One of the struggles in grad school is the 30 minute conundrum. Think of all the activities you have to choose from that, if you just invested 30 minutes a day, would improve your productivity, foster your self image, and win with war for the allies.
Well, here’s an interesting study by Charles Emery and colleagues that went like this. When older, sedentary folks were given a small skin injury, half were assigned an exercise regime of 1 hour, 3 times a week. The couch potato controls healed, on average, in 39 days; the new exercizers healed 10 days earlier.
You have only one body. Exercise and good diet is the way you take care of it.
Just do it.