Outcome measures
TAA
BLOOD, OXIDATIVE STRESS
The primary outcome measures were urine and blood biomarkers for oxidative stress and antioxidants. Morning urine was collected of all participants at the day of the second exercise test (pre-exercise) and the following day (post-exercise). Urine and plasma aliquots were frozen down to −20 °C before stored in liquid nitrogen and −80 °C. However, for vitamin C analysis an equal volume of plasma were acidified with 10% meta-phosphoric acid (MPA) and then stored in −80 °C [Blood samples were collected at six time points, on the day of the second exercise test; before the test (baseline), after high intensity exercise (1–2 min after third interval), after maximal effort (1–2 min after termination), at 5 min post-exercise, 30 min post-exercise, 60 min post-exercise and 24 h post exercise [Measurement of plasma vitamin C (ascorbate (AA), dehydroascorbate (DHAA) and total AA (TAA)) and DHAA/TAA ratio (a plasma marker of oxidative stress) was performed as described by Karlsen et al. [Measurement of plasma carotenoids (lutein, zeaxanthin, β-kryptoxanthin, α-carotene, β-carotene, and lycopene), vitamin E (α-tocopherol) were performed as described by Bastani et al. 2012 [