Mitochondrial Coupling Efficiency, Respiration and Vitamin B2 status in Untrained and Endurance-trained Young Females

- 18-28 year old female
- BMI 18.5-25 kg/m2
- VO2max ≤ 37 mL/kg/min or VO2max ≥ 47 mL/kg/min;
- Performed a valid VO2max test In order for the test to be considered valid two out of three of the following conditions should be met:
1) The maximal heart rate is within 10 beats of the predicted maximum (220 – age)
2) A plateau in in VO2 was reached; VO2 fails to increase with 150 mL/min, despite an increase in work load
3) Respiratory exchange ratio (RER) ≥ 1.00 has been achieved

• Health concerns regarding respiratory and pulmonary diseases, for example COPD or (exercise induced) asthma
• (Known symptoms of) chronic diseases, for example cardiovascular disease and cancer;
• (Known symptoms of) metabolic diseases, for example type I or II diabetes or hyperthyroidism;
• (Known symptoms of) inborn metabolic diseases, for example glucose-6-phosphate dehydrogenase (G6PD) deficiency;
• (Known symptoms of) hematological disorders, for example anemia or disturbed red blood cell formation;
• Haemoglobin concentrations below 7.5 mmol/L;
• Regular smoker (defined as smoking >5 cigarettes per week);
• Lactating or pregnant;
• Following a veganistic lifestyle, i.e. excluding the consumption of animal or animal-derived food products. Vegetarians are allowed to participate in the study.
• Usage of hormonal contraceptive medications other than the birth control pill Microgynon 20/30 or a generic variant containing 0.02/0.03 mg ethinylestradiol and 0.10/0.15 mg levonorgestel. Examples include IUD contraceptives or contraceptive rings. The use of condoms or pessaria is allowed;
• Recent use (within four months) of supplements with suggestive training effects, for example creatine phosphate, EPO or anabolic steroid;
• Recent daily usage (within four weeks) of supplements containing vitamin B2 (including multivitamin supplements) and usage of vitamin B2 supplements during the study;
• Usage of recreational drugs, for example marihuana, amphetamines and cocaine during the study (starting after first screening day);
• Suffers from (sport) injury that hampers maximal exercise performance;
• Blood donation during the previous 2 months or during the course of study;
• Current participation in other clinical trials;
• Not subscribed to a general practitioner (GP) practice;
• Employed or undertaking a thesis or internship at the department of Human and Animal Physiology.