When it comes to waking up during the night, there are a few things to consider. We will list a few common scenarios below and when we recommend measuring in each case.
The most important thing to remember for getting good temperature data is to measure when your body is at its most rested state so that you’ll get a chance to catch your basal body temperature (BBT) – your body’s lowest resting temperature. Learn more about BBT here.
Waking up in the middle of the night
If you tend to wake up during the night, for instance, to use the restroom or have a glass of water, and you quickly fall back asleep, this will usually not affect your temperature. In this case, you can measure as usual at your usual waking time in the morning.
If you stay awake for some time after waking up at night (for instance, to tend to a child or struggle with getting back to sleep), it may be harder to catch your BBT. If you regularly get up and struggle to fall back to sleep at night, our recommendation in these instances is that you measure after what is usually your longest stretch of sleep. However, if this only happens occasionally, you can exclude your temperature the following morning.
Waking up close to your regular measuring time
If you wake up close to your measuring time but go back to sleep, your body may not be rested enough when you measure later. In this case, we recommend measuring as soon as you wake up the first time in the morning. If you measure after returning to sleep, you should exclude your temperature for that day.
As a reminder, movement (sitting up/getting out of bed), interrupted sleep, drinking water, and being awake before measuring will affect your temperature. You need to measure while lying down and as soon as you wake up; otherwise, the temperature will be affected by not measuring right away.
Knowing when to exclude a temperature
It is important to keep in mind that everyone is unique, and your body may react differently to different circumstances. For instance, waking up at night might affect your temperature more or less than others. Exclude your temperature if you feel that something was out of the ordinary for you and you feel differently in the morning.
To help you determine whether to exclude a temperature we encourage you to look at your graph frequently, preferably every day after you have logged your daily temperature, to help you understand how your temperature varies throughout your cycle and track whether your temperatures fluctuate. Over time, you will learn when to exclude your temperature, for example, if you see that a temperature is unusually high or low for the cycle phase that you are in and something was out of the ordinary for you that night.
While the average temperature for the follicular and luteal phases differs from person to person, your temperature follows a curve with lower temperatures in the follicular phase and higher temperatures in the luteal phase. During your follicular phase (first period day to ovulation), your temperature generally stays below your cover line. In the luteal phase (ovulation to period), your body releases progesterone, raising your temperature above the cover line. When the temperature has risen enough to confirm ovulation, the most likely ovulation day gets calculated from the temperature curve.
We write more about ovulation detection in this article.
Note: If you're struggling with your measuring routine, know that you now have the option to use Natural Cycles with one of our approved wearable devices (the Oura Ring and the Apple Watch). When using Natural Cycles with a wearable device, your temperature data gets measured overnight while you sleep. This means that you no longer need to remember to take your temperature before getting out of bed in the morning! Learn more about using Natural Cycles with the Oura Ring here, and with the Apple Watch here.