Wednesday, 30 November 2011

Double summertime: Double trouble? Part 2

To determine whether we should the UK should have single double summertime (SDST) in the UK in this second blog post I will review large-scale trials of SDST. What effect that has had on the population health? I will also look at evidence comparing people in the same time zone: those living in the west, where the sunrises later in the day. Can the time of sunrise really impact our health?

Interpreting data over large scale trials is hard to establish, due to the amount of factors involved.When SDST was trialled in the UK between 1968-71 Parliament were unable to determine any clear benefits and reverted back to Britisth Summer Time.  One of the factors they were looking at was the rate of road traffic accidents. However, the introduction of a legal drink drive limit in 1967, and the first roadside breathalyser in 1968, made it difficult to determine the influence of SDST in the reduction in road traffic accidents. 

Breathalyser and the Drink Drive Limit reduced road traffic accidents in the late 1960s, obscuring any positive effects directly from the SDST trial (C) Isabelle Adam
Portugal, who are currently on the same time zone as Britain, moved to SDST in 1992, and soon moved back in 1996. SDST was unpopular in Portugal, despite the advantage of being on the same time zone as neighbouring Spain.

Portugal noticed the fall in children’s exams rates. The later light in the evening made it harder for the children to sleep, getting few hours sleep each night and causing their grades to fall. In my opinion, reduced performance at work would be a risk for most age groups, however children’s grades are the easiest to measure.

The Daily Mail reported that Portugal during SDST had an increase in insomnia, sleeping pill usage, and stress levels.

Will SDST increase sales of sleeping pills? (C) pinprick
The time of sunrise also impacts winter depression. Dr Michael Terman, an expert in circadian timing and depression, has researched the rates of winter depression in the US. He studied 5114 persons aged between 18-60 over 3 years across the US. His findings indicate that people further North, who receive less hours of daylight, are more prone to the "winter blues".

There's not a lot policy can do about the number of hours of daylight, but interestingly, the time of sunrise in this trial was also an important factor. Those living in the western edge of a timezone above 38 °N, where sunrises later than the eastern edge, have 26% more cases of winter depression[1].

The UK lies 50-60 °N, and this data provides a strong case for the UK not to enforce a later sunrise, and for further investigation to determine how the time of sunrise effects cases of winter depression in the UK.

The current bill requires a review of the success to be established; the effects on health such as rates of sleeping disorders and depression, sale of sleeping pills, should be clearly assessed as part of this. Also, research should be undertaken to understand the relationship between time of sunrise and rates of winter depression in the UK, before changing it.


[1] "Predictors of winter depression: latitude and longitude in relation to photoperiod and sunrise"
Terman, et al, Soc Light Treatment Biol Rhythms Abstracts 2008; 20:56

Tuesday, 15 November 2011

Double Summertime: Double Trouble? - Part 1

This year MP Rebecca Harris has proposed the Daylight Saving Bill. This bill requests a 3 year trial of advancing the clocks by one hour for the entire year. This has been termed “single double summer time”, SDST, and will result in the UK being one hour ahead of GMT during winter, and two in summer. Many social and economic factors have been discussed in the media and Parliament, however the impact on the circadian system, or body clock, has received less attention.

This is quite a large topic, which I’ll deal with in a few blog posts. In this post I will review why light in the morning is important for our body clock. In the second blog post I will review other trials that have tried shifting time zones, and what effect that has had on the population health. Finally, in the third blog post I will respond to the supposed benefits advocated by supporters of SDST.

Light in the morning is the strongest time cue to synchronise our internal body clock with the environment. Our internal clock is responsible for synchronising many bodily functions, including the sleep/wake cycle, metabolism, appetite, digestion, alertness, cognition, athletic performance, blood pressure, body temperature, sex-drive, body repair, energy levels...you get the idea?

Common examples of a desynchronized body clock are seen in shift workers, travellers with jet-lag and sleep disorder sufferers. You will probably even notice this desynchronisation after pulling a few late nighters. A healthy body clock is vital for a healthy body and mind.

Light in the morning provides the strongest cue to sync our body clock with the day (C) jozerC
The influence of light on the human body clock has been widely investigated using bunker isolation units, blind people, and large scale studies. These studies show how our body responds to same amount and type of light differently at different times of the day. 

Bright light in the evening, a result of SDST, delays our body clock. This delay can cause us to need to sleep later, and when we still have to wake up at the same time, can cause ‘social jet-lag’.

Light can also directly affects our hormones, in particular suppressing melatonin production within 20 minutes of light entering our eyes. Melatonin is produced from the brain at night and induces sleepiness. A lack of morning daylight increases the duration of melatonin production, causing sluggishness and inattentiveness.
Key brain regions involved in circadian timekeeping. The brain receives light input from the eye, and uses this signal to co-ordinate time of day information to the rest of the body.

Light at night, which is increased during the summertime with SDST, disrupts our body clock even further. Dr Malcolm von Schantz, an expert in circadian rhythms and sleep research at the University of Surrey, has voiced concerns that light later into the evening can result in poorer sleep quality and less sleep than required. SDST will result in areas in Scotland not having sunset until 11.30pm during summer

It is not sufficient to just count the number of daylight hours, the timing of these hours needs to be considered.

Thursday, 3 November 2011

The SCN Song

On the 1st Nov 120 people gathered in a pub to watch the second Science Show-Off, an evening of acts from Scientists explaining their science in an entertaining manner. Adam Strang told us why chillis taste "hot", and gave us a demonstration as he preceded to eat 5 in increasing "hotness". Suze Kundu made ice cream from custard and liquid nitrogen to explain the different states of matter. And my personal favourite, I'm entirely biased here, was my lab partner Catherine Cox's song on the SCN with a ukelele.

Catherine singing the SCN song (c) Katherine Belessiotis
This was Catherine's debut performance on the ukelele, and from the audience reaction it was a resounding hit.

Catherine's song is all about the suprachiasmatic nucleus (SCN), the master clock in the human brain. The SCN is a brain region that co-ordinates and synchronises all the daily biological rhythms in our body. It has direct connections with the eyes so can be re-set by light, otherwise we would never get over jet-lag!

Here is a video of the performance, sorry we didn't get good enough visual, hopefully you'll enjoy the lyrics! I think the audience did great, especially without any practice!



Thanks Catherine for this amazing contribution to the education and communication of body clocks!! For those of you interested in attending (or presenting) at a Science Show Off event please visit: http://www.scienceshowoff.org/

Wednesday, 2 November 2011

Running the Venice Marathon 2011

I haven't written a sciency blog post for a while, and the reason for my absence (besides the PhD) is that Simon and I have been spending our evenings and weekends training for the Venice Marathon. I'm so pleased that all those months and late night runs paid off, we both finished mostly-injury free, and had the most amazing experience doing it!

We decided to take on this crazy endeavor to raise money for the Royal National Children's Foundation. Thank you so much to everyone who has donated, there's still time to contribute here.

The Sunday morning of the race started at 6am with a quick breakfast and off to get the bus to the start. We had been advised to get the 3 min shuttle to Tronchetto, inventively named the "People Mover". When we arrived it was closed, but was going to open early at 7.10 for the marathon, however the last bus would have already left. A bit of a fail on the organisation, this wasn't boding well.

We joined the crowds and walked over to the bus stop. It was still before sunrise when we huddled onto a crowded bus for the long ride to the start, it felt like we were going in the wrong direction - away from Venice. When we arrived at the start it was still very cold, and I felt I was already being brave just taking my coat and trousers off to them on the truck - why were we doing this?

An hour later we crossing the start line, the sun had come up and there were brilliant blue skies. We soon started to warm up on the run. The route was idyllic, running alongside the Brenta River through small towns with great crowd support.

Early on in the race, struggling to get into a pace, but enjoying the spirit of the runners
We were sticking with the blue balloons for the 4hr30 pacemakers for several miles, but then had to do a quick toilet stop and never managed to catch up with them again. At 12 miles I was struggling, I felt I still hadn't got into a good rhythm (this had been taking longer the longer our training runs had gotten). I took some ibuprofen, gels and water, and gave the rucksack to Simon, and started singing an awesome running song.

By the half way point I was feeling much better and running through Mestre at mile 16 I was feeling amazing. I was finally in the "zone", the crowd support was amazing, and my legs were feeling great - we could finish this! Mestre had been described in the guidebook as Venice's ugly sister...I felt this was completely unwarranted, the streets were beautiful to run through and I was really enjoying this.

Awesome crowd support in the local towns, this was Mestre, Venice's not-so-ugly sister
The rest stops were now supplying awesome Italian cookies and fruit as well as Gatorade and water. They were all well stocked. My feet were definitely blistered and it really felt as though I'd lost a toenail (I hadn't).

Running through San Guiliano Park at 18 miles we were surprised to hear one of the bands singing Shinedown's Simple Man - how amazing!! We love this band and especially this song, there had been lots of rock bands dotted along the route, and it's so uplifting when you hear a song you love. We were going to need this for what was to come.

Liberty Bridge. How ironic. This is the 4km long bridge that stretches on for eternity. Connecting Venice to the mainland running onto this bridge you get your first glimpse of Venice, very exciting for the first time. However, after 30 minutes of running and Venice isn't getting any bigger you get to the point of despair.

We were very grateful when we did arrive in Venice that there would be only 3 miles left of the course to do. We reached the first bridge and saw the small sign "14 bridges to go". No bridges, no fun!

No bridges, no fun! Running in Venice, with the Santa Maria Salute in the background
At 38km I had a sharp pain in my left leg, and panicked...how could I get this close to the end and then be injured! I spent 20 seconds walking and massaging it and then pushed on with the running, we were putting every bit of effort into running this race, and nothing was going to stop us pushing ourselves to the limit. No one would say that we didn't put everything into this race. We were going to achieve this. Pain is temporary, glory is everlasting!

Running into San Marco Square was electric. People were calling out our names, the Basilica and architecture was overwhelming, it was everything I could do not to cry! I could not wipe the large smile off my face, all these months of training were paying off, and Simon was beside me the whole way!

Running around San Marco Square!

Running hand-in-hand, the crowd support in here was electric!
The last 1km was frustrating, 5 more bridges to go and that finish line was still not in sight. The crowd were so impressive, they really kept us going. Finally, the last bridge and we could see the finish line, I told Simon we were going to sprint through, he was not impressed, but I'm not sure he had the energy left to complain. We put up our arms and the 4 hour 39 minute time was ours!!

Crossing the Finish Line

Our actual time (minus how long it took us to get to the start) was 4 hour 39 mins! Woo!

Simon very relieved it's all over
Thank you to everyone who has supported us and the RNCF charity. It's been a lifetime achievement for both of us and I'm so grateful for Simon sticking with me and doing this - I love you!

Space blankets and medals! There was also pasta, what a great incentive to finish!

Our official finishers photo

Aww!