Human Relationships with Other Animals

Having a visit with my parents' dog, Casey

In recent years, quite a few studies have looked at human relationships with other animals, ranging from animals as companions to their effects on blood pressure, stress, and minor health problems. 

For example, a 2009 study found that compared to a control group, patients with acute depression who spent just thirty minutes with a dog experienced a significant reduction in levels of anxiety.

Dog Owners More Likely to Be Alive One Year after a Heart Attack

A 1995 study published in the American Journal of Cardiology examined the effects of pet ownership and social support on patients’ one-year survival rates after a heart attack. The researchers discovered that heart-attack survivors who were also dog-owners were much less likely to die within one year than those without a dog. Interestingly, being a cat owner did not offer the same protection.

The study also demonstrated that patients who had more social support were more likely to be alive after one year. The researchers suggest that both dogs and social support provide buffers against stress.

Caring for Other Animals

Some studies have also found that pets reduce feelings of loneliness and social isolation.

In my research and conversations with veterans, I’ve learned numerous stories about how a veteran’s a dog has supported him or her through the darkest hours. Animals keep post-traumatic stress survivors focused on the present moment, and provide a reason to get up in the morning—a dog, for example, needs to be fed and taken for a walk.

The act of caring for other animals can help to bring us out of ourselves and become more open to the world around us.

References

Erika Friedmann and Sue A. Thomas, “Pet Ownership, Social Support, and One-year Survival after Acute Myocardial Infarction in the Cardiac Arrhythmia Suppression Trial (CAST),” The American Journal of Cardiology 76 (1995): 1213-1217.

Andreas O. M. Hoffmann, Ah Hyung Lee, Florian Wertenauer, Roland Ricken, Joanna J. Jansen, Juergen Gallinat, and Undine E. Lang, “Dog-assisted Intervention Significantly Reduces Anxiety in Hospitalized Patients with Major Depression,” European Journal of Integrative Medicine 1 (2009): 145-148.

Playing in the dirt makes you more intelligent

Have you ever noticed how a walk outside seems to clear your head?

In my last post, I shared the research about how a strain of bacteria commonly found in soil, Mycobacterium vaccae (M. vaccae for short), triggers the release of serotonin, which helps to regulate mood.

Serotonin’s role in learning and cognition

In addition to mood, many bodily processes are regulated by serotonin—among them, aggression, appetite, sleep, respiration, and endocrine function.

Serotonin also supports learning and cognition. Knowing this, two researchers at The Sage Colleges, Dorothy Matthews and Susan Jenks, decided to find out whether ingesting live M. vaccae would decrease the stress response in mice, while at the same time improving the mice's learning ability.

And their research found this to be true!

Bacteria in the soil makes us temporarily smarter and less anxious

Mice that ingested live M. vaccae prior to and during Matthews and Jenks’ experiment were able to navigate more quickly through a complex maze—almost twice as fast as the control group!—while also demonstrating fewer anxiety-related behaviors.

But the M. vaccae effects were temporary; Matthews and Jenks tested both groups of mice again three weeks later (after none of the mice had ingested M. vaccae for three weeks), and there was no longer a difference in their maze performance and anxiety levels.

The bottom line

The primary way that we take in M. vaccae is by ingesting or inhaling it while spending time outdoors. This research suggests that continual interaction with natural environments brings the most benefits.

So turn off your computer and get outside. You might just start to feel a bit smarter!

References

Dorothy M. Matthews, and Susan M. Jenks. (2013). Ingestion of Mycobacterium vaccae decreases anxiety-related behavior and improves learning in mice. Behavioural Processes 96, 27–35.

Nature’s Antidepressant – How working with the soil might boost your spirits

Have you been looking for an excuse to get your hands dirty? If so, here it is!

In 2002, Graham Rook and Laura Brunet published an article called “Give us this day our daily germs,” in which they argued that our modern-day lifestyles in wealthy countries, including both hygiene and antibiotics, have reduced our exposure to organisms, such as mycobacteria, that live in soil and water.

This reduced exposure, they suggest, is improperly activating our immune systems, resulting in higher rates of allergies and disease. And in the past ten years, many researchers have become interested in the ways that the human immune system is triggered by the world outside our bodies.

Bacteria improves quality of life in cancer patients

Of particular importance are some of the studies examining the effects of Mycobacterium vaccae (M. vaccae)—a strain of bacteria commonly found in soil. For example, while testing the effects of heat-killed M. vaccae on lung cancer patients receiving chemotherapy, oncologists made an unexpected discovery: 

The bacteria did not seem to affect patients’ survival rates, but patients did report an improved quality of life, including better cognitive function and a sense of vitality, as well as some relief of both the chemotherapy-related treatment symptoms and cancer symptoms. 

Bacteria in soil triggers release of serotonin 

Serotonin is vital to nearly all of our physical and behavioral processes, including mood regulation, and many common antidepressant drugs are designed to affect serotonin levels.

Neuroscientists at the University of Bristol decided to investigate the oncologists' findings further, and discovered that heat-killed M. vaccae altered emotional behavior in mice. Specifically, the bacteria produced antidepressant-like effects by triggering neurons in the brain to produce serotonin.

Chris Lowry, lead author of the University of Bristol study, in his conversations with the media, noted that such studies are leading to a better understanding of the connections between healthy immune systems and mental health. “They also leave us wondering if we shouldn’t all be spending more time playing in the dirt,” he also said.

Which leads me to ask:

Have you had your dose of M. vaccae today?

Stay tuned for my next post about how regular contact with M. vaccae might also make you smarter...

References

Lowry, C.A. et al. (2007). Identification of an Immune-Responsive Mesolimbocortical Serotonergic System: Potential Role in Regulation of Emotional Behavior. Neuroscience 146, 756-772.

Medical News Today. (2007, April 2) Soil Bacteria Work in Similar Way to Antidepressants. http://www.medicalnewstoday.com/articles/66840.php

O’Brien, M.E., et al. (2004). SRL172 (killed Mycobacterium vaccae) in addition to standard chemotherapy improves quality of life without affecting survival, in patients with advanced non-small-cell lung cancer: phase III results. Annals of Oncology 15(6), 906-914.

Rook, Graham and Brunet, Laura. (2002). Give us this day our daily germs. Biologist 49(4), 145-149.

Military Veterans and the Outdoors

A few weeks ago, I was excited to learn about a new study involving military veterans and the outdoors, conducted by researchers Jason Duvall and Rachel Kaplan at the University of Michigan’s School of Natural Resources and Environment.

The results? Veterans who participated in outdoor programs—specifically multi-day camping and hiking trips—reported an improved sense of mental wellbeing, as well as feeling less socially isolated. (In the interest of full disclosure, the study was funded by the Sierra Club, which runs the Military Family and Veterans Initiative, an outdoor program for veterans and their families.)

I was not surprised by the results—they align with what I hear every day from the veterans I talk to: that being in nature—whether it’s camping, hiking, biking, canoeing, fishing, farming and gardening, or spending time with animals such as horses and dogs—is helping them to manage their post-traumatic symptoms, and to feel more connected to their communities and life in general. And in many ways, the study’s results parallel the other research I’ve been writing about in this blog.

But a common problem I hear from veterans is that despite their anecdotal reports, there’s very little funding available for these types of activities. And why is there no funding? Because according to the funders (not the veterans), there’s no proof that these activities work(!).

So that’s why this study is exciting. It focuses specifically on veterans, and provides the numbers and proof that funders require. In fact, the reason the Sierra Club sponsored this research was to study whether their Military Family and Veterans Initiative and similar programs were benefiting veterans. From the anecdotal stories of veteran participants, the Sierra Club knew that their programs were important, but hoped that quantitative analysis and results would further support their work.

Most interesting? Many of the veterans continued to experience an improved sense of wellbeing a month after their excursion, and those who were suffering the most seemed to report the most improvement. The researchers acknowledge that more studies are necessary, but this one, at least, is a start.


References:

Duvall, Jason and Rachel Kaplan. (2013). Exploring the Benefits of Outdoor Experiences on Veterans: Report prepared for the Sierra Club Military Families and Veterans Initiative. Retrieved from:

http://www.sierraclub.org/military/downloads/Michigan-Final-Research-Report.pdf

U-M study of veterans finds links between outdoor activities, improved mental health. Retrieved from:

http://ns.umich.edu/new/releases/21605-u-m-study-of-veterans-finds-links-between-outdoor-activities-improved-mental-health

U-M, Sierra Club to study links between outdoor experience, veterans’ mental health. Retrieved from:

http://www.snre.umich.edu/news/01-30-2012/um_sierra_club_to_study_links_between_outdoor_experience_veterans_mental_health

Exciting News - Book due out next spring!

I have not updated this blog recently due to health issues and general busy-ness, but I hope to start posting again next month.

In the meantime, some exciting news:

My book, Field Exercises: How Veterans Are Healing Themselves through Farming and Outdoor Activities, is due out in next spring (2014) with New Society Publishers. This book tells the stories of North American military veterans who are relieving their stress and trauma, creating community, and finding ways to reintegrate into civilian life through small-scale organic farming and other outdoor activities, such as canoeing and hiking.

Nature and Restoration

Over the past few months, I’ve been writing about the different ways that nature affects human health, from lowering blood pressure and decreasing aggression, to healing trauma and helping us think more creatively, and act more cooperatively and respectfully towards others.

Why does nature affect us in these ways? 

One interesting theory is that nature requires a different type of attention than human-built environments, leading it to play a restorative function for human attention.

Slow Rates of Biological Evolution

Researchers who support the restoration hypothesis propose that the importance of nature in human life stems from the fact that our human brains co-evolved with other creatures and with rivers, rocks, winds, skies, mountains, trees, and plants.

And while over the years humanity has experienced high rates of cultural and technological change, the rate of biological evolution has been quite slow, leading human nervous systems today to be virtually the same as those of our long-ago ancestors.

In fact, the role of nature in renewing humans’ ability to concentrate is considered by many scientists to be an evolutionary adaptation. The type of constant, linear attention to a specific task required within urban lifestyles and jobs increasingly over the last 100 years would have been dangerous, even deadly, for our ancestors, since they could have been easily surprised by predators.

Instead of focusing for a long time on one thing in particular, our ancestors needed to be constantly aware of their surroundings and to frequently shift their awareness. Stephen Kaplan argues that natural settings require a reduced amount of energy and effort compared with urban, or what some might consider to be more ‘civilized’ settings, even if the latter settings are more familiar to many of us today. 

Specifically, the human body is thought to respond instinctively to nature in a way that it cannot to the built environment. 

The bottom line

I don't fully buy the restoration hypothesis as the answer to the 'why' question - I suspect there is more going on than just restoration (remember, for example, how plants have biomedical properties that are affecting us every time we step outside, whether we realize it or not). 

But no matter! Just get outside today, away from the buildings and constant demands that surround you, and let those instincts take over. And then do it all over again tomorrow.

References

Kaplan, Rachel. (2001). The nature of the view from home: Psychological benefits. Environment and Behavior, 33(4), 507-542.

Kaplan, Stephen. (1995). The restorative benefits of nature: Toward an integrative framework. Journal of Environmental Psychology, 15(3), 169-182.