As the days grow shorter and colder, many of us will resign ourselves to fewer outdoor activities. But, fighting the lethargy of winter months and getting outside may do more than just boost vitamin-D and combat seasonal affective disorder. Moving through a natural environment has been shown to enhance attention and memory, relieve stress and depression, and boost immunity.
The therapeutic benefits of being outside may partly stem from alleviating what’s termed directed-attention fatigue, or essentially an overworked prefrontal cortex. In a typical multi-tasking, computer-centric day, your prefrontal cortex is constantly helping you to focus attention, tune out distractions, and shift from one task to another – and back again. A growing body of research supports the idea that spending time in nature provides some cognitive downtime and helps to restore or refresh these cognitive capacities. This notion has led to an entire field of cognitive science known as Attention Restoration Theory (ART).
A prominent study on ART was released in 2008 by a team of scientists from the University of Michigan. It revealed that adults performed 20 percent better on tasks of attention and working memory after a 50-minute walk in a park, compared to a walk in a noisy urban setting. In contrast to natural environments, the authors surmise that urban environments are less cognitively restorative because they are filled with mental stimulations, many of which demand our directed attention (e.g., to avoid getting hit by a car). A 2012 study by this same team of scientists showed similar cognitive benefits in patients with clinical depression. Attention and memory benefited more so from the nature walk; however, mood was lifted by walking – regardless of the setting. This is good news for those who may not have easy access to green spaces (more on exercise and depression later!).
Preliminary work by Dr. Jason Duvall (also at University of Michigan) suggests that to most benefit from exercising in nature, you really need to be present in it. He suggests that heart-rate monitors, iPods, or GPS devices can all subtly alter the experience of being outdoors. If you are constantly dialed in to a device and addicted to its output, you are not allowing yourself the same cognitive downtime that you would without it.
It almost seems that exercising in the great outdoors can elicits a type of meditation. I think this is one place where endurance-type activities have an enormous advantage. You just can’t get “lost in the moment” during a tennis match, cross-fit workout, or game of pick-up basketball. Be it running, walking, hiking, or biking, the repetitive nature of the movements can transport you to a calm, near zen-like “zone” where you are totally caught up in the here and now. For me, this is never more true than when I’m running through wooded trails. It turns out; this is precisely the premise behind “mindfulness training.” Mindfulness training essentially teaches the mind to be attentive to the present and not dwell in the past or project to the future.
Because of this link between exercise and mindfulness, a new study in the Frontiers in Human Neuroscience caught my eye this week. Using fMRI, the authors found that 8-weeks of mindfulness training can reduce the amygdala’s response to emotional stimuli. The amygdala is a region deep within our temporal lobes that plays a key role in processing emotions. Abnormalities here have been linked to anxiety, depression, and phobias. So, they essentially found that by regularly engaging in mindfulness, we can provoke enduring, beneficial changes to how our brains process emotions in everyday life. Interestingly, mindfulness training has even been shown to boost immunity by reducing pro-inflammatory gene expression. How’s that for a mind-body connection?
The mind aside, Dr. Miyazaki and his colleagues in Japan have unearthed some fascinating physiological changes that stem from being in nature. Walking through natural environments for just 15-20 minutes can lower pulse rate, decrease blood pressure, and lower sympathetic nerve activity (responsible for the fight or flight response). It also seems that it can physically ease stress, as concentrations of cortisol (a stress hormone) were nearly 13 percent lower after the short outdoor walk. This group has even found benefits of forest walking on the expression of certain anti-cancer proteins and the immune system.
As winter kicks into full gear, you might reconsider hopping on the treadmill or trainer again and bundling up for a dose of nature instead. You might even try leaving those gadgets behind.