Less Rhythm = Less Sleep

I recently spent an extended holiday with my grandparents in South Africa. It was an amazing trip all round. But I found myself sleeping very little, waking up at insane hours, and surviving on vast amounts of coffee, which I have since managed to wean myself off of. It got me thinking though; a lot of the old people I know find it difficult to sleep, why is that?

The body clock which maintains circadian rhythm (sleep-wake patterns among many other patterns) is called the suprachiasmatic nucleus (or SCN) which is located in the hypothalamus in the brain. Neural signals from many parts of the body are received by the SCN which, coupled with other minor body clocks, generate a pattern of rhythmic activity, all in response to various factors including daylight, hormone levels and temperature.

A study lead by UCLA Chancellor Gene Block involved examination of the signals emitted by the SCN in mice. Results showed that the signals from this clock start to decline in middle age, and this may be true for humans as well. Normally during the day, SCN brain cells are active, while at night they are silent. It was suggested and proven the case that it is a change in this pulsing that affects sleep patterns in older mice (or people). Indeed, disruptions in the SCN lead to disrupted sleep, dysfuntion in memory, the cardiovascular system and even the body’s immune response and metabolism. The study suggests that one of the causes of these changes is a reduction in the amplitude of the signals being emitted from the SCN.

So now I get why old people struggle to sleep and why they are often tired. Even more than that, the decline of rhythm affects so many other body functions. I don’t think it accounts for bad dancing though…

Retrieved August 1, 2011, from http://www.sciencedaily.com­ /releases/2011/07/110719093808.htm