Search strategy of Pubmed #1 physical exercise OR physical activity OR exercise OR fitness OR training OR aerobic exercise OR cardiovascular exercise OR resistance training OR stretching OR mind-body exercise OR flexibility exercise #2 working memory OR cognitive task OR executive function OR executive control OR updating OR short-term memory #3 old people OR elderly OR old age OR the aged OR senior citizen #4 randomized controlled trial OR controlled clinical trial OR RCT OR clinical intervention #5 #1 AND #2 AND #3 AND #4