You need oxidants to live. Issues stemming from oxidants are about levels of free radicals getting too high in the wrong places for too long.
Getting good sleep, eating a balanced diet, reducing stress, and getting enough exercise are the best ways to reduce the chances of such a scenario. Realistically, these things are also just a way to maximize wellness and health overall and it is probably not very useful for most people to think of this in terms of oxidation.
Oxidative stress happens every time you exercise. People need exercise to have better health. Oxidative stress is actually a necessary part of a healthy life.
If aliens exist they would probably have many things just as strange. They would also need a way to harvest energy via some cycle. It is possible they would require even more reactive substances to live.
When we and other known organisms take energy from food we are actually taking molecules with higher-energy electrons, converting them into the high-energy molecules our cellular processes can use to do make cell things happen, and producing very similar molecules with lower-energy electrons. Rather than infinitely accumulating these molecules, our cells dump low-energy electrons onto another molecule that is amenable and thereby convert into a molecule ready to accept high-energy molecules from food (with a bunch of steps in between).
For us, as aerobes, the electron acceptor at the end of respiration is oxygen.
Oxygen as an electron receptor is newer than several others. Anaerobes came first. It was only after photosynthesis had produced a ton of atmospheric oxygen that it became a viable option, really. But it O2 is a comparatively good electron acceptor because the process in which it accepts those electrons allows cells to grab quite a bit of energy from that last step. It is fairly “electron needy” compared to earlier electron acceptors.
So, basically, aerobes get more energy per food unit (sugar molecule) than the vast majority of other creatures. You need it to live because it is an essential part of how your cells get food, namely, how it can recycle molecules at the last step of the respiration cycle.
The dietary antioxidant fad is mostly BS. They’re supposedly meant to counteract oxidative stress and specifically free radicals. Both of those things are part of a healthy life and you would die without them. So any real impact is not so simple as “just counteract those bad things”. Dietary antioxidants don’t always lead to higher intracellular antioxidant levels, either.
Some dietary antioxidants so lead to higher intracellular levels and may help buffer oxidative stress (like from exercise) but there isn’t much evidence that it doesn’t just boil down to “eating your vegetables is good for you”.
I think they more commonly say, “what is wrong with my advisor and why did I choose grad school?”
Peak performance