2016 is the International Year of Pulses,
which aims to heighten public awareness of the nutritional benefits of
pulses as part of sustainable food production aimed towards food
security and nutrition. I spoke to Daniel Tan from the University of Sydney's Faculty of Agriculture and Environment about his research into pulses, including genetic resistance to heat waves and climate change, plant physiology and genetics, crop modelling and why he is known throughout the University as "The Hot Scientist".
Feel free to leave your favourite pulse recipe below in the comments! Some good ones are here.
This is quite a simple one. Grab some carnations (or other white flowers), a vase, some food colouring and water. Add a generous amount of colouring to the water (20-odd drops), add the flowers, and wait. It can take longer than a day, especially if you haven't quite added enough colouring, so be patient. Here are some shots we took of our red and blue flowers (I reckon you can be more impressive than this!):
The flowers turned blue quicker than red for me, and others have seen similar things (anyone know why?)
The science on display is the capillary action of the water - that is, how the flower drinks even without its roots. This ability draws water against the force of gravity up the stem and into the petals. It works because the water evaporating from the petals and leaves of the plant "pulls" water up the narrow tubes in the stem (the xylem) to replace that which is lost. The tubes need to be narrow so that the combination of the surface tension of the water (caused by cohesion in the water - how well it sticks to itself) and the adhesive forces between the water and the walls of the xylem are strong enough to lift the water against the force of gravity. The adhesive forces are proportional to the diameter of the tube, whilst the weight of the water is proportional to this diameter squared - hence a smaller diameter favours the adhesive forces.
Something funky to try is to split the stem and put one half in blue and the other in red. You can get multi-coloured flowers.
Over the Easter break, I spoke with Lish Fejer on ABC 666 Canberra on her Experimentarium segment. We spoke on various things to do with science blogging and podcasting, and matters Easter related including:
Royal Jelly (the Royals were in town, a great link if ever I've seen one),
Determining the speed of light using your microwave and left-over Easter chocolate.
On determining the speed of light using a microwave, see the post Instascience by Tom Gordon in which he uses paper. We used chocolate and it worked pretty well, albeit very messily. You will enjoy trying this at home, and failing just gives you another shot! Note in the broadcast I mentioned that the speed of light was 2.97 x 108 when it's actually 2.99792 x 108 (please forgive such a grievous error...)
Listen to this show here - the audio is courtesy ABC 666 Canberra:
Here is a nicely produced video on how to do this - I started out making one and made a mess of my kitchen.
In the second of a two part series on zombies, this week we go deeper in the dark world of the undead. In part one we managed, through a combination of drugs, to create zombie-like creatures who were sluggish and largely brain-dead. This week we have a shot at recreating the zombies of films such as I am Legend - creatures created through the transmission of a virus, who are filled with rage and enjoy the taste of brains. Topics covered include:
Mad cow disease and the use of prions to transmit disease,
Chimpanzees who eat brains,
Methamphetamines for the creation of rage,
Mathematical modelling a zombie pandemic and how the zombies could do this sustainably.
Somehow we ended up proposing a "Planet of the zombie apes" movie idea, and a methamphetamine-infused biodome. It might not pass an ethics committee. Tune in to this episode here.
Zombies have been fodder for science fiction books and movies for years, but could we actually create one in the lab? And why indeed would you want to do this? Surely the whole "eating brains" concept would mean that making one is probably not in your best interests.
This week on the podcast, Dr Boob takes us on a journey through zombie science fiction, Haitian zombies and zombie-style animals in nature, including a fascinating scenario where ants are hijacked by a fungus. This episode is part 1 - next time we will tackle, among other things, brain parasites, eating brains (cultural, cooking and animals that do
it), mad cow disease, the 'zombie' bath salts attacks (face eating), and
a mathematical model of a zombie pandemic.
We have looked at zombies in the past. In the post Correlation of the Week: Zombies, Vampires, Democrats and Republicans we looked at how the political party of the US presidency seems to influence the style of science fiction movie made during their presidency. A recent upsurge in zombie films could augur well for the Republicans next time round, although there are still plenty of vampire films and TV shows around.
Well I never. Generations of children owe their lives to this phenomenon!
The researchers were actually testing something a little more subtle than this appears. They wanted to test whether alcohol consumption influenced the contraction of HIV via unsafe sex, or whether certain personality traits, such as a disposition to risky behaviour, would lead to both alcohol use and unsafe sex - that is, if the unsafe sex would have happened anyway, regardless of alcohol.
They found that the more people drank, the worse the decisions they made. An increase in blood alcohol level of 0.1 mg/mL led to a 5% increase in the likelihood of unprotected sex.
"Drinking has a causal effect on the likelihood to engage in unsafe sex, and thus should be included as a major factor in preventive efforts for HIV," said principal investigator Juergen Rehm in a statement. "This result also helps explain why people at risk often show this behaviour despite better knowledge: alcohol is influencing their decision processes."
So remember this over the holidays at your work Christmas parties when your boss starts to look good after 8 beers. And at your family gatherings, your second cousin is still related....
References: Rehm, J., Shield, K., Joharchi, N., & Shuper, P. (2012). Alcohol consumption and the intention to engage in unprotected sex: systematic review and meta-analysis of experimental studies Addiction, 107 (1), 51-59 DOI: 10.1111/j.1360-0443.2011.03621.x
And we're back! It's been a while, but finally it's time for another podcast, so we've made it a long one. Take this episode on a long train ride or car trip, as Dr Boob and I explore the science of the spells of Harry Potter.
Attempting to find scientific and engineering solutions to Harry Potter spells is probably the most difficult task we have set ourselves yet, so we would be very interested to hear how you would made the Harry Potter spells a reality. The spells dealt with in this episode are:
Lumos - Producing light from the end of a wand (A voice activated torch seems a logical solution),
Aguamenti - Shooting water from the end of the wand,
Although some of these are quite clearly impossible at the moment, in every case we have come up with a scientific or engineering solution to take us at least part of the way there. Listen in to find out what we came up with, and please write in and let us know where we have gone wrong or what you would do.
Santos, V., Paula, W., & Kalapothakis, E. (2009). Influence of the luminol chemiluminescence reaction on the confirmatory tests for the detection and characterization of bloodstains in forensic analysis Forensic Science International: Genetics Supplement Series, 2 (1), 196-197 DOI: 10.1016/j.fsigss.2009.09.008
A.J. Barnier and D.A. Oakley (2009). Hypnosis and Suggestion Encyclopedia of Consciousness DOI: 10.1016/B978-012373873-8.00038-4
Research published in Biological Invasions shows that Australian redback spiders are invading New Zealand and could become established in many urban areas around major ports.
The paper, The invasive Australian redback spider, Latrodectus hasseltii Thorell 1870 (Araneae: Theridiidae): current and potential distributions, and likely impacts,details recorded sightings of redback spiders in New Zealand, then used biological and climatic information to reveal where redbacks could establish. Warm, dry conditions in some eastern areas of New Zealand are suitable for redback spiders to become established, and they are likely to spread further as they are surviving in places with relatively high rainfall. Urban areas, for example, provide shelter from the rain. The spread of redbacks is likely to have arisen from the establishment of new invasions through New Zealand's ports.
There is genetic evidence that redbacks have interbred with the protected, endemic katipo and there is a danger that redbacks could competitively displace katipo or cause extinction by interbreeding. Redbacks are also a public health issue as they have the potential to become established in areas close to urban populations. Successful border control already produces regular interceptions of the redback as well the invasive brown widow and the western black widow. Both these species are related to the redback and have similar habitat and climate requirements.
I spoke to lead researcher Dr Cor Vink about this work and how they are developing new approaches and tools to ensure harmful organisms are kept out of New Zealand.
References: Cor J. Vink, José G. B. Derraik, Craig B. Phillips, & Phil J. Sirvid (2010). The invasive Australian redback spider, Latrodectus hasseltii Thorell 1870 (Araneae: Theridiidae): current and potential distributions, and likely impacts. Biological Invasions
Being able to see your unborn child is truly an amazing experience. Ultrasound (diagnostic sonography) is a common diagnostic tool for, among other things, imaging the foetus to determine its age, look for abnormalities and observe blood flow in the umbilical cord. But possibly its most memorable effect is seeing your baby's heart beat - and in 3D/4D ultrasounds, seeing your baby's face.
The term "ultrasound" applies to acoustic energy (sound) with a frequency above the audible range of human hearing (20 Hz -20 kHz). When used in medical imaging, an ultrasonic sensor (or transducer) is placed on the mother's belly and produces pulses of sound. The frequencies used for medical imaging are generally in the range of 1 to 18 MHz. High frequencies (7-18 MHz) can be used to look for fine details but have low penetration, so to image deep tissue, lower frequencies (1-6 MHz) are used.
The sound waves are partially reflected from layers between different tissues inside the mother's body. Sound is reflected anywhere there are density changes - for example, at the baby's skin where it meets the amniotic fluid. The baby's internal organs can also be imaged depending on what frequencies you use. The reflected sound is then "heard" by the transducer, and the data analysed to produce the image. The amount of time it takes for the echo to rebound relates to how deep the sound penetrated, and the strength of the return signal relates to both the material it is reflecting off and its depth. The deeper the tissue from which the signal is being echoed, the quieter the return, simply because there is more sound loss (attenuation) the further the sound travels (it gets absorbed, scattered and reflected along the way). This information allows an image to be built up, whereby pixels at the appropriate depth are coloured by the strength of the return at that point. Generally, the sound waves are not 100% reflected at any stage - you can see "behind" objects because some sound penetrates through. However, as less sound is penetrating the deeper you go, the signals become fainter.
2D Ultrasounds
The typical ultrasound imageis a "2D" image like the one above. In this image, the transducer is at the top and is sending sound waves down. The image is essentially a slice through the mother. It's called a 2D image as we can only see two dimensions - left/right and up/down. The 2D image is built by firing a sound beam down, waiting for the return echoes, and then firing a new pulse at a slightly different angle. This continues until an arc is swept. Combining the data from each line after the arc is swept gives the 2D image. The following images come from the excellent resource Basic ultrasound, echocardiography and Doppler for clinicians, by Asbjorn Støylen. The left image shows the transducer scanning whilst the right image shows how the pulses are sent down in lines.
Continual rescanning means that a 2D video can be produced with roughly 50 frames per second. The human eye can see about 25 frames per second and so the video looks smooth. This frame rate is also more than enough for 2D temporal visualisation of the baby's heartbeat (~70-150 beats per minute depending on age) and to watch blood flow through Doppler ultrasound. Due to the Doppler effect, the sound pulse will rebound with a higher frequency if it hits something moving towards it, and a lower frequency if it echoes from something moving away from it - this is the same reason the noise of a car has a high pitch when moving towards you, and a low pitch as it moves away. As blood is moving in the umbilical cord, the ultrasound can be coloured by the Doppler information to show the blood flow.
3D Ultrasounds
3D images are a fairly recent advance in diagnostic sonography. Instead of just seeing a slice through the mother, the images can show a surface - essentially adding depth (the third dimension) to the 2D image. Imagine you are looking at a car from front on - you have no idea how long the car is and you have no information on how many doors it has or if the boot is open. However, if you look at the car from another angle, you can figure this out, and the more angles you look down, the more depth information you can gain. This is essentially what a 3D ultrasound does - it stitches together multiple 2D shots from different angles to produce the image. Modern transducers have the ability to scan multiple cross-sections. If the baby is moving, there may be some blur, but as image processing is becoming quicker, the 3D images are becoming clearer. The colour of the image is not real as there is no way to see colour inside the mother. 3D scans provide information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations, and also helps the parents bond with their unborn child (it's very cool). However, when compared to 2D scans, they aren't as useful for the diagnosis of congenital heart disease and central nervous system anomalies. One of the reasons why this is the case is because they are static, which leads us to...
4D Ultrasounds
The term 4D refers to the addition of time to 3D scans. This is a very recent advance as it is only in the last few years that we have had the computing power to not only stitch together the 2D images to make the 3D images, but to create the 3D images quickly enough to play them consecutively as a video. Modern 4D scans play at roughly 12 frames per second, so they are a little jumpy.
Here is a little video I put together of our 4D scan.
I don't know if there is an upper bound on what ultrasound technology can do - as the speed of sound is ~1540 m/s in human soft tissue, and you have no choice but to wait for the return signal before you can process the image, it may be that a high video frame rate with decent resolution is unobtainable. Resolution depends on how many different lines you fire down to make the first 2D image - more lines mean better resolution, but currently you have to wait for the echo from one line before sending down the next, which means it takes longer to produce an image. I imagine one way of improving this would be to send down all the lines at once with slightly different frequencies or waveforms, and as such when the echo is received you would know where it came from. Perhaps this is already being done - let me know if you know more!
Kurjak, A., Miskovic, B., Andonotopo, W., Stanojevic, M., Azumendi, G., & Vrcic, H. (2007). How useful is 3D and 4D ultrasound in perinatal medicine? Journal of Perinatal Medicine, 35 (1), 10-27 DOI: 10.1515/JPM.2007.002
Carrera, J.M. (2006). Donald School Atlas of Clin. Application of Ultrasound in Obs/ Gyn www.jaypeebrothers.com DOI: 10.5005/jp/books/10226
Khanem, N. (2007). Donald School Textbook of Ultrasound in Obstetrics & Gynecology The Obstetrician & Gynaecologist, 9 (2), 140-140 DOI: 10.1576/toag.9.2.140.27325
Although they look and behave differently, at birth they have the same genome. Young queen larvae are fed a diet of Royal Jelly, a substance secreted by the worker bees which includes B-complexvitamins, proteins, sugars and fatty acids. It also contains trace minerals, enzymes, antibacterial and antibiotic components, and vitamin C. This concoction not only feeds the queen bees, it turns on and off various genes with what are known as epigenetic effects. Epigenetic effects - meaning "above the genome" - alter gene expression without affecting the baseline genetic code. They are the reason why cells in different parts of the body do different things. For example, liver genes are turned on in your liver but not elsewhere, even though every cell in your body contains all your DNA information. For humans, much of this happens when we are embryos before we are born, with various chemical signals switching on and off genes in various parts of the body.
The work is quite profound as it is a step towards understanding how our environment can change our DNA. There is a growing body of evidence that suggests some epigenetic traits may be passed on to following generations rather than just affecting the individual, and this could drastically change our understanding of the process of evolution. The work also has implications for the nature vs. nurture debate, if indeed our nurture can actually change our DNA - that is, our nature.
I had a fascinating chat to Ryszard about this study, the future of this work and his opinions on how this may change our understanding of evolution. Listen in to this show here (or press play below):
Please excuse the noise in the recording of the phone call.
References: Lyko F, Foret S, Kucharski R, Wolf S, Falckenhayn C, & Maleszka R (2010). The honey bee epigenomes: differential methylation of brain DNA in queens and workers. PLoS biology, 8 (11) PMID: 21072239
Charles Darwin described sexual selection as "struggle between the individuals of one sex, generally the males, for the possession of the other sex" and nature abounds with strange examples of where animal features have evolved way past their survival needs - for example, reindeer antlers, peacock plumes and quite possible human vocabulary - humans and other primates survived quite nicely without a wide vocabulary, why do we now possess one?
Rob is a leading world expert in the area, listen in to find out what he had to say.
Listen in to this show here (or press play below):
References: Brooks, R. (1999). The dark side of sexual selection Trends in Ecology & Evolution, 14 (9), 336-337 DOI: 10.1016/S0169-5347(99)01689-4
Brooks, R., Hunt, J., Blows, M., Smith, M., Bussiére, L., & Jennions, M. (2005). EXPERIMENTAL EVIDENCE FOR MULTIVARIATE STABILIZING SEXUAL SELECTION Evolution, 59 (4), 871-880 DOI: 10.1111/j.0014-3820.2005.tb01760.x
I do. My brother does. Both my parents do. In fact, we are a family of Photic Sneeze sufferers.
The Photic Sneeze Reflex (PSR), also known rather ridiculously as Autosomal Dominant Compelling Helioophthalmic Outburst (ACHOO) Syndrome (how long do you think it took researchers to figure out that acronym....) is a dominant genetic condition affecting around 10% of the population. When a sufferer moves from a region of darkness to a region of bright light - for instance, walking outside and looking at the Sun - multiple sneezes occur. Research into the disorder has yet to explain either its mechanism or an evolutionary reason for why it occurs. One theory is that there is a "short circuit" in the brain, with the stimulated optic nerve somehow triggering the sneeze reflex.
Professor Louis Ptáček runs the Laboratories of Neurogenetics at the University of California, San Francisco. The aim of the lab is to study familial disorders with strong genetic contributions, and thus localise and identify genes that cause human disease. Other conditions in which he is interested include migraine and epilepsy, and an intriguing condition whereby certain sounds cause seizures. He considers PSR to generally be a midly annoying condition, unless you are a combat pilot, where sneezing at the Sun could indeed be life threatening.
I had a really interesting chat to Louis about PSR, and I've left the recording a little longer than usual, as we were really able to explore some fascinating ideas involved with PSR - it was a great chat. Listen in to this show here (or press play below):
This topic came in as part of my call for questions for Science Week, so thanks @lisushi for the question! I'll be putting up more blogs and podcasts to answer the other questions that came in over the next few weeks.
References: Breitenbach RA, Swisher PK, Kim MK, & Patel BS (1993). The photic sneeze reflex as a risk factor to combat pilots. Military medicine, 158 (12), 806-9 PMID: 8108024
Langer N, Beeli G, & Jäncke L (2010). When the sun prickles your nose: an EEG study identifying neural bases of photic sneezing. PloS one, 5 (2) PMID: 20169159
MADIGAN, J., KORTZ, G., MURPHY, C., & RODGER, L. (1995). Photic headshaking in the horse: 7 cases Equine Veterinary Journal, 27 (4), 306-311 DOI: 10.1111/j.2042-3306.1995.tb03082.x
If you understand all the mathematical references in the following video, you're doing well. Enjoy the classic mathematical a capella (bet you thought you'd never read that sentence) Finite Simple Group (of Order Two).
If you think that dance is the best medium to portray protein synthesis, then the next video is for you. Made in 1971 by Robert Alan Weiss for the Department of Chemistry of Stanford University, this short film is narrated by Paul Berg, 1980 Nobel prize winner for Chemistry. It makes me wish I had taken science in the 70s - there is no other word than awesome to describe seeing 30s ribosome in the form of hippy interpretative dance. Gotta love the acid-trip music.
The science of superheroes is taking a green and nasty turn this week as we discuss the largest superhero of them all, The Hulk. Join myself and our regular superhero expert Dr Boob as we delve into the science of how we might realise The Hulk in the lab. It was one of the more entertaining interviews I have done for the podcast.
Listen in to this show here (or press play below), and read further for more info:
The Hulk is alter-ego of Dr Bruce Banner, who allegedly bares a striking resemblance to Dr Boob. Banner is a reserved physicist who involuntarily transforms into The Hulk when triggered by a strong emotion such as anger, fear, terror or grief. The Hulk himself is a massive green monster who gets stronger the angrier he gets. He also has bullet-proof skin.
The 2003 movie version "Hulk" includes many of the topics we discuss in the podcast. The movie starts with genetics researcher David Banner – Bruce Banner’s father - working with the military to "improve" human DNA. The opening credit sequence depicts experiments with jellyfish and starfish DNA, and Banner’s notepad mentions bioluminescence. This suggests that the Hulk gets his green colour from jellyfish DNA as some jellyfish bioluminesce at around 450 nm, which is at the blue/green end of the spectrum. In 1961, Osamu Shimomura extracted green fluorescent protein and another bioluminescent protein, called aequorin, from Aequorea victoria while studying bioluminescence. He eventually received the Nobel prize in Chemistry in 2008 for this work. The mention of starfish is also interesting because, as we found with Wolverine, starfish and sea cucumbers have great healing powers and are able to regenerate lost limbs. Evidently, Banner wanted to splice bioluminescence and improved healing into human DNA.
Banner’s experiments then moved to lizards and monkeys, but unfortunately they all died. Naturally, he then decided if his experiments did not work on animals, he would try them on himself – clearly, ethics committees are not part of superhero science. After conducting experiments on his own DNA, he eventually passes on his mutant DNA to his unborn son Bruce. Once David realises this, he changes his approach and works to cure his son of his genetic afflictions, however the research is shut down and an explosion kills David’s wife. David is taken to a lunatic asylum and Bruce is adopted.
Years later, Bruce has followed his father’s line of work and is conducting military research – Bruce’s area of interest is the use of nanomeds in soldiers. This might include such things as targeted drug delivery for rapid recovery from injury. An experimental accident subjects Bruce to an enormous dose of gamma radiation which “activates” his mutant DNA (possibly combining with the nanomeds) and the building rage/stress transforms him into The Hulk for the first time.
Whether or not this is scientifically possible – well, that’s the topic of the podcast so tune in!
Other issues that we discuss include:
Gamma radiation and radiation poisoning;
Genetic transfer and gene therapy – could David Banner change his own DNA in such a way that this change would be copied to his progeny? For more information, check out the Weismann Barrier;
The Hulk’s size – is it possible to rapidly increase your size? Simple conservation of mass equations would suggest no, and bacteria in a Petri dish generally have a 24 hour doubling time. There are also enormous metabolic requirements involved – we need to have resources available to feed these growing cells and Bruce Banner is not excessively fat. Perhaps to do this we need to accelerate Bruce Banner to the near the speed of light, at which point he may relativistically pick up some mass - however, this is not particularly practical!
The Hulk’s strength – is it possible to rapidly increase your strength?
The Hulk's healing properties - could we use some of the science of Wolverine here?
The materials used to create bullet-proof skin. The toughest skins in the animal kingdom are crocodile, elephant, shark and armadillo; however none are bullet (and knife) proof;
What materials could we use to make his "one-size-fits-all" pants? You will notice that no matter what size Bruce Banner or The Hulk are, and no matter what the ripped state of his other clothes, his undies always fit.
And of course, whether The Hulk has irritable bowel syndrome and wears giant green snuggies.
Hope you enjoy this show - we certainly enjoyed recording it, as you will be able to tell by the end! Listen in to this show here (or press play below):
NB: I've now discovered there's a Red Hulk - future show perhaps?
Samples in this podcast are broadcast courtesy of ioda PROMONET. They were:
References: Shimomura, O., Johnson, F., & Saiga, Y. (1962). Extraction, Purification and Properties of Aequorin, a Bioluminescent Protein from the Luminous Hydromedusan,Aequorea Journal of Cellular and Comparative Physiology, 59 (3), 223-239 DOI: 10.1002/jcp.1030590302
Moghimi, S. (2005). Nanomedicine: current status and future prospects The FASEB Journal, 19 (3), 311-330 DOI: 10.1096/fj.04-2747rev
This is a question that has been bugging us at work.
What would happen to a chicken egg in space? Equally interesting is the question what would happen to a chicken egg if placed in a vacuum chamber?
Eggshells are able to withstand quite large forces from the outside because of their dome structure, but are not so strong from the inside. This makes sense - they need to be strong enough to withstand the force of the mother chook sitting on them, but need to be fragile enough from the inside for the baby chick to escape. If placed into a vacuum, would the pressure of the small amount of air inside the egg be enough to break the shell? Let's assume for the sake of argument that the egg was laid at normal atmospheric pressure.
Other things to consider include temperature. Would the egg white and egg yolk freeze and therefore expand? This could break the shell. Is there enough empty space inside the egg into which the mainly water interior could expand? Or would this happen too suddenly? Is temperature actually a factor?
Or perhaps a sudden change in pressure might cause the interior to rapidly boil, exploding the egg? Water only boils at 100 degrees at normal atmospheric pressure - the more you lower the pressure, the lower the temperature that water boils at. For instance, at the top of Mount Everest, the boiling point of water is 69 degrees. Human blood would boil in space except for the fact that our skin is strong enough to protect our blood from the rapid drop in pressure. Is an eggshell similarly strong, or is it too permeable?
Is there a difference between the scenario where the egg is in space - let's say at about the Earth's orbit - and so is heated by the Sun (or at least half of it), and in a vacuum chamber where there is no heat source?
As much as we like to ponder these questions, we don't have an answer. What do you think? Please feel free to speculate and throw ideas into the mix.
For extra reading, check out the references for work conducted on hatching chickens in low gravity, and also hypergravity.
References: SUDA, T., ABE, E., SHINKI, T., KATAGIRI, T., YAMAGUCHI, A., YOKOSE, S., YOSHIKI, S., HORIKAWA, H., COHEN, G., & YASUGI, S. (1994). The role of gravity in chick embryogenesis FEBS Letters, 340 (1-2), 34-38 DOI: 10.1016/0014-5793(94)80168-1
Jones SM, Warren LE, Shukla R, Browning A, Fuller CA, & Jones TA (2000). The effects of hypergravity and substrate vibration on vestibular function in developing chickens. Journal of gravitational physiology : a journal of the International Society for Gravitational Physiology, 7 (3), 31-44 PMID: 12124183
Professor Chris Gore, head of Physiology at the Australian Institute of Sport, has had over 20 years experience in the science of sport at altitude, including the study of the physiological effects of altitude on the body and designing altitude training regimes for athletes.
The effects of altitude have been known for some time, however their effects on sport became prominent during the 1968 Mexico Olympics, which were held at over 2000 metres. At these games, endurance sports suffered whilst records were set in sprint events. Many games in the current 2010 FIFA World Cup are being held at altitude, and all of the highly professional teams have had some form of altitude training before the competition.
I spoke to Chris about the science of sport at altitude, including the physiological effects on the body, the different physics that apply to sports played at altitude, how altitude training works and the ethics of artificial altitude training. Listen to this show here, or press play below - and read on for some more info. This question came in from the guys at Green and Gold Rugby as part of our call for science stories for science week. With the World Cup currently being played at altitude, I thought it best to bring this particular question forward - thanks for the question guys! I will be writing up a more comprehensive story on the topic soon.
Much of the effect of altitude on sport concerns our aerobic performance. As the atmospheric pressure is less at altitude than at sea level, less oxygen is taken into the blood. The maximum capacity of the body to utilise oxygen is known as VO2 max. At altitude, VO2 max decreases, meaning that for every 1000 metres climbed, our aerobic performance (VO2 max) decreases by 7%. For endurance and aerobic events, if you are not acclimatised, your performance will decrease.
The body reacts to the decreased atmospheric pressure by making more red blood cells to help the uptake of oxygen. This is where the benefit of altitude training comes in. If you spend a number of weeks at altitude and then return to sea level, these extra red blood cells could help your aerobic ability on your return. The Live High, Train Low concept has become reasonably well established. What this means is that for most of the day, you live at altitude, but you conduct your training at low altitude. As you are less able to work at high altitude because of your decreased aerobic ability, and hence less able to build strength or work on skills, training is conducted at low altitude. However, you live most of the time at high altitude in order to increase your VO2 Max.
The second part of the problem is the different physical dynamics that are present at altitude. For ball sports, as the air is thinner, there is less drag and hence balls tend to travel further. There is also less curve on the ball (or swing in cricket) as there is less friction caused by the air. This can mean that skills learnt at sea level are not necessarily attuned to the higher altitudes.
This mix of physiology and physics means that some sports are better performed at high altitudes and others at low altitudes. Foot races up to about 400 metres are faster at high altitudes as these are sprint events where aerobic capacity is less important (that is, they are anaerobic sports that don't require much oxygen) and the decreased drag improves the time. Chris Hoy famously attempted to break the World 1 kilometre Cycling sprint time at altitude in Bolivia and Bob Beamon smashed the long jump world record in Mexico, both largely due to decreased drag.
However, sport at altitude is not simply a matter of VO2 max and air friction. More than 200 genes are turned on during hypoxia, which is the condition where the body is deprived of oxygen. The AIS is studying many aspects of the problem including how lactic acid builds up in muscles differently at altitude than at sea level. Studies are also being conducted into the effect of altitude on skills. Chris considers that for a mid altitude of 2500 metres, it takes at least 2 or 3 weeks of acclimatising to be ready to compete, and possibly up to 8 months to be completely adjusted.
High altitude football teams have been found to have an advantage at home, but interestingly, low altitude teams have a similar advantage as it has been found (but not yet explained) that people coming down from altitude can struggle to adjust at sea level, becoming sluggish and lethargic. However, this is only for very high altitudes of 4 - 5 kilometres.
Chris considers that altitude training will only improve your performance by 1 or 2% and only for elite athletes. The effects may last up to 3 weeks but those who have spent a lifetime at altitude may see positive effects for much longer at sea level.
The use of "artificial altitude" - that is, hyperbaric chambers - has been ruled OK by the World Anti-Doping Agency. To hear more on this topic, all the topics mentioned above, and plenty more, tune in here, or press play below:
Here are some videos of the two altitude feats mentioned in the podcast, the Long Jump World Record of Bob Beamon in Mexico, and the attempted 1km Cycling World Record of Chris Hoy in Bolivia:
References: McSharry, P. (2007). Effect of altitude on physiological performance: a statistical analysis using results of international football games BMJ, 335 (7633), 1278-1281 DOI: 10.1136/bmj.39393.451516.AD
Loland S, & Caplan A (2008). Ethics of technologically constructed hypoxic environments in sport. Scandinavian journal of medicine & science in sports, 18 Suppl 1, 70-5 PMID: 18665954
Friedmann-Bette B (2008). Classical altitude training. Scandinavian journal of medicine & science in sports, 18 Suppl 1, 11-20 PMID: 18665948
Levine BD, & Stray-Gundersen J (1997). "Living high-training low": effect of moderate-altitude acclimatization with low-altitude training on performance. Journal of applied physiology (Bethesda, Md. : 1985), 83 (1), 102-12 PMID: 9216951
Bärtsch P, Saltin B, Dvorak J, & Federation Internationale de Football Association (2008). Consensus statement on playing football at different altitude. Scandinavian journal of medicine & science in sports, 18 Suppl 1, 96-9 PMID: 18665957
This is the second part of our series on the science of Wolverine - specifically, how can we create Wolverine in the lab? Join Dr Boob and myself as we journey through Wolverine's characteristics and how they may be recreated in a human. Read more on Wolverine in part 1 of this series. To listen to this show, tune in here (or press play below):
Specifically in this episode, we tackle the topics of:
What would happen to your bones if you completely covered them with metal? Bones are living parts of your body and make red blood cells, platelets and bone marrow - among other things - that are vital for life.
Would a lack of platelets reduce Wolverine's ability to heal?
Wolverine is likely to be on a cocktail of drugs, including anabolic steroids to beef him up, immunosuppressants so his body doesn't reject the metal coating on his bones, and various drugs to supply red blood cells, bone marrow and platelets.
Could we really harness the healing powers of the sea cucumber for Wolverine, and would they work quickly enough?
Are carrots enough to improve his sight?
What metal could we use to coat his bones? It needs to be able to be injected as a liquid and then harden at body temperature. Most steels have melting points over 1000 degrees Celcius, and this would cause terrible trauma to his body. Dr Boob's suggestion was CerroLOW117, which is 44.7% Bismuth, 22.6% Lead, 8.3% Tin, 5.3% Cadmium and 19.1% Indium. CerroLOW117 has a melting point of 47 degrees Celcius, however lead and cadmium both accumulate in the body and have adverse health effects. It is highly likely CerroLOW117 would not be strong enough to help Wolverine anyway.
