For the last 30 years I have regularly enjoyed time away in a natural setting. Invariably I would feel emotionally and mentally recharged, even if physically I was recovering from an extended bushwalk, mountain bike or weekend climbing. In my own terms this was like a reboot for my soul, where the benefits would last for weeks until my next nature fix. There are now more and more scientists researching how “forest bathing” makes changes to our health and wellbeing.
The term forest bathing is a translation of the Japanese movement “shinrin-yoku”. So strong is the movement that the Japanese Society of Forest Medicine has formally conducted research. Indeed the Japanese, Taiwanese and South Korean governments are investing heavily into this area. Of interest is that these nations are the big users of technology, and many of the populous are disconnected from the natural world.
A series of studies have measured cortisol, heart rate and blood pressure to demonstrate the measurable benefits of wellbeing and performance by simple contact with nature. Interestingly some Japanese research has shown that exposure to nature not only mediated the stress response, but also impacted the immune response. A group of Japanese businessmen had a 40% increase in natural immune “killer cells” after a walk in the woods. These killer cells are our immune systems first line defensive weapon against infection like the influenza virus. Interestingly these killer cells were still elevated by 15% over baseline figures one month later!
In the book “Your Brain on Nature: The science of natures influence on your health, happiness and vitality”, the authors a medical doctor and naturopath, cite various examples around the world supporting the title of their book. Among them, subjects in an aged care facility in Texas showed decreased stress hormones when in a garden setting; a study in Kansas using EEG showed less stress in subjects when plants were in the room; researches in Taiwan using measures like EEG and skin conductance noted therapeutic effects in subjects viewing natural settings; a group in Japan had lower heart rates after viewing natural scenes for 20 minutes; another 119 research subjects in Japan showed less stress response when transplanting plants in pots than they did simply filling pots with soil.
So what are the mechanisms for these reported changes to wellbeing?
In the 1970’s, research showed changes to alpha brain wave activity when partcipants drove along tree line boulevards instead of freeways. Alpha waves are associated with serotonin production and had a positive effect on depression, anxiety, anger and aggression. More recent, research into phytoncides- phytochemicals that are given off by trees and plants, showed they had a profound effect on the brain. Not only did they lower stress hormones, they regulated pain and reduced anxiety. Simply taking a walk in the forest and breathing deep was providing a direct chemical pathway to the brain via our olfactory system.
It appears that our brain has evolved in nature. There is only a minority of humanity that has existed for more than a couple of generations in a purely urban environment. Nature is ingrained in our DNA and neurobiology! Researches using fMRI have pinpointed where in the brain nature works its magic. In particular the parahippocampus gyrus, which is rich in opioid receptors. Nature is like a little drop of morphine to the brain!
But there are other benefits of being in the outdoors. Firstly, play in nature exposes children and everyone else to a full range of microbes to support a healthy gut flora and challenge and tune ones immune system. Otherwise known as the hygiene hypothesis -where modern, urban people are showing a rapid increase in autoimmune disease because they live in an over sanitized environment. To be healthy our internal ecosystems need to be connected to external ecosystems.
Other researches propose the hypothesis that sleep disorders have become epidemic because of widespread Vitamin D deficiency. Being outdoors exposes people to the full spectrum of light, with a variety of benefits, not the least amongst them regulating melatonin and sleep cycles but also making healthy levels of vitamin D. Vitamin D deficiency is an epidemic in its own right, but in this light it is the subject of the epidemic of nature deficit disorder!
So how do I get my nature fix? Prior to the birth of my son Samuel this involved regular weekends away camping and walking. These days I enjoy gardening when at home or lying in the hammock enjoying the surrounding tree canopies. A simple mindful walk in the Botanic Gardens or down by the Yarra River is another great place to forest bath. My wife Karen knows that I need a regular nature fix every 4-6 weeks to maintain emotional regulation at home and work. Apparently I am not nice to be around when in nature deficit.
Your Brain on Nature: The science of natures influence on your health, happiness and vitality.
Eva M Selhub MD & Alan C Logan
Go Wild: Eat fat, run free, be social, and follow evolutions other rules for total Health and wellbeing.
John J Ratey MD & Richard Manning
The Nature Fix: Why nature makes us happier, healthier and more creative.
Dr. Ming Kuo’s extensive research scientifically proves what we intrinsically know to be true: That spending time in nature has profoundly positive and long-lasting effects on our psychological, physical, and social health.
Fasting has always been a part of human evolution. Back in hunter-gatherer days we would go prolonged periods without food, expending energy as we hunt our prey. It wasn’t until 10,000 years ago when agriculture emerged, going without food became less normal. However, fasting has never been truly absent in many cultures and religions: e.g. short fasting in Judaism’s 24-hour Yom Kippur, and Buddhism’s daily post-midday fast, to the prolonged 30-day dawn-to-dusk fasting for Muslims in Ramadan
Fasting- The science
In recent times fasting has become a hot topic amongst scientists and has fueled much research into the mechanism of associated health benefits associated with reduced calorie consumption and intermittent fasting (IF).
Back in 1945, a study in the Journal of Nutrition discovered that rats could increase life expectancy (20% for males and 15% for females). This was achieved by reducing calorie consumption with an intermittent fast of 1 day in 3 achieving best results.
Since this time there has been a variety of studies both in animals and humans to see how health and longevity were affected by IF. A review of such research in the American Journal of Nutrition found that IF modulated several risk factors, thereby preventing chronic disease in animals. Human trials to date have reported greater insulin-mediated glucose uptake. The limited human evidence suggests higher HDL-cholesterol concentrations (healthy cholesterol) and lower triacylglycerol concentrations.
Currently some of the reported benefits of IF:
So how do we explain the benefits of daily energy restriction (DER) and IF? A breakthrough came from a Japanese biologist Yoshinori Ohsumi who won the Nobel prize in 2016 for his work into autophagy (pronounced ‘or-toffa-gee’) – when pathogens (infectious agents), cell ‘junk’ or old and damaged structures are broken down inside a cell and the parts reused.
This is basically what happens in the body everyday as a byproduct of its metabolic processes. Otherwise known as “oxidative stress” it’s a bit like rust building up on your engine over time. It will inevitably happen unless we give our body an opportunity for essential maintenance. This is where autophagy kicks in and fasting taps into this process of cell repair and regeneration.
This is how physiologist believe it happens…
When we don’t eat for several hours the liver stops secreting glucose into the blood stream and instead uses it to repair damaged cells. Simultaneously the liver releases enzymes that break down stored fat and cholesterol. Hence during an (IF) our liver is repairing oxidative stress and burning fat.
The key is that what we eat, and when, affects this process. Sometimes what we eat pushes cells to keep multiplying and not recycle, called an anabolic state. Sometimes our body moves into a different state – one where we tidy up cells, kill off and recycle old ones. This is called the catabolic state, and it happens when we don’t eat. For optimal human health, the balance between anabolic and catabolic processes is crucial. Unfortunately this has been disrupted by modern society- readily available food sources, high-density calorific processed food and environmental influences such as marketing that promote regular snacking!
Putting Intermittent fasting into practice.
Michael Mosley has popularized (IF) with his books the 5:2 and the fast 800….
Time-restricted feeding (TRF): has been gaining popularity in recent years as perhaps an easier way of reducing the calories you consume every 24 hours. The basic premise is to only eat within a set period of time – anything from an 8 to 12-hour window being typical. In practice this means you finish eating after dinner at, say, 8pm – and you don’t eat again until 8am the next day (12-hour window for eating) or 12pm the next day (8-hour window for eating).
I have been trialing this 16 hour fast in every 24-hour period, as I am asleep for half and need only miss breakfast. From a compliancy perspective this is more realistic and the key for me is not to overcompensate in volume or quality. As previously reported I mainly stick to a Mediterranean diet, mainly plant based with fish, legumes, nuts (and red meat 1 -2 times week).
Finally for any eating plan to work it must be specific to your dietary needs attractive to you and sustainable for the long term. Certain Individuals should reframe from severe calorific restriction and fasting protocols. Michael Mosley has some guidelines, but best speak to your physician or qualified nutritionist/ dietician first.
Have you tried Intermittent fasting? If so what has your experience been?
I would love to hear from you J
Listen to Michael Mosley on RN podcast
Inflammation: a new approach to obesity and depression
Centenary Institute Oration recorded 16 September 2019