From: veritasium
Traveling to and living on other celestial bodies like Mars presents significant challenges to human health, particularly concerning exercise and maintaining physical well-being in altered gravitational fields [00:01:31].
Gravitational Differences
The gravity on Mars is approximately 37% of Earth’s gravity [00:00:48]. This reduced gravity would allow an average jumper to achieve double the airtime compared to Earth, making it easy to dunk on a regulation basketball hoop [00:01:04]. The Moon’s gravity is even lower, at about 1/6 of Earth’s, enabling extensive “crazy aerobics” without quick exhaustion [00:01:19].
Effects on the Body
The primary concern in low-gravity environments is the weakening and shrinking of muscles, known as atrophy [00:01:53]. Studies indicate that muscle mass can decrease by up to 20% on space flights lasting only 5 to 11 days [00:01:58]. On Earth, simply lifting an arm provides a minor workout because the arm accounts for about 5% of body weight [00:01:39]. This resistance is absent during a trip to Mars and only a fraction of it is present on the Martian surface [00:01:46].
Furthermore, the lack of weight pushing on bones leads to a decrease in bone density [00:02:24]. Astronauts can lose 1-2% of bone mass per month, predominantly in their lower extremities [00:02:30]. This rate of bone loss is more than ten times faster than that experienced by people on Earth due to osteoporosis as they age [00:02:33].
Other Difficulties
In weightless conditions, even everyday activities become challenging due to the significance of other forces, such as the surface tension of water [00:02:41]. Washing one’s face, showering, brushing teeth, and using the bathroom become much harder when dealing with liquids in microgravity [00:03:09].
Bodies are not evolved for these different gravity situations, which can lead to nausea [00:06:36].
Exercise and Mitigation Strategies
Since traditional weightlifting is ineffective in low gravity [00:02:09], astronauts rely on elastic resistance [00:02:12]. For example, astronauts on the space station are elastically tethered to a treadmill and typically exercise two and a half hours every day to combat muscle and bone loss [00:02:14].
For future colonists on Mars, simply stepping into a spacesuit, which can weigh as much as 310 pounds, would make them feel as heavy as they are on Earth [00:06:05]. This added weight from the spacesuit could help maintain muscle and bone mass [00:06:19].
While radiation is a separate concern, shielding is possible through materials like ship insulation or water, which is an excellent radiation absorber [00:06:23].
These difficulties are considered challenges to be overcome for humanity to become a multi-planetary species [00:05:51].