Nutritional supplementation boosts aerobic exercise effects on functional brain systems.

There is growing evidence that aerobic exercise protects against age-related cognitive decline and that cardiorespiratory fitness is an important factor for these benefits. Studies also suggest that combining physical activity with cognitive enrichment is beneficial. We further examine these predictions by comparing effects of a nutritional supplement promoting exercise capacity to a lower-intensity activity with cognitive enrichment on functional network and cognitive outcomes that otherwise decline with aging. Inactive healthy older adults were randomized to one of four groups including a low-intensity activity with complex cognitive demands (dancing), walking, walking+supplement, or an active control. Results showed that walking+supplement increased salience network functional connectivity (FC), with less training benefit for default mode network FC. Although cognitive performance did not increase for any training group, participants in the walking+supplement group who were on medication that boosted key neurotransmitters (e.g., selective serotonin reuptake inhibitors) showed improved processing speed. Overall, this study provides new insight into how to boost the protective effects of exercise on brain systems that otherwise deteriorate with aging. NEW & NOTEWORTHY Aerobic exercise effects on brain networks that otherwise decline with aging can be boosted with a nutritional supplement including beta-alanine. Beta-alanine supplementation could enhance the extent to which aerobic adaptations benefit the brain. In contrast, cognitive enrichment with low-intensity physical activity through dance did not affect functional networks. Medications that modulate neurotransmitters affected by aging (e.g., selective serotonin reuptake inhibitors) may modify effects of exercise on cognition.