By Marcel Daane

It’s Monday morning, and Michael, a senior management professional, faces the week utterly exhausted. Only 38, he’s been a high-level leader for more than a decade. Now, Michael is perpetually depleted, and his pinpoint focus has given way to constant brain fog. He struggles with stress and anxiety every day—a state of mind (and body) that’s killing his performance capacity.

As demands grow and resources shrink, we all struggle to do more with less—and without proper coping skills, we slide down a slippery slope of chronic exhaustion into debilitating burnout. That’s bad news for the middle-age-ish among us who work with younger team members.

Working while fatigued once in a while is okay, but when this state becomes chronic, our resilience against stress drops. Enthusiasm and motivation plunge, and before we know it, we can no longer perform at our best.

What’s more, this endless fatigue ages us rapidly. You don’t just feel older than your age; you are older. Your capacity to regenerate the cells in your body and brain falls off sharply.

That’s right: Stress is a potent cause of neurodegeneration. The brains of people who are chronically fatigued show signs of shrinking, which means stressed executives have about the same brain capacity as people decades older.

This deterioration of critical brain regions hinders memory processing, strategic planning, and the ability to manage anxiety, which are all crucial skills for the executive. The deficiencies can knock you out of the game. Mental sharpness and the ability to innovate, collaborate, and connect are the price of admission in today’s world.

The good news is we can affect how fast our brain ages, depending on how we treat it throughout life. Research at King’s College in the United Kingdom shows the brains of elderly people who practice a healthy lifestyle are the same as people decades younger.

The lesson is clear: Overworked executives can go a long way toward keeping their brains young and high-performing. We may not be able to control our workload but we can control our lifestyle choices.

We may be committing predictable brain-aging “sins” on a regular basis. Here are nine of the most damaging:

1. You regularly forgo a daily walk in favor of a flop on the couch. After a long day, it’s tempting to talk yourself out of exercise with a weary, “I’m just too tired.” But sedentary behavior doesn’t reward your fatigued brain and body—it makes you more fatigued. It may sound counter-intuitive, but it’s true: Your brain recovers better and faster when your body moves.

Movement produces proteins and hormones in the brain that stimulate memory and make you more alert. One such protein is called brain-derived neurotrophic factor (BDNF), which is produced only during exercise and works like fertilizer to help new brain cells grow. Thus, a daily walk in the office, around the parking lot, or through the airport helps keep your energy level up and your brain awake.

Even short bouts of exercise make a difference. Just 12 minutes of moderate-intensity cardiovascular exercise, such as brisk walking, improves cognitive function and oxygenation and provides energy. You’ll feel the results right away.

2. You hit the snooze button (again) and run out of time for breakfast. While you’re still lying in bed, it may seem like a good idea to stay there for an extra 30 minutes at the expense of breakfast. But robbing your brain of essential nutrients in the morning is a big mistake. In the same way that an athlete needs fuel for the body to perform and recover from training, an executive needs fuel for the brain to perform and recover from stress.

In fact, just as an athlete’s muscles shrink without proper refueling, so do the executive’s “mental muscles.” Neurons in the brain die with repeated exposure to stress, resulting in a loss of brain mass and ability.

To fuel and protect your brain, start your day with breakfast; however, don’t zip through the drive-thru window. Instead, choose oatmeal topped with berries, cinnamon, and walnuts. This takes only a few minutes to prepare. You may even be able to hit snooze once or twice and still have time to make and eat a healthy breakfast.

3. You skip lunch to take an emergency conference call. If your workday includes last-minute meetings, emergency conference calls, staffing issues, or other urgent craziness, taking time to refuel your brain can seem impossible. Interruptions can derail the most well-intentioned healthy meal plan. It may be tempting to skip a healthy lunch or snack and just keep working, but a brain can’t perform without fuel.

The brain has a minimal capacity to store its own glucose, which is the primary brain fuel, so it relies on you to feed it regularly. When you skip meals, the regions of your brain responsible for self-regulation, empathy, and solution-based thinking begin to shut down. You become hyper-responsive to stress, brain cells in your memory processing centers die, and your brain ages more rapidly.

Bring your own healthy lunch or snacks to work, so you have food available no matter how crammed your day becomes.

4. You don’t stock up on good snacks (so you naturally grab bad ones when temptation strikes). Stress and fatigue are notorious triggers for bad-food binges. That’s why many people grab chips or cookies and mindlessly devour them while multitasking. The problem is that stress causes chronic brain inflammation, and processed foods like cookies, sodas, and cakes only add fuel to the inflammation fire. They speed up brain cell destruction from stress, resulting in memory decline similar to what can be seen in Alzheimer’s patients.

If your workplace (or your home) is stocked with cookies, sodas, candies, and chips, of course you’ll reach for them when stress hits. The remedy is to plan ahead. Bring your own healthy snacks—those that build memory capacity, improve physiological brain balance, help you perform complex mental tasks, reduce symptoms of stress and anxiety, and keep you focused—and eat them instead.

I suggest an apple or banana with a handful of almonds or walnuts. Bananas are a quick source of glucose and potassium, and potassium improves physiological brain balance. Cottage cheese is another good option because it includes whey protein that’s been shown to remove symptoms of stress and improve cognitive function. Bring a container of chopped celery, carrots, and broccoli with organic almond or coconut butter for dipping. Finally, you can top anything with almonds, which improve cognition and memory.

5. You swill coffee and soda instead of water. You may think your morning jolt of caffeine is revving you up, but it really isn’t. Yes, it creates a momentary lift as it blocks neurons in the brain that make you feel tired, but the lift quickly declines and fatigue sets in. The more you consume, the greater the impact of stress on your brain, and the more dehydrated you become. The best hydration is water, which transports nutrients and oxygen into your tissues and brain cells.

Without enough water, our bodies and brains can’t function properly. Imagine your blood slowly turning to mud, making it difficult for nutrients to travel throughout your body. Imagine your brain cells turning from juicy grapes to dried-out raisins. Dehydration leads to serotonin deficiency, which means less stress-resilience, more depression, poor sleep, and memory loss.

How much water should you drink to keep your body and brain hydrated? I recommend a half-ounce to one ounce of water per pound of bodyweight per day. So someone who weighs 150 pounds needs between 75 to 150 ounces of water per day. An easy solution is to keep a 20-ounce water bottle with you at all times and refill it at least three times a day. Your brain and body will thank you.

6. You regularly “relax” with an after-work beer or a nightcap.  No one is saying you have to be a teetotaler. The occasional drink with friends is okay. But don’t go beyond one 250-milliliter glass of wine or two 8-oz glasses of beer a day—at most. Any more and you’re accelerating the aging of your brain.

Alcohol is not so much a relaxant as it is an anesthetic combined with a stimulant. During a stressful day, the brain cells in the hippocampus (our memory-processing center) are stretched beyond capacity. As we drink alcohol, our brains are anesthetized and overstimulated, which causes additional trauma to the hippocampus and compounds the damage. The brain can recover from the occasional trauma of drinking, but if it’s too much and too often, it loses its capacity to recover.

There are more effective ways to recover from stress. You can practice mindfulness meditation, go for a walk or a run, or take a yoga class. All of them reestablish calm in the brain and body, and help you build brain cells rather than kill them. And if you insist on drinking alcohol, train yourself to do so only after relaxation exercises and rehydrating with water.

7. You sacrifice sleep on the altar of work. On occasion we all have to burn the midnight oil to finish a project. Yet many executives think it’s a badge of commitment to regularly sacrifice sleep in favor of working late or starting up in the wee hours of the morning. The irony is that a bit more sleep would make them far more effective by allowing the body to recuperate and super-compensate (a fancy word that means to store excess energy for the next day).

A chronic lack of sleep has serious effects on brain health and function. One study showed a single 90-minute reduction in sleep decreased performance and alertness by a whopping 32 percent, and another study showed that a chronic lack of sleep caused significant decreases in brain volume and memory. To top it off, poor sleep has also been associated with body fat gain, high blood pressure, heart disease, and diabetes.

We all need different amounts of sleep at different stages of our lives, but the magic number still seems to be around the eight-hour mark. Aim for eight, but if you find yourself needing to pull an all-nighter, try taking periodic naps during the day. A 30-minute nap can greatly increase alertness, focus, and memory.

8. You skip water cooler chats. In today’s always-on technology-fueled culture, it can be tempting to lock yourself in your office or hide away in your cubicle, chasing the rabbits of deadlines all day. No wonder research suggests that more than 50 percent of employees suffer from feelings of isolation at work. This is bad for organizational and personal performance.

Humans need interaction and connectivity, just as we need food and water. One study showed that social isolation results in reduced capacity for planning, communicating, impulse control, imagination, and empathy. Conversely, social interactions help us learn and see other perspectives. They help us relax and feel happier. They make us more effective when we do return to focusing on work.

Plan regular social sessions for yourself and your team when you can bond, share, and laugh. Structure your day to allow social time even if your brain tells you it has too much work to do. Some people need much more social time than others, but we all need some form of social connection for optimal brain function.

9. You sit and sit (and sit some more). Every day, millions of executives and office workers suffer the ill effects of sitting too much. Scores of research show that sitting more than six to eight hours a day increases brain stress and early mortality, not to mention exhaustion, stiff necks, heavy limbs, and aching backs. If all that isn’t disturbing enough, consider that too much sitting actually thickens your connective tissue over time until you lose your range of motion (not unlike the “Tin Man” in The Wizard of Oz).

Fact is, the human brain was designed to function best in an environment that required physical movement such as foraging and hunting for food. Many of the brain regions involved in our current daily functions are directly linked to the brain neurons involved in movement. While sitting for hours, the neurons switch off, and your brain’s capacity drops below that of a person who is decades older than you.

Hardworking neurons need oxygen and nutrients to function, build memory, remain alert, and stimulate creativity. That’s why you must stand up and move around during the day. Stand at your desk; conduct stand-up or walking meetings; take regular walks away from your desk; walk or stand while thinking. These small changes will greatly increase oxygenation and reinvigorate the neurons needed for your brain to excel at any cognitive task.

It’s unfortunate and ironic that almost everything about our workplace and our culture conspires to harm our performance and make us less competitive. That’s why we must make a conscious and deliberate effort to maintain the youthfulness of both mind and body.

If you’re guilty of any “brain-aging,” start now to incorporate small changes that can boost your mental capacity, reverse brain-aging, and give you a competitive edge. Anyone can become an energizer in the workplace. It just requires making a commitment to stop some bad habits before they stop you.