It’s one of the most common conditions in the country — but no matter how many times your doctor has seen it, he still doesn’t know the first thing about treating it.

Some 80 percent of us have or will face back pain, and if you’ve “been there, done that” with your own doc, you know the drill. He’ll make a few sympathetic noises, and then prescribe painkillers and steroids.

If that didn’t work for you, you’re not alone — because neither the drugs nor the steroids will actually correct the problems that caused your back to bark in the first place.

And now, a new study confirms what you learned the hard way: Steroids simply don’t work at all for back pain.

Researchers randomly assigned 84 patients who had battled sciatica for at least a month to injections of either steroids, the arthritis drug etanercept, or plain old saline solution in two sessions, two weeks apart.

After a month, those who got the drugs — either one — improved. That might sound good… until you see that the patients who got the saline solution also improved.

In fact, while patients who took steroids got a little more short-term relief, in the end there were no statistical differences between patients in any of the three groups.

In other words, simple saline matched drugs that cost $500 to $700 per treatment.

Obviously, no one is going to run out and get saline injections. And I’m sure patients (or their insurers) will continue to shell out big money for the drugs anyway.

Some will get better on their own and think it was the drugs. Others will get worse and end up with a referral to a surgeon.

But you don’t have to go down that road. You can get real relief starting today, and all it takes is a little more movement.

The researchers behind the new study concluded that ordinary exercise is still the most effective way to beat back pain — and I’ve found that stretching exercises in particular work well for many people.

If you need a little more immediate help, don’t turn to painkillers. Turn to a natural anti-inflammatory proven to ease pain, such as MSM, bromelain, and turmeric or a non-drug treatment such as cold laser, chiropractic, acupuncture, and massage therapy.

Videogames are often blamed for everything wrong with kids today — but in most cases, they get a bum rap.

Believe it or not, videogames can be an enriching, engaging, and even productive way to pass the time — and as I’ll tell you later in the week, some games might even slash the dementia risk in seniors.

But there’s one thing videogames can’t do. They can’t help you lose weight, and that includes games that require movement, like Nintendo’s Wii Fit.

In a new study, 84 overweight kids were randomly assigned to either a Nintendo Wii with Wii Fit games that require active play — like sports and dancing — or a Nintendo Wii with a more traditional game that can be played in the usual couch potato position.

The kids also wore accelerometers to measure total daily activity, which 13 weeks later revealed virtually no difference at all between the two groups, according to the study in Pediatrics.

The kids who played Wii Fit got between 25 and 28 minutes of moderate to vigorous physical activity a day, while the kids who played less active games got between 26 and 29 minutes a day — both a far cry from the hour or so kids should spend engaged in active play each day.

The researchers say they’re not sure if the movements of Wii Fit were so minimal that the accelerometers didn’t pick them up, or if the kids balanced out their Wii Fit sessions by spending less time engaged in other forms of physical activity.

Either way, the results speak for themselves: No one’s getting fit off Wii Fit.

Surprised? Don’t be — one of the company’s own studies found that many Wii Fit games don’t even reach the levels of exercise achieved by ordinary walking.

Another study found that 10 minutes of Wii Fit burned just 25 calories — less than cleaning or vacuuming, and a fraction of what you can burn in 10 minutes of running on a treadmill.

That’s not to say you need to slave away in a gym — or even on a treadmill — to lose weight and stay fit.

You don’t.

But you do need to get out and get moving, whether it’s a brisk walk through the local park, a daily “workout” in your garden or a regular tennis habit.

And by that, I mean “real” tennis… not the one in Wii Sports.

Nearly two years ago, an FDA panel rejected the Qnexa diet pill over safety concerns.

Now, that same panel has given the drug the OK, which means the agency itself will almost certainly approve it for sale soon.

But don’t be fooled by this about-face, because the drug hasn’t magically gotten any safer over the last two years.

Qnexa still comes with all the same potential risks that caused the panel to think twice back in 2010: birth defects, suicidal thoughts, depression, memory loss, attention problems, bone problems, kidney stones, and more.

Even worse, the drug can increase heart rate and cause heart palpitations — and the panelists who approved it admit they don’t know if those side effects will lead to heart attacks and other cardiovascular problems down the road.

But they went ahead and approved it anyway.

“The potential benefits of this medication seem to trump the side effects, but in truth, only time will tell,” Dr. Kenneth Burman of the Washington Hospital Center confessed to Time magazine.

Allow me to translate:

“It could help people lose a bunch of weight, and it could well kill a whole bunch of people at the same time. Let’s find out, shall we?”

I say let’s not — because if this drug’s history is any indication, its widespread use will lead to more problems than this panel is letting on.

Qnexa isn’t a new drug — it’s actually a combination of two older drugs: the amphetamine phentermine, better known as the “phen” in fen-phen (yes, THAT fen-phen), and the seizure drug topiramate.

It’s more of a side-effect cocktail than an actual drug — so much so that 40 percent of the people who took the high dose in a company-funded trial had to drop out.

Many of those who stuck with it were rewarded with weight loss of close to 10 percent of their body weight. But 10 percent for an obese person isn’t an achievement. It’s someone who’s just a little less obese — and it took them a full year to get there to boot.

What’s more, patients who take the drug still have to make diet and lifestyle changes and get more exercise. And if you have to do all that to get thin, why bother messing around with drugs like Qnexa in the first place?

Skip the meds and eat better instead.

Try a low-carb or Mediterranean-style diet, and the pounds will melt away as if by magic — and you’ll soon find yourself reaching in the back of your closet for clothes you never thought you’d wear again.

It almost sounds like the benefits of some promising new blockbuster drug: Just a little bit can help lift mood, concentration and energy levels — with virtually no side effects.

Well, there is one side effect: You might need to pee a little more.

Of course, this isn’t some experimental new drug — just plain old water, and new research shows how letting yourself run dry can throw your whole day out of whack.

In a set of three experiments, 25 healthy young women were given either enough H20 to keep hydrated or brought just below their optimal levels with exercise and diuretics.

By “just below” I mean really just below — they were missing only between 1 and 2 percent of their needed water. But those small changes led to big differences as these women suffered from measurable dips in mood and focus and were more likely to feel fatigue and suffer headaches.

Although the study didn’t look at men, there’s no reason to think mild dehydration would affect them any differently.

In other words, you need your water — but don’t get carried away.

You know the old saying about drinking eight 8-ounce glasses a day? Forget it. It’s never been proven by science (although the bottled water companies would like you to think otherwise).

In fact, too much water can be even worse for you than too little.

The only time you need to whet your whistle is when you feel thirsty — and despite what you’ve heard, it doesn’t have to be plain old water.

Coffee and tea, for example, are just fine. Both of them are mildly diuretic, but they’ll still leave you with a net gain of water and keep you hydrated.

Just one warning here: Water may not be a drug on its own… but there’s a good chance there are drugs in your water.

U.S. water standards are plunging like a barrel over Niagara Falls. Hormones, sex meds, antibiotics and more are regularly turning up in our drinking water — and in some places, you can add illegal drugs, rocket fuel and toxic waste to the list.

Even in trace amounts, do you really want to drink that?

Drink only filtered water. You don’t have to shell out big money on bottled year after year if you invest in a quality reverse osmosis system for your home.