On the morning of my 40th birthday, I saw a TV commercial targeted at men my age. Of course, it didn't look like a commercial at first; it could have passed for a government-issued public service announcement. The commercial warned about the perils of "low T," aka low testosterone, as if hitting the big four-oh was doomsday for your manhood.

I could have been frightened or offended, but I realized that the purpose of the commercial was simply to sell me a product. With ads like these becoming more common and better-produced all the time, it's no wonder so many Americans over 40 assume they have no choice but to deteriorate with age.

But you do have a choice—and more than that, you have an opportunity. Ask anyone who has successfully achieved the best shape of their life after the age of 40, and they'll tell you it's more satisfying than it ever was at age 30.

Yet it's also trickier to achieve.

I said tricky—not impossible. You can do this, but you'll have to take it more seriously than you did as a 17-year-old metabolic furnace that could run on the No. 4 at Taco Bell as easily as it could on clean food. Start by following these principles and working hard, and soon enough you'll be able to out-lift and out-run your younger self.

DANNY'S DO'S FOR OVER-40 FITNESS

1 Do keep your workouts simple

Many folks from my generation were taught to train according to a strict split routine, oftentimes isolating one or two body parts a day. While that is a great way of training, it's not the only way. And once you hit 40, it's also harder than ever to maintain. Get behind on your super-precise program, and it can be hard to catch up—a surefire recipe for skipped workouts and disappointment. That's just one reason among many why I'm increasingly fond of full-body training and movements.

To start, focus on building proficiency in the basics like squats, push-ups and pull-ups. There's no reason to overcomplicate things. Trends come and go, but these exercises are the foundation of most strength training. Soon enough, you can certainly add other exercises like lunges, rows, and dips. Throw in some ab flexion and back extension, and that's all you really need.

For the past several years, I've done nothing but bodyweight variations of these classics to get in by far the best shape of my life at 40. Trust me; it can be done!

2 Do work hard

If an exercise doesn't feel strenuous, it isn't. In life and fitness, lasting results almost never come without hard work. Sweat, muscular soreness, and an accelerated heart rate are all necessary parts of the game. It's not supposed to be effortless!

By the same token, be wary of fitness systems that boast of easy success. No matter what anyone says, fitness after 40—or any age, really, but especially after 40—must be earned. That's part of what makes it so spectacular when you achieve it.

3 Do be consistent

People in our age group tend to overthink when it comes to training. They dwell on questions such as "Should I train Monday and Thursday? Run Tuesday? Take a class on Sunday?" they ponder, often talking themselves out of training at all. The simplest—and in my opinion, best—answer is this: Train more days than you don't. If you didn't work out yesterday, do it today.

Consistency and frequency are more important than duration when it comes to wellness. I work out 3-5 days a week, sometimes for 20 minutes, never more than 90. I try to move around every day. That's it.

4 Do put good things in your body

Another funny thing about age 40: It's right about the time when many of us find ourselves telling our kids the same things our parents told us. Case in point: "Fruits and vegetables are good for you. They make you lean and strong, have vital nutrients, and are delicious if you're willing to give them a chance."

Want to know how to really get your kids to eat right? Lead by example and keep your foods closer to the source. Eat out of fewer packages. Cook more meals. Drink more water. Have less sugar.

By employing invasive medical procedures, gastric surgeries, and lots of expensive drugs, modern medicine can keep your bloated, flaccid body above ground for longer than in the past. If that sounds like less of a triumph than it should be, you're right. Don't be one of those people who would rather take cholesterol meds than eat a salad every day. By putting good, pure things in our bodies, we can prevent disease rather than have to treat it.

By no means am I saying that everyone over 40 must adhere to strict dietary procedures every moment for the rest of their lives. Nope—just most of the time. Aim for 80-90 percent, and you'll be way, way ahead of the curve.

5 Do treat yourself right

You work hard; don't forget to reward yourself too. Having said that, midlife is a great time to learn that a reward doesn't have to be in the form of an ice cream sundae. It can be a fun excursion, a new experience, or even just a little downtime—a rare commodity once you hit 40!

The writer Tom Wolfe uses the phrase "workhorse and intercourse" in his novel "The Electric Kool-Aid Acid Test" to describe an experiential approach to reward. As someone with a "work hard, feel good" approach to life, that phrase has always resonated with me. Sure, we've gotta pay our dues, but it's important to love life too.

DANNY'S DON'TS FOR OVER-40 FITNESS

1 Don't make excuses

Often times we dupe ourselves into thinking we don't have the time to make healthy choices, but that's not true. We all have time, and each one of us chooses what to do with it.

At this stage in life, it's likely that you have more responsibilities than you did at, say, 27. Jobs and families consume more time than they ever have before. This is not a bad thing. If anything, this adds value to the time you do have. In my experience working as a trainer in New York City, possibly the most hectic city in the world, the busiest people are the ones who train. They find the time.

2 Don't expect change to

happen overnight

If it took you 20 years to put on that superfluous body weight, don't expect it to come off right away. Transformations don't happen instantly, despite how close together those "before" and "after" pictures are to one another on the page. When you're no longer a young machine with an endless ability to burn calories, living fitness as a lifestyle becomes all the more important.

Make consistency and daily effort toward the task at hand your mantra. Over time, with attention and hard work, results will come.

3 Don't worry about anyone but you

You put on the TV and see weight-loss competitions, commercials making totally unrealistic claims, and celebrity diet pageants. You show up at work, and there's a transformation contest that's got everyone making lifestyle changes that may or may not be sustainable.

The truth is, in real fitness, the only competition is you. When you're committing to hard work and discipline over the long term, you need to be able to look at yourself in the mirror and know why you're doing this. You probably do a lot of things for other people—as you should—but when it comes to staying strong, lean, and powerful, do it for yourself and your loved ones, period.

4 Don't waste time

A lot of well-meaning folks waste time in the gym. This isn't totally their fault. In fact, many modern fitness facilities seem deliberately designed to waste time. Don't believe me? Just look around at all the TV screens, products for sale, smoothie bars, and other similar distractions. It's as if the focus has shifted from working out effectively to taking as much time as possible!

There are ways you can maximize efficiency. Get to know the gym. Circuit training, supersetting and self-stabilizing bodyweight and free-weight movements—as opposed to using benches or machines—are surefire ways to get the most bang for your proverbial buck. Get more done in less time, and you'll be able to come back more often.

5 Don't believe everything you read

These days, anyone can come across as an authority if they know how to design a nice website and rack up a lot of views. A website's attractiveness doesn't necessarily validate its content, nor does the forcefulness with which some forum poster or author phrases their point of view.

No, when it comes to fitness, the only thing that makes something true is if it works for you. To succeed, you will have to experiment for yourself, taking care to employ your own reason and common sense. Don't believe everything you read—not even everything by me—unless it makes sense and works for you.

Good luck, and keep me posted!

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