Loving your parents can IMPACT you at work, at home, and in your soul. The last sounds dramatic, but it's true.
WORK
You think about your folks at work, not a good idea since you're being paid by your employer to give your full attention to them. But it's hard NOT to think about your parents if their health is declining. The best advice is to compartmentalize the different areas of your life. Put work in its own box and when you're there, be fully present.
Just like with children, if the school calls and they're sick and you have to go take care of them, that doesn't look good to your supervisor, unless you have a really understanding supervisor. Maybe once or twice, the office will tolerate it, but not likely on a continuing basis.
Same with your folks. If they are on their own, do your best to stay in contact with them only on your lunch break. Ask them not to call you unless it's an emergency, and let them know when you will call them. Then call. Keep the commitment.
If Mom or Dad lives with you and you have a caregiver looking after them, give the caregiver the same instructions. After all, you're paying the caregiver to be you in your place while you work.
Find someone who is responsible to take that burden from you so that you can give your best at the office. If you start having problems at work because of caring for your parents, you will make things worse for yourself and your family, and you have to protect yourself.
Caring for your parents does not entail becoming a slave to them or giving up your life and all you have built to date. If you sacrifice yourself in the process, you will only end up resenting your parents and the situation "they" have put you in, and you will be no good for yourself or for them.
Work through the challenges to give all you can without sacrificing yourself. It's not easy, but it's worth the planning and boundary-keeping -- for your and your loved ones.