Are you sleeping restlessly, feeling irritable or moody, forgetting little things, and feeling overwhelmed and isolated? Don't worry. We've all been there. You're probably just stressed out. Stress isn't always a bad thing. It can be handy for a burst of extra energy and focus, like when you're playing a competitive sport, or have to speak in public. But when its continuous, the kind most of us face day in and day out, it actually begins to change your brain. Chronic stress, like being overworked or having arguments at home, can affect brain size, its structure, and how it functions, right down to the level of your genes. Stress begins with something called the hypothalamus pituitary adrenal axis, a series of interactions between endocrine glands in the brain and on the kidney, which controls your body's reaction to stress. When your brain detects a stressful situation, your HPA axis is instantly activated and releases a hormone called cortisol, which primes your body for instant action. But high levels of cortisol over long periods of time wreak havoc on your brain. For example, chronic stress increases the activity level and number of neural connections in the amygdala, your brain's fear center. And as levels of cortisol rise, electric signals in your hippocampus, the part of the brain associated with learning, memories, and stress control, deteriorate. The hippocampus also inhibits the activity of the HPA axis, so when it weakens, so does your ability to control your stress. That's not all, though. Cortisol can literally cause your brain to shrink in size. Too much of it results in the loss of synaptic connections between neurons and the shrinking of your prefrontal cortex, the part of your brain the regulates behaviors like concentration, decision-making, judgement, and social interaction. It also leads to fewer new brain cells being made in the hippocampus. This means chronic stress might make it harder for you to learn and remember things, and also set the stage for more serious mental problems, like depression and eventually Alzheimer's disease. The effects of stress may filter right down to your brain's DNA. An experiment showed that the amount of nurturing a mother rat provides its newborn baby plays a part in determining how that baby responds to stress later in life. The pups of nurturing moms turned out less sensitive to stress because their brains developed more cortisol receptors, which stick to cortisol and dampen the stress response. The pups of negligent moms had the opposite outcome, and so became more sensitive to stress throughout life. These are considered epigenetic changes, meaning that they effect which genes are expressed without directly changing the genetic code. And these changes can be reversed if the moms are swapped. But there's a surprising result. The epigenetic changes caused by one single mother rat were passed down to many generations of rats after her. In other words, the results of these actions were inheritable. It's not all bad news, though. There are many ways to reverse what cortisol does to your stressed brain. The most powerful weapons are exercise and meditation, which involves breathing deeply and being aware and focused on your surroundings. Both of these activities decrease your stress and increase the size of the hippocampus, thereby improving your memory. So don't feel defeated by the pressures of daily life. Get in control of your stress before it takes control of you.
Da li nemirno spavate, osećate se iritirano ili razdražljivo, zaboravljate sitnice i osećate se preopterećeno i izolovano? Ne brinite. Svi smo prošli kroz to. Verovatno ste samo pod stresom. Stres nije uvek loš. Može biti koristan za nalet dodatne energije i koncentracije, kao kada se takmičite u nekom sportu ili morate da javno govorite. Ali kada je stalan, kao onaj sa kojim se većina nas svakodnevno suočava, stres zapravo počinje da menja vaš mozak. Hronični stres, poput preobimne količine posla ili svađa kod kuće, može da utiče na veličinu mozga, njegovu strukturu, način na koji funkcioniše, sve do nivoa vaših gena. Stres počinje nečim što se zove hipotalamusno-hipofizno- nadbubrežna osovina, niz interakcija između endokrinih žlezda u mozgu i bubrezima, koje kontrolišu reakcije vašeg tela na stres. Kada vaš mozak otkrije stresnu situaciju, vaša HNO se odmah aktivira i luči hormon kortizol, koji vaše telo priprema za trenutnu reakciju. Ali visoki nivoi kortizola tokom dugih perioda vremena izazivaju haos u vašem mozgu. Na primer, hronični stres povećava nivo aktivnosti i broj nervnih veza u amigdali, centru za strah u vašem mozgu. Kako rastu nivoi kortizola, električni signali u vašem hipokampusu, delu vašeg mozga koji je povezan sa učenjem, sećanjem i kontrolom stresa, smanjuju se. Hipokampus takođe smanjuje aktivnost HNO, pa kada ona oslabi, slabi i vaša sposobnost da kontrolišete vaš stres. Ipak, to nije sve. Od kortizola vaš mozak bukvalno može da se smanji. Previše kortizola za posledicu ima gubitak sinaptičkih veza među neuronima i smanjivanje vašeg prefrontalnog korteksa, dela vašeg mozga koji upravlja ponašanjima, poput koncentrisanja, donošenja odluka, rasuđivanja i društvenih interakcija. Takođe dovodi do toga da se u hipokampusu proizvodi manje novih moždanih ćelija. Ovo znači da vam hronični stres može otežati učenje i pamćenje stvari i takođe stvara osnovu za ozbiljnije mentalne probleme, poput depresije i konačno Alchajmerove bolesti. Posledice stresa mogu se odraziti i na DNK vašeg mozga. Jedan eksperiment pokazao je da količina brige koju majka pacova pokaže prema novorođenom mladunčetu igra ulogu u tome kako će mladunče kasnije u životu reagovati na stres. Mladunci brižnih majki odrasli su kao manje osetljivi na stres jer su njihovi mozgovi razvili više receptora za kortizol koji se lepe za kortizol i ublažavaju reakciju na stres. Mladunci majki koje nisu bile brižne imali su suprotan rezultat i postali su osetljiviji na stres tokom svog života. Ove promene smatraju se epigenetskim, što znači da utiču na to koji geni se izražavaju bez direktne promene genetskog koda. Ove promene mogu se preokrenuti ukoliko se majke zamene. Ali posledice su iznenađujuće. Epigenetske promene koje izazove jedna majka pacova nasleđuju mnoge generacije pacova nakon nje. Drugim rečima, posledice ovih akcija bile su nasledne. Ipak, nisu sve vesti loše. Postoji mnogo načina da se preokrene ono što kortizol radi vašem mozgu. Najjača oružja su vežbanje i meditacija, gde se duboko diše i gde ste svesni i usredsređeni na svoju okolinu. Obe ove aktivnosti smanjuju vaš stres i povećavaju veličinu hipokampusa, čime se poboljšava vaše pamćenje. Stoga se nemojte osećati poraženo zbog pritiska svakodnevnog života. Preuzmite kontrolu nad vašim stresom pre nego što on počne da kontroliše vas.