It really depends whether or not by "sacrifice" someone is just saying "opportunity costs." There are trade offs in all actions/inactions.
Also, isn't literally every sacrifice just an opportunity cost? That kinda what makes it a sacrifice. Sacrifice your first born and give up the extra productivity possible. Sacrifice a lucrative but over taxing job and lose out on the money. Sacrifice a meal for someone and you go hungry. Sacrifice is always about the opportunity cost of the thing you're sacrificing. If it doesn't hurt, if it doesn't cost you something, it's not a sacrifice.
e.g. if you overtrain or don’t wait long enough after an injury, you may permanently damage something forever. Speaking from personal experience and knowing a lot of people who have done the same. There’s also some documentaries about athletes doing it and losing it all. Go the extra mile but don’t look back and have regret about that one time.
And since "important" is relative to the person making the sacrifice, it's easy for a person to declare something a sacrifice when what they were giving up was not especially important to them, or on the other hand for someone to dismiss a "real sacrifice" that someone else has made as unimportant.
Not that this matters, really. But I think it's important not to use them synonymously. In the case of an opportunity cost, you are acknowledging that there were things given up. In the case of a sacrifice, you are saying there were things given up _and it hurt_.