Twenty-three RCTs were included in the review (n=1,725, range 20 to 210 participants). Seven studies were deemed high quality (two in cognitively health participants and five in those with cognitive decline). Programme durations ranged from eight to 42 weeks in those without cognitive decline and six to 52 weeks in those with cognitive decline.
Cognitively healthy participants: Five out of 15 RCTs reported significantly beneficial effects for exercise programmes on some measures of cognition (quality scores were 2 or 3 in these studies). Improvements were reported in memory using the Corsi block-tapping test, Rey-Osterrieth figure, face recognition and digit span (three RCTs). Improvements in information processing abilities (organisation and auditory processing; one RCT) and executive function (word fluency; one RCT) were reported. Aerobic exercise (two RCTs), strength exercise alone (one RCT) or combined with balance and exercise (one RCT) or a combination of aerobic, strength. balance and flexibility training (one RCT) were effective. No significant effects were reported in the two high-quality RCTs.
Participants with cognitive decline: Five out of eight RCTs reported significantly beneficial effects for exercise programmes; three were defined as high quality and two scored 3 points. Improvements were reported in general cognitive function using the Mini Mental State Examination (MMSE) (two RCTs). Improvements were reported in executive functions (category fluency, trail making, clock drawing; three RCTs). One RCT found there was a beneficial effect on memory (15 word learning test) in men that attended more 75% or more of the sessions. Aerobic exercise (three RCTs) and strength exercise combined with flexibility or balance exercise (two RCTs) were effective.