Another long post. Sorry. But hopefully less technical than last week’s!
- What does science have to say about how mental and behavioral changes can protect me from chronic stress or reverse its effects?
In 2014, the journal BMC Psychiatry published an excellent review article on the effects of our behavioral decisions on our physical and mental health (Sarris et al. 2014). I recommend it to anyone interested in improving his or her overall health. Here is a brief summary of their findings.
Sarris defines lifestyle medicine as “application of environmental, behavioural, and psychological principles to enhance physical and mental wellbeing.” The authors argue that several lifestyle choices dramatically affect our health including activity level, diet, relaxation and recreation, sleep patterns, social interactions, mindfulness meditation (see below), and use of recreational substances. Take-home points include the following:
- Poor diet (high carbs, especially refined sugars) is associated with anxiety and depression.
- High-quality diet (especially protein and omega-3 fatty acids) is associated with good mental health.
- Diet influences brain plasticity (ability to adapt) and function, stress response, and inflammation, all involved in determining depression and anxiety.
- Adequate exercise reduces depressive symptoms.
- Inadequate exercise is a risk factor for depression.
- Exercise may modulate levels of brain-derived neurotrophic factor (BDNF), cortisol, and another anxiety/depression hormone, 5HT.
- Mindfulness-based stress reduction (MBSR) activates brain regions involved in calmness and increases brainwaves associated with a clam state.
- Alcohol, especially hangovers (chemical withdrawl), increase risk of both acute (short-term) and chronic (long-term) anxiety and general sadness due to an increase in a stress hormone called glutamate.
- Nicotine, both first-hand and second-hand, has similar effects on anxiety and depression as alcohol.
- Caffeine may increase anxiety while decreasing depression.
- Poor sleep habits and low sleep quality are risk factors for depression as well as heart attack, stroke, obesity, diabetes, and heart disease.
Of all the non-medicinal solutions to stress, anxiety, and depression, there is none with more scientific backing than exercise. Both aerobic and resistance exercise have been shown to decrease anxiety and depression (Portugal et al. 2013; Stanton and Happell 2013; Strickland and Smith 2014). Beyond anxiety and depression relief, exercise has been shown to decrease our sensitivity to stress (i.e., increase our tolerance to it). It also improves mood, thinking skills and academic performance, memory skills, self-image, stress coping, neuron growth and activity, and productivity (Portugal et a. 2013; Strickland and Smith 2014).
Sound too good to be true? Exercise stimulates the production of an important hormone called brain-derived neurotrophic factor (BDNF) through the process of muscle contraction (Portugal et al. 2013). BDNF stimulates nerve maintenance and growth, resulting in improved learning, memory, and higher-thinking skills. Exposure to too much cortisol for too long (e.g., due to chronic psychological stress) decreases BDNF production. Exercise restores it.
Aerobic exercise has also been demonstrated to reduce HPA axis reactivity thereby reducing our biological response to stress. So exercise for increased nerve cell maintenance and mental functions (increased BDNF), and decreased HPA axis sensitivity.
It’s also worth pointing out here that while exercise increases cortisol levels in the short term, a regular regimen of moderate exercise decreases long-term cortisol levels (Portugal et al. 2013). Consistent, moderate exercise is the key.
Yoga has grown in popularity in the west largely due to its gradual divorce from eastern religion. The practice is, at its essence, slow, thoughtful meditation, stretching, and resistance exercise. The most scientific study I have found looked at brain waves, electrical impulses that indirectly speak to neurological activity (Desai et al. 2015). It was shown that yoga increased α-, β-, and θ-brainwaves, all of which are linked to improved memory, mood, and thinking skills, and to reduced anxiety. The authors claimed that yoga increased memory, reaction time, mental focus, and verbal task performance while decreasing pain perception, stress perception, and measured cortisol levels in the blood. They demonstrated that yoga practice led to re-structuring of particular locations within the brain, a phenomenon commonly known as neural plasticity.
The University of California at Berkeley’s Greater Good Program (http://greatergood.berkeley.edu/) defines mindfulness as “maintaining a moment-by-moment awareness of our thoughts, feelings, bodily sensations, and surrounding environment.” And Psychology Today magazine says that mindfulness meditation “helps us be present with whatever is happening, no matter what it is.” In short, mindfulness meditation is a way of quieting our minds for a few minutes each day to reduce our natural tendency to retreat from psychological and physical pain. It not only calms our minds, but also reduces our vulnerability during stressful situations.
Evidence in the published scientific literature supports the claims that practicing mindfulness can reduce anxiety, depression, and physical pain (Goyal et al. 2014). The effects are equal to those resulting from active treatments (e.g., medication, exercise).
One recent study (Zeidan et al. 2014) showed clear activation of brain regions involved in regulating negative emotions and determining the value of emotional events (the anterior cingulate cortex, the ventromedial prefrontal cortex, and the anterior insula). In other words, mindfulness meditation empowers our brains to process psychological stress and emotional challenges in a healthy way, avoiding the downward spiral that often results when we are overloaded.
The same study also revealed that the brain regions involved in fear (the amygdala) and rumination (the anterior insula) were downregulated with mindfulness meditation. Fear is a common response when we feel overwhelmed and leads to anxiety, including panic attacks and other anxiety disorders, and depression. Rumination is just a fancy word for stewing on events of the past or obsessing over future events, imagined or real. This rumination is one of the primary causes of anxiety and depressive disorders, and mindfulness can help us avoid it.
If you are interested in more information about mindfulness, I recommend UCSD’s Center for Mindfulness (http://health.ucsd.edu/specialties/mindfulness/Pages/default.aspx).
Virtually every publication on stress management includes something about the central role of slow, deep breathing exercises in the reduction of symptoms. Despite this universal acceptance, I have found it difficult to find a definitive scientific explanation for the mechanism of deep breathing stress reduction.
The American Institute of Stress claims that slow, deep breathing from the abdomen (not the chest) for several minutes a day can reduce the symptoms of stress and anxiety. Many scientific publications make similar claims.
Kimura et al. (2005) and Brown and Gerbarg (2005) demonstrated the beneficial effects of specific types of deep breathing exercises called Nishimo breathing and Sudarsha Kriya breathing, respectively.
Reiner (2008) used a portable heart monitor that gave its users real-time information on their heart rate (biofeedback) as an indicator of stress arousal status. Use of the device resulted in decreased measures of anxiety and anger, and alleviated some sleep disorders associated with stress.
Conrad et al. (2007) discovered that clear instructions for how and when to do deep breathing exercises had an impact on the degree to which the exercises could reduce stress symptoms.
Although I have yet to find a satisfactory explanation of the mechanism of stress relief from deep breathing exercises, the scientific and medical communities have universally accepted their validity. I can also attest to benefits I have personally gained from deep breathing exercises both in the moment of stress and on a daily basis for the reduction of stress sensitivity.
From what I can gather so far, it appears that deep breathing slows the heart rate. These two together, slow breathing and slow heart rate, send signals to the brain via the vagus nerve indicating that all is well. The brain responds by stimulating the parasympathetic nervous system, which tells the entire body to be calm. The specific anatomy and biochemistry (neurochemistry and endocrinology) involved elude me. But I will continue to work on this question until I am satisfied!
A word about gut health
Very recent research in the worlds of microbiology and neurobiology indicates that there is two-way communication between the human gut, which is filled with billions of microorganisms, and our brains (Zhou and Foster 2015). While the details are still emerging, it appears that our mental health can dramatically influence our gut health and vice versa. So, if your gut is not working right, it may put you at risk for anxiety or depression. Conversely, it may be anxiety or depression that is causing your gut to malfunction. A vicious cycle is the result. If you are struggling in both areas (gut and emotions), see your doctor. The cycle can be broken.
References (I can email you any of these on request)
Brown and Gerbarg. 2005. Sudarsha Kriya yogic breathing in the treatment of stress anxiety, and depression: part I – neurophysiologic model. J. Altern. Complement. Med. 11:189-201.
Conrad et al. 2007. Psychophysiological effects of breathing instructions for stress management. Appl. Psychophysiol. Biofeedback 32:89-98.
Desai et al. 2015. Effects of yoga on brain waves and structural activation. Compl. Ther. Clin. Prac. 21:112-118.
Goyal et al. 2014. Meditation programs for psychological stress and well-being: a systematic review and meta-analysis. JAMA Intern. Med. 174:357-368.
Kimura et al. 2005. Beneficial effects of the Nishimo breathing method on immune activity and stress level. J. Altern. Complement. Med. 11:285-291.
Portugal et al. 2013. Neuroscience of exercise: from neurobiology mechanisms to mental health. Neuropsychobiol. 68:1-14.
Reiner. 2008. Integrating a portable biofeedback device into a clinical practice for patience with anxiety disorders: results of a pilot study. Appl. Psychphysiol. Biofeedback 33:55-61.
Sarris et al. 2014. Lifestyle medicine for depression. BMC Psychiatry. 14:107-119.
Stanton and Happell. 2013. An exercise prescription for people with depression. Issues in Ment. Health Nurs. 34:626-630.
Strickland and Smith. 2014. The anxiolytic effects of resistance exercise. Front. Psych. 5:article 753
Zeidan et al. 2014. Neural correlates of mindfulness meditation-related anxiety relief. SCAN 9:751-759.
Zhou and Foster. 2015. Psychobiotics and the gut-brain axis: in the pursuit of happiness. Neuropsychiatric Dis. and Treat. 11:715-723.