Heather Jackson Uses the MightySat Pre-Kona

In my last post, I described how the Masimo MightySat™ works- the numbers it shows you and what those readings can tell you about how your training and recovery are going. Now, I thought I’d share some specific readings I’ve had throughout my Ironman World Championships training block to demonstrate an even clearer picture.

Wattie, my husband, and I drove down to Tucson from Bend, OR on Friday, August 26th. We made the trip over three days to break it up and be able to get some training in over the travel days. Going from Bend to Tucson meant a drop in elevation from about 3800 feet to about 2900 feet where we were staying in Tucson. The temperature shift went from approximately mid to high 70s when we left Bend, to over 100 degrees for at least the first week we were in Tucson. It was blazing! I only mention this information because it definitely affects your body’s ability to train and recover until you are acclimated, which was the whole point of coming to Tucson prior to Kona.

On the first day we arrived to Tucson (Monday, August 29th), I did a swim and an easy spin to try and flush my legs out from the travel. On the next morning, when I woke up around 6am, I rolled over and checked my Masimo MightySat™.

So this was Tuesday, August 30th at 6:07am

Since I am just waking up, my heart rate is pretty low at 38 Pulse Rate (PR) and my oxygenation is also pretty low at 94. This shows some definite fatigue and probably being tired from the travel, as well as the continued training I kept up while traveling down. The low Sp02 could also be attributed to the heat in Tucson and me not being acclimated. The upper right number is my breathing rate, or the number of breaths I was taking per minute. Again, as I was just waking up, it was pretty relaxed and low. Later this day, I had a run with some efforts but they were short, an easy recovery swim, and then another easy run in the evening, so nothing too intense that I would have necessarily felt this fatigue.


On the next day, Tuesday, August 31st, I woke up, swam a hard 5k swim set, and then checked my Masimo MightySat™:

Checking my Masimo MightySat™

The above picture shows that my Sp02 was starting to go up a bit, meaning I was getting over the travel days after an easier day prior. My body was also adjusting to the lower altitude in Tucson compared to Bend.

About two weeks into my time in Tucson, on September 7th, I checked my Masimo MightySat™ at 7am:

Checking my Masimo MightSat™ at 7:00am

At this point, I was ten days into a hard training block. While many readers may think this pulse rate is low, normally when I wake up my pulse rate is anywhere from 36-40, so this was actually a bit high for me. And my Sp02 was pretty low, considering most mornings in Tucson had been showing 96-98. My breath rate was also a bit high for just waking up, compared to my normally lower RRp. I woke up feeling borderline like I was catching a cold, very tired, and very unmotivated to even get out of bed. If I had woken up feeling that way and my Masimo MightySat™ had shown some different numbers (a higher Sp02 and lower pulse rate), I would have probably made a bit more of an effort to at least try a workout and see if I felt okay to continue. But after waking and feeling like I possibly had a cold (slight scratch of the throat…), and I took this reading, I texted my coach and relayed this information. I then took the entire day off to give my body the rest it needed. I drank a lot of electrolytes, took a few epsom salt baths, and watched a lot of movies all day.


After taking Wednesday completely off and then an easier day getting back into things, on Friday, September 9th at 5:46 am my pulse rate was back down and my Sp02 was starting to go back up to its more ‘normal’ (for me) numbers:

Friday, September 9th at 5:46 am

So far, my examples of my MightySat numbers have always been in the morning. You can use your MightySat throughout the day to also monitor your levels, but its important to know that you should always compare your numbers to numbers at the same time of day, as your body shifts throughout the day. Or that your readings are going to be affected by the training you have throughout the day, so you can look at your readings after similar style workouts to compare. Here are a few examples.

This reading was on September 13th at 11:30 am.

Here you can see my pulse rate is higher than when I first wake in the morning, as I had already done a swim and a run on this day. My Sp02 is a bit low, probably affected by the swim and run and overall fatigue at this point in my training block. But I could compare this reading to the second picture I shared above as both reading are after just a swim in the morning and around mid-morning after I’ve eaten breakfast. Fast forward eight hours and the rest of the day off recovering…I took a MightySat reading later that evening at 5:50pm:


Here, you can see my pulse has dropped back down to its normal and my Sp02 went way up! So your levels are definitely affected by your training/time of day, etc.

Here is an example from September 17th at 3:49pm.

This was following one of my hardest V02 sessions on the bike with a very hard run off. This was right after the workout so my Sp02 has dropped significantly and my pulse is pretty high for me.

And finally, a number that I always hope to see…

On September 23rd at 12:15pm.

A 100 for my Sp02! haha. This was following a few easier days after such a hard block of training to prepare for Kona. My Masimo MightySat was confirming for me that my body was absorbing the training and recovering. I was also used to the heat in Tucson and acclimated. My pulse is a bit high here but I think I had just been up walking around and eating…


I hope that providing a few of these numbers gives a little more insight into how you can use your Masimo MightySat! It’s become an integral part of my daily routine and just gives that added confidence to the decisions you make regarding how hard you should push in your sessions or if your body is telling you it needs some rest. Again, let me know if you have any questions and thanks for reading!

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