Well, here’s yet another good reason to get off of the couch and into an exercise program: A large new study reports that aerobic exercise, resistance training and even, perhaps, tai chi can improve the cognitive abilities of adults aged 50 and older — regardless of the current status of those abilities.
The authors believe their study — a review of 39 randomized controlled trials published as recently as last fall — is the most comprehensive examination to date on the connection between exercise and cognitive function in older adults.
Plenty of previous reviews and meta-analyses have looked at this topic, but those results have been inconclusive because they tended to focus on a single type of exercise or limited the publication years from which they chose their studies, say the Australian researchers who conducted the current review.
Those researchers decided, therefore, to address the existing research gaps by not imposing similar limits. Their results were published online Monday in the British Journal of Sports Medicine.
All of the 39 studies analyzed for the review assessed the effects of at least four weeks of some kind of physical exercise intervention on the cognitive function of adults aged 50 or older. The adults lived “in the community” — in other words, not in nursing homes.
The exercise interventions used in the studies included aerobic exercise (activities like brisk walking, swimming and biking), resistance training (muscle strengthening), “multi-component” exercise (a combination of aerobics and resistance training), tai chi and yoga.
The studies assessed the effects of these interventions on several types of cognitive abilities, including global cognition (overall brain capacity), attention (the ability to focus on one thing while ignoring distracting stimuli), executive function (the ability to perform high-level cognitive processes, such as goal-setting and decision-making), and both long-term and short-term memory.
The Australian researchers’ analysis of all that data revealed that aerobic exercise and resistance training — when done separately or in combination — improved cognitive function “regardless of baseline cognitive status.”
“The effect of exercise on cognition was statistically significant for all [cognitive] domains, except global cognition,” the researchers write.
Tai chi — but not yoga — also appeared to bestow cognitive benefits, but the researchers say the tai chi results involved too few people to produce definitive results.
“Tai chi may be a promising intervention aimed at brain health for the over 50s, although further high quality randomized controlled trials are required to confirm the benefits shown in this study,” the researchers note.
Possible reasons for benefits
Background information presented in the study offers several possible explanations for why exercise enhances cognition: by promoting the growth of new brain cells (neurogenesis); by stimulating the growth of new blood vessels (angiogenesis), which brings more oxygen and nutrients to the brain; by decreasing potentially harmful pro-inflammatory processes; and by reducing damage to brain cells caused by oxidative stress.
How often and how long do older people have to exercise to reap the cognitive benefits observed in this review? The authors scoured the data to get an answer. They found that “exercise of between 45 and 60 [minutes] in duration, of moderate or vigorous intensity and of any frequency or length is beneficial to cognitive function.”
In other words, it appears that doing anything is better than nothing.
“The findings suggest,” the researchers conclude, “that an exercise programme with components of both aerobic and resistance-type training, of at least moderate intensity and at least 45 min per session, on as many days of the week as possible, is beneficial to cognitive function in adults aged [50 or older].”
Definitely time to get off the couch.
FMI: You’ll find the study on the British Journal of Sports Medicine’s website.