I’m sorry but since posting I’ve looked more closely at the data (I work in miles not kilometers for pace). I’ve realised that my heart rate is quite elevated in the first 3 or 4 stages. My MAF pace runs are usually around the same pace as stage 3 (10:04 per mile) with a 128 bpm heart rate.
I’m not really sure what caused it, they let me have a 10 minute warm up.
I usually run in the morning fasted but the tests can only be done in the afternoons. Would you recommend fasting until then if I can?
As a bonus I called the lab after I realised and are happy to carry out a free retest.