Heather Jackson: Ironman Champion
Over the past few months, I’ve had the benefit of using a nifty little device called the MightySat made by Masimo to help track a number of different measurements such as my blood oxygenation level, pulse rate, blood circulation, and overall hydration level. Knowing and tracking these numbers from day to day has added an extra layer of knowledge for me and my coach in regards to how my training is affecting my body. The best part is that it’s noninvasive, super easy to use, and is the most accurate pulse oximeter out there, so I know the numbers I’m reading are completely accurate and truly letting me know what’s going on inside.
It is just a little device that you slide onto your ring finger and let it settle on there for a minute or two in order to populate the readings.This pic is just an arbitrary reading I chose from a morning last week but below I will give a brief description of what each number means.
On the top line you can see my blood oxygenation level (Sp02), which is reading at 95%. The highest you can be is 100% oxygenated and a 100 is the most optimal for being able to perform the best you possibly can as an athlete. The more oxygenated your cells, the better your muscles can fire, thus hitting higher paces, power levels, etc. When your Sp02level is lower, it is more difficult to reach high levels of exertion and your brain isn’t operating as efficiently. But there are a variety of things that will affect your oxygenation rate- training load, stress level, altitude, time of day, etc. and these are things that you can figure out as your track yourself daily with the MightySat.
The bigger number on the bottom left or “PR” stands for Pulse Rate. Your pulse is a good number to track throughout your training and day to day to see how you are recovering. If your heart rate stays elevated long after a hard workout, or if you can’t get your heart rate up for a certain workout, these can be indicators of being fatigued, tired, or overtrained.
The upper right smaller number is “RRp” and stands for your respiratory rate. This number is basically measuring the rate of breaths you are taking within a minute (usually between 12-20 breaths for an adult). This number is giving a rate of oxygenation (Sp02). Basically, it is proven that with slower, deeper, more oxygenated breaths, we can deliver more oxygen to our muscles, organs, and brain. If we are stressed, not breathing as well or effectively, then our Sp02 level (the big number on the top left) will be lower, which then affects our muscles and their ability to fire, as well as our brain and its ability to function, make decisions, etc. You can control the RRp as you use your MightySat and can practice deep breathing exercises to see how this is affecting your circulation, blood flow, and overall oxygenation.
The middle smaller number is “PVI” and stands for Pleth Variability Index. This number is a marker of fluid responsiveness, and thus may have some direct correlation on how hydrated you are. There is still research being done on this tracking number but in tracking personally, it’s very easy to see when it’s higher, I am usually more de-hydrated and then I make the necessary adjustment with my fluid intake.
The bottom smallest number reads “Pl” and stands for Perfusion Index, or basically your blood flow levels. A higher number means higher blood flow rate or circulation.
To be perfectly honest, I wasn’t really sure of my MightySat’s usefulness in the first few weeks of using it day to day and tracking those numbers. What I mean is, I didn’t exactly change any training or effort levels given the numbers I would see in the morning, or after a hard workout, etc. I just kind of tracked the numbers and generally saw around the same figures most days. When I was initially given it, my friend, mentor, and huge advocate of it, 2012 London Olympic Silver Medalist Dotsie Bausch, explained how she used it in her lead up to the London Games in track cycling. If her Sp02 was extremely low, then she would completely adjust her training by taking a day off, or just a super easy day until her SpO2 number was back up to 98, 99, or 100% showing that she was recovered. Or, the same if her Pulse was off from its normal, indicating overtraining or fatigue. From my initial use of the device, I wasn’t seeing any readings above 95 and 96 with my Sp02 reading, even if it was following a recovery day. On top of that, I train 3 different sports and it’s quite impossible to just keep taking days off until my levels went up. So I just kept tracking my numbers, not really adjusting anything with my training but just seeing how the numbers were reading. It wasn’t until August 22nd at 9:59am that I had an “Aha!” moment with my MightySat.
Here was my reading:
MY FIRST 100% !!!! hahaha. I hadn’t seen a 100% oxygenation level in the six weeks I had been using the device. I had really just been seeing 95-96 every single day and thinking that it would never really change. I remember I saw the 100 and took a picture on my phone so quick to send to Dotsie immediately that it hadn’t even registered my PVI yet! Dotsie asked me how I was feeling and if it correlated to feeling recovered, or fresh, etc. To be honest, I didn’t feel really that different than most mornings, although I had slept in on that particular day since it was a Monday and all I had that day was a swim and spin later. I had run long early the day before (7-9am on Sunday morning) and did a recovery swim immediately following (9-10am) and had had the rest of Sunday off. So, this meant I was taking a reading after about 12 hours off. Again, I didn’t think I felt that different. I thought I felt a bit of fatigue from the 2 hour run still. It wasn’t until I went to the pool for my hard swim after taking this reading where it was LITERALLY the first swim since prior to Ironman Lake Placid, which by that point had been a month ago, that I felt great! I could breathe!
Usually, when I leave Bend for longer than a week or so, it feels hard for me to breathe due to the altitude for anywhere from a week to two weeks. I had been at sea level for Lake Placid for about 3 weeks and so when Wattie and I got back to Bend, I could feel it in my breathing and it’s always the roughest in the pool. Anyways, that morning, it was the first day back to breathing like I was at sea level, even though I was at 3,800 feet in Bend, OR. It had also been 4 weeks since Ironman Lake Placid, which had taken quite a bit out of me. I had taken about two weeks easy following it and then eased back in during that third week, and then even into the fourth week after I still couldn’t get my paces/watts back up to levels I saw prior to the race. It was only that past weekend that I had started to feel somewhat normal. So waking up that Monday, I think it was a combination of finally feeling recovered, as well as finally used to the altitude back in Bend (yes, I know Bend isn’t as high as some places like Boulder, but altitude tends to affect me much greater than other people). It was just this “OMG” moment and from there I started tracking my numbers even more diligently.
As you use the Masimo MightySat to track your numbers daily, it becomes super interesting and addicting to see how they correlate with great workouts you have, or ones when you may feel flatter. It also gives you the confidence as an athlete to tell your coach that you are tired and that you have numbers to prove it. On the opposite end, it also shows you that you took your recovery day properly and are fully oxygenated and refreshed, ready to hit the day’s session.
This was meant to be just a brief intro into the Masimo MightySat and how it can be huge in helping you know if you are recovered, or hydrated, or possibly if a workout is going to go well or if you should wait for another day. I’m currently compiling a more specific daily log that corresponds to my workouts over the past 3 weeks here in Tucson to show you first-hand my numbers and how they shift day to day, and from week to week as training piles up.