So, a human would travel in a rocket in outer space. There is little to no gravity, and the pressure may or may not have an affect (?) on what i'm about to ask. It has been proven that when a human flies in space, they age slower than they would on earth. I know that time is slowed when the speed of light is approached, and time is also sped up when your closer to or touching an object with a large mass, such as Earth. Humans were never meant to travel at the speeds that we can on Earth with the use of cars, planes, etc. The vehicles we use have a large range of speeds.Does us traveling at the speeds we achieve on a daily basis, such as 60-90+ mph, have a long-term affect on how we age?
If you spent 80 years driving around at 60 miles per hour, you would age 10 microseconds less than someone who didn't. You can compute this from the time dilation factor
If it did, it would be so minuscule that it would be unnoticeable.
Time will not speed up if you are close to a large body, it will actually slow down. (The bigger the mass, the more time slows down. Why is this?)
Something that many people do not take a count of, is that cosmic rays age astronauts when they exit the atmosphere. Cosmic rays strike astronaut cells damaging their DNA leading to the astronauts "aging" prematurely.