April is National Stress Awareness month, but many of us might not be aware of how stressed we are or why we are stressed in the first place. Although a constant state of stress has become the new norm for many working adults, the physical and mental toll is crippling their chances at success, workplace and happiness experts Annie McKee and Emma Seppälä argue. "Most of us work more than eight hours a day," McKee writes in her latest book "How To Be Happy At Work" based on decades of working with Fortune 500 companies. "That means that if we are unhappy at work, we are miserable from more than a third of our lives." McKee notes that "slow-burning stress, anger and other negative emotions can literally kill us."

"Some people face the reality of their unhappy work situation only as a result of a heart attack, a broken relationship, or a tragedy. Don't wait that long," she writes. Based on McKee and Seppälä's research, here are the ways stress affects your body and the measures you can take to prevent or decrease the harmful results of working too hard.

Why you're probably feeling so stressed at work

People today live by the "faulty theory" that in order to succeed, "you need to continually be getting things done and moving on to the next goal as quickly as possible," Seppälä, a Stanford psychologist and science director of Stanford's Center For Compassion and Altruism Research, notes in "The Happiness Track." This is further perpetuated because "work addiction is rewarded by our culture," she adds, and is "therefore considered a good thing despite its long-term negative impact on well-being." Providing historical context, McKee notes that "as societies industrialized, the notion that work should be painful grew and spread as workers lost autonomy, the joy of seeing the fruits of their labors and even fresh air."

Today, McKee writes, "we live in a world where overwork is overvalued," thanks to constantly changing company structure, the burden of needing to do more with fewer resources, longer work days and the advancement of technology. "Overly competitive colleagues, too little time for what needs to get done and poor leadership are just three of the many problems that can cause constant stress at work, which in turn causes physical, mental and emotional problems," McKee writes. This is not a sustainable way to live.

The physical, psychological and social effects of chronic stress

It's important to note that some stress is normal and does have its benefits. McKee and Seppälä both define "good stress" as a product of our human fight-or-flight response, "where our bodies prepare to fight off a potentially deadly attack or run away," Seppälä writes. Here are the physical responses that occur as a result of our brains communicating a threat to our nervous system, according to McKee: Our muscles become tense

Our hearts beat faster take consume more oxygen and nutrients

Our bronchial airwaves expand

Our pupils dilate to see more around us

Our cognitive processing briefly enhances so we can think faster "These responses are helpful when we're facing real dangers such as a physical attack or a natural disaster," McKee writes. But here's the catch: "Unfortunately, our brains don't do a very good job of distinguishing this type of serious danger from the kinds of pressures and threats we experience at work."

Seppälä notes that stress in small doses can help us achieve short-term goals, which may resonate with plenty of procrastinators. But over time, "chronic stress," or feeling stressed all the time, "is the number one enemy of success," Seppälä adds. While this is by no means an exhaustive list, effects of chronic stress, also known as long-term acute stress, include: Proneness to illness and chronic infections

High blood pressure

Heart problems

Increased susceptibility to diabetes and cancer

Gastrointestinal issues

Muscular and skeletal problems

Restlessness throughout the day and night

Substance abuse Chronic stress also has the ability to interfere with social well-being and spread to your co-workers, friends and family. "Anxious emotions such as fear are physiologically contagious through pheromones, chemicals released in our sweat," Seppälä writes. "When someone emits 'fear pheromones,' the people who come into contact with that person show greater activation in brain areas corresponding to anxiety and fear (particularly the amygdala)." And if you have found yourself working more to avoid your stress, McKee notes that can also be a dangerous coping mechanism. "It makes things worse as we ignore our relationships, cut out fun and eat and sleep poorly. Working like this doesn't help us get more done, it does just the opposite," McKee writes. "We are too tired and worn out to do our jobs well. Our resources are depleted."

How to beat stress and feel better