Day 5: Why You Should Track Your Cycles

Welcome to Day 5 of The Science of Your Cycle, Groove’s amazing (and 100 percent FREE) 7-day mini-course that will teach you everything you need to know about how your body (and your period) works. Period tracking has exploded in popularity over the last few years, but why do so many people do it? Sure, it helps you keep track of when your next period might show up, but there are MANY other amazing benefits we don’t often discuss. Today, we’ll cover the numerous, life-changing benefits of tracking your menstrual cycle data. Period tracking isn’t just about convenience — it can also help you keep your body healthy, prevent pregnancy, get pregnant, predict upcoming periods with unbeatable accuracy, and more!  


  1. Download Groove to start tracking and benefiting from your menstrual cycle data.

  2. Learn the rules that MUST be followed to prevent pregnancy using your menstrual cycle data.

  3. Download today's slides.

  4. Sign up for The SCIENCE of Your Cycle

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Video Transcript

00:00 - The SCIENCE of Your Cycle Day 5, Day 5! Welcome back to Day 5. Today we’re going to be covering why you should track your cycles. I know that yesterday’s information was pretty long, so I promise that we’re going to get through this much faster today. Today’s goals are to learn how understanding the menstrual cycle can benefit you, your life, and your health; secondly, know how to predict your next period with ridiculous accuracy; learn how the menstrual cycle data that you gather can help you effectively prevent pregnancy or get pregnant. You heard that right: menstrual cycle data can help you prevent pregnancy or get pregnant…pretty amazing! And then lastly, understand how to determine if your period problems might be caused by an underlying issue.

01:05 - First a quick recap of the amazing information and we learned over the past two days. You’re a total boss, and you’re just completely crushing it for bearing with me through that. But now we get to the really good stuff after we go through this one last thing. Menstruation is when the lining of the uterus sheds. The vagina’s acidity makes it a sperm-killing machine. Developing follicles make estrogen that triggers the cervix to make cervical fluid. Cervical fluid becomes progressively wet and slippery as ovulation gets closer, and without slippery cervical fluid sperm cannot survive in the body. Ovulation occurs when a mature follicle’s estrogen production triggers the luteinizing hormone surge, and this luteinizing hormone surge turns the newly empty follicle into the corpus luteum, or yellow body. The corpus luteum makes progesterone heats up the body, dries up cervical fluid, prevents another ovulation. and thickens the uterine lining in case there is a pregnancy. And if a pregnancy does not occur, the corpus luteum dies, meaning it no longer creates progesterone. So the progesterone drops, the uterine wall breaks down, and your period starts again.

02:35 - Now we’re going to get into the good stuff — how does this help you, and what benefits does knowing all of this information have in your life? That’s what everybody wants to know. The benefits of tracking your cycle: you determine when you ovulate, you know exactly when your period will start, you can pinpoint when you’re fertile, you get super effective (and essentially free) birth control, and you can detect health problems. Now let’s go through each of those points in more detail.

03:18 - The first benefit is that you can determine when you ovulate. Ovulation can actually be pinpointed by measuring your body temperature each morning. But why is that? We talked about progesterone and how it’s made by the corpus luteum (or yellow body) after ovulation. Remember, the corpus luteum is the empty egg follicle, and the corpus luteum makes progesterone. One of the things that progesterone does is it makes your body heat up — so after you ovulate, your body heats up. The corpus luteum can only make progesterone if you ovulated because if there’s no follicle that releases a matured egg, then there’s nothing to convert into the corpus luteum. Once your body temperature heats up, you know that you have ovulated. Pinpointing ovulation is very useful if you want to get pregnant, if you want to prevent pregnancy, or if you want to know exactly when to expect your next period.

04:24 - The next benefit: know exactly when your period will start. The reason you’re able to do this is because the lifespan of the corpus luteum is very specific. I mentioned already that the lifespan of the corpus luteum is between 11 and 16 days long, and this lifespan is going to be consistent from cycle to cycle for each individual — even if your cycles are highly irregular. Just to give you an example: my luteal phase, or the lifespan of my corpus luteum, is almost exactly 13 days long every single cycle. Someone else’s might be 12 days long every single cycle, and someone else’s might be 14 days long every single cycle. But it’s always going to be almost identical for each person. Measuring your resting body temperature, which is called basal body temperature, every morning shows you when your body heats up. This tells you that you recently ovulated. To give you an example of how you would apply this information: I measure my body temperature every morning, and once I see that my body temperature rises, I know that I can expect my period in exactly 13 days. And, lo and behold, 13 days later my period starts. Science is awesome!

06:15 - This is just a graphic representation of body temperature. The height of the bars represents body temperature in Fahrenheit, and the colors just represent menstruation so don’t worry about that. But you can see that the body heats up after ovulation, so that sudden increase in body temperature represents the luteal phase. That’s because of the progesterone that’s made by the corpus luteum. Once ovulation happens, that temperature is going to jump up and it’s going to stay up until your next period.

06:55 - The third benefit: pinpoint when you’re fertile. We talked about this quite a bit already, but when cervical fluid is present, sperm can stay alive for up to 5 days. In very, very rare cases, it has been seen to stay alive for up to 7 days (which is super rare) waiting to fertilize an egg. If cervical fluid is not present, sperm cannot survive. Cervical fluid production is triggered by estrogen that’s made by growing follicles before ovulation, and after ovulation progesterone that’s made by the corpus luteum makes cervical fluid dry up. This once again creates a hostile vaginal environment for sperm. And sperm, once again, cannot survive in the female reproductive tract unless cervical fluid is present.

08:14 - The fourth benefit is super effective (and free) birth control. Just a quick overview of why collecting this data actually works as birth control: the reason it works is because sperm cannot live without cervical fluid, which is made when your body is ramping up to ovulate. You only ovulate once per menstrual cycle. You might be wondering how fraternal twins happen. Two eggs can be released, but in the rare case that it does happen, it will happen within 24 hours of one another. So if one egg ovulates, a second egg (in some cases) does ovulate, but it will happen within 24 hours of the first one. But then once a follicle converts to the corpus luteum and that progesterone production kicks in, then it stops all follicle development and prevents another ovulation. So progesterone that’s made after ovulation dries up cervical fluid and prevents another ovulation. Measuring body temperature tells you when you ovulated. Then, the egg dies within 24 hours if it isn’t fertilized, and no eggs means no pregnancy! That’s why you can use this information for super effective birth control.

09:35 - This birth control method is over 99% effective when it’s used correctly and consistently, which is so amazing! It’s not something we usually talk about. Its effectiveness is on par with the birth control pill, which is awesome. But this is so so important for me to say: in order to use this as birth control, you can’t just willy-nilly collect data and think you know exactly what your body is doing, because that makes room for an error, which could lead to an unintended pregnancy. There’s a specific set of rules that has been created by researchers and by the scientific community that must must must must be followed in order for this to be effective as birth control. If you are interested in learning those rules, you can find those in one of the links right below the video. But, like I said, never just collect this information willy-nilly and assume that you know what your body is doing, because there are cases that you could never plan for. Also, your cycles can be affected by environmental factors, and there’s no way of measuring how those environmental factors are going to affect your cycle. So you need to follow that set of rules because those are the rules that have been tested, and those are the rules that will lead to this high effectiveness of this method. Data-driven birth control is a thing that exists, and when I learned about it I was just as excited as these fine folks are here.

11:28 - Another awesome benefit of tracking your cycles: it helps you detect health problems. Keeping track of your body temperature and cervical fluid helps you actually indirectly measure the hormones estrogen and progesterone. Remember, body temperature heats up from progesterone, and cervical fluid is triggered by estrogen, so measuring body temperature and cervical fluid is actually an indirect measurement of estrogen and progesterone, which can actually tell you a lot about the state of your health and the state of your hormone levels. Tracking these could tell you if you might have low progesterone or estrogen, vice versa, or maybe a combination of the two. Tracking symptoms like acne, period pain, digestion, sleep, and other things can help you spot really important patterns in your cycle and spot potential problems. And lastly, tracking your cycle means you know what’s normal for your body and what’s abnormal for your body. It can give you a lot of information about the state of your health. For more information on how to track menstrual cycle data, or if you’re interested in learning more about the rules that you need to follow in order to use this data for birth control, check out the links right below the video. It’s super important to understand all of that stuff before you move forward with something like that.

12:55 - One of the takeaways that I want you to have from today is that when you understand how your periods work, it becomes very easy to detect potential health problems. Here’s a summary of day 5. Cycle tracking tells you when you ovulate, cycle tracking tells you when your period will start, tracking your cycle data lets you know when you’re fertile and when you’re not fertile, cycle tracking (plus following certain rules, which are super important) is a highly effective form of birth control that’s over 99 percent effective when practiced consistently and correctly, and tracking your cycle data helps you uncover potential health problems.

13:45 - If you want to put all of this new knowledge to use (shameless plug here), Groove has an amazing period tracking app that can help you do just that. It’s loaded with info. You can go and tell Groove about your unique cycles and then tons of educational information will be tailored within the Groove app just for you. If you already use the app, keep on keepin on! If not, make sure to check it out because it’s amazing.

14:25 - Tomorrow we’re going to discuss how to figure out what’s normal and what’s not normal when it comes to your menstrual cycles. We’re also going to learn what symptoms are the result of a deeper problem that might need to be addressed. And then lastly, we’re going to discuss what exactly your menstrual cycle data (things like temperature, cervical fluid, flow, pain, cycle regularity or irregularity) means about the state of your health.

14:55 - Just so you know, me and Queen Bey are hella proud of how smart you are because the information that you learned is not necessarily easy, but it’s super empowering! It’s super transformative, and I can personally attest to how life changing it is. I want you to give yourself a big high-five, a big pat on the back, and whatever else you need to do to tell yourself that you’re amazing, because you are amazing! I’m super excited about the information we’re going to go over tomorrow, and I will see you then.