If you’re over 40 and haven’t had this thought at least once, you’re clearly not the result of the union between a man and a woman. You’re the construct of artificial intelligence.

And the thought? If I could only turn back the hands of time.

But there’s no way that’s happening. Not even if you’re befriended by a Silicon Valley billionaire who insists upon footing the bill for you to be cryogenically frozen so he has a solid wingman after being revivified from his own liquid-nitrogen slumber.

Now I don’t have billions nor the desire to be stored like a popsicle upon my demise, but a Mother Jones magazine article reports many of America’s wealthiest do -and have paid handsomely for that to happen.

Instead, my strong desire as I creep up on 65 is to function as I did when I was 45. But if I fall short of my goal by about 10 years, I could live with that.

And live really well.

At the age of 55, I set a personal best on a time trial bicycle course I had raced a number of times in my 40s - and won my age group while doing so. And the total miles I rode that year fell just a few short of 10,000.

To live really well as you age: Shouldn’t that be your goal also?

It’s a rhetorical question that requires no answer. However, here’s one that does: How much effort should you give now for the chance of a better later?

Your response needs to match your personality, suit your mindset, and accommodate your work and home-life commitments, which means there’s no one-size-fits-all answer. But you are reading a column called The Fitness Master, so chances are you exercise and do so with the now and then in mind.

To take that exercise and make it better, add in interval training.

It’s an addition, ironically, that requires a subtraction. A dismissal of the idea that doing intervals always makes your muscles burn - and sometimes makes your stomach rebuff your lunch.

The results of a study published in the March 2015 issue of the Annals of Internal Medicine help sack that misconception.

Researchers funded by the Canadian Institutes of Health Research assigned 300 abdominally obese adults to one of four groups. One group did a low amount of low intensity exercise (referred to as LALI); another a high amount of low intensity exercise (HALI); a third a high amount of high intensity exercise (HAHI); and a fourth served as the control group and performed no exercise at all.

The researchers’ definition of high-intensity exercise in this study needs to be addressed. Maybe because of the participants’ obesity, they claim high-intensity exercise occurs at 75 percent of maximum oxygen uptake (VO2 max) for the purposes of their paper.

But if you’re in shape, exercising 75 percent of your VO2 max, also called Zone 2 training, isn’t intense at all.

For instance, here’s how exercise expert and author Peter Attia - the guy who’s written the bestseller Outlive - knows he’s reached Zone 2. “I can talk [during the exercise]. I just don’t want to.” In other words, conversation is possible during Zone 2 exercise, but speaking at length leaves you short of breath.

All but the control group in the aforementioned study exercised five times per week for 24 weeks, but those groups did not exercise for a set amount of time.

Instead, the LALIs exercised until they burned between 180 and 300 calories at 50 percent of VO2 max, the state an in-shape sort reaches on a leisurely walk while experiencing no noticeable change of breath. The HALIs and HAHIs exercised until they burned between 360 and 600 calories at 75 percent of VO2 max.

After the researchers factored in the age and sex in of the participants surprisingly, they found the reductions in waist circumference and total amount of weight loss did not differ among all three exercise groups. So if you’re obese and don’t want to be, easy and steady exercise seems to do the trick.

But what if you’re not? And what if you want to keep all that aging eventually takes from you for as long as you can?

Then - after an appropriate warmup - you alternate between the two aforementioned degrees of effort in interval style, keeping the “talk test” in mind. Your overall objective is to incrementally decrease the interval time at 50 percent of VO2 max while increasing interval time at 75 percent of VO2 max, which increases your amount of Zone 2 exercise.

Zone 2 exercise has not only been shown improve aerobic capacity, insulin sensitivity, and overall well-being, but also the efficiency of your mitochondria.

Increased mitochondria efficiency allows your body to produce more energy, thereby providing your immune system with what it need to fight the aging process and age-related disease.