Major Ager: Bad Genes and Short Telomeres
Its Effect: Memory Loss

Maybe you've been dealt a bad hand of genetics, but that doesn't mean you can't exchange a few cards, or at least change how you play them! When it comes to your body and longevity, here's what we know: It's less about what genes you have and more about how you express them. Genes work by manufacturing proteins, but whether or not a specific gene is turned on or off is largely under your control. For example, exercise isn't good for you just because it helps burn fat, but it can also alter the expression of your genetic codes to decrease your risk of getting cancer. So how else do you change the function of your genes? One way is through the rebuilding of the tips of your chromosomes, called telomeres. Think of them as being like those little plastic tips of shoelaces—once these protective coverings are gone, your DNA begins to fray, which can contribute to age-related conditions like memory loss. One way to avoid losing your telomeres? Learn to manage stress—telomeres of people who feel more stressed are almost 50 percent shorter than people who say they're less stressed.

Major Ager: Oxidation and Inefficient Mitochondria
Its Effect: Rusting Arteries

Mitochondria are the fundamental drivers of metabolism, converting the food you eat into energy. The problem is, as they produce energy they also produce oxygen free radicals—molecules that cause dangerous inflammation in the cell when they spill over. Think of them as the power plants of our bodily city. Just like an old factory, aging mitochondria spill more industrial waste into the environment. The damage this inflammation causes to your cells and to the mitochondria within your cells is responsible for many aging-related problems. This oxidation, for example, is what causes a "rusting" of your arteries, which is partly responsible for the aging of your cardiovascular system.

Major Ager: Stem Cell Slowdown
Its Effect: Damage From Stress

Say the words stem cell and you've triggered almost as much controversy as any other two words in the English language! But here's a fact about which there is little controversy: Your stem cells are an incredibly powerful tool, and they play a key role in how you recover from stress. At all stages of your life, your body responds to damage by recruiting stem cells. When you smoke, stem cells are sent to the lungs to respond to damage. Or when your skin burns from the sun, stem cells go there to make repairs. The problem is, we lose stem cells as we age, whether by using them to repair damaged organs or because they're destroyed by toxins like oxygen free radicals, leaving us vulnerable to stress-related conditions.

Major Ager: Declining Defenses
Its Effect: Run-down Immune System

When we hear the word infection, we usually think of green mucus oozing from our nostrils. When it comes to aging, however, we're concerned not only with the acute infections like colds and the flu. We're also concerned with the chronic infections—the behind-the-scenes inflammatory response in your body that ages your entire system. In fact, much of the aging process is a side effect of defense mechanisms that our body has designed. An overworked and tired immune system causes chronic inflammation in your body, which increases the risk of mutations that can lead to cancer.

Major Ager: Toxins
Its Effect: Cancer, Asthma, and Allergies

Though hell on our nerves and the person stuck cleaning the floor, we should all be thankful for humans' propensity to puke. Throwing up is nature's way of clearing toxins from our body, and we are exposed to hundreds daily, which stress our systems and tax them as we age. We live in a world where all kinds of chemicals surround us. They come from cars and factories, they're in our foods and shampoos, and they're in our homes and offices. All of these potentially toxic substances act as pollution to our biological city. Some of the toxins that we encounter are potentially very harmful and can cause cancer, asthma, or allergies, though they can also reduce your quality of life in more subtle ways. They may cause minor irritations or fatigue or a general feeling of blahness. And all of those effects—as subtle or subconscious as they may be—can chip away at our overall health so that we're much more prone to feeling the effects of aging.

Major Ager: Glycosylation
Its Effect: Heart disease, Diabetes, Nerve Damage

Most people hear the term "glycosylation" and think of something you order up at Jiffy Lube. But glycosylation, unfortunately, is a process deep inside your body that has dramatic effects on your cells. It occurs when excess sugar molecules float around in your blood and attach to proteins, diminishing their effectiveness. The excess sugar is a little bit like acid rain—it damages the things it touches and makes them leaky. When the sugar latches onto protein on the outside of a cell, the sugar stays in the blood and gunks up the proteins in our body, making glycosylation the source of many aging-related problems such as heart disease, diabetes and nerve damage.

Major Ager: Calorie Consumption & Slowing Sirtuin
Its Effect: Obesity, Digestive Issues, Age-Related Problems

The greatest year for aging Americans: 1935. That April, it was found that the lifespan of laboratory rats could be extended considerably by putting them on a serious calorie-restricted diet. And when it comes to calorie restriction, the mechanism that slows aging comes in the form of a protein called sirtuin, which seems to change the chemistry in your body to help neutralize the effects of aging. But, not everyone's sirtuin protein-manufacturing gene is activated! Researchers have found that calorie restriction helps activate sirtuin; that is, eating fewer calories acts as the light switch that turns it on. But sirtuin production can also be turned on by other things—resveratrol in wine being a biggie, as well as quercetin in apples and onions, and physical activity—and may end up being the ultimate anti-ager of them all.

Major Ager: Neurotransmitter Imbalance
Its Effect: Emotional Issues like Depression, Cognitive Decline, Sleep Problems

All of us get messages on the phone and computer. Some of us get messages in bottles. And the lucky ones get messages on steamed-up bathroom mirrors telling them that someone's waiting for them in the bedroom. Now take the same concept and apply it to your brain. It's in the business of sending and receiving messages that help dictate how you act, how you feel, whether you want to be asleep, or whether you're craving triple-chocolate cake. This all happens via neurotransmitters, which are just messengers that your brain uses to communicate. As you age, your brain actually shrinks (don't worry, it's normal), and you lose some of the neurotransmitters you produce, which has been linked to emotional issues like depression as well as other cognitive abilities, like how well you sleep. The good part, however, is that food, exercise and sleep work as dials on your neurotransmitter radio, regulating how you feel from day to day and hour to hour, and thus can have a profound impact on the emotional side of aging.

Major Ager: Wacky Hormones
Its Effect: Menopausal Issues in Women and Men

From an evolutionary perspective, hormones may be considered the most important system in your body. Testosterone and estrogen, the major sex hormones in men and women, respectively, give us the urge and ability to try to reproduce and continue the survival of the species. Biologically, it don't get bigger than that. But once we're past our reproductive prime, our hormone levels drop. The tangible outcomes: lack of sex drive, insomnia, impotence, weight gain, and countless other potential health problems that can chip away at the quality of your life.

Major Ager: Declining Nitric Oxide
Its Effect: Erectile Dysfunction and Other Age-Related and Artery-Related Problems

Most of us have a pretty limited view of what's swirling around inside our bodies: We've got our organs, our bones, our blood and water, and our chemicals. Inside your body, you also have a short-lived gas that tremendously affects your body's function. This gas—nitric oxide (NO)—was discovered to be the neurotransmitter in the nerve cells that control erections and helps other blood vessels in your body to relax and dilate. And that makes the declining functioning of NO over time a key cause of erectile dysfunction and other age-related and artery-related problems. The bottom line when it comes to nitric oxide and aging is this: Nitric oxide plays a fundamental role in keeping a body healthy, and the reverse is also true. In many diseases, the production of nitric oxide is impaired, and that leads to cell injury or the dysfunction of organs.

Major Ager: UV Radiation
Its Effect: Cancer, Wrinkles, Vision Problems

You'd really have to be living in the dark not to know the value of the largest object in our solar system. Yet we also know that that bright little bugger can be a real sun of a gun. How do the sun's UV rays cause damage? One way is through connective-tissue breakdown. UV radiation causes the structural protein of our skin, collagen, to break down and disables our ability to repair damage. Another way sun ages our skin is through the formation of free radicals—those aggressive charged compounds that damage cells and break down collagen as well. Free radicals can cause cancer by changing our DNA and preventing our body from repairing it. But the flip side is that we also really need UV rays. Natural sunlight creates active vitamin D, which we need for bone health, since it helps regulate calcium. It also helps ensure the proper function of the heart and nervous systems. This good-and-bad argument is really another example of being balanced. As is the case with many things we've covered, finding the perfect equilibrium is one of the real secrets to slowing the aging process.

Major Ager: Disuse Atrophy
Its Effect: Weakening Limbs and Bones

We've all heard the "use it or lose it" mantra before. The principle? If you let your body parts shrivel up and die, they'll be happy to take you up on your offer. The reason? Your body is too efficient to waste energy feeding limbs and organs that aren't being used. So if you ain't using it, then your body says you're losing it. And the nerves that help control those limbs and organs will wilt away too. This mechanism of aging—disuse atrophy—is a classic example of resource allocation. If your body knows that you're using crutches instead of quadriceps, then it figures, forget this, I'll put energy elsewhere—and so your leg muscles atrophy when you don't use them for long periods. We need to put our bodies to work in our lives: We need to work our muscles, our brains, and virtually every other organ and system in our bodies to make them stronger for longer.

Major Ager: Wear and Tear
Its Effect: Age-Related Conditions like Hearing Loss

When you grind down your body simply by the act of living—whether it be your joints or your ears—your body is going to experience some kind of damage. It's the slow churning away at the efficiency and productivity of our body's systems that causes many of the ailments we associate with aging. But our own behavior and choices play a part too! Constantly listening to your iPod at full blast? Then expect hearing loss later in life! What we have to be careful about is falling into the trap of thinking that deterioration is normal when it comes to aging. Just because it's common to creak like a haunted house as we get older doesn't mean it's inevitable; our bodies ought to be able to make those necessary repairs. It's when we are unable to make those repairs—be it due to chronic disease or damaged DNA—that we slip into what most of us think of as, simply, old age.

Major Ager: Unforced Errors
Its Effect: Accidents

Much of aging certainly is about preventing the decrease in quality of life from chronic disease and long-term wear and tear. But the ultimate form of aging is the kind of that bypasses all the details and kills us off immediately: a car crash, a fall from a cliff, or a freak encounter with a rabid antelope. Most of us like to write off accidents as unfortunate circumstances of fate, but many accidents are very preventable and not really the end result of some cosmic master plan of evil. When it comes to accidents and unforced errors, the big picture is this: It’s all about leverage points—tipping life into your favor by doing the things that make your body better equipped to handle the unexpected things that will be hurled your way. It means making sound decisions in life (non-slip mat in the shower, helmet when you’re riding a bike) to stack the odds in your favor. It means knowing where the trouble spots may be, so you can plan to avoid them—and cope with them if you can’t.
As a reminder, always consult your doctor for medical advice and treatment before starting any program.