IPhone Sleep Cycle App - A Clinician's Review

I am writing this review because of feedback from my Twitter friends. Over the past few weeks there has been a lot of interest in all things iphone and I believe the best seller in many countries, if not the world, is an app called "Sleep Cycle". The picture you see here is a readout of the app, kindly provided by a colleague, Lewis King, who was one of the people who tried out the app and then wondered what it meant. At first sight a graph such as this, with a lot of spikes in it might seem alarming, especially if you have had a restless night. This is, in fact, a near "normal" reading, as I will explain presently. 

The app retails for $.99(US) or 59p (UK) and does exactly what it is meant to do which is to measure your sleep cycle. It also wakes you up within a half hour window with music and the timing of that is meant to be the moment when you are approaching an awake state. It is produced by Lexware Labs. The idea is not new but in the past such machines have been considerably more expensive and it is very much to the credit of the software developers that they are prepared to offer this app at such a price. The principle is very simple. The iphone has an "accelerometer" which is able to detect the extent of your movement in bed. Since different phases of sleep are characterised by different amounts of movement it is possible to map the one to the other, the result being what you see on the screen. From what I have seen of it so far I have to say it works and if I were still in clinical practice I would have a few uses for it without hesitation.

The obvious problem which arises is that people don't actually know much about sleep so they are at a loss to interpret the data. In fairness to Lexware Labs their website does explain what you get for your bucks and what various graphs mean. So at least if you have had a bad night's sleep and you see a graph that suggests you have had a bad night's sleep you know you have had a bad night's sleep. Perhaps that is just a little bit too cynical. After all we live in an age of freely available medical information and much of that, I don't doubt, will be misunderstood. That is not an argument for restricting information. Anyone who really wants to know can read more about the subject and, hopefully, discover something useful about themselves.

 So where do we go from here? Much as I would love to write a detailed scientific paper on sleep and specific sleep problems, I am the first to acknowledge that all that information is available already on the web. The scientifically minded would do well to look at the wikipedia (I kid you not) entry on sleep and for those who like a straight forward approach the Royal College of Psychiatrists have done a brilliant job of writing the whole thing up to make it look easy, in their best bedside manner.

The diagram you see here is borrowed from the wikipedia entry and shows a textbook "normal" night's sleep. I put the word "normal" in speech marks because many people who are otherwise symptom free do not have this pattern and might, therefore, be considered "normal" and because, although there have been significant advances in the field, there is still much we still don't understand so, ever cautious, I remain unsure about what is "normal". Anyway, the pattern is of a series of 90 minute cycles starting at the far left in a state of consciousness and progressing into deep sleep and then rising into a lighter phase of sleep. The pattern is repeated throughout the night with the deep sleep phases diminishing as the night wears on. Deep sleep is dreamless sleep but the shallower parts are what are called REM (Rapid Eye Movement) sleep when dreaming occurs. These are marked in red on the diagram. There are also around 3 periods of only a few minutes duration when we wake up but often we don't remember this. If we do we may think it lasts a long time when, in fact, it is only a few minutes.

If you compare the diagram above with the iphone one you will notice that the progression toward lighter sleep is less obvious in the iphone diagram. I think the correct interpretation of the iphone diagram is that Lewis was very tired at the start of the night and fell into a deep sleep very quickly. At the end of the first cycle his body attempted to bring him into REM sleep but failed because he was still very tired so off he went into more deep sleep. A second attempt to bring him into REM sleep was mounted by his body but this also failed and more deep sleep followed. I would argue that this is a good example of his body knowing what is best for him and giving it to him. The next 2 phases see a return to REM spikes suggesting he can, now, cope with lighter sleep. The only difference here from a "normal" pattern is that the deep sleep end of each of these 2 cycles is just as deep as at the start of the night. The final section is a fair compromise with a total absence of very deep sleep and, curiously, of REM sleep also. The graph finishes before we can see the final stage but we can assume that if he remained at this mid position of sleep he would have woken up feeling quite dazed but if he was able to progress nearer to a waking state he would have awoken feeling relaxed.

I chose this particular example because I suspect that many of us are a lot like Lewis - overstimulated. We cram as much as possible into the day, whatever our interests happen to be. Even people who do nothing more than watch television most evenings are still stuffing as much stimulation into themselves as they can muster. The trouble is many of us don't know when to stop and the result is that we don't sleep in a still, dark room and we don't spend as long as our bodies need recovering. We are a sleep deprived culture in a light polluted world. It is reckoned that around one third of us have some kind of sleep disorder and yet we don't give this anything like the prominence it deserves. Perhaps when we know more precisely how sleep repairs the body and what happens when it all goes wrong our attitude will change. We don't have figures to show how many people developed cancer or diabetes or heart problems because they didn't get enough sleep. One day we will.

So, is Lewis normal? He's certainly typical. What of his graphs? Do they show a body coping with what he demands of it or has he got some terrible ailment that makes him so often tired out of his skin? Medically and psychologically I have to say he is fine. Does the iphone app help him? Yes, it shows how much of a strain he puts on himself. It also indicates that he needs a bit more sleep. He might do wonders for himself by aiming for 7 and a half hours a night and I guess he didn't know that before.

I suppose for people who have a more worrying condition they might be alerted to it and be that much more inclined to go and see their GP. Many just won't make a good diagnosis but then, many think they can diagnose using common sense whereas, in truth, it is the hardest thing we do.

Tags: iphone sleep cycle review twitter app Lewis King Lexware Labs sleep wikipedia Royal College of Psychiatrists REM overstimulated diagnosis