How exercise works to improve depressed mood
Many studies show that infrequent physical activity increases the risk of developing depressed mood. Physical exercise increases the levels of brain-derived neurotrophic factor (BDNF) and may enhance neural plasticity and new synapse formation. Regular exercise is associated with increases in the relative size of the frontotemporal and parietal lobes, which are important centers for learning, memory, and executive functioning. Brain levels of endorphins, dopamine, norepinephrine, and serotonin are increased following sustained exercise.
Regular exercise is as effective as antidepressants
Two meta-analyses of controlled trials confirmed consistent positive effects of regular exercise on depressed mood. Aerobic conditioning and strengthening exercise are equally effective against depressed mood. The optimum duration and frequency of exercise for depression have not been determined but are probably related to age and fitness level. In a 16-week study (156 subjects), depressed patients older than 50 years randomized to aerobic exercise three times a week versus sertraline (Zoloft) (up to 200 mg per day) versus exercise plus sertraline experienced equivalent improvements in standardized measures of mood, self-esteem, and negative thoughts. Patients in the antidepressant-only group initially improved faster. However, patients in the exercise-only group had a lower 6-month relapse rate.
Exercise is as effective as cognitive behavioral therapy
The antidepressant effects of running or fast walking may be equivalent to those of CBT and conventional antidepressants for moderate depressed mood. Depressed individuals who exercise in a brightly lit (2,500 to 4,000 lux) indoor environment reported greater improvements in mood and vitality than depressed individuals who exercised indoors in ordinary room light (400 to 600 lux).
Regular moderate exercise reduces the risk of dementia
Routine physical activity is associated with reduced risk of all categories of dementia. More than 2,000 physically nonimpaired men aged 71 to 93 years were followed with routine neurological assessments at 2-year intervals starting in 1991. At the end of the study period, men who walked less than 1/4 mile daily had an almost twofold greater probability of being diagnosed with any category of dementia than men who walked at least 2 miles daily. Findings of the Nurses’ Health Study based on biannual mailed surveys over 10 years showed that women aged 70 to 81 years who engaged in regular vigorous physical activity were significantly less likely to have been diagnosed with dementia than women with more sedentary lifestyles.
Exercise does not slow the rate of cognitive decline after onset of dementia
A small randomized study found that regular daily exercise in individuals with moderate dementia receiving in-home care reduced depressed mood but did not improve cognitive functioning, suggesting that regular exercise does not slow the rate of cognitive decline once dementia has begun.
Regular exercise reduces anxiety symptoms
A period of 20 to 30 minutes of regular daily exercise significantly reduced symptoms of generalized anxiety. A prospective 10-week study on exercise in individuals diagnosed with panic disorder found that regular walking or jogging (4 miles three times a week) reduced the severity and frequency of panic attacks.
Alcoholics report improved well-being with regular exercise
In a small open study of alcoholics who exercised regularly while hospitalized for acute detoxification reported significant improvements in mood and general well-being. Abstinent alcoholics enrolled in outpatient recovery programs reported improved mood with regular strength training or aerobic exercise.
Regular exercise improves overall quality of sleep in the elderly
A systematic review of studies on the relationship between exercise and sleep in the elderly concluded that exercise probably enhanced sleep quality and improved overall quality of life.
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