I find your two quoted lines as vastly different. The first is accurate and the second is not. Synchronized means to happen at the same time. For a rate to be synchronized, I expect the same rate value at the same time (each person at say 65bpm). If the rate change is in sync, I expect the same rate of change value for each person (everyone is slowing their heart rate at 2bpm per minute). In unison means at the same time (but not the same value).

One headline means we are excited at the same time, the other says we mysteriously communicate the state of our heart to our neighbors.

Edit; a concrete example. Let's synchronize watches, you move yours forward quickly and I'll move mine forward quickly. Even though we moved in unison, we are not synchronized and showing the same time together.

A headline which gives people the wrong impression is still misinformation. It makes the world less informed than before, as people rarely read articles after reading the headlines.

Edit: And it is super important to point out this misinformation in the top comment to an article, so that we can correct as many people as possible. So stating that this is misinformation isn't just some pedantic complaining, it helps correct the view of a lot of people and maybe will help make more people think a bit before writing headlines.

It's the same difference as if two cars were told to "synchronise speeds" (rates) and instead they synchronised accelerations (rates of change).