The relationship between stroke and physical activity: effects of exercise on prevention and rehabilitation: a review article

Stroke is a medical condition in which occluded blood flow to the brain causes cell necrosis. The main types of stroke are ischemic (due to lack of blood flow with much higher prevalence) and hemorrhagic (due to bleeding with low prevalence). Ischemic stroke is caused by the reduction of blood to the brain tissue or complete occlusion of brain vessels by a blood clot following arterial plaques rapture of cerebral arteries due to atherosclerosis, cerebral myocardial infarction and small vascular lesion infarction. Inflammatory reactions, increased oxidative stress, cell death and autophagy are the most aggravating factors in this condition. Instead, hemorrhagic stroke is caused by spontaneous intracranial hemorrhage and subarachnoid hemorrhage, highly common in men. To prevent the possible causes of stroke, investigators attempted to study about the ways that may decrease the risk factors such as trauma, high arterial hypertension, alcohol, low-density lipoprotein and glycerides, tobacco and drugs. Physical activity is a potent inhibitory factor which reported to be effective in prevention of stroke and post-stroke rehabilitation. Aerobic, combined or strenuous activities protect brain tissue by balancing apoptotic and anti-apoptotic pathways, stimulating angiogenesis, reducing oxidative stress, increasing antioxidant activity, optimizing Integrity and preservation of the blood-brain barrier, improving nerve functions and preventing neuronal death. The mechanisms involved in rehabilitation after ischemic stroke with physical activity mostly refer to improved dendrites and synapses, synaptic flexibility, regulation of inotropic receptors with glutamate, increased BDNF, GAP43 and insulin-like growth factor. In patients with cognitive impairments following acute ischemic stroke, high intensity exercise improves processing timing and attention allocation, self-independence, walking ability, aerobic power and reduces memory degradation. Moreover, early start of physical activity after ischemic stroke inhibits the initial physiological response to stroke and prevents optimal recovery. In contrary, reports show positive effects of onset of physical exercise a day after stroke. In hemorrhagic stroke, exercise reduces systolic blood pressure, moderates resting blood pressure via parasympathetic regulations and triggers angiogenesis in the nervous system. Light to moderate or long-term physical training is recommended in comparison to short-term high-intensity training. In addition, early onset of physical activity during recovery after stroke may be beneficial.