Sleep matters – and yet many of us know how difficult it can be to get enough unbroken slumber.
Research has shown that getting less than seven to eight hours' sleep daily is associated with increased risk of:
- cardiovascular disease and diabetes
- car and workplace accidents, and
- learning and memory problems.
Given this, it’s worrying that, in the US, approximately 28% of people get less sleep than this each night. Australian adults do slightly better according to one study, with approximately 15% of adults reporting six or fewer hours a night.
There are more than 80 different sleep disorders, with estimates suggesting 20%-33% of the US population having suffered from insomnia. Estimates put the prevalence of adult obstructive sleep apnea – where a person momentarily stops breathing during his or her sleep – at 3%-7% of the population, with increasing evidence of a link between sleep apnea and Type 2 diabetes.
The starting point for dealing with a sleep issue is to recognise there is one. To do so, people need a way of measuring the amount and quality of sleep they are getting. That’s where the iPhone comes in.
Measuring brain waves with the iPhone: the Zeo
The Zeo is essentially a headband that can be worn at night and feeds data to the iPhone. The headband contains sensors that pick up electrical signals from the brain as well as information about eye movements.
The information is sent to the phone and analysed to produce a graph showing when you slept, when you were awake and how long you spent in each phase of sleep.
Zeo uses, appropriately enough, an artificial intelligence mechanism called neural networks to take the brain’s electrical activity and classify it into light sleep, REM sleep, deep sleep and wakefulness.
Using the data the Zeo provides, the iPhone application then rates your night’s sleep with a score called the ZQ between zero and 120 – the higher the number, the better the sleep. The data can then be uploaded to the myZeo website, which provides a range of tools, including various assessments and a sleep journal.
Zeo’s accuracy is actually quite high. When compared with polysomnography – the gold standard for assessing sleep – researchers found the Zeo was only slightly less accurate in detecting sleep phases, and just as accurate at detecting when people woke up and went back to sleep.
So let’s imagine you’ve collected some sleep data on your iPhone. What can this tell you?
First and foremost, it’s worth noting that this process doesn’t replace seeing a doctor and getting a professional sleep assessment.
Although the information may be useful in pointing to a problem, it will probably not allow you to self-diagnose any of the specific sleep disorders, including obstructive sleep apnea.
For this, a sleep or respiratory physician may perform a more detailed assessment using polysomnography. This involves more equipment than just the Zeo headband.
But your sleep data will increase self-awareness about how long you are sleeping and how many times you are waking up. With that awareness comes an appreciation of how dramatically factors such as coffee, alcohol, exercise and TV and computer use affect how you sleep.
You can then modify your behaviour and get direct feedback on the results, hopefully with an improvement to your sleep.
One of the features of devices such as the Zeo is that they create a social network of people willing to share their experiences, concerns and strategies regarding sleep.
In and of itself, that’s important in dealing with sleep issues and reinforcing support for making life-changes that will improve health outcomes.
Measuring sleep through movements
The Zeo headband isn’t the only approach to measuring sleep quality. A popular iPhone application called the Sleep Cycle professes to be able to do this by measuring the amount of movement during sleep. The concept is relatively simple.
You put the iPhone under your pillow and the accelerometers in the phone track any movement. This movement is then correlated with four phases: falling asleep/dreaming/waking up, light sleep, medium/deep sleep, and deep sleep.
According to an online post citing a professor of sleep medicine at Harvard Medical School, there is no evidence of movement being used to accurately determine sleep phases; other than potentially being able to distinguish between being asleep and being awake. Even in that regard, it may not be that accurate.
This has not deterred other manufacturers from making the same claims. A bracelet device called the UP also feeds movement data into the iPhone, and presents a graph of hours slept and light and deep sleep.
Personal health monitoring – the future
The use of the iPhone as a data collection and analysis platform is set to become more common. The next step is to alert wearers – or people monitoring the health of wearers – when there are potential problems.
One recent experiment used heart rate monitors and motion sensors to monitor nurses for episodes of stress. This provided the potential to intervene when someone was experiencing prolonged stress that was adversely affecting their health.
Many of us are unaware of the impact our environment, job and lifestyle are having on our health. As a result we’re unable to intervene before lasting damage has been done.
Sleep is central to our wellbeing. In this, and other health areas going forward, the iPhone may be able to help.