[♩ intro ] stress happens. and that’s not always bad—starting a newjob or getting married can both be happy things, but they also can be really stressful. there are some kinds of stress that just don’tseem to go away, though. like the feeling that you’re drowning inwork, but still perpetually worried about making ends meet. if you deal with a lot of stress every day,for months or years on end, then stress doesn’t just feel awful—it actually causes you physicalharm.
psychologists call any event or situationthat puts pressure on you or threatens your well-being a stressor, while stress refersto your psychological and physical reactions. stressors that are one and done—like lockingyour keys in your car, or forgetting your wallet—bring on acute stress. but when stressors are repeated or continuous,that’s chronic stress. things like abusive relationships, livingin poverty, and being discriminated against have all been shown to cause chronic stress. and that psychological anguish takes a tollphysically. when you experience acute stress, your bodyactivates a system called the hypothalamic-pituitary-adrenocortical
axis, or just hpa axis because why would youwant to say all that other stuff over and over again. it starts deep in your brain, in the limbicsystem — the part responsible for a lot of your automatic emotional reactions, amongother things. there, a region called the hypothalamus releaseshormones that start a whole chain of more hormones being released — first by yourpituitary gland, and then by your adrenal glands, which release a bunch of adrenalineand cortisol into your bloodstream. and those two hormones trigger the “fight-or-flightâ€response. they boost physical activity by increasingyour blood sugar and the blood flow to your
muscles, and bump up your metabolism at thesame time. the idea is that the physical boost helpsyou fight the stressor or run away. so, like, if you were suddenly face to facewith a bear, the surge in energy would help you either outrun it, or go all like revenanton it. the same system is activated by chronic stress,but things get a bit more complicated. researchers have found that people under somekinds of chronic stress have perpetually high cortisol levels, as if their hpa axis is runningconstantly. for others, it can depend on the timing, withhigher cortisol levels near the start of the stress before it actually dips lower thanusual.
but we do know that while this stress reactioncan be helpful at times, having it running all the time is a problem. people under chronic stress are at higherrisk for all kinds of ailments, like heart disease, autoimmune diseases, and mental disorderslike anxiety and depression. that’s because, in addition to it beingsuper unpleasant to be stressed out all the time, the stress response is constantly sappingyour energy. the resources used by fight-or-flight haveto come from somewhere, and one of the places they come from is your immune system. on the molecular level, the same cortisolthat works to get extra glucose to your muscles
also stops your body from making as many infection-fightingwhite blood cells as it normally would. so stress can tank your ability to fight infections. it's kind of like evolution is telling yourbody not to worry about fighting off that cold right now, because you need to fightthat bear that is right in front of you. except with chronic stress, the bear isn’ta bear. it’s your crappy job. or your unhappy relationship. or whatever it is that stresses you out allthe time. and that means your immune system never getsthe chance to recover and deal with that cold
as easily as it normally would. one famous experiment demonstrating this involved11 dental students who volunteered to have their mouths biopsied twice: first duringsummer vacation, and then again during exam week. it took an average of 3 days longer for thewounds to heal while they were stressed about exams. all kinds of other studies have gotten similarresults — some by punching small holes in people like they did with the dental students,and others by observing how stress affects recovery from surgery and other major wounds.
there's also research suggesting that chronicstress explains part of the relationship between poverty and health. even just the perception of being in a lowersocioeconomic class is associated with an increase in respiratory infections. stress can also advance the aging process. by the time you get older, your dna has hadto replicate so many times that the protective parts at each of the ends of the chromosome,called telomeres, can kind of start to fray. when telomeres are shorter, it's more likelythat there will be errors in copying genes. and those errors increase your risk of disease.
there’s evidence that having more cortisolin your blood interrupts the repair of telomeres. which might explain why stress is linked todiseases that are also associated with age, like heart disease, cancer, and anemia. to stay healthy, the best thing you can dois get rid of the chronic stress. but, easier said than done. if you can’t get rid of it completely, thingslike meditation and relaxation therapies can help lower your stress response. and, weirdly enough, so might changing howyou think about stress. studies have shown that when people thinkabout the source of stress as a challenge
to overcome instead of a threat to their well-being,that seems to lower their perceived stress and reduce their body’s physical response. there’s another way you might be able toimprove your health, too: help others reduce their stress. in a sample of over 800 older adults, thosewith high stress who also reported helping friends or neighbors with things like houseworkor childcare had mortality rates similar to those with low stress. whereas those with high stress who didn’thelp out had reduced odds of survival. so, chronic stress is not good for anyone.
but even if you can’t avoid being stressedout all the time, there are ways to help yourself relax — and sometimes you can even reduceother people’s stress in the process. thanks for watching this episode of scishowpsych! if you want to keep up to date with our latestvideos explaining how these big ole noggins of ours work, head over to youtube.com/scishowpsychand click on that subscribe button because it’ll all come into your subscription boxand you’ll watch every single one of them and it really helps… with the youtube algorithm. thank you! [♩ outro ]