From The Brain To The Immune System, How Stress Pirates Your Whole Body


Too much stress doesn’t just mess with your head. (Photo: Stocksy/Robert Kohlhuber)

You’ve probably heard that some stress is good for you. Maybe it’s pressure from your dad, the college basketball star, to do well in this week’s big game. Or perhaps it’s the weight of an impending deadline nudging you to finish a big project.

Stress can be a powerful tool, unavoidable and beneficial at times, according to Robert London, MD, a practicing psychiatrist for more than three decades and a national columnist for Elsevier/Frontline.

“Short-term stress can be valuable in situations that require an immediate response,” he tells Yahoo Health. “When you’re preparing for an exam, the anxiety you feel will motivate you to focus on your work— or stress can help push you when you’re trying a new activity where you may be fearful, producing a ‘live-saving,’ flight-or-fight response when you feel you’re in immediate danger.”

But acute stress and chronic stress can invoke a sense of danger — and some serious effects on the body. From crying to sweating, panic attacks to mental breakdowns — and even physical illness — relentless anxiety can swing a person into a tizzy. (Think: extreme responses to a disaster or traumatic event, or celebrities who have crumbled under the spotlight’s glare.)

Stress As A Signal Of Danger

Biologically speaking, since caveman days, our bodies have been primed to respond to stressors indicating danger — even though “danger” today no longer includes saber-tooth tigers, says Diane Robinson, PhD, a neuropsychologist at UF Health Cancer Center - Orlando Health.

If you don’t immediately tap into calming powers after a stressful situation — meditation, yoga, sleep, whatever works for you — your body will enter fight-or-flight mode. “With intense stress on a short-term basis, your body thinks there might be a threat, which triggers a release of chemicals,” Robinson tells Yahoo Health. “You’ve got fast-acting adrenaline affecting every organ in the body. Your cortisol levels are rising. At the same time, the autonomic nervous system is also triggered.”


Within that system, there are the sympathetic nervous system and the parasympathetic nervous system, which work in tandem during your average day, says Robinson. The sympathetic system works to overcome the threat, aka your average stressor. Lungs expand to ready the body for movement, and non-essential functions like the digestive system shut down to funnel glucose to the muscles as you prepare to “flee.” Your heart rate rises.

Related: 5 Surprising Ways Stress Wreaks Havoc On Your Health

Let’s say your stress is work-related. You go home. You meditate, do yoga, take a nap. “This person can usually recover quickly,” says Robinson. “The parasympathetic nervous system is activated, telling your body to calm down. Think about it like a lullaby, or like a car where you brake, accelerate, brake, accelerate.” Your heart rate slows, your eyes un-dilate, your body releases energy.

However, sometimes during periods of acute stress, the switch for the sympathetic nervous system “gets jammed on,” says Robinson. This means you’re in an extended version of fight-or-flight mode. Non-essential processes will continually be in shutdown mode, from digestion to immune function. “You’re not worried about fighting a cold virus when your body perceives an immediate threat and you’re suffering acute stress,” Robinson says.


This can happen if you’re stuck in prolonged stress mode — maybe a big project at work is taking up all your time, or a troubled relationship is requiring all your energy. Your body may perceive the rigors of these situations as immediate danger. “If you interpret getting very little sleep and less food as life-threatening, then this can trigger a panic attack,” says Robinson. “It’s because your system is being triggered to fight — but you’re not. You’re just sitting there, with heart pumping out of control.”

And everyone responds to varying degrees of psychological stress differently. “Our systems are so unique physiologically,” she explains. “We all have our own internal needs, sleeping well and eating well for our own bodies, and they have massive implications on our health. If these needs aren’t being met adequately, you can have a full-blown incident.”

Related: 10 Surprising Stress-Busters

The Slow Burn Of Stress

Yet, there’s more to it. If stress is not intense and acute for a time, but slow, steady and chronic over time, you can also encounter some major health problems — a buzzy topic of study right now in the field of psychology. “Stress day in and day out, on end, can change the brain chemistry,” says Robinson, “and it has huge implications for our immune systems.”


Scientists call this psychoneuroimmunology, where stress can actually alter the immune system in a big way. “There are several cytokines that transport information throughout the body, particularly important here are interleukins,” says Robinson. “When you are chronically stressed, they are overpopulating, overworking, and sending mixed messages throughout the body.”

Your immune system doesn’t know what to do with those messages, leading to real, worsening, even lasting changes in immune function. “This is why we often see autoimmune conditions develop after periods of chronic stress,” she says. “Sometimes we see Crohn’s disease, sometimes we see shingles.”

London has also seen how ruminating in moderate stress long-term can have catastrophic impact. “It can lead to a host of destructive health issues — depression, headaches, and gastrointestinal problems like heartburn, colitis, irritable bowel syndrome,” he says. “It can also impact your ability to concentrate. It can cause insomnia. Your ability to focus on work and relationships will also be affected.”

Finding An Outlet

Bottom line, says London: Stress, whether chronic or acute, is a big deal if you don’t find an outlet. “The best way to handle stress is to expel it,” he says, suggesting outdoor exercise foremost. “Exercise can reduce stress hormones, flooding the body with endorphins that improve mood, boost energy, and provide a healthy distraction. Yoga is another effective [outlet] for your anxiety.”


If you cannot find a solution that works for you, seeking a therapist’s advice can be helpful — especially before stress becomes “chronically debilitating,” says London.

However, you have more control over your stress than you realize, according to Robinson. “You have the power to consciously activate that parasympathetic nervous system, which will calm you down,” she says. “People always say, ‘Just breathe.’ It’s actually really true. Something as simple as slowing down your breath is a really sound physiological strategy.”

When your body is dumping adrenaline, she says, there’s a feedback loop. Continue to stew in stress, and you’re telling your body there is an imminent threat. Practice methods of calmness, and you’re signaling that all is well. The moment you break the pattern of stress, is the moment you send a message to your brain that you are OK — slowing down that release of chemicals.

So, next time you’re stressed? Remember: you’re in control, and channel those inner-superpowers.

Read This Next: The One Thing Most Of Us Are Stressed About

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