Multiple biological mechanisms for the potential influence of phytochemicals on physical activity performance: a narrative review

Natural phytochemicals (PCs) are responsible for the taste, colour, and aroma of many edible plants. Cohort studies have linked higher intake to a reduced risk of chronic degenerative diseases and premature ageing. The ability of foods rich in PCs, such as phytanthocyanins, apigenin, flavonols, flavonoids, bioflavonoids, gallic acid, ellagic acid, quercetin, and ellagitannins, to support physical activity has also been highlighted in a number of published pre-clinical and prospective clinical studies. This literature mostly emphasises the ability of PCs to enhance the adaptive upregulation of antioxidant enzymes (AEs), which reduces exercise-associated oxidative stress, but there are several other mechanisms of benefit that this narrative review addresses. These mechanisms include; protecting joints and tendons from physical trauma during exercise; mitigating delayed-onset muscle symptoms (DOMS) and muscle damage; improving muscle and tissue oxygenation during training; cultivating a healthy gut microbiome hence lowering excess inflammation; cutting the incidence of upper respiratory tract viral infections which disrupt training programmes; and helping to restore circadian rhythm which improves sleep recovery and reduces daytime fatigue, which in turn elevates mood and motivation to train.