A recent global sleep survey by ResMed, the US-based digital health and medical device company, revealed that Indians are getting roughly 7.82 hours of sleep each night. According to the survey, which was based on inputs from 25,000 respondents in 12 countries, stress has had a big impact on people’s sleep since the start of the covid-19 pandemic.
What about Indians? The survey revealed how returning to the office has impacted the way people believe their sleep quality will change. Many people – in India 65% of the respondents – said they have slept better or longer while working remotely and believe more in-office working time will make it difficult to wake up in the morning. These recent findings make for interesting analysis, given their relevance to World Sleep Day, held every year on 18 March.
The pandemic has essentially changed our relationship with sleep and its restorative benefits. How much can technology – like wearables – help in this department? After all, many of us use sleep tracking technology to understand more about our sleep patterns. Conor Heneghan, lead sleep research scientist at Fitbit, believes while wearable devices do give people enough information, how they interpret it is up to the user. As part of his work and research at Fitbit, which was acquired by Alphabet Inc in 2021, Heneghan focuses on various aspects of consumer health, especially algorithms for sleep, stress and mental wellness.
In a video interview from San Francisco, US, Heneghan spoke to Lounge about the next frontier for wearables, why short naps are underrated and the importance of understanding the ideal length of sleep a typical person needs. Edited excerpts:
What has been the impact of the pandemic on our sleep patterns?
We saw a very dramatic change in sleep patterns, as you might expect. It varied slightly by country, but typically, most people in the working age (20-55 years), saw an increase in their sleep of about 25 minutes. That was a net positive, which was obviously related to commuting and maybe not having to bring children to school.
We also did a country by country analysis. Countries like Spain and France had very strict lockdowns at the beginning of the pandemic. They saw a greater increase in sleep time and a reduction in daily steps, which was more significant than countries like the UK and Germany, which were a little bit more relaxed about their lockdowns at the beginning.
How has sleep tracking technology in wearables evolved over the years?
The first generation of wearable technology just used the accelerometer, which is the movement sensor. That's pretty good for picking up whether you are asleep or awake. But it doesn't give you any information about the type of sleep – whether you are in deep sleep or REM (rapid eye movement) sleep, for example.
We added in the heart rate information in 2017. What happens with your heart rate is that during different stages of sleep there are different types of variability. That allowed us to break out your sleep pattern into deep, light and REM. Other manufacturers have been looking at the same thing. So effectively, the current state of the art is to use the combination of movement and heart rate information to make those sleep stage determinations.
There's also the ring wearables. They have done a nice job in the last few years. We also have a pretty good signal on the finger in terms of movement and heart rate.
Sleep apnea — or obstructive sleep apnea — has become a big cause for concern for people in recent times. How important is it for us to understand more about this?
I think the big challenge in sleep apnea is that it can be pretty undiagnosed. The symptoms are not necessarily apparent to you as an individual because you are asleep. People who have sleeping partners – they might hear the loud snoring but then followed by gasping or actual silence. There is still an estimate that there could be 70-80% of people who have sleep apnea but are unaware of it. That's the number one issue devices like Fitbit can help to tackle – by making people aware of their sleep habits and highlighting the possibility that they could have sleep apnea. That's the direction we are going in with our research. The good thing about sleep apnea is that it is a very treatable condition.
So, wrist worn devices can actually help in such cases?
Yes. The later versions of the Fitbit, for example, actually have an estimate of your blood oxygen (the SPO2 level). What happens in apnea, is that as you stop breathing, the oxygen levels will drop in your blood. What we are researching right now – and there are some ongoing trials – is algorithms that automatically estimate the severity of your apnea. We'd like to get it through the regulatory process in different countries to have it approved as what they call a "software medical device".
Everyone targets that magic figure of “8-9 hours” when they sleep. What has your research told you about the ideal length of sleep a person needs?
Firstly, when people think about the 8 hours, they are discounting the natural amount of time you spend awake at night. So if you go to bed for 8 hours, a typical person would still have 35-40 minutes of wakefulness. That is actually normal. So that usually translates to about 7.5 or 7 hrs 15 minutes of sleep. What we find globally is that the average Fitbit user gets around 6 hours 45 minutes (of sleep). So people are probably sleeping a little bit less. I wouldn't say it (the 8-hour mark) is a myth but there's no direct science which says that you have to have 8 hours.
We don't know yet if there is an optimal amount of time that every person should sleep for. It does vary by person. Some people, genetically, will probably do better with longer sleep or slightly shorter sleep.
An MIT study last year — based on a field experiment of low-income workers in Chennai, India — pointed out that night-sleep interventions provided no big positive effects. Short daytime naps did, however, help them with productivity and well-being. Your thoughts?
I think it is getting to be more and more accepted that short naps during the day - maybe 20-30 mins - can be very restorative, particularly to improve mental function and mood. Personally, I think napping is a good thing if it is something that can be built into the work schedule or culture. So I am not surprised by those results at all. I think napping is underrated as a positive thing for your health.
Is there any optimal time for a person to take this so-called power nap?
I think taking it later in the day is a bad idea. Let's say: (taking a nap) after 4 pm, for a typical person, is probably going to interfere with their sleep later that evening. There's a natural dip, a window in the early afternoon, around about 1-2 pm for most people on a 9-5 work schedule.
Millennials have often been described as the “sleep-deprived” and “tired” generation. What would you suggest as certain lifestyle changes for this demographic to get a better night’s rest?
I would say trying to build in some sort of wind down routine at night time is probably the key thing. The thing that is affecting a lot of people now is the use of technology late at night. If you are sending emails at 11pm or scrolling through long social media feeds, it does tend to be not very relaxing. It could be emotionally engaging content...
In an ideal world, people would get themselves a good hour or so before going to bed to try to wind down. For some, it could be mindfulness practice, it could be reading a book, listening to light music, fixing the darkness level in your room. Melatonin levels are very much influenced by the light in our environment.
There’s constant debate about how technology helps - but also hurts - a person’s sleep. What are some ways in which people can use tech responsibly for better sleep?
What wearable devices can do is just give people information. How you interpret that is up to the individual. There are things people can benefit from: it (technology and wearable devices ) gives them an objective look back on the consistency of their schedule. That seems to be a proven benefit because you try to stay, plus or minus, on the same schedule. You can review the data to see if you are doing well or not. It can also help you link things like alcohol, which can influence your sleep negatively. That's a useful feedback mechanism. It's all about understanding your own body and lifestyle.
After measuring things like stress, SPO2 levels, what is the next frontier for wearables?
I would say, having more wearables that provide medical functionality -- that will happen slowly over time. In the case of Fitbit, we have developed technology to look at atrial fibrillation, which is a heart condition. Some of our competitors have developed similar features.
I could see other cardiac issues that can be reliably picked up by wearables: sleep apnea, probably even things like insomnia. If you want to tell someone that they have a medical condition, you need to get into more structured research and regulatory protocols.
We can speculate about blood glucose, because from a diabetics point of view that would be an amazing breakthrough should a wearable be able to do that. Blood pressure is also a very challenging area. I think a continuous blood pressure monitor in a wearable would be a super addition. That's something a lot of wearable companies are looking at.