“When all is said and done, more is said than done.”

It’s certainly a witty one-liner, but is what legendary Notre Dame football coach Lou Holtz once said and then - in his inimitable fashion - said again and again and again really true? I’m not sure how you’ll answer, but I’m torn between “Unfortunately” and “Of course.”

It’s those two answers to a large extent that determine what you read every week in this column. Articles that suggest ways to make Holtz’s infamous adage false for you and improve your health.

Besides a boatload of success at ND, Lou Holtz is the lone college football coach to lead six different schools to bowl games as well as the only one to place four different schools in the final top-20 rankings. The only acting he has ever done, though, occurred in a Discover Card commercial a dozen years ago.

Which means he’s not the actor referred to in the title - and that it’s time to explain who is.

He’s somebody I’m told everyone knows. Everyone, that is, except me.

The first time I knowingly laid eyes on Chris Hemsworth was not in one of the several Marvel Cinematic Universe movies where he portrays Thor or any of the other 13 movies listed by Fandango in his filmography. But when I clicked on a WebMD article about Alzheimer’s disease written by Batya Swift Yasgur, MA, there Hemsworth was at what appeared to be a press conference.

The article explains that the 39-year-old Aussie has decided to take a break from acting upon learning about a potentially bad one. Because he took a series of genetic tests as part of Limitless, a National Geographic docuseries available at Disney+, Hemsworth now knows he has two copies of the APOE4 gene (one from each of his parents).

That statistically increases the risk that he eventually develops the disease that would frighten even the most fearless movie superhero.

Now I’m not a geneticist. And I don’t know that much about heredity and the potential variations of inherited characteristics.

But I am an optimist, one that’s pretty good at plucking out the positivity in whatever I’m reading.

So I can find solace in the aforementioned WebMD article despite the fact it calls having two copies of the APOE4 gene one of the most significant genetic risk factors for getting Alzheimer’s disease. Or that it increases a person’s risk of it by about 15 percent, and “people with two copies may start having symptoms 10 years earlier than the average person [who develops Alzheimer’s].”

The solace comes from Howard Fillit, MD, co-founder and chief science officer at the Alzheimer’s Drug Discovery Foundation because he stresses your genes are not your destiny.

Uma Naidoo, MD, director of nutritional and lifestyle psychiatry at Massachusetts General Hospital in Boston, says just about the same. “Our genes may influence our risk of developing a certain condition,” but those genes can be “turned on” or “turned off.”

And just as often as not, the control switch gets flipped either way by how you live your life.

For instance, the Lancet Commission on Dementia Prevention, Intervention, and Care has identified “12 changeable risk factors” that increase the odds of Alzheimer’s disease. The commission, in fact, believes they play a role in 40 percent of all cases of all forms of dementia.

By my count, having exercise play a central role in your lifestyle reduces the inherent risk in half of them.

That’s because serious exercisers aren’t going to smoke, consume excessive amounts of alcohol, or eat so much or so poorly they develop type 2 diabetes or obesity. They’ll probably avoid the other health problems linked to physical inactivity as well - including depression since so many forms of exercise also increase social activity.

While it would seem too obvious to say that by exercising seriously you are significantly increasing the odds the Alzheimer’s switch in your DNA never gets flipped on, any mention of DNA serves as a suitable segue, so I’ll do so. Because it’s already possible you feel exercising is such a part of you that - in a manner of speaking and a rather-hard-to-explain way - it’s in your DNA.

I know I do.

But I also feel something else, something just as hard to explain. That somewhere inside all of us there’s not a switch but an exercise “dial.”

Years ago, for instance, I got significantly better as a cyclist by imitating a guy on our weekend training rides who was totally out of my league. A local legend. A former pro. A guy who cycling genes were certainly superior to mine.

After weeks and weeks of not riding any harder or farther but simply imitating him, however, I felt a change. I was getting more speed out of the same effort.

It was as if I had found the exercise dial and adjusted the setting.

Why not see if you can find yours the next few times you exercise?