Sleep Survey for Radio 4 ‘Today’ Programme
In the Summer of 2007, Loughborough Sleep Research Centre undertook an on-line sleep survey of listeners to the Today programme, with the findings featured on the programme. The questionnaire had to be limited and thus had shortcomings. Of course it was biased towards these listeners and the findings can only be used as a rough guide. Nevertheless there are some worthwhile and interesting findings. There were 4893 respondents, but not all provided answers to all questions. There were more women than men. Most were in the 40-60 year age range, with the women predominantly in the 50-60 year range.
SLEEP – asleep waking up times The most likely time of sleep onset was 11:30 pm. Few (1.5%) reported typically being asleep before 10 pm, or going to sleep after 2 am (1%). Most (78%) were awake by 7am.
SLEEP – actual and desired sleep lengths – The overall average sleep duration for men was 6.9 hours and 7.2 hours for women (about 20 minutes difference). Although the women were, on average, a little older, this age difference would not have had much of an effect, here. Few (5%) people slept more than 8 hours.
In response to the desired amount of sleep, most (66%) people wanted between 7 and 8 hours. Women tended to want about 30 more minutes sleep than men.
SLEEPINESS Apart from bed-time, the most likely other time to feel sleepy was early-to-mid-afternoon. The better one’s sleep at night the less likely the afternoon ‘dip’. About 30% of people felt it likely that they would fall asleep then. Surprisingly, this was only slightly greater (36%) for those taking less than 5 hours sleep at night.
Another clue to whether people have adequate sleep is the extent to which they feel alert and refreshed mid morning, about 2 hours after awakening. Most people (67%) felt alert on most mornings.
INSOMNIA 26% of women and 18% of men considered they had insomnia more than twice a week. This was most evident in the 50-70 year olds.
Interestingly, mid-afternoon sleepiness was not particularly greater in those having insomnia for at least 2 nights of week.
Of the 1079 people with at least some insomnia (on 2 or more nights per week), 247 people were had insomnia on most nights. One might expect that the shorter their sleep the more likely they would fall asleep in the afternoon. However, this was not so, as can be seen in the next graph below. Interestingly, in this respect they differed little from those people having the same sleep lengths but not complaining of insomnia. There are various interpretations. For example those with insomnia and with shorter nighttime sleep might be sleeping better at night than they realise, or maybe the stress or anxiety, which interferes with nighttime sleep onset at night also stops them sleeping in the afternoon.
MEMORY FOR PAST SLEEPINESS There seems to be little point in being able to remember feelings of sleepiness some hours after it has disappeared. This has a bearing on other issues, for example, sleep-related road crashes, where most drivers deny having been sleepy before the crash. Apart from obvious legal reasons why they might respond this way, even at the best of times it is difficult to remember. The questionnaire asked recollection of last night’s sleepiness. Almost half (47%) of the TODAY respondents were not certain. We should have asked about the night before, as well, to see how the memory had faded further !
BREAKFAST – hunger (and thirst) – Hunger at breakfast time can be a clue to whether one is a ‘morning-type’ (‘lark’) or evening type (‘owl’). Most people lie somewhere in the middle, though. Larks usually have a hearty appetite and hunger at breakfast, and feel at their best in the morning, but tend to fade out in the early evening and go to bed earlier. The ‘owl’ has little or no morning appetite, is not so alert in the morning but livens up as the day progresses, and is on best form in the evening. Older people naturally become more lark-like. Here are the responses to recollection of appetite before breakfast that morning. Most people (75%) had some sort of appetite at breakfast, but only 36% were ‘hungry’.
We added a question on thirst, more out of curiosity, as this does not relate to sleep length or quality, or to being a lark or owl. Only 17% were particularly thirsty.
BODY WEIGHT AND SLEEP – There is some controversy that short sleep might be a cause of obesity, and we wanted to see whether there is any link between usual sleep length and body size. Here are the distributions of body size for the TODAY respondents, based on national criteria. Around half of men and women were within a normal body-weight-for-height (body mass index – BMI) range. Whereas more men (43%) were overweight compared with women (26%), more (11%) women than (5%) men were obese. There was a weak link, with both overweight or obese people sleeping, on average, 11 minutes less than those within a normal weight range. This is an unimpressive difference even though it is statistically significant. Of course, obesity brings with it a variety of problems, including sleep disturbance, and so these rough findings need to be treated with caution.
