Depression, mood state, and back pain during microgravity simulated by bed rest.

Area of Science:

• Space physiology
• Human adaptation to microgravity
• Psychosomatic responses

Background:

• Microgravity poses significant challenges to human physiology, including spinal adaptation and psychological well-being.
• Developing accurate ground-based models is crucial for understanding and mitigating these effects.
• Previous models have limitations in replicating the full spectrum of microgravity-induced changes.

Purpose of the Study:

• To develop and validate a ground-based model simulating spinal adaptation to microgravity.
• To investigate the impact of this simulated microgravity on pain intensity, mood state, and depression.
• To compare the efficacy of different bed rest configurations in mimicking spaceflight conditions.

Main Methods:

• Six subjects underwent two 3-day bed rest protocols: 6-degree head-down tilt with balanced traction and horizontal bed rest.
• A 2-week recovery period separated the protocols.
• Pain intensity (lower back, abdomen, headache, legs), depression (Beck Depression Inventory), and mood (Bond-Lader questionnaire) were assessed.

Main Results:

• Head-down tilt bed rest significantly increased lower back pain, abdominal pain, headache, and leg pain.
• Subjects reported higher depression scores and lower activity levels during head-down tilt compared to horizontal bed rest.
• The Beck Depression Inventory and Bond-Lader questionnaire scores indicated significant mood alterations.

Conclusions:

• 6-degree head-down tilt bed rest with balanced traction serves as a superior model for inducing pain and psychosomatic reactions associated with microgravity.
• This model effectively simulates low back pain, mood disturbances, and altered self-rated activity levels.
• Findings support the utility of head-down tilt bed rest in spaceflight analog research.