What can a team do when one coworker is doing the work of 4–5 people?

One coworker on our team is consistently handling what looks like the workload of 4–5 people, despite being paid the same as the rest of us.

As far as I can tell, management isn't explicitly forcing her to do all of this. She seems to take on a lot herself and keeps getting everything done.

I'm worried about two things:

1. I'm genuinely concerned she's going to burn herself out.
2. Her output may eventually become the benchmark management uses for everyone else: “She can handle this much, so why can't you?”

I don't want to blame or attack her. She's obviously making her own choices, and I don't think it's our place to tell her how much she should work.

My question is specifically:

What can we, as coworkers, do about this without involving management?

I'm interested in hearing from people who have actually been in this situation. What worked, and what made it worse?