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 keep in mind for getting good temperature data is that you measure when your body is at its most rested state. This is when you will 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 standard 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 if you just struggle with getting back to sleep), it may be harder to catch your BBT. Our recommendation in these instances is that you measure after your longest stretch of sleep. If this only happens occasionally, you can instead 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 in a rested enough state when you measure later. In this case, we recommend that you measure as soon as you wake up the first time in the morning. If you measure after having gone back to sleep, you should exclude your temperature for that day.
As a reminder, movement (sitting up/getting out of bed), interrupted sleep, and being awake 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 situations. 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 because of it.
To help you determine if a temperature should be excluded, we encourage you to look at your graph frequently, preferably every day after you have logged your daily temperature. This will help you understand how your temperature varies throughout your cycle as well as track whether your temperatures fluctuate. Over time, you will understand 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.
While the average temperature for the follicular and luteal phase 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.