My husband and I got WHOOPs last year and tried them out. Our annual contracts were up for renewal earlier this month, and we decided not to renew them mostly due to the high cost and figured we already learned quite a bit from them. Coincidentally, my Garmin watch that I’ve been running with for maybe 7 years completely died on me last week and I had to go two full days without a watch! I upgraded to the new Garmin and it actually has many of the features of the WHOOP that we liked without the yearly fee!

The WHOOP, is a device that is worn usually on the wrist or upper arm that transmits data to an app in your phone. The data includes heart rate, respiration rate, sleep data, stress data, activities, heart rate variability, etc. Every morning it summarizes this data and gives you a recovery score. This number is supposed to show you how recovered you are from the activities from the day before. It takes sleep into account and heart rate variability to give you your recovery number.

It also gives you recommendations, like taking a rest day if you overreached the day before, etc.

Heart rate variability (HRV) can be used as an indicator of fitness, but also recovery. So a higher HRV indicates a higher level of fitness. The day after a big workout or long run, your HRV would be lower, indicating you need a recovery day. Then when you see that number go back up, it typically indicates you’re recovered. So your number alone doesn’t really mean much until you’ve had several weeks of data.

So here’s what I learned, as a female runner with a years worth of data.

The first thing you may notice right away is how alcohol affects your recovery and your HRV. I’ve heard of many people actually completely giving up alcohol after using the WHOOP. My husband is kind of one of those people. I can see why. It’s one thing to know that alcohol is going to negatively impact your health when used in excess. It’s another thing to visibly see it’s effects in real time.

I’m not a big drinker to begin with. I consider myself a social drinker and I typically don’t have more than one or two drinks on days when I am drinking, which is typically only socially. Still, I definitely saw a much lower HRV, regardless of the activity I did the day before with even just one drink the day before. The absolute lowest recovery score I ever received was the day after my friend’s birthday, when I had probably had a little more than a couple drinks. My recovery was a big fat zero and even had a picture of a skull! It made me laugh, but also it was true that I wasn’t feeling so great. What I used to be able to handle in my 20’s completely kills me in my 40’s. Good thing I don’t make nights like that a regular occurrence.

What was surprising to me, was how much my monthly cycle had an effect on my HRV and therefore my recovery score. It caused me to actually do some research on how female hormones affect the body systems and I really uncovered something interesting.

For a long time, women were not represented in studies because our cycles completely threw off the results (imagine that). Now, for most research grants to be approved, the researchers must include women, unless it’s something that really doesn’t apply to us at all. So things are getting better, but unfortunately many of the decades worth of research into sports really only applies to men. So I’m going to break down what I learned.

The beginning of your cycle, is generally considered the first full day of your period, day 1. Day 1 is when both the female hormones estrogen and progesterone are both very low. What was crazy interesting to me was that my HRV and my recovery score were always very high on this day, and actually throughout the entirety of my period. What? Even when I had terrible sleep the previous night, even if I did a long run or a workout.

After my period ended and I started the estrogen dominance phase of my cycle where the body is preparing the eggs for ovulation, my HRV would go down but still stay higher than they would during the later half of my cycle. This is when patterns would emerge and I would see lower HRV the day after a strenuous workout and higher HRV after recovery days.

Then, about a week after ovulation, when progesterone is dominant, my HRV would suddenly drop, even after recovery days or even rest days. Only to spike up again once my period started. After noticing this pattern for months, I dove into the research.

As it turns out, the low HRV during the progesterone phase, or luteal phase is almost a sure sign that you did in fact ovulate that cycle. During this phase, you’re more likely to be dehydrated and your body is not as readily able to break down carbohydrates for fuel. Your metabolism is actually higher and you need more calories than during the rest of your cycle. And your basal body temperature is higher, which means you can over heat faster. Now how is it that I lived 41 years as a woman and am just finding this out?

So I thought back to some of the times when I had a bad workout for no reason in particular and just shrugged it off as a fluke, or even a race that I thought I was prepared for but just felt flat. Could it be, that at least some of these events happened to be during the luteal phase and I really was competing with less available resources.

Interesting to me too, was that I can recall some of the best workouts I had ever done were on the first few days of my period. What was that all about?

It’s well known that heat generally has a negative impact on running performance. As your body makes fitness gains, one of the adaptations it makes is being able to more efficiently cool yourself off. Humans and horses are able to do this by sweating. When our body starts to overheat, our blood vessels dilate, bringing to blood closer to the surface of the skin and away from our core to cool it down. We also start to sweat. The more fit you are, the more you will sweat, which can be rather embarrassing is some situations but it really is an indicator of good fitness.

This ability to cool yourself down is what allows you to keep performing at high levels. It’s why heat training in the summer can lead to faster fall races. And there’s a whole market right now for interesting ways to cool your body down to allow you to keep performing. My husband is trying one of these out currently. It’s a device that you can freeze and then use it to cool the palms of your hands during an intense workout of either lifting or running. In small studies, participants were able to take on more training loads and the gains they achieved held up over time.

So the fact that your temperature is lower during the first half of your cycle is not some minor thing. It makes a big difference. If your starting temperature is lower, it’s going to take longer to overheat. This allows you to run faster, for longer.

Your also better able to break down carbohydrates for energy and your body holds onto more water, which means your better hydrated. In practice this means you’ll be better able to crush your workouts and your races.

So does that mean that your workouts and races are doomed if they happen to fall during the later half of your cycle. Not entirely. Knowledge is powerful though. Once I learned these things, I started making changes during the later half of my cycle.

First of all, I need to hydrate much more than I do during the first part of my cycle. That’s something that’s easy enough to do. I also started to notice that I tend to pee more frequently during the later part of my cycle. So I just need to keep drinking, and often closer to the time that I’m going to run. And make sure I’m not peeing out all my electrolytes by adding some kind of electrolytes into my pre run water. (Right now I’m really liking using Nuun tablets and LMNT).

Also, I need to eat more food, and again, more food closer to the times I run. Even if that means simple sugars because they are quickest and easiest to digest.

Lastly, I need to dress lighter. If it’s hot, it’s going to be hot and there’s not much you can do clothes wise if you’re already planning on running in a light tank and shorts. But you can try to wet your face or hair before your run or try the palm cooling method on your run too. An easy way to do this is to freeze water bottles and set them along the course you plan on doing your workout at so you can grab them during any rest portions to help cool down.

Then of course, during the beginning phases of your cycle, if you’re feeling great, don’t be afraid to go for it. Set new PR’s, crush that workout. Still make sure you have adequate recovery periods in your plan though so you don’t get injured.

I hope you can find this useful. The other strange insight I found was that when I’m sick, my HRV and recovery score go through the roof. It’s odd because I feel like crap, but my HRV is telling me I’m set to take on new fitness challenges! Ha! I don’t recommend that. I did try to dig in to understand this trend and found LOTS of other people on the internet experiencing this strange phenomenon but the only real explanation I could find for it was parasympathetic overshoot. Basically the part of the nervous system that is trying to get you healthy again goes overboard.

It’s definitely interesting and fun to look at the data but I don’t think I need to pay for it all the time now that I’ve learned so much. Have you tried tech devices like WHOOP or something similar for your fitness? What was your experience?