A heart will have to pump more to move blood above it since the weight of the blood increases. So you might get some people right on the brink getting heart attacks left and right .
I don't think that the collapsing earth core scenario Thomas Ulrich stated is viable. The inner core is iron so its hard to compact and the outer core is fluid so it’s incompressible
But due to extra pressure there might be more rock melting in the outer core impacting the Earth’s magnetic field. Also some rock melting closer to the surface could impact convection currents in the asthenosphere and as a result tectonic plates movements.
At the Earth’s surface some magmatic chambers can collapse and the mountains on top of them too.
I guess the effect of the atmosphere coming closer to the Earth will be compensated by a loss of it due to inertia when the change in orbit takes place.