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NCT Number: NCT06961773

Bone Metabolism in Premenopausal Exercising Women

The main goal of this study is to examine how sex hormones and low energy availability affect the concentrations of bone remodelling markers at rest and after a running protocol. The research questions to be addressed are:

1: Does the ovarian hormone profile influence serum bone marker concentrations in women exercising resting and in response to to exercise?

2. Are there differences in response to low energy availability in bone marker concentrations between eumenorrhoeic female athletes and oral contraceptive users?

3: Is the response of bone markers affected by different exercise stimuli: endurance or aerobic endurance?

4: Do bone markers return to baseline levels after 24 hours of high energy availability diet after 6 days of low energy availability?

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Key information

Conditions

Contraception Bone Metabolism Eumenorrhea Low Energy Availability

Age range

18 year–30 year

Sex eligibility

Female

Study type

Interventional

Phase

Not applicable

Primary location

Faculty of physical activity and sport sciences

Madrid, Comunity of Madrid, 28040, Spain

About this study

To achieve the aim of the study, there will be two experimental groups - e.g. eumenorrhoeic females and oral contraceptive users - who, after screening, will be randomly assigned to a low- or high-energy diet. After 6 days on this diet, the participant will undergo an intervallic running protocol and blood samples will be taken before and after the test. The following month the participant will do the other type of diet.

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Be healthy and between 18 and 30 years old.
  • Engage in endurance sports that involve running (such as athletics, running, triathlon, trail running, etc.) for 3 to 12 hours per week..
  • Eumenorrheic females with regular menstruation at least 6 months prior to the study.
  • Monophasic oral contraceptive users at least 6 months prior to the study.

Exclusion criteria

  • Amenorrheic females.
  • Pregnant females.
  • Affected by any disorder related to the hypothalamo-pituitary-ovarian axis.
  • Having suffered a bone fracture in the year before the study.
  • Taking any medication or supplements that affect bone metabolism.

Treatment and study plan

Low energy availability

Other

Participants follow 6 days of a low-energy availability diet. The kilocalories of each diet are prescribed individually based on their fat-free mass.

High energy availability

Other

Participants follow 6 days of a high-energy availability diet. The kilocalories of each diet are prescribed individually based on their fat-free mass.

Primary outcomes

  1. Concentration of bone metabolism biomarkers

    Time frame: immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise

    Concentration of procollagen type I N-propeptide (P1NP), cross-linking telopeptide of type I collagen (βCTX-1), paratyroid hormone, calcium, sclerostin, osteoprotegin, osteocalcin, bone alkaline phospatase, Receptor Activator for Nuclear Factor κ B Ligand (RANKL) measured in serum samples.

  2. Concentrations of other biochemical biomarkers

    Time frame: Immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise

    Concentrations of Triiodothyronine (T3), Albumin, Sex Hormone Binding Globulin (SHBG), etc. measured in serum

  3. Concentrations of sex hormones

    Time frame: Immediately pre-exercise and immediately, 15 minutes and 24 hours post-exercise

    Concentrations of 17β-Oestradiol and Progesterone measured in serum.

  4. Bone mineral density

    Time frame: At the screening phase

    Total, lumbar spine and femoral neck bone mineral density (g/cm^2) measured by dual x-ray absorptiometry

Secondary outcomes

  1. Training status variables

    Time frame: At the screening phase

    Oxygen uptake at ventilatory threshold 1, ventilatory threshold 2, and maximal oxygen uptake (ml/kg/min) measured with a gas analyser.

  2. Body composition variables

    Time frame: Immediately pre- and post-nutritional intervention (bioimpedance) and DXA at the screening

    Fat mass (kg), fat free mass (kg), fat mass percentage, fat-free mass percentage (FFM), total mass (kg) measured by dual x-ray absorptiometry

  3. Body metrics

    Time frame: Measured at the screening phase

    Height (cm)

Sponsors and collaborators

Lead sponsor

Universidad Politecnica de Madrid

Other

Registry information

Official study title

Bone Metabolism in Exercising WOMEN: Influence of Low Energy Availability and Sex Hormone Fluctuations

Acronym: BeWOMEN

Important dates

Study start
2024
Primary completion
2025
Study completion
2026
First posted
May 8, 2025
Registry last updated
May 8, 2025

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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