Docs get so hung up on matching the numbers on patients’ charts to mainstream guidelines that they often forget these things are written on paper — not set in stone.

But in addition to being meaningless, many of those targets are actually dangerous — and quite possibly deadly.

Case in point: blood pressure.

The guidelines are often meaningless to healthy people, and a new study shows how they could be dangerous and even deadly for stroke victims — because meeting those targets could actually boost the odds of another stroke.

Researchers reviewing data on more than 20,000 stroke patients found that those who had systolic readings — that’s the top number — of below 120 had a higher risk of second stroke than people who were between 130 and 140.

To put that into perspective, below 120 is right on target — at least as far as the mainstream is concerned, and there’s even talk of lowering that target to 115. Meanwhile, 130-140 is considered “prehypertension” — and many docs now prescribe BP meds for people in this range.

What’s more, patients who had the technically perfect systolic reading of under 120 had only an ever-so-slight decrease in the risk of another stroke when compared to patients with readings between 140 and 150.

That’s flat-out hypertension, at least if you’re following guidelines. And if that’s not the surest sign we’ve gone overboard with all this worry over blood pressure, I don’t know what is.

The researchers behind the new study aren’t quite ready to abandon those guidelines — they suggest waiting six months after a stroke to lower BP levels.

But why bother, especially in borderline cases? In addition to being harmful to stroke victims, studies have shown there’s not much benefit for healthy people.

One study earlier this year found the entire prehypertension category — systolic readings between 120 and 140 — to be essentially meaningless. Patients under the age of 50 didn’t face any increased heart risk until their systolic numbers topped 200 — while the over-50 crowd didn’t see increased risk until they reached 140.

Read more about that here.

So forget 120 and don’t even think about 115 — those numbers may have succeeded in getting more people onto BP meds, but they haven’t succeeded in saving lives.

Next time your doctor says “cut back on the salt, or else” ask him one question.

Or else what?

He’ll tell you how all that salt is responsible for the high blood pressure that leads to heart disease. But if you’ve tried to cut back on salt, then you already know how well it works — not at all.

It’s not just you.

A low-salt diet is actually scientifically proven to have little to no impact on your BP levels, and a new study confirms it: Researchers in Europe say cutting back on sodium trims just 1 percent off a healthy person’s BP levels, and 3.5 percent off those of someone battling hypertension.

And in exchange for those meaningless dips in blood pressure, patients who stuck to the low-salt lifestyle saw a 7 percent surge in deadly triglycerides and a 2.5 percent overall boost in cholesterol levels.

In other words, if your BP spikes a little and your doc tells you to stick to a low-salt diet to avoid hypertension meds, he’ll almost certainly end up giving you those meds anyway — and a statin to boot.

Consider that a bonus.

If this was the first study of its kind, it would be easy to be a little skeptical — and there’s absolutely nothing wrong with being skeptical. But it’s not — and it’s not the second or third study either.

In fact, it’s the fourth study just this year to find no benefit to a low-salt diet — not to mention the dozens of other studies that have reached the same conclusion over the years.

If you’re concerned about blood pressure, forget about salt. Cut back on sugar instead — because the research on this has been remarkably consistent: People who consume the most sugar have the highest blood pressure levels.

That’s why one of the most immediate benefits of a low-carb diet is a swift reduction in blood pressure.

Once you get the sugar out, don’t focus on salt so much as your salt-to-potassium ratio. Thanks to processed foods, most people get more salt than potassium. In reality, you should get about three times as much potassium as salt.

Make those two changes, and you can hit the saltshaker to your heart’s content — and never have to worry about your BP levels again.

You don’t need to hunt wooly mammoths to be a “caveman” these days. In fact, you don’t even need a cave.

The “caveman” diet is more about what you eat than where you live — and if you can stick to a 100-percent natural lifestyle of fresh meats and vegetables with no processed foods, congratulations.

You’re officially a caveman.

It’s hard to find anything wrong with this diet, and science now confirms what should have been obvious all along: Eating only fresh foods can help put you in the best shape of your life and slash your risk of illness and disease.

Researchers at the University of California San Francisco asked a group of unhealthy people to stick to a “caveman” diet high in healthy fats and proteins from meats, fish, and nuts as well as generous amounts of fresh fruits and veggies.

After just two weeks, everyone’s blood pressure and cholesterol levels plunged — with triglycerides alone falling by an average of 30 points.

“That’s the kind of drop you get by taking statins for six months,” Dr. Linda Frasettom, who led the research, told Medical News Today.

I’d almost agree — except statins come with a risk of severe muscle pain, liver problems and kidney damage. A diet of fresh natural foods will do none of those things to you.

Statins can even increase your risk of diabetes — but a diet with no added sugars and zero processed foods will practically guarantee that you’ll never get the disease.

Dr. Robert Lustig, an endocrinologist at the university, says diabetics who’ve tried this back-to-basics approach have seen a reversal of the condition — and some have actually been cured.

That’s right. The “c” word — and while most of the media is of course only too happy to trash the diet and even mock the people who follow it, one reporter got an up-close and highly personal look at just how well it works.

Dr. Kim Mulvihill of the CBS station in San Francisco had been battling a weight problem and pre-diabetes when she volunteered for the UCSF study. In just 10 days, she saw dramatic changes to her cholesterol, blood pressure and blood sugar levels as well as a boost in energy.

She eventually lost 30 pounds, and after seven weeks was no longer considered a pre-diabetic — causing her own doctors to tell her to stick to the diet permanently.

If you’re facing your own battle with disease — or simply want to avoid ever having to worry about one — maybe it’s time to go caveman yourself.

You might think the only “exercise” you’ll get from drinking wine comes from lifting the glass — or maybe struggling to open the bottle.

But it turns out resveratrol, the famous “red wine antioxidant,” can actually trick the body into thinking it’s getting some actual exercise — giving you a big-time metabolic boost with every little sip.

In just 30 days, 11 obese-but-healthy volunteers — as healthy as obese people can be, anyway — given 150 mg of resveratrol a day had real and measurable changes throughout their bodies.

They shaved five points off their blood pressure, lowered their blood sugar, and even reduced their levels of liver fat. In fact, just about the only thing it didn’t do would be one thing you’d really hope for the most — because none of the volunteers actually lost any weight.

I know. So much for the “red wine diet.”

But while they didn’t look any different from the outside, what took place on the inside was nothing short of amazing: The researchers wrote in Cell Metabolism that the volunteers had dramatically slower metabolisms during sleep.

These were the kinds of changes normally seen in people who try the impossible-to-follow ultra-low calorie diet… except these volunteers didn’t cut back on their calories at all.

The only “catch” here is that you can’t expect to get these types of benefits from red wine alone — because while it might be the tastiest way to get the antioxidant, it’s not actually the best way to get it.

In fact, you’d need between 50 and 100 glasses of red wine a day to get the 150 mg of resveratrol used in the study!

So clearly, if you want the benefits of resveratrol, you’re going to have to invest in a quality supplement or an antioxidant blend with resveratrol in it. It’s worth the money: Other studies have shown that it can protect the heart, save your vision, reduce blood sugar levels and even help you live longer.

But don’t toss the wine, either. It’s loaded with polyphenols that can boost your heart health and stimulate your immune system.

And booze in general is packed with benefits: Studies have also shown that moderate drinkers who enjoy any type of alcohol live longer, healthier lives than people who don’t drink.

So get a little exercise tonight and raise a glass to your lips. It’s the best workout of all.

Resveratrol isn’t the only way to boost your health and longevity — keep reading for something even simpler.