Brain Chemicals and Modern Life
It all comes down to our chemistry. Fidgeting, concentration, sleep, energy levels, mood swings, even the ability to sweat are controlled by the chemicals lurking about our bodies. Serotonin, dopamine, norepinephrine, melatonin, insulin, and prostaglandins are some of the more important ones...and these in turn are influenced strongly by stress, diet, exercise, sunlight, sleep and other life style factors. Of course the life style of today is radically different than it was 20,000 years ago. Consider how these factors from modern life commonly influence us:
Being indoors (lack of sunlight): Reduced melatonin
Stress: Reduced serotonin
Modern food processing: Fatty acid imbalances and chemical sensitivities
High sugar/carbohydrate and low-fat diet: More insulin; prostaglandin imbalance
Lack of exercise: Decreased serotonin and dopamine
Lack of sleep: Reduced serotonin
Poor nutrition: Reduced serotonin
Boring classes/job, lack of activity: Reduced dopamine & norepinephrine.
Deionized air: Reduced serotonin
Reduced serotonin levels from stress, lack of sleep & exercise, poor nutrition, and lack of sunlight are connected with ADD, irritability, depression, aggression, anxiety, lack of concentration, chronic pain, restlessness or fatigue, nausea, obsessive-compulsive disorder, weight gain or loss, fibromyalgia, arthritis, chronic fatigue syndrome, heat intolerance and other syndromes. Fluctuating serotonin levels are connected with bipolar disorder (manic depression) and hypomania. You don't have to feel depressed or anxious; symptoms may be purely physical.