What does the end of the Actiwatch mean for aviation?
Last month, Philips Respironics sent out an email that threw the sleep research community into a tizzy. The “Actiwatch obsolescence announcement” was sent to current Philips customers in clinician or research markets and detailed the abrupt end of sales of all Actiware, Actiwatch 2, Actiwatch PRO, and Actiwatch Plus products after December 29, 2022. Previously sold merchandise will be supported through 2027. The reason that Philips gives for discontinuing the Actiwatch line is “reorganization of the Philips business”. The announcement also states that the Philips Health band (the company’s consumer fitness tracker) would not be offered for clinicians or research sales following December 29, 2022. Although it made no mention of Actiwatches, a July 2022 press release from Philips states that the company is adapting a new business model that will concentrate on consumer needs moving forward (1).
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If you’re unfamiliar with the Actiwatch series, it is the Philips line of research-grade actigraphs, a wrist-worn device that collects sleep data. Actigraphs have been used to estimate sleep-wake patterns by researchers since the 1970s whereas consumer devices like Fitbit began tracking sleep in the mid-2010s or later (2). Five years ago, sleep scientists (myself included) considered consumer wearables to be nothing more than toys. The sleep data from Fitbits was so inaccurate that the company faced a class action lawsuit from consumers who paid for a Fitbit with sleep tracking (3). Researchers and clinicians started to take wearables more seriously in 2021 following a publication by the Naval Health Research Center (NHRC) that compared seven different consumer devices against laboratory measures of sleep and found their performance to be “as good as, and in some cases better than,” research-grade actigraphy for the detection of wake (4). The actigraph that was rudely dethroned in this multi-device study was none other than the Philips Actiwatch 2.0.
Since November is National Aviation History Month, let’s talk about how Philips’ decision affects aviation. Aviation is one of the most regulated industries when it comes to fatigue. Commercial airlines are required to have a Fatigue Risk Management Plan (FRMP) and if a carrier wishes to exceed any of the flight and duty limits that must have an approved Fatigue Risk Management System (FRMS) to demonstrate to government regulatory bodies that their flight routes are within acceptable parameters compared to operations within the limits. The Federal Aviation Administration (FAA) is the commercial aviation regulator for the United States. Appendix 2 of the FAA’s Title 14 of the Code of Federal Regulations (14 CFR) part 117, § 117.7 says that FRMS procedures “should be designed with supporting validated data collected and analyzed from various sources associated with the FRMS operation. Such data sources include, but are not limited to, actigraphy, performance tests, biomathematical modeling, and fatigue monitoring and reporting” (5).
For regulators who have been using Actiwatches to support their FRMS, Philips’ decision means they will have to find a new device provider. Fortunately, Philips Respironics is not the only company that sells actigraphs. Airlines could simply switch to another actigraph provider and hope that the new company does not send an “obsolescence announcement” in the near future. Alternatively, many consumer fitness trackers and smartwatches now collect sleep data that is comparable to an actigraph. It is possible that smartwatches could be used in place of Actiwatches to support FRMS.
Switching to a consumer device like Apple watches or Fitbits can create headaches for aviation though. First of all, FAA’s 14 CFR part 117, § 117.7 mentions actigraphy by name. Consumer wearables that have been evaluated against laboratory measures for sleep-wake determination are not technically actigraphs. The terminology in the rules may need to be updated to address a change in available technology. Next, laboratory validation may not translate to accuracy in the field. IBR’s Zulu watch has been tested against self-report of sleep in long-haul pilots during operations (6) but neither the majority of consumer wearables nor the majority of actigraphs have been evaluated for sleep detection in the aviation context. Best practices for the use of actigraphy in the field recommends confirming data against self-report and manual processing of the data by a human researcher. In contrast, sleep tracking in consumer wearables is automated. Few wearables even allow the individual to edit their own sleep events, which constitutes an oversight for data validity. An issue specific to smartwatches is that they may automatically adjust to a new time zone. Some devices allow the user to turn off the automatic time zone function. If the researcher is unaware of how time zone data is being stored by wearables, however, it may be very confusing when they extract data from transmeridian flight routes.
Extracting data from consumer wearables may be the biggest issue when considering replacing actigraphs. Consumer wearables are designed for personal use rather than as an objective data collection tool. That means that the data are designed to go back to the wearer instead of being delivered to a researcher. Figuring out how to access the data from a wearable is an extra step. Some consumer device manufacturers provide researcher support or application programming interface (API) solutions but crew members may not like the idea of their employers pulling data from their personal devices. Data cannot be extracted from a personal device without user permission and crew members must always give their consent to collect data for FRMS, but it is possible that an individual would be less willing to give consent if the data comes from a personally-owned device. Conversely, pilots may complain about wearing a research actigraph like the Actiwatch 2.0 if they already collect sleep data on their Garmin or Apple Watch. Privacy versus convenience is a delicate balance to strike as wearable technology becomes more prevalent. IBR has conducted a series of surveys about wearables preferences for sleep researchers and general consumers; we are planning to replicate this survey with an airline employee population to determine how best to collect data in a way that respects the preferences of the aviation community.
In the short term, the end of the Actiwatch should not be too disruptive to aviation. Fortunately, SAFTE-FAST can use sleep data from any source - sleep diary, actigraph, smart watches, or even PSG-- as long as we have sleep timing and duration information in a properly-formatted CSV file. In the long run, however, it is possible that actigraphy as a technology is headed towards obsolescence. If this is the case, then the FAA and their counterparts in other regions will have to update regulations. In the interim, if you are a Philips Actiwatch user who is searching for a new way to track sleep, I have included a link to our operational sleep tracker match-making quiz below:
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