed?

Number of groups / cohorts

2

Cohorts and Interventions

Group / Cohort
12 women with oral contraception
12 women without any contraception

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	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.	during exercise (between 12h and 12h45)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
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	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.	before (8h, 8h45), during (12h, 12h20, 12h30, 12h45) and after exercise (13h15, 13h45; 14h45)

Collaborators and Investigators

• Sponsor: University Hospital, Clermont-Ferrand
• Collaborators: French Federation of Physical Education and Gymnastic (EPGV)
• Investigators: Principal Investigator: Martine DUCLOS, Pr, University Hospital, Clermont-Ferrand

Study record dates

Study Major Dates

• Study Start: February 1, 2010
• Primary Completion (Actual): November 1, 2010
• Study Completion (Actual): November 1, 2010

Study Registration Dates

• First Submitted: February 16, 2010
• First Submitted That Met QC Criteria: March 29, 2010
• First Posted (Estimate): March 30, 2010

Study Record Updates

• Last Update Posted (Estimate): January 19, 2011
• Last Update Submitted That Met QC Criteria: January 18, 2011
• Last Verified: January 1, 2011

More Information

Terms related to this study

• Keywords: Exercise; Women; Substrate utilization; Hormonal status; Women Hormonal Status (with oral contraception or without any contraception)
• Other Study ID Numbers: CHU-0068; AU818 (Other Identifier: CPP)