From: joerogan
The experience of space travel offers unique insights into the incredible adaptability of the human body but also presents significant challenges. From bone density loss to the heaviness felt upon return to Earth, space travel affects astronauts in numerous ways.
Muscle and Bone Loss
During extended periods in space, astronauts were historically known to lose up to 1% of bone density per month. This was the situation on missions in 2008, as noted by an astronaut who experienced this firsthand during his 95-day stay in space [00:01:58]. However, thanks to advances in workout technology and exercise regimens, modern astronauts can return with negligible losses in bone and muscle mass. The introduction of resistive exercises, particularly those focusing on high load and low reps, has proven effective in countering these issues [00:02:51].
Vestibular System and Muscle Atrophy
Upon returning to Earth, astronauts often struggle with movement and balance because their vestibular system, which assists in maintaining balance and spatial orientation, is significantly affected by microgravity [00:01:29]. Muscle atrophy, particularly in the legs and postural muscles, occurs since they aren’t used in the absence of gravity. Astronauts in space predominantly use their arms for movement, which emphasizes the need for specific workout routines to stimulate bone and muscle activity in the lower body [00:08:03].
Fluid Shift and Congestion
Another phenomenon experienced in space is fluid shift, where body fluids move upward due to the absence of gravity. This can cause congestion, impacting senses such as taste and smell, and results in facial puffiness, often described as the sensation of being upside down [00:10:16]. The changes in fluid distribution can lead to feelings similar to having a cold, which is why astronauts consume food with strong flavors, like hot sauces, to accommodate reduced taste sensitivity [00:11:00].
The Psychological Impact
Space also has psychological impacts, including what some refer to as “space brain,” a slight deficit in short-term memory encountered by some astronauts [00:08:26]. The overview effect, a cognitive shift in awareness, emphasizes the unity and fragility of Earth as seen from space. This realization encourages a perspective of global cooperation and unity [00:15:03].
Mitigating Adverse Effects
To mitigate these effects, astronauts engage in a rigorous 2-hour daily exercise regime, focusing on exercises that maintain muscle mass and bone density [00:04:18]. Advancements in spacecraft design, like providing better equipment for effective workouts, have increased the likelihood of maintaining astronaut health during long-duration missions.
Countermeasures and Exercise Regimens
A combination of high-load, low-rep resistive exercises and improved spacecraft design enhances countermeasures against bone density and muscle mass loss [00:02:53].
Understanding these effects is crucial as humanity continues to explore deeper into space, potentially leading toward long-term missions to places like Mars and developing sustainable living conditions in space .