Muscle oxygenation

Nov 16, 2019
Hi guys,

I don't know if this is the best place to ask this but I'll have a go. I'm doing a university assignment on muscle oxygenation and I have one chart that confuses me a bit.

As you can see, for the first few seconds of constant cycling (100 watts) muscle oxygenation went up. Prior this the subject performed 6 mins warm up so I believe this early spike is because of that? But how to explain that early drop? The remaining part where muscle oxygenation stays constant is clear to me because the load is not increasing (stays at 100w) so it means muscle oxygen supply and demand are evenly matched. But what about that early spike and sudden decline? Because the load remained the same throughout (100watts) so I don't understand. Thanks for your help.

I don't see the chart you mentioned, but my 'novice guess' is that the change in oxygenation level is due to physiology not reacting in a precisely balanced immediate demand/supply manner. In takes some time and there are probably diminishing time periods of 'too much / too little' until a level balance point is reached. Perhaps visually similar to a balance beam scale swinging up/down around its final stationary point.
Another consideration that I've heard about is the psychological impact on physiology just before beginning an exercise bout can change various levels in anticipation of their future need during the actual exercise. That could account for the O2 rise at the start, and when the 100W exercise level did not need such an extreme rise the drop occurred. Only to be corrected by a lesser rise and then a more gradual balancing through the session.