Kristian Blummenfelt

VO2max Testing

The video documents a two‑day VO2max lab session in Bergen, where elite triathlete Christian tracks his aerobic efficiency as the season progresses. After a January test that showed unusually high oxygen consumption, the current session evaluates whether his efficiency has normalized and what adjustments can further improve performance. Key data reveal a modest rise in gross efficiency to roughly 20.5 %, up from 18 % in winter, though still shy of the 22 % benchmark seen in cycling specialists. A recent bike fit—switching to an extra‑small frame—lowered frontal area by about 2 cm, translating to an estimated 15 W power gain. Despite higher power outputs, lactate levels are climbing, suggesting a shift toward greater carbohydrate reliance as oxygen uptake dips. Christian notes, “If you can improve efficiency from 20 to 21 %, that’s a 5 % performance boost,” likening the goal to a race car using less fuel for the same speed. The session also includes step tests on both bike and run, confirming that aerobic metabolism remains dominant, with low CO₂ output indicating limited anaerobic contribution. The findings will inform training tweaks ahead of an altitude camp in Switzerland and the upcoming Challenge Hawaii race. By fine‑tuning bike aerodynamics, nutrition, and pacing, Christian aims to lower his oxygen cost further, potentially translating into faster race times and better placement against rivals.