What is known?
It is common knowledge that people’s mental abilities tend to slow with age.1,2 In fact there is a well documented cognitive decline which accelerates around the age of 50.3,4 Research has shown that a regular exercise programme can slow down or even prevent functional decline associated with ageing. The health benefits for older people who regularly participate in endurance, balance and resistance training programmes are well established. Such health benefits include improved muscle mass, healthier arteries, improved energy, cardiovascular fitness, muscle strength, and overall function.5 However there is also increasing evidence that exercise may help maintain good cognitive function as we age.6
Animal studies have found that increased aerobic fitness improves the oxygen supply to the brain as well as the ability of its cells to utilize nutrients.7 As well exercise stimulates the release of growth factors which improve the structure of the blood vessels which support and nourish the brain’s cells. Human trials support the link between physical activity and cognitive vitality.8-11 Evidence for this link is provided by several longitudinal studies 12-17 as well as a number of randomised controlled trials.18-21
Angevaren et al. (2008)22 reviewed previously published scientific studies that investigated the effects of aerobic exercise on cognitive function in older people. Eleven studies were identified, of which eight reported that aerobic exercise resulted in increased the fitness of the trained group and resulted in an improvement in at least one aspect of cognitive function. The largest effects were on cognitive speed, auditory and visual attention. This report joins several other recent systematic reviews 6,23,24 in concluding that aerobic fitness training enhances the cognitive capacity of healthy older adults.
What remains to be determined?
Although it is clear that physical activity is good for our bodies and our minds, there are a number of things that needs clarification:
- The fact that improved cognition occurs after aerobic training in older people suggests that there’s a causal link between the two. However larger studies are still required to confirm whether the aerobic training component is necessary, or whether the same effect can be achieved with any type of physical exercise.
- Thus far the longest trials conducted have been 14 weeks long and we don’t know if the cognitive differences between trained and untrained people continue to widen or trail off and this will likely be studied in future trials.25
- Results from training studies performed by Hill et al. (1993)26 and Blumenthal et al. (1991)27 have not found consistent correlations between changes in aerobic power and cognitive measures. For this reason it isn’t yet clear how much exercise is required to achieve a set increase of cognitive improvement in the average person.
- Although previous studies have reported a strong effect of physical activity on cognitive function, it remains unclear whether the important thing is actually improvement in cardiovascular fitness or whether other physiological or psychological mechanisms might be responsible.
- There is evidence that aerobic physical activities which improve cardiorespiratory fitness are beneficial for cognitive function in healthy older adults, with effects observed for motor function, cognitive speed, auditory and visual attention. At the same time, it would be informative to understand why some cognitive functions seem to improve with (aerobic) physical exercise while other functions seem to be insensitive to physical exercise.
It is evident that improvements in cardiovascular (aerobic) fitness can result in benefits in cognitive capacity.9,28,29 This would imply that a physically active lifestyle resulting in enhanced fitness could affect a person’s cognitive abilities in the future and would enable them to partially influence their mental health.
References to studies included in this review
- Martin M et al (2003) Are changes in cognitive functioning in older adults related to changes in subjective complaints?. Experimental Aging Research29:335–52.
- Newson RS & Kemps EB (2006). The nature of subjective cognitive complaints of older adults. International Journal of Aging and Human Development 63:139–51.
- Salthouse TA (2003). Memory aging from 18 to 80. Alzheimer’s Disease and Associated Disorders;17:162–7.
- Verhaeghen P et al. (1997).Meta-analyses of age-cognition relations in adulthood: estimates of linear and nonlinear age effects and structural models. Psychological Bulletin
- Lemura LM et al (2000). The effects of physical training of functional capacity in adults. Ages 46 to 90: a meta-analysis. Journal of Sports Medicine and Physical Fitness;40:1–10.
- Colcombe et al. (2003). Fitness effects on the cognitive function of older adults; a meta-analytic study. Psychological Science 14:125–30.
- Churchill JD et al (2002) Exercise, experience and the aging brain. Neurobiology of Aging 23:941–55.
- Aleman A et al (2000). Relation between cognitive and physical function in healthy older men; a role for aerobic power?. Journal of the American Geriatrics Society 48:104–5.
- McAuley E et al. (2004) Cardiovascular function in older adults: a brief review. Brain, Behavior and
- Prins ND et al (2002).Homocysteine and cognitive function in the elderly: the Rotterdam Scan Study. Neurology 2002;59: 1375–80.
- Rogers RL et al (1990). After reaching retirement age physical activity sustains cerebral perfusion and cognition. Journal of the American Geriatrics Society; 38:123–8.
- Abbott RD et al (2004). Walking and dementia in physically capable elderly men. JAMA 2004;292:1447–53.
- Barnes DE et al(2003). A longitudinal study of cardiorespiratory fitness and cognitive function in healthy older adults. Journal of the American Geriatrics Society 51:459–65.
- Laurin D et al (2001). Physical activity and risk of cognitive impairment and dementia in elderly persons. Archives of Neurology 58:498–504.
- Richards M & Hardy R, Wadsworth ME (2003). Does active leisure protect cognition? Evidence from a national birth cohort.Social Science & Medicine 56:785–92.
- Sturman MT et al (2005) Physical activity, cognitive activity,and cognitive decline in a biracial community population.Archives of Neurology 2005;62:1750–4.
- Van Gelder BM et al (2004) Physical activity in relation to cognitive decline in elderly men. The FINE Study. Neurology 2004;63:2316–21.
- Bakken RC et al (2001). Effect of aerobic exercise on tracking performance in elderly people: a pilot study. Physical Therapy;81:1870–9.
- Binder EF et al (1999). The relation between psychometric test performance and physical performance in older adults. Journal of Gerontology A Biological Science Medical Science 54:M428–32.
- Emery CF et al (1998). Psychological and cognitive outcomes of a randomized trial of exercise among patients with chronic obstructive pulmonary disease. Health Psychology ;17:232–40.
- Fabre C et al (2002). Improvement of cognitive function by mental and/or individualized aerobic training in healthy elderly subjects. International Journal of Sports Medicine 23:415–21.
- Angevaren M (2008) Physical activity and enhanced fitness to improve cognitive function in older people without known cognitive impairment. Chochrane Library. Issue 3
- Etnier JL et al (1997). The influence of physical fitness and exercise upon cognitive functioning; a meta-analysis. Journal of Sports and Exercise Psychology 1997;19:249–77.
- Heyn P et al (2004) The effects of exercise training on elderly persons with cognitive impairment and dementia; a meta-analysis. Archives of Physical Medicine and Rehabilitation 2004;85:1694–704.
- Salthouse TA.(20007). Mental exercise and mental aging. Perspectives on Psychological Science 1:68–86.
26.Hill RD et al (1993). The impact of long-term exercise training on psychological function in older adults. Journal of Gerontology 48:12–7.
- Blumenthal JA et al.(1991) Long-term effects of exercise on psychological functioning in older men and women. Journal of Gerontology B: Psychological Science and Social Science 46:352–61.
- Colcombe SJ et al (2004) Cardiovascular fitness, cortical plasticity, and aging. Proceedings of the National Academy of Science USA 101:3316–21.
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