The Stress-Exercise Connection—How Does it Work?

With today’s societal demands, there is no shortage of stressors in our daily lives. We deal with so many issues such as health, education, relationshps, finances, and more. Sometimes when things are stressful, we go for a walk, jog or swim and come back feeling calm and better equipped to deal with the issues at hand. Did the stress go away? It’s probably still there but something happened in your brain to be able to handle the information better in a less stressful way. What happened? 

75% of the general population experiences at least “some stress” every two weeks according to the National Health Interview Survey. Since psychological stress begins in the brain when we perceive a threat, let us first understand how the body handles that stress with something called the fight-or-flight response.” The fight-or-flight response refers to a physiological reaction that occurs in the presence of something that is terrifying, either mentally or physically. The fight-or-flight response was first described in the 1920s by American physiologist Walter Cannon. Cannon realized that a chain of rapidly occurring reactions inside the body help mobilize the body’s resources to deal with threatening circumstances. In response to acute stress, the body’s sympathetic nervous system is activated due to the sudden release of hormones. The sympathetic nervous system stimulates the adrenal glands triggering the release of adrenaline and noradrenalin. This results in an increase in heart rate, blood pressure and breathing rate. After the threat is gone, it takes between 20 to 60 minutes for the body to return to its pre-arousal levels.

The fight-or-flight response is also known as the acute stress response. Essentially, the response prepares the body to either fight or flee the threat. It is also important to note that the response can be triggered due to both real and imaginary threats. Imagine yourself driving along a road near your house. Suddenly a car zooms out of nowhere! You slam on the brakes just in time to avoid an accident. That’s the stress response at its best.

Stress and the Brain

There are three regions of the brain that control the stress response: The Amygdala, which detects, treats and triggers the fight-or-flight response; the Prefrontal Cortex, which helps us deal calmly with stress, and can shut down the fight-or-flight response; and the hippocampus, which supports our stress recovery. Neroscientists now know that chronic stress can change these brain regions in a way that makes us more sensitive and less resilient to stress.

When we have stress all the time, these areas weaken and the brain gets worse at managing stress. When this goes on for a prolonged period of time, these changes in the brain stress effects the braincan lead to depression, cardiovascular disease and accelerated aging. But as we mentioned at the beginning of this article, exercise can be a way to manage or even cure stress. Let’s see how that works.

Using Exercise to Combat Stress

Numerous studies in 2011 and 2012 have shown that exercise has shown tremendous promise as a neuroprotective intervention. Exercise protects our brains from stress in several ways. When we exercise (and the more intense we can exercise the better the result) we increase something called Brain-Dirived Neurotphic Factor (BDNF), which maintains brain health. Not only does exercise give us more BDNF, it also triggers the brain’s self-repair processes. And last, exercise also activates the brain’s self calming system by releasing a neurotransmitter called GABA (gamma-Aminobutyric acid) in order to restore balance in the autonomic nervous system. Perhaps the most encouraging research is that for someone who makes exercise a part of his or her life, exercise can create a STRESS RESISTANT BRAIN! (Fleshner et. al. 2011).

How much does one need to exercise and at what intensity?

As previously stated, intense exercise is good, but intense exercise for a prolonged period of time is not good for our cardiovascular system, our immune system or our brains. So it seems that moderate exercise for less than an hour at a time brings the best results. Overtraining, meaning intense exercise for a prolonged period of time, can have the opposite effect of what we are trying to achieve. An over-trained athlete can actually develop exaggerated stress response and fail to recover between his workouts. That results in elevated stress hormones, and instead of exercise giving us long-term protection against stress, it amplifies our stress.erotonin, norepinephrine and dopamine.

Remember that exercise in all of its forms, aerobic and resistance training does help us manufacture more of the feel-good neurotransmitters in our brains, serotonin, dopamine and norepinephrine. These are the same hormones that anti depressant medications work on. The now famous SMILE (Standard Medical Intervention and Long-term Exercise) study at Duke University in 1999 the researchers followed 156 patients between the ages of 50 and 77 who had been diagnosed with major depressive disorder (MDD). They were randomly assigned to one of three groups: exercise, medication or a combination of medication and exercise.

The exercise group spent 30 minutes either riding a stationary bicycle or walking or jogging three times a week. The anti-depressant used by the medication group was sertraline (trade name Zoloft), which is a member of a class of commonly used anti-depressants known as selective serotonin re-uptake inhibitors. To the surprise of the researchers, after 16 weeks, all three groups showed statistically significant and identical improvement in standard measurements of depression, implying that exercise is just as effective as medication in treating major depression and it doesn’t have the negative side effects of the various medications.

We are all familiar with the wonderful physiological advantages of exercising, helping to prevent heart disease, cancer, diabetes and a host of other diseases. But we now know that exercise can help us in our battle against all types of daily stress. Reducing stress through exercise will add hours to your day, days to your year, and years to your life.”

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