As it’s the New Year, some of us health-conscious souls might be turning their attention to making positive changes in our lifestyles. For some, that might mean being more active, while other may see this as a time to redouble their efforts with regard to healthy eating. However, positive lifestyle habits can sometimes be easy and effort free. For instance, getting a bit more sun exposure is likely to bring benefits for health, and is something most people find not only easy, but enjoyable too.
Another potential lifestyle change that is low on effort but might still return considerable health benefit is sleep. While the time we spend in a semi-coma each night is easy to view as wasted time, there is emerging evidence that sleep is important for the health of both body and mind.
I was reminded of this earlier this week on reading some reports of a study which assessed the effects of sleep disturbance on the body’s ability to regulate blood sugar. This study, published on-line in the Proceedings of the National Academy of Sciences, has been widely reported in the media, though I have not been able to trace the actual study. Apparently, it was published on-line on 31st December, though the most recent update of the PNAS on-line edition is dated 28th December. Anyway, no doubt the actual study will appear once the PNAS site is updated in due course. In the meantime, I’ve only got the reports of this study to go on.
In this study, 9 men and women aged between 20 and 31 were assessed over two nights of undisturbed sleep followed by three nights where their sleep was deliberately disrupted. Specifically, the subjects were prevented from getting into what is known as slow-wave sleep (deep sleep) by being exposed to sounds loud enough to keep them from drifting into deep sleep though not loud enough to actually wake them.
Each subject was injected with glucose solution and their blood sugar levels were monitored. After the three nights of disturbed sleep blood sugar levels were, on average, 23 per cent higher than after undisturbed sleep. Apparently, this reduced ability to handle sugar is equivalent to that that would be expected if an individual gained 9-13kg (20-30lb) in weight.
The authors of this study claim that their findings show as a clear role for slow-wave sleep in glucose control. They also suggest that strategies to improve sleep quality and quantity may help to prevent or delay the onset of type 2 diabetes.
This research is interesting, at least in part, because it comes on the back of other research which has linked sleep time with diabetes risk.
For instance, November of last year saw the publication of a Canadian study in which the sleep times and risk of diabetes was assessed in a group of about 750 men and women aged 21-64 . Compared to those sleeping 7-8 hours a night (deemed ‘normal’ sleepers), those sleeping 5-6 hours a night were found to be at more than twice the risking of having type 2 diabetes or ‘impaired glucose tolerance (‘IGT’ ” thought be a precursor to diabetes). This study also found that those sleeping 9-10 hours a night were, compared to ‘normal’ sleepers, at increased risk of types 2 diabetes and IGT too. These findings are consistent with other research which has linked either short of long sleep times with an increased risk of type 2 diabetes.
It is not known how longer sleep times may boost diabetes risk, if they do at all that is. It is possible, after all, that individuals who have impaired blood sugar regulation feel the need to sleep longer. In other words, perhaps its not that long sleep times that is causing diabetes, but the other way round.
The PNAS study just out does seem to provide at least some good evidence that sleep disruption can lead directly to changes in the biochemistry and physiology of the body that could explain, at least in part, why individuals who sleep for relatively short periods each night are at generally increased risk of diabetes.
Other research has linked sleep habits with other conditions including cardiovascular disease. Back in September, I wrote about a study which showed a strong correlation between cutting back on sleep and an increased risk of cardiovascular disease (and overall risk of death, as it happens).
Taking the research as a whole, it’s reasonable to believe, I think, that getting the right amount of sleep may have a very important bearing on health, just like being active and eating well may do. However, part of getting the right amount of sleep means appreciating its value, and not seeing it as wasted time. It can also mean overcoming any tendency to insomnia (see this article for some tips regarding this). And finally, sleeping for longer obviously takes a little more time – something that is a very precious commodity for most of us. See this blog post for some tips about this too. One strategy that tends to work well here is to keep the TV switched off in the evening and to get into bed that bit earlier…
1. Chaput JP, et al. Association of sleep duration with type 2 diabetes and impaired glucose tolerance. Diabetologia. 2007;50(11):2298-304.