"Mental alertness" refers to being mentally awake, focused, and aware. It means having a quick-thinking and attentive mind, ready to respond or think critically. Full definition
A small tin of tuna provides a decent serve of protein power as well as essential fatty acids, which are great for improving mental alertness. (womenshealthandfitness.com.au)
Memory Support for brain circulation, oxygenating cerebral cortex, improving recall, increasing mental alertness with anti-aging herbs. (store.newwayherbs.com)
It gives athletes a boost enhancing mental alertness. (clifbar.com)