Another lifestyle factor that can really zap your memory power is stress. Feeling stressed is of course just another part of being human. But overwhelming stress can take a tremendous toll on our overall health, not to mention our memory.
How would you describe stress? For most of us stress is a feeling of pressure and lack of control. Yet formally defined, stress is merely the way you react to change. Stress in and of itself is not problematic. In fact, both “good” and “bad” life events are stressful. What distinguishes “good” stress from “bad” stress (distress) is the degree to which we feel we are in control. For example, most people would consider losing their job as more stressful than getting married. It is the sense of the former being more out of your control that makes it more distressful.
To understand how stress affects memory, let’s look at what happens when we feel stress. When we experience stress, our body triggers a “stress adaptation” response, otherwise known as the “fight or flight” response. So what happens?
– Hormones, including adrenaline and glucocorticoids, are released
– Heart rate increases
– Breathing becomes more rapid and shallow
– Stored sugar is released toy the liver
– Senses are heightened
– Muscles, tense to prepare for movement
– Blood flow to digestive organs and extremities is restricted
– Blood flaw to brain and major muscles increases
This response to stress is a remnant of our primitive past. After all, this kind of preparation was essential if we were faced with something life-threatening, such as an attacking bear. Rarely today do we find ourselves in such life-or-death situations. But our bodies can’t tell the difference between such events and the relatively mundane pressures of modern living, such as being stuck in traffic or getting into an argument with your spouse. The stress-adaptation response kicks in, again and again, exposing us regularly to low levels of this stressed condition.
This unrelenting chronic stress has been associated with various medical and emotional conditions, ranging from cardiovascular disease, gastrointestinal ailments, immune suppression; and endocrine changes. What about memory? Stress lowers memory performance secondarily because of its impact on overall health. Stress also makes us more distracted, which lowers our ability to acquire information we may want to remember.
There is growing evidence that stress may directly impair memory function as well. Research has linked excess stress to shrinkage of the hippocampus, the area of the brain associated with new learning. Evidence for this has come from animal studies as well as studies in human populations exposed to excessive stress, such as individuals suffering from post traumatic stress disorder. Scientists theorize that stress-induced increases of glucocorticoids are responsible for such changes. While more work is needed in this area, these findings suggest that stress is bad for memory in more ways than we previously understood.