Paulo Sousa wrote:
Glad you made an appearance here, I have a question for you:
What is the reason for measuring O2 saturation everyday? I couldn't find ANYTHING about measuring O2 saturation in the (extensive) literature pertaining overtraining.
Thanks!Fantastic question. In short, there is
zero demonstrated correlation between compromised SPo2 and over-training. Which begs the question: why do we include it in our list of tracked markers? Four reasons, of admittedly varying validity...
1) Tracking SPo2 can be an "early warning system" for low-grade anemia. We know that a "normal" SP02 reading is above 95%. Anything below 95% when measured at your fully acclimatized altitude indicates that something is wrong. We don't know what that "something" may be, but it is a data point worth knowing. As an example, this scenario played out for five international-caliber athletes, all cyclists, and all women. Prior to use Restwise (warning: shameless sales pitch ahead!) each had requested a complete blood workup due to a sense that their RPE relative to output was not as it had been, nor as it should be. The blood workups all came back "normal". When the athletes later returned to their doctors with several week's worth of SPo2 data, a more "precise" (whatever that means?) workup was ordered and they were discovered to be iron deficient. Personally, this sounds like poor medicine rather than a justification for including Spo2 in our tool, but it was certainly interesting... and earned the gratitude of these athletes.
2) Training at altitude. With the increased popularity of altitude-based training camps (without commenting on the efficacy of them, just noting that they have become more popular), many people are entering a high-stress environment in which their body's natural recovery capacity is negatively impacted. Tracking SPo2 can be a useful tool to ensure that an athlete doesn't overload his/her system before he/she has adapted to the altitude. The GB triathlon team did an altitude camp in St. Moritz, and used SPo2 extensively to monitor athletes and make small modifications in training load. Simon Lessing, who is a Restwise user, had several interesting comments about the rate at which he acclimated vs. some of the other athletes, and specifically mentioned SP02 as a valuable reference point.
3)
Some literature suggests that pre-symptomatic bronchitis manifests itself first through compromised SPo2, as inflamed bronchial passages constrict before mucus is released via coughing. Although this should be referred to a medical doctor for confirmation and diagnosis, we recommend that if and athlete is experiencing a URTI
accompanied by a drop in SPo2, they refrain from doing any intensity which might trigger a more problematic bronchial condition. Again, this is at best a guideline rather than a scientifically supported fact, but one that might be helpful for those athletes who like to "train through a cold".
4) This one is a bit of a "toss it into the mix" answer, but one of the reasons we are tracking it is because it comes built into the pulse oximeter... and we find the pulse oximeter is by far the easiest way to capture resting heart rate. We also plan to do a fair amount of data analysis on this marker, just looking for correlations. As you point out, there is no evidence that SPo2 is in any way correlated to OTS. However, it is also true that very little research has been done on the marker. It may be that, by aggregating millions of data points on a variety of markers, and then running analytics that might identify patterns, that we can highlight areas of research worthy of pursuit. This is definitely a "pie in the sky" reason to track the marker, but... wouldn't it be cool if we identified something of true value for the endurance community? After all, cortisone is a known corrosive to recovery - perhaps there are some unexpected, downstream, consequences to over-reaching that effect the oxygen-carrying capacity of an athlete's blood!
There you have it: four reasons to track SPo2, none of which relate to over-training. Feel free to form your own conclusions as to whether or not we should include the marker in our algorithm. But you should also know that the marker's weighting is quite low, that it only triggers when the athlete records below "normal" (95%), and that you can choose not to enter it at all... the algorithm automatically adjusts the other marker's weightings.
Hope that helps understand this particular marker, and thanks for flagging the one point in our system which is, admittedly, pretty darn opaque.
Matthew