According to the Netherlands Brain Institute, too much stress causes your brain to work less effectively. 'Stress itself is completely normal, and even healthy' confirms neuroscientist Erno Hermans. 'Without stress, life would be rather boring. Too much stress however changes your brain. Relaxing regularly is vital'.
When we think of stress, the first thing that comes to mind is work-related overload. Our biological 'stress system' however is first and foremost a mean for survival, created at the time when our ancestors had to run away from bears, battle enemy tribes and survive the bitter cold. It is an alarm mechanism: it makes us alert, gives us extra strength and helps us to survive, and nature intended this to only be active for short periods of time.
In terms of neurobiology, two systems come into play when we are stressed: a fast system and a slow system, as Erno Hermans describes. Hermans is a psychologist and neurobiologist with Radboud University and the Donders Instituut Nijmegen. His main area of research is the biology of our brains. Part of this means focusing on the influence of stress in particular: what happens, what are the effects and how does our brain fix itself?
According to Hermans, the fast stress system is fuelled by adrenaline. This elevates your muscle tension and increases your heart rate, causing you to make a fight-or-flight decision, and activates areas in your brain which allow you to react extremely quickly. Very useful in dangerous situations, but with one downside: this alertness causes other functions to go into low-power mode. When under stress you are less focused, you think less clearly and cannot remember things. Stress is an acute survival mode You are able to relax later, once 'the bear has gone'. The cortisol hormone, the slow system, then begins to work. This releases energy, but also ensures your stress reaction has time to decrease so you can relax again, usually after about half an hour. The body decides this 'high alert mode' cannot carry on for long.
This is why things start to go wrong during long periods of stress: your body begins to release stress hormones and so cannot go back to its original state. Hermans: 'It's like being on high alert all day, and with all the consequences this brings about. Important systems are put on standby, your immune system works less, and your reserves are drained'. This is not only exhausting, but actually changes something in your brain. 'If you are very stressed, your brain adapts to this: connections in the prefrontal cortex diminish, while creating connections in the amygdala, the part of your brain that deals with shock and fear. Your alertness areas get stronger: stress mode becomes your default, whilst clear thinking, remembering and concentration become more difficult. You can see this very clearly in people who suffered trauma during their early childhood: they have measurably different brain structures and functions'.
“Relaxing and going outside is demonstrably good for your brain”
The question then is what do we do? Neurobiology has the answer. “Plan your moments of rest”, says Hermans. 'Keep to your natural pace so your stress and sleep systems, as well as all other biological systems, have room'. This way you stay within your 'window of tolerance', the space in which you are not over-stimulated (fight mode, flight mode, irritable, angry or panicked) or under-stimulated (desensitized, lazy, absent or lethargic), but a good midpoint between the two: calm, relaxed and able to reflect. This is where you function best.
Hermans has a final piece of good news for people who have been working under huge pressure for a long time and are wondering if they really can recover. 'Recovery is possible, even after long-term stress. When you relax and go outside, and move your body more, this is demonstrably good for your brain. Movement stimulates neurogenesis, the creation of new connections, particularly in the hippocampus, the area of the brain where you store new things and create new memories. This is possible even at an older age'. So it's never too late to get moving.