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.
Estás durmindo sen descansar, estás irritable ou de mal humor, esqueces pequenas cousas e sénteste desbordado e só? Non te preocupes. Todos vivimos iso. É probable que esteas estresado. O estrés non é sempre algo malo. Pode producir un estoupido de enerxía e concentración como cando participas nunha competición deportiva ou tes que falar en público. Pero cando é continuo, como o que a maioría sufrimos día tras día, comeza a cambiarche o cerebro. O estrés crónico, cando traballas moito ou rifas na casa, pode afectar ao tamaño do cerebro, á súa estrutura e ao seu funcionamento ata o nivel dos xenes. O estrés comeza con algo chamado eixe hipotálamo-hipofisario-adrenal, unhas interaccións entre as glándulas endócrinas do cerebro e as suprarrenais, que controlan a reacción do corpo ó estrés. Cando o cerebro detecta unha situación tensa, o eixe HHA actívase decontado e libera unha hormona chamada cortisol, que prepara o corpo para actuar. Pero altos niveis de cortisol nun período longo causan estragos no cerebro. Por exemplo, o estrés crónico aumenta o nivel de actividade e o número de conexións neuronais na amígdala, o centro cerebral do medo. Ó aumentar os niveis de cortisol os sinais eléctricos no hipocampo, a parte do cerebro asociada á aprendizaxe, á memoria e ó control do estrés, deterióranse. O hipocampo tamén inhibe a actividade do eixe HHA, polo que cando se debilita tamén se debilita a capacidade de controlar o estrés. Pero iso non é todo. O cortisol pode facer que o cerebro diminúa o seu tamaño. Un nivel excesivo provoca unha perda de conexións sinápticas entre as neuronas e a diminución do córtex prefrontal, a parte do cerebro que regula condutas como a concentración, a toma de decisións, o xuízo e a interacción social. Tamén diminúe a formación de novas células cerebrais no hipocampo. Isto implica que o estrés crónico dificulta a aprendizaxe e debilita a memoria, pero tamén abre a porta a problemas mentais máis graves como a depresión e, co tempo, o alzhéimer. Os efectos do estrés poden filtrarse ata o ADN do cerebro. Un experimento amosou que a cantidade de comida que unha rata nai lle dá á súa cría relaciónase con como a cría responderá ó estrés na súa vida. As crías de nais que alimentan son menos sensibles ó estrés porque o seu cerebro aumenta os receptores de cortisol, que se pegan ó cortisol e minoran a resposta ó estrés. As crías de nais desleixadas tiveron o efecto contrario e foron máis sensibles ao estrés ó longo da súa vida. Estes son considerados cambios epixenéticos, que alteran como se expresan os xenes sen modificar o código xenético. Os cambios poden ser reversibles se as nais se intercambian. Pero hai un resultado sorprendente. Os cambios epixenéticos que causa unha rata nai transmitíronse a moitas xeracións posteriores. Noutras palabras, os resultados desas accións foron herdados. A pesar diso, non todo son malas novas. Hai moitos xeitos de desfacer os efectos do cortisol nun cerebro estresado. Os máis efectivos son o exercicio e a meditación, que consiste en respirar profundamente, e tomar conciencia e concentrarse no que nos rodea. Ambas as actividades diminúen o estrés, incrementan o tamaño do hipocampo e axudan a mellorar a memoria. Non te sintas vencido pola presión do día a día. Toma o control do estrés antes de que el te controle a ti.