TMZ spoke to a handful of high-end personal trainers in and around the L.A. area -- and they all say they're going to keep working one way or another ... to keep themselves financially afloat, obviously, but mostly for the health and wellness of their clients who need it most.

Fact is ... while some people can afford to take the next few weeks off their gym game, we're told several others simply cannot -- for health-related reasons and otherwise. The trainers we spoke with say many of their clients MUST keep working out, and to meet the demand amid mass shutdowns throughout California, speakeasy gyms are becoming the go-to locale.

It's not as seedy or clandestine as it might sound. Basically, we're told a lot of these trainers -- who work with very affluent people, BTW -- have access to studio gyms ... which are way smaller than your run-of-the-mill LA Fitness joint. It's more intimate and personal, and can normally accommodate 4 to 5 people max at a time, trainers included.

Other trainers are making house calls, while some bigger names are actually making people come to them ... like celeb trainer Mike O'Hearn, who tells TMZ his own clientele is swinging by his pad for their regular 1-on-1 services. He says he's got a home gym, which is fully equipped and constantly being cleaned and sanitized to avoid any risks.

That said, Mike tells us he's encouraging people that are actually feeling ill to stay home. But, if not, he thinks exercise is a good way to keep the immune system strong in these contagious times.

When there's a will ... there's a way to break a sweat.