Basal Temperature Charting 101: Track Your Hormones At-Home
Did you know that the first thing you do in the morning could give you a ton of information about your hormone health? It’s called basal temperature charting – and it’s actually pretty easy to implement.
Basal temperature charting involves documenting your lowest body temperature each day, which happens to occur when you first wake up. Before doing anything (like sitting up, getting water, or yes, even checking your phone) you take your temperature with a basal thermometer. It looks pretty much the same as a regular thermometer, but a basal thermometer is more sensitive, so it will provide a more specific temperature reading.
Once you’ve done that, you just need to record the day’s temperature in a chart for the month (there are tons online, and you can often add space to document other symptoms of the cycle, which is what I do for my clients!). And that’s it - all that’s left to do is to keep an eye on your chart as the month progresses.
So how can something as simple as morning temperature tell you so much about your hormones? The reason basal temperature charting is so useful is that our temperature actually shifts with the hormonal changes of the menstrual cycle, so we can 1) look to see if those changes occur, 2) see if they occur on time, and 3) get clues for what might be going on if 1) or 2) don’t happen as planned.
Here’s what a typical basal temperature chart should look like:
from days 1-13 (1 being the first day of your period), your temperature will be at its lowest for the month
around day 14, you may see a small temperature dip (this comes from a hormonal surge that triggers ovulation and occurs on the day of ovulation for some people)
around day 15, you’ll see a rise in body temperature of about 0.4 degrees Celsius, which demonstrates that ovulation has already occurred (note that you need to see a consistent rise in temperature of at least 3 days to confirm ovulation, so it's always identified after it's happened)
after day 15, body temperature should stay consistently high until just before your next period, because the hormone progesterone is being produced during this time and results in slightly higher body temperature
around day 27 or 28, you may see temperature drop as progesterone decreases a day or two before your next period will occur (if you’re pregnant, progesterone will stay high and so will your temperature!)
once your period arrives, your temperature will drop back down to its lowest levels, and the cycle will begin anew
These timings are estimates, so there’s no need to worry if you ovulate on day 13 and have a 26-day cycle, or if you ovulate on day 15 and have a 30-day cycle. However, dramatic deviations from this pattern are clues that there may be underlying hormonal imbalances. Here are some common examples:
no rise in temperature at the midpoint of the cycle can suggest no ovulation (which may be a result of high stress, imbalances in thyroid or adrenal hormones, or a hormonal syndrome like PCOS)
a rise in temperature significantly earlier than 2 weeks into the cycle, suggesting early ovulation (which may be a result of high stress or approaching menopause)
a rise in temperature significantly later than 2 weeks into the cycle, suggesting late ovulation (which may be a result of high stress, liver congestion, or imbalances in thyroid or adrenal hormones)
a rise in temperature that is not sustained, indicating that ovulation occurred but that adequate progesterone is not being produced (this may be a result of high stress or imbalances in thyroid or adrenal hormones)
And while basal temperature charting is a great tool to have in your hormone balance toolbox, it isn’t ideal for everyone. It won’t be a great option for the following people:
folks taking hormonal birth control that prevents ovulation from occurring (like the birth control pill or patch and some hormonal IUDs)
people who have frequent changes in their sleep-wake cycle and can’t wake up at roughly the same time each day, such as shift workers
anyone whose morning routine doesn’t allow them 2-3 minutes to take their temperature first thing after waking each day!
I love basal temperature charting as an at-home tool to help you learn about your cycle, and this general information is certainly enough to get you started. But there are a few scenarios where I’d encourage you to work with a professional to make sure you get the personalized information you need, such as:
if you’re looking to use it as one of your contraceptive methods (aka to prevent pregnancy)
if you’re looking to use it as one of your fertility tools (aka to help you get pregnant)
if you’re noticing the deviations in the cycle mentioned above that suggest there may be a hormonal imbalance at play
For contraceptive advice, a doctor (naturopathic or medical) is a great person to ask, and as for the fertility and hormone balance pieces – I may be able to help you there! You're welcome to grab a free half-hour hormone call under the Contact tab so that we can chat about what might be going on and how to get you feeling your best! Until then - I hope you enjoy using a simple thermometer as your new hormone-tracking best friend.