This was one of the highlights of the conference. Not only did he share my passion for preventative medicine, and opinion about the current lack of it in our healthcare system but he also gave an exquisite overview of the developmental origins of non-communicable diseases (NCDs) – a recurrent theme in IUPS this year.
Most interestingly he started off with an overview on obesity – demonstrating the current focus on it with the google search “how can I lose weight?’ coming up with 229, 000, 000 results! I think this raises some interesting questions. Do we concentrate on obesity so much as a public health issue for good reason? Yes we clearly have an obesity epidemic (http://www.iaso.org/iotf/obesity/). Yes obesity has increased substantially over the last 30 years. However how many google search results did “inactivity” get compared to “obesity”? 15 vs 52 million hits whilst inactivity is the fourth leading cause of death worldwide – a place above obesity (source – World Health Organisation: http://www.who.int/healthinfo/global_burden_disease/GlobalHealthRisks_report_full.pdf ). The sceptic in me would argue this is because there is no drug we can buy, or surgery we can do to cure it. Perhaps we could have some physiological prospectives on physical inactivity in Rio 2017, and maybe even a symposium dedicated to it!
Anyway, moving quickly back to obesity – when should we intervene? Well Mark Hanson argued that long term dieting doesn’t change the “appetite-stat” so we’ve missed the boat if we get to that stage. He even went on to point out that pregnant women with a less “prudent” diet had fatter infants at birth (which was still true at 4 years old!), and that high protein/fat diets could cause epigenetic changes which could greatly influence the fat levels of children. It seems we need to act now to change the health of not only our own children but also our grandchildren!
This presentation from the Insights from Comparative Physiology symposium explored a couple of interesting points on thermoneutrality and vasoconstrictor tone in Women:
- Transmission of sympathetic nerve activity into vasoconstrictor tone is offset in women – this mediates there pre-menopausal lower cardiovascular risk compared to males. This is due to differences in sex hormones and beta-adrenergic receptors.
- Thermoneutrality matters. Many studies ignore comparative physiology by not taking into account the ambient temperature in which the study was carried out in. Mice have a higher lower critical temperature (LCT) than human’s so carrying out studies on them at human’s ambient temperature (20 degrees) will increase their metabolic rate disproportionately, increase their blood pressure, increase their lifespan etc. so we need to take this into account. We can not ignore this basic principle!
This was part of the physiology of fasting and starvation research symposia. The diet in the study compromised of consuming just 500 kcal every other day between 12-2pm, with the major carrot of then eating whatever you wanted on the other days. The results were fantastic from this study with 5-7 kg of weight loss after 1-2 months. This weight loss strategy also seems to have retained more lean mass then more traditional weight loss strategies. One of the other big positives of this kind of diet is that it doesn’t require as much motivation as others because even though you may be “fasting” for one day you can look forward to eating as much as you want on the others! Future research needs to address if there are any long term adaptations to this kind of diet. In the meantime I might try it for myself!!
Sportspeople aren’t your typical patients as they aren’t unwell – in fact they are often healthier and fitter than most of the public! They can also be a good study population as their fitness is unlikely to change significantly in a trial so will not confound results – the so called “training effect”. This lecture explored how we discovered the “fuel” we use for endurance activity, and showed how the speciality has developed so much over the last 100 years that we now know how our “athletes” are so physiologically different that we can have a whole medical speciality devoted to it (sports & exercise medicine)!
This public lecture was a real tour de force on the circadian rhythm! He was a very engaging, “down to earth” speaker who’s presentation I’m sure would have interested anyone wondering about the “ins and outs” of our sleeping patterns. Some interesting facts raised in the lecture included:
- Our core body temperature varies by 1 degree during the day which would allow swimmers to become 2.7s faster if they were to swim at their coldest!
- Blood pressure also varies greatly during the day, in fact, it rises as you wake up causing you to be 49 times more likely to die between the hours of 6-12am! Foster pointed out at this point that we had all passed the most dangerous part of the day…. Could this be an interesting target for blood pressure drug regimens?!
- Foster described to us a study that showed that alertness at 6am in the morning was at a worse level then if you were just legally over the alcohol limit! This point is demonstrated by the fact that you are 5 times more likely to have a car accident in the morning (if you account for traffic density)!!
- You spend 36% of your life asleep – so that would mean 32 years if you live to 90 years old! Nowadays, we’ve moved into a world where we take our sleep for granted. This was pointed out to us by Foster with quotes such as “money never sleeps” and “if you need a friend, get a dog” yet we need our sleep for cellular restoration, processing information and laying down memories (to name a few reasons).
- Our body clock is controlled by the suprachiasmatic nuclei, and the cells here seem to have been preserved throughout the animal kingdom! The sleep/wake cycle is basically controlled by a negative feedback loop whereby these cells produced clock proteins that stimulate sleep but act to reduce their own production.
- Apparently there is good evidence for early and late birds driven by our genes producing clock protein variations! Providing good evidence that we don’t need to be looked down upon by those early risers! Foster even commented that – “Morning people are horrible smug”!
- Despite having completed my ophthalmology placement this year I was completely unaware about the effects of blindness on the body clock. pRGC are cells in the eye that help our body recognise light. These can function regardless of your eyesight! So it’s important that blind individuals expose themselves to sufficient light to maintain their circadian rhythm!
- It’s been shown that an adults’ concentration is better at 10am in the morning compared to a teenagers’ who’s concentration peaks at 12 or 2pm. This inspired a headteacher to start the school day later with remarkable improvements in their school’s performance in GCSEs!
- Shift workers generally gain weight – this is mediated by increases in ghrelin and decreases in leptin. Shift work also causes increases in the stress hormone, cortisol, and this decreases your insulin sensitivity and increases the amount of gastric acid you produce which can lead to reflux.
- Lastly Foster went into the possible overlap between sleep disruption and psychiatric illness. People with schizophrenia often suffer from awful sleep/awake patterns and Foster argues this is partly due to the chemical imbalances in their brains which is similar to those who suffer from sleep disruption alone. This is independent of medication or social constraints that these individuals may be under! In fact sleep deprivation often precedes the mental illness itself, and if treated by “sleep hygiene” measures can in fact help resolve some of the symptoms the individual is facing.
- He left us with some tips for our “sleep hygiene” including not napping more than 20 minutes during the daylight hours and not drinking caffeine after 12 o’clock, and some questions to be answered, such as – Why do the elderly have such fragmented sleep? Should we start the school day later?
I’m extremely keen to promote “Exercise Is Medicine” within the field of medical education. I see first hand how we operate such a reactive healthcare system and have little to no education on lifestyle advice. We need to become more proactive and preventative medicine should be higher up in our healthcare agenda, especially when exercise is such an effective preventative agent in many non-communicable diseases. So this presentation by Juleen Zierath was of particular interest to me. Some interesting points she covered (and that I’ll be looking further into) included:
- Exercise is one of the greatest changes you can make to your metabolic rate!
- Overexpression of calcineurin re-programmes the muscle to be more oxidative increasing insulin sensitivity.
- Exercise increases Glut 4 translocation to the plasma membrane.
- TBC1D4 is triggered by endurance exercise (not resistance exercise) and activates the machinery for docking of Glut 4 vesicles in the plasma membrane.
- Epigenetics can play a significant role over a lifetime.
- Inactivity alters the promoter specific methylation level.
I arrived at the International Convention Centre, Birmingham, for the 37th IUPS meeting, having had my poster abstract accepted many months before. I had little idea what was ahead having been swamped by my final medical examinations for the previous two months. This year I’ve organised two national conferences, and attended several sport and exercise medicine meetings (my research interest), so I thought I knew what went into producing conferences similar to this! Nevertheless, I was staggered by the sheer size of the event (it’s the biggest conference I’ve ever been to by a long way!) and with every last detail cared for – I cannot even imagine the level of organisation that must have gone into it. From day 1 – 5 the ICC was filled to the brim and there was a “buzz” from the expectant delegates awaiting the physiological feast on offer. The academia on display was in an area that I wasn’t over familiar with and it was clearly way above that I had encountered before, but it proved to inspire and prompt me into looking further into areas which I hadn’t explored previously.
The biggest surprise of the conference for me, however, was the poster presentation sessions. The sessions, held in their own slot in the evening, were jam packed with delegates discussing the latest research in the field. This was a refreshing change to what I had previously experienced at other meetings, where poster sessions were crammed into lunch with only the judges really paying any attention to them. As such, I found it a highly rewarding experience. My research was critiqued and questioned by leading academics, even more so than when I had entered posters into competitions at other conferences, whilst the discussions also provided me with new research ideas and angles. It was such an inspiration to be surrounded by this breeding ground for new research that I will certainly be trying to make the trip to Rio in 2017 with some new research! I would like to thank The Physiological Society for this fantastic opportunity to attend and present at this prestigious event.