Space week day 3: Is there gender equality on Mars?

Space travel presents a range of challenges to the human brain, and sex and gender do play roles in how individuals respond to cosmic voyages.

The human brain (on Earth) shows key differences between men and women in structure, neuron development, and chemical pathways, which may affect how astronauts cope with experiences in space.

Space sickness
Spaceflight impacts several critical aspects of vestibular and balance function, including posture and movement control, gaze stabilization, spatial orientation (kind of important in space), susceptibility to space motion sickness, and the vestibular system's role in regulating cardiovascular functions.

The vestibular system, which helps us with balance and spatial orientation, also differs between the sexes. Women have fewer nerve fibers in the vestibular nerve, which might explain their higher risk of dizziness and other balance-related issues in women.

Despite popular belief, recent studies show men and women are equally susceptible to motion sickness in space, though women tend to report vestibular issues more often after returning to Earth.

Neuroinflammation
Females generally exhibit more robust immune responses than males, potentially providing better protection against infections during space missions.

However, this heightened immune defense also correlates with a greater tendency toward autoimmune conditions and neuroinflammation, which requires more comprehensive health monitoring for female astronauts.

There are also differences in how neurons die in men and women, which may be relevant during long missions.

Space brains have reduced fertility
Reproductive health concerns also arise, with both males and females potentially experiencing infertility from short-term exposure to the ionizing radiation i space.

But space travel also directly affects the excreating of the brain hormones that control the sex hormones and thereby the fertility. Changes have been observed in the hypothalamic-pituitary-gonadal axis observed during space travel, potentially affecting sex hormone levels.

The hypothalamic-pituitary-gonadal axis is the body's hormone control system for reproduction. The brain's hypothalamus signals the pituitary gland, which then signal to the gonads (ovaries or testes) to produce sex hormones like estrogen and testosterone.

These hormones regulate puberty, fertility, and reproductive health, with the brain adjusting levels as needed.

Space, memory, and gender
Being a woman, it is no surprise that one notable gender difference is in our memory processing.

Women tend to use the left side of the brain’s amygdala for emotional memories, while men rely on the right. This could affect how each sex remembers and processes emotional experiences in space.

Brain and mental health
Some brain-related conditions, like anxiety, PTSD, and neurodegenerative diseases, also differ in frequency between the sexes.

In space, these differences could influence how male and female astronauts respond to the demanding environment of microgravity and isolation. And having read the blog yesterday about mental health in space, you know it's super important.

Too few female astronauts means too little knowledge
Since very few astronauts so far have been female, very little is known about how space flight affects the sexes differently.

There are many good reasons to increase the number of women in space. One being that if we plan to colonize space at some point, it seems important to know how both women and men respond to prolonged space travel.

About the scientific papers:

First author: Millard F. Reschke, USA
Published in. Journal of Women's Health. November 2014. 
Link to paper: https://www.liebertpub.com/doi/10.1089/jwh.2014.4908

First author: Deborah L. Harm, NASA, USA
Published in: Journal of Applied Physiology
Link to paper: https://journals.physiology.org/doi/full/10.1152/jappl.2001.91.5.2374?rfr_dat=cr_pub++0pubmed&url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org