The menstrual functions of the Apple Watch Series 8 in the test

With the “Cycle Log” is available for people who are menstruating Apple been able to record periods for a long time. As with classic menstrual apps, the entries are used to estimate when the next period is due and when ovulation is likely to take place (unless hormonal contraception is used). Symptoms such as abdominal cramps, chest pain or headaches can also be logged.

Those who use hormonal contraception can use the “cycle log” app to check whether the cycle is going according to plan or whether there are any deviations. Under “Factors” users can enter whether and which contraceptive they use and when they started using it.

Apple Watch 8: New period tracking feature

With the Apple Watch Series 8 Apple has introduced another cycle function that should be of particular interest to women who do not use hormonal contraception. The Apple Watch 8 can be based on temperature measurements retrospectively the time of ovulation calculate and thus predict the date for the next period even more precisely. I have the Apple Watch Series 8 one long-term test and examined the new period tracking features.

This is how the temperature measurement works

In the Apple Watch 8 were both on the back of the watch as well as under that Display Built-in sensors that record body temperature. This double measurement makes that possible minimal changes the body temperature of 0.1 Degree Celsius can be detected. The “Health” app therefore has its own menu item entitled “Temperature on the wrist”. However, there is no display of the body temperature, but only a so-called “initial state“. That means I don’t find out how high my temperature actually is, only how high it is on average.

The starting temperature is determined by using the Apple Watch Wear at night for 5 days. For at least 4 hours a night the Sleep focus must be enabled to collect wrist temperature data. The “Sleep” menu item is also in the Health app. After 5 days you will be informed that the data of the “initial temperature” are ready.

Why you can track ovulation with the watch

Apple promises to determine the timing of ovulation based on wrist temperature retrospectively to be able to calculate. This is possible because the temperature usually 1 to 2 days after ovulation increases before they are around 1 to 2 days falls again before the period. In between it is round 8 to 10 days elevated.

When we say “usually” it means it’s not the same for every cycle, as women’s endocrine systems are very sensitive to environmental and external factors such as stress. It is normal, especially as women get older, if ovulation fails completely in a cycle, or if the “hormone cocktail” is composed differently than usual.

Basal temperature

If you don’t have an Apple Watch Series 8 at hand, you can Basal temperature also measure differently. This is usually done right after waking up, without moving or doing any physical activity, and always in the same place. The temperature can be measured in the vagina (vaginal measurement), in the anus (rectal measurement) or in the mouth (oral measurement).

If this is not strictly observed (always after waking up and in the same place), the data is not reliable. It is important that the result is as accurate as possible if you use ovulation tracking as a natural contraceptive method.

On the subject, Apple itself writes that the cycle log, which is created based on the temperature on the wrist, “not as a contraceptive method should be used”. The data should also not be used to “diagnose health status”.

Apple recommends that the watch always “fits well” on the wrist. Of course, the position of the watch can also vary here, for example if you use a flexible sports bracelet.

Data collection for ovulation tracking

In practice, I collected a lot of data when I tested the temperature function on the Apple Watch Series 8. I wore the Apple Watch Series 8 to sleep every night. As a result, in addition to the temperature log, I also received an extensive sleep log with all sleep phases.

The Apple Watch also got to know my cycle, in which I dutifully entered my period: My normal cycle is 26 Roofs (that each cycle is exact 28 Roofs is a myth, the norm is anything from 24 to 38 days).

On the first cycle fully tracked with the Apple Watch, my wrist temperature increased 10 Take long above baseline, only to drop sharply one day before your period. The highest measured temperature was at +0,45 Grad from baseline, the lowest measured -0,4 Grad from the initial state. The Apple Watch sent me an “estimated ovulation” notification a few days after the start of the next period.

This day coincided exactly with the day that I had defined as such based on my symptoms. While other people have period pains and cramps, especially during their period, I can feel ovulation. The temperature measurement had worked excellently in the first month tested.

This month I also prefer as reference month approach, because a month followed in which no ovulation took place. As already explained, this is completely normal. But there was nothing to measure on the part of the Apple Watch Series 8 and nothing to notify. Further cycles are still pending.

How well does Apple’s cycle protocol work?

I was already a user of an Apple Watch Series 6 before the Apple Watch Series 8 review and was very happy with the cycle tracking app. The cycle log in Apple’s Health app works reliably if you have a reasonably regular cycle and mainly serves as a reference to be able to check when your next period starts.

The tracking is also practical when you are on vacation planning and doesn’t want to spend the whole week on the beach with menstruation. Or, of course, to track whether you pregnant could be or not. As mentioned, the app itself also works in combination with contraceptive methods.

Get to know your own body better

The new function that measures the temperature on the wrist, the cycle tracking even more precise and the longer one uses the function, an even better prediction of when the next period will start is possible. Cycle tracking also helps you get to know your own body better.

Perhaps one or the other who has been on the pill for a long time will notice that in a natural cycle around ovulation there are other things that happen than any possible “ovulation pain”. For example, the composition of a possible discharge and the associated “hormone cocktail” also change.

What happens to the data?

The Apple Watch needs to be worn continuously to get any useful data. In practice, this means that you can use the watch whose battery only lasts one day (more precisely: 18 hours) keeps, can’t charge at night. Personally, I usually used the evening as a time window to take off and charge the watch during the – rather low-calorie – TV/streaming/reading program. One hour of charging is not enough to get the battery to 100%, but 1.5 hours – the length of a feature film.

The rest of the handling is very easy. The data is recorded on its own and you only have to call it up and compare it in the health app.

But what about the data collection? Ultimately, this is about sensitive health data. The collected data is first stored on the device, i.e. the Apple Watch Series 8, and the associated paired iPhone, stored locally and encrypted. Whether the data is subsequently transferred to the iCloud depends on the settings that you make. When iCloud is enabled, Health app data is backed up by default. iCloud backup can be disabled at any time. In general, if iCloud backups are activated, the data is always transferred in encrypted form.

What else can the Apple Watch Series 8 do?

The Apple Watch Series 8 scores with a selection of numerous training types such as boxing, cross training, functional strength training, gymnastics, tai chi, dancing, sailing, etc. In addition to an ECG and blood oxygen measurement, there is precise sleep tracking that breaks down the respective sleep cycles.

The Apple Watch Series 8 is from 499 euros available. Recommended for people with small wrists 41 mm size (I tested this), but it is also available in 45 mm. The aluminum case of the Apple Watch Series 8 is available in North Star, Midnight, Silver and Red, while the stainless steel case is available in silver, graphite and gold.

Conclusion

The Apple Watch Series 8 as a whole is highly recommended, because, like the previous models, it works perfectly with the paired iPhone. The health features like EKG, blood oxygen as well as the sleep tracking and the periods app are the most important features of a health wearable for me and the Apple Watch Series 8 masters them perfectly.

However, I would not recommend people who, like me, had an Apple Watch Series 6 or 7 to switch to an Apple Watch Series 8 because of the new “temperature measurement function” – unless of course they want to use contraception and, in addition to the basal body temperature, want a “second opinion ” of an Apple Watch to feel as safe as possible. Since Apple itself does not recommend using the function for contraception, I can see that though no real purpose for the temperature function.

Personally, I would have preferred it to be one concrete temperature displayed, because then the Apple Watch could not only measure the temperature for menstruators, but generally as clinical thermometer be used.

All other menstruators who do not yet have an Apple Watch and who want to get to know their body better will definitely have a tool with which they can work with the Apple Watch Series 8. I wouldn’t buy the Apple watch just because of the function. But if you are considering buying a health and fitness tracker anyway, you know that Apple has one with the watch strong focus on women’s health and the data is well protected against external access.

A bonus is that you no longer need menstrual apps, which are often data-hungry and share data with other companies. Apple doesn’t do that on its own.