An interesting piece of research has recently been published in the journal, Nature Human Behaviour. The research demonstrated that the simple act of recalling positive memories after a stressful event lowers a stress-related hormone and increases activity in parts of the brain that regulate emotional and cognitive control.
Cortisol and Stress
After a stressful event, people will usually experience a rise in their cortisol levels. Cortisol is a steroid hormone produced in the adrenal glands. Although this is a crucial hormone for our well-being, high levels of cortisol can cause problems including hypertension, high blood sugar and suppression of the immune system. In addition, when we are exposed to stress, the parts of the brain that control emotional regulation and cognitive control are suppressed.
The Effect of Happy Memories During Stressful Situations
The authors in this study, M. Delgado and M. Speer[i], tested the effect of past memories by exposing 134 volunteers to a stressful situation; being videoed while immersing their hands in icy water. Some of the subjects were then asked to spend 14 seconds thinking about a positive experience (e.g. a holiday). Others were instructed to spend the same amount of time thinking about an emotionally neutral event (e.g. carrying out a mundane task). Results showed that the subgroup who recalled positive, happy memories felt better and experienced only a small increase (15%) in their cortisol levels compared to those who focussed on neutral memories (85%).
Using an fMRI[ii] scan to test the same stressful situation, researchers found that those who recollected happy memories experienced increased activity in their prefrontal brain regions. These regions are the ones associated with regulating emotions and controlling cognitions. They become suppressed under acute stress. The research concludes that thinking about happy memories appears to go right to the core of the physiological stress response, cutting cortisol levels and activating the reward centres in the brain.
It may seem obvious that recalling happy memories can make you feel better. However, demonstrating that such a simple technique really can lower your stress levels is important. There is much research that supports the theory that those who are able to lower physiological levels of stress after a difficult event tend to be healthier in body and mind.
The authors of the study explain that self-generated positive emotions help the brain widen its focus from a current bad situation. They add that recalling happy memories appears to work better than simple distraction or the use of positive imagery. They also note that this technique is different from mindfulness, which encourages people to focus on the present, rather than the past or future.
In conclusion, recalling happy memories is simple, and has been scientifically demonstrated to improve mood and lower stress. Next time you are in a stressful situation, why not try it for yourself?
[i] Delgado, M. & Speer, M. (2017) ‘Reminiscing about positive memories buffers acute stress responses,’ Nature Human Behaviour, April
[ii] Functional Magnetic Resonance Imaging