1) Beatles nonsense syllables 2) Part of a White Album chorus 3) Start of a Beatles title 4) Syllables before di or da 
Onset of blood lactate accumulation. Although there are normally traces of lactate in the blood, it is generally agreed that a level of about 2 - 4 millimoles per dm3 (litre) represents OBLA, which correlates to the term 'anaerobic threshold'.