A study was conducted in 2 phases.
In the first phase, the researchers assessed the change in brain size in exercising mice compared with non exercising mice , using MRI. The results showed that exercising mice had an increased brain size in the hippocampus region especially the dental gyrus subregion. When the dental gyrus subregion was assessed for comparison, the researchers found that exercise induced brain cells proliferation (neurogenesis).
In the second phase, the researchers assessed the change in the brain size of adults before and after exercise by using MRI. The researchers found that exercise increased brain size in the hippocampus and the dental gyrus, the hippocampal subregion is important for memory and implicated in cognitive ageing, similar to the study in mice[243].
In a another study, the researchers assessed the hippocampus region of the brain of patients with Alzheimer’s disease before and after aerobic exercise intervention. The results showed that aerobic exercise training was effective in reversing hippocampal volume loss and improving memory function[244].
In one more study patients with Alzheimer’s disease having mild cognitive impairment were randomized either to an aerobic exercise or no-exercise control group. The results showed that patients from aerobic exercise group had an improvement in cognitive functions compared to control group[245].
In A randomized study, sedentary elderly women were divided in two groups and were subjected to either walking at normal heart rate or moderate-intensity exercise (fatigue until not remaining capable of singing a song) group at 60% of maximum heart rate, for 30 minutes, 5 days/week for 12 weeks. The results showed that both groups had their fitness improved by measuring as VO2max (maximal oxygen uptake), however, moderate exercise group had superior immunity cells (NK and T cell) function[246].
A systematic review and meta-analysis of studies of 977,925 people found that moderate-intensity exercise (fatigue till unable to sing a song) for 2.5 hours/week led to reduction in mortality risk by 19%, while 7 hours/week of moderate exercise reduced the mortality risk by 24%. The researchers also found a smaller effect on mortality risk by walking alone[247].
A systematic review and meta-analysis of 21 studies on exercise in postmenopausal women concluded that exercise was associated with a reduction in the incidence of breast cancer[248].
In a prospective trial 1,490 women, diagnosed with breast cancer, were studied for their food consumption and exercise for 2 years. The results showed that women consuming plant-based diet which was five or more daily servings of vegetables-fruits combined with exercising equivalent to walking 30 minutes, 6 days/week, and maintaining a normal body mass index, were associated with a reduction in mortality rate compared with those who did not consume plant-based diet, did not exercise and could not maintain their weight [90].
A physiological study found that sedentary activity (sitting without otherwise being active) resulted in atherosclerosis, ischemic heart disease, impaired insulin sensitivity, impaired metabolic function and attenuated endothelial function. Prolonged sitting behavior led to reduced muscular activity of the lower extremities which decreased blood flow to the legs, increased blood pooling in the calf, augmented mean arterial pressure, and deformed arterial segments resulting in low mean shear stress (SS) which is a measure of the force of friction between blood and arterial wall. Low shear stress (SS) resulted in a reduced production of nitric oxide causing arterial constriction,increase in blood pressure, and subsequently leading to ncreased risk of cardiovascular disease [249].
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