The effects of short-term low energy availability, achieved through diet or exercise, on cognitive function in oral contraceptive users and eumenorrheic women

Abstract

To date, no research has explored the effects of low energy availability (EA) on cognitive performance using dietary and exercise regimens relevant to athletes. Twenty female participants (10 eumenorrheic, 10 oral contraceptive [OC] users) completed three, 3-day conditions: 1) controlled-balanced EA without exercise (BAL; 45 kcal·kg·LBM-1·day-1), 2) diet-induced low EA without exercise (DIET; 15 kcal·kg·LBM-1·day-1) and 3) exercise-induced low EA (EX; 15 kcal·kg·LBM-1·day-1, including 30 kcal·kg·LBM-1·day-1 treadmill running at 70% V̇O2max). A cognitive test battery was completed before and after each 3-day condition. Mental rotation test accuracy improved in the BAL condition, but there was a decline in accuracy in the EX condition (BAL, +2.5%; EX, -1.4%; P = 0.042, d = 0.85). DIET (+1.3%) was not different to BAL or EX (P > 0.05). All other measures of cognitive performance were not affected by condition (P > 0.05) and OC use did not affect cognitive responses (P > 0.05). Accuracy in the mental rotation test was impaired when low EA was induced through increased exercise energy expenditure. All other aspects of cognition were unaffected by three days of low EA through diet or exercise. OC use did not mediate the effect of low EA on cognition. Novelty bullets • Cognitive function was not affected by 3 days diet-induced low energy availability (EA). • Only spatial awareness was impaired during 3 days exercise-induced low EA. • Reproductive hormones affected spatial awareness independent of EA.