It’s 7 am and my alarm clock goes off. Time to get up for work, it is dark outside, grim. Autumn is in full swing; pumpkins and ghosts everywhere and even the Christmas decorations are going up in Glasgow’s George Square. It’s that time of the year where mornings are dark, and days are short. But one thing to look forward to is the approaching weekend when the clocks go back, and the UK finally switches back to Standard Time.

We engage in this process of changing our clocks twice a year; in spring we move our clocks an hour ahead (or “spring forward”), and in autumn we move our clocks back (or “fall back”, a nice mnemonic for our American readers).

Between those times we observe Daylight Saving Time (DST or Summer Time as we know it in the UK). Many people relish DST because they erroneously think we are getting more sunlight, but all we are doing is shifting our schedules.

So, by changing our clocks forward in the spring all we are doing is getting up an hour earlier. If you usually get up at 6:30am to get to work, this becomes 7:30am after we shift. To ensure you are not late for work, you have to get up an hour earlier, and because we are getting up an hour earlier, we lose an hour of sleep.

Many of you will be familiar with the negative impact of having one hour less sleep. There are many studies that now show an increase in negative heath events such as heart attacks and stroke or poorer academic performance after the shift forward.

While increased rates of driving accidents have also been reported, there are many other variables that influence driving that are difficult to control for. Importantly though, many underestimate the negative long-term impact of DST throughout the summer when our clocks are no longer co-ordinated with sun time.

During Standard Time, which is what the UK observes in the winter months outside of DST periods, our clocks mostly align with sun time. At the prime meridian, which goes through Greenwich, when our clocks say 12noon, the sun is at the highest point in the sky (noon = solar noon).

However, when we move our clocks forward and observe DST, our clocks say 1pm when the sun is at the highest point in the sky (noon + 1hr = solar noon).

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Now at first this one-hour difference may seem trivial, but the impact of it becomes apparent when we think about the morning and evenings.

When we shift our clocks forward and we get up an hour early to ensure we are not late for work/school, sunrise and sunset still stay the same. On Monday morning after the clock change we get up at 6:30am, it is as light (or dark) as it was on Sunday morning at 5:30am. And when we go to bed at 10pm on Sunday evening it will be as dark (or light) as it was on Saturday evening at 9pm.

Effectively during the spring and autumn months of DST it is too dark for us in the morning to use light to help us wake up. Light is the most important “Zeitgeber” for our body clocks and particularly exposure to bright natural light in the morning helps us regulate our body clock.

During the summer months of DST, sunrises are so early that getting up an hour early doesn’t have much of an effect on us. But sunsets in contrast are late, and shifting our schedules may mean for some that it is simply not dark enough in the evening to helps us fall asleep easily. Those readers with young kids who struggle to go to bed on time during the summer because it is too light out, will know exactly what I mean.

(Image: Should we be changing the clocks?)

For all these reasons, there are many who want to abolish the clock change. Alarmingly though, some have suggested that we implement DST all year round. This would be detrimental because it would deprive the nation of important opportunity for natural light exposure in the morning.

If we were to observe DST in the winter, we wouldn’t see the sunrise until around 9am. Further north in Glasgow for example, that wouldn’t be until 9:45 am, or further west in Londonderry/Derry that wouldn’t be until 9:50 am.

For those who start work/school at 9am, you would not be seeing any sun in the morning before work/school. The position statement by the British Sleep Society that was published in the Journal of Sleep Research argues that the UK should abolish the clock change and reinstate all-year-round Standard Time.

Dr Megan Crawford is deputy director of the Strathclyde Centre for Sleep Health at Strathclyde University