When to use the reflexive pronouns

Hi everyone, my today's question is when we use the reflexive pronouns on these sentences:

For instance: (Oh, if I'm not asking too much, call you tell me if this use of "For instance" is really right or I have to use "for example")

"A recent survey showed that 58 percent of people do not exercise enough."

"A recent survey showed that 58 percent of people do not exercise themselves enough."

Which one has a more appropriate use?