The cognitive benefits of aerobic exercise are well established, but resistance training produces its own distinct set of benefits that are complementary rather than overlapping. A growing body of research over the past decade demonstrates that progressive resistance training improves executive function, working memory, attentional control, and processing speed in older adults, through mechanisms that differ from the aerobic exercise pathway and that suggest a combined approach to exercise is optimal for brain longevity.
The IGF-1 Pathway
Resistance training is a potent stimulus for insulin-like growth factor 1 production in muscle and liver. IGF-1 crosses the blood-brain barrier and promotes the survival and growth of neurons, particularly in the prefrontal cortex. It also enhances synaptic plasticity and supports the signalling cascades involved in memory consolidation. In animal models, blocking the IGF-1 receptor eliminates many of the cognitive benefits of exercise, suggesting that the IGF-1 pathway is a primary mechanism rather than a secondary correlate.
The Clinical Evidence
A randomised controlled trial by Liu-Ambrose et al., published in Archives of Internal Medicine in 2010, enrolled 155 women aged 65 to 75 in progressive resistance training, balance training, or stretching for 52 weeks. The resistance training group showed significantly better executive function and attentional conflict resolution compared to both control groups. Subsequent trials have replicated this finding and extended it to men and to adults with mild cognitive impairment.
Sources
- Liu-Ambrose, T., et al. (2010). Resistance training and executive functions: a 12-month randomized controlled trial. Archives of Internal Medicine, 170(2), 170-178.
- Northey, J.M., et al. (2018). Exercise interventions for cognitive function in adults older than 50: a systematic review with meta-analysis. British Journal of Sports Medicine, 52(3), 154-160.
- Bherer, L., et al. (2013). A review of the effects of physical activity and exercise on cognitive and brain functions in older adults. Journal of Aging Research, 2013, 657508.