A 60 Days Head Down Tilt Bedrest With Artificial Gravity and Cycling Exercise on 24 Healthy Male (BRACE)

Summary

The objective of this study is to investigate whether a cycling exercise coupled with artificial gravity via a short-arm human centrifuge helps to prevent and / or reduce the deleterious effects induced by 60 days of anti-orthostatic bedrest.

The secondary objective is to investigate whether the combination of a supine cycling exercise with artificial gravity is more effective than the same supine cycling exercise alone in preventing or reducing the effects of head-down bedrest.

During a randomized, 60 day bed rest study, in 24 healthy male adults, the two following aims will be undertaken:

* Fourteen scientific protocols will assess the changes in the cardiovascular, metabolic, musculoskeletal, neuro-sensorial, haematological, and immunological systems.
* In the above-mentioned systems, the comparative potential beneficial effects of the two countermeasure protocols will also be investigated by the scientific protocols and bedrest standard measurements (BSM).

Conditions

• Simulated Microgravity by Head Down Tilt Bedrest
• Weightlessness

Interventions

BEHAVIORAL

Control Group

60 days of strict head down tilt bed rest at all time. No countermeasure program is performed.

BEHAVIORAL

Countermeasure Supine Bike

60 days of strict head down tilt bed rest at all time. The exercise starts at 40% of VO2max for 5 minutes, followed by a series of 2-minute high- and low-intensity intervals for 20 minutes. 2-minute high-intensity intervals are at 65% VO2max, 70% VO2max, 80% VO2max, 80% VO2max, 70% VO2max and 65% VO2max. 2-minute low-intensity intervals are at 40% VO2max. 3 minutes at 40% of VO2max will end the exercise. VO2max is measured for each volunteer in supine position.

BEHAVIORAL

Countermeasure AG-Bike

60 days of strict head down tilt bed rest at all time. The exercise starts at 40% of VO2max for 5 minutes, followed by a series of 2-minute high- and low-intensity intervals for 20 minutes. 2-minute high-intensity intervals are at 65% VO2max, 70% VO2max, 80% VO2max, 80% VO2max, 70% VO2max and 65% VO2max. 2-minute low-intensity intervals are at 40% VO2max. 3 minutes at 40% of VO2max will end the exercise. VO2max is measured for each volunteer in supine position. The supine bike exercise is performed in a short arm centrifuge in rotation. Volunteers will start pedalling and the centrifuge will start at 0.15 Gz less than individual's threshold. Every 4 minutes thereafter, the AG will be increased by 0.15 Gz, synchronized with the ramping up of cycle ergometer interval intensity. The AG will increase only up to 70 % of their tolerance level,. It will then decrease by 0.15 Gz every 4 minutes, and until the 30-minute exercise is completed.

Sponsors & Collaborators

• European Space Agency

  collaborator OTHER

• MEDES - IMPS

  collaborator UNKNOWN

• Centre National d'Etudes Spatiales

  lead OTHER_GOV

Principal Investigators

• Rebecca Billette de Villemeur · MEDES - Institut de Médecine et Physiologie Spatiale

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

20 Years

Max Age

45 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2023-02-06

Primary Completion

2024-04-20

Completion

2026-06-06

Countries

• France

Study Locations