Evolution from healthy to diseased brain

The word “dementia” is used to talk about a set of neurodegenerative diseases, associated generally with aging. Because of the longer life expectancies, number of people suffering from dementia is rising consistently, with estimated numbers well over 100 million by the year 2050, making it a health priority for the World Health Organization.

Alzheimer´s disease (AD) accounts for 60-70% of dementia cases, and is characterised by a marked cognitive deterioration that affects memory, thinking and behaviour, and unaccountable to a normal ageing process. AD was long explained by the amyloid cascade hypothesis, as observations in brain tissue during post-mortem examination found accumulation of proteins, called amyloids which deposited intracellularly, affecting neuronal synapsis and causing neuronal death. Nowadays the explanation for AD onset is more complex, involving several pathogenic processes, which can be affected by genetic and environmental factors, and that goes beyond this entry.

In the development of AD have been distinguished three stages:

1/ Subjective Cognitive Decline (SCD): preclinical stage, without symptoms.

2/ Mild Cognitive Impairment (MCI): preclinical state, with some symptoms.

3/ Alzheimer´s Disease (AD): cognitive impairment, affecting daily activities.

Worthy to remark that not every individual in the SCD or MCI stages develops AD.

Physical activity (PA) has been considered beneficial on general health, as it decreases the risk of stroke and diabetes, among other diseases. A sedentary lifestyle has been associated with a higher risk of AD, so it was logical to study the effects of PA on it, as it would be an easier intervention than the pharmacological approach.

There are evidences that PA on the SCD stage may be a strategy to delay the AD progression, as it stimulates brain plasticity. Not every PA is the same, as it has been found that the PA related to work activities has not the same beneficial effects than the leisure PA. And for the leisure PA it was found that it offered more benefits when it was combined also with other mental and social activities, as it could be expected.

During lifetime it is obvious that generally there are different patterns regarding PA. Retirement should allow for more leisure time, although it is usually accompanied by a decrease in PA. Individuals with sedentary occupations otherwise generally increase their level of PA, especially if the economic status is good. PA at a higher age would be also beneficial in preventing, or delaying the effects of brain function decay associated with AD.

There have been found some genetic alterations that make people more susceptible of suffering AD (APOE4 for example). In these people is still unclear if a healthy lifestyle including PA could be enough to counteract the detrimental effects of these genetic alterations.

Until recently there were no many studies on PA at latter stages of AD. An article focusing on late running proved that, although the protein abnormal development was not altered in AD patients, it was able to improve memory performance and the agitation that also accompanies the illness.

As a conclusion we can say that PA (whether it is running or not), is useful in preventing and delaying AD at early stages, and also improves some of the symptoms in later stages.


Never is too late to exercise your body: it will also contribute to keep your mind and brain healthy.



Late running is not too late against Alzheimer’s pathology

Herring A, Munster Y, Metzdorf J, Bolczek B, Krussel S, Krieter D, et al.

Neurobiol Dis 2016; 94:44-54.


Physical Activity and Alzheimer’s disease: A Systematic Review

Brini, S., Sohrabi, H.R., Peiffer, J.J. et al.

Sports Med (2018) 48: 29.


Physical Activity in Preventing Alzheimer’s disease and Cognitive Decline: A Narrative Review

Stephen, R., Hongisto, K., Solomon, A., Lönnroos, E.

The Journals of Gerontology: Series A, Volume 72, Issue 6, 1 June 2017, Pages 733–739 

KARL MELTZER: MADE TO BE BROKEN (2016, 42min, M Katsolis)

“He is just a normal guy with a running problem” Eric Beltz, Meltzer´s crew member

Appalachian Trail Map

 This is a short film, available on streaming (Netflix and also on the Red Bull webpage) that follows the 2016 attempt of ultrarunner Karl Meltzer, 48, to break the record on the Appalachian Trail (AT).

We are given some basic information. The trail is 2188 miles long, it goes from Maine to Georgia, crosses 14 states, and has a 25% finishing rate among hikers. A tough course, it crosses mountains and forests, and the bad weather is inevitable. Most hikers do the AT in 4-6 months. Doing it running is a different story. Meltzer will try covering the whole distance, non-stop, and break the 46 days and 8 hours set by Scott Jurek one year earlier.

On his attempt, Meltzer is accompanied by an essential supporting crew, composed by his father and a friend, and sometimes also his wife. No easy work for them, as they must be aware of Meltzer´s every need, including, but not only, food, drinks and clothes, driving a van (that also works as sleeping quarter) from each check point to the next one, for a planned 46 days race.

Experience and careful planning are important, as this is going to be Meltzer´s third attempt, after failing in 2008 and 2014. To break the record, he must run around 45 miles per day for one month and half. Not only will his physical stamina be determinant, but also his mental strength.

We follow his ups and downs, and see him accompanied by some other ultrarunners, Scott Jurek among them, offering support and useful advices. We have the chance of learning how to empty a blister with a surgical needle, and although some physical problems and tiredness make Meltzer fell 12h behind the record pace, an 8h night sleep gets him back on track. We witness his last efforts, as he arrives to Springer Mountain, Georgia, and sets a new record of 45 days and 22 hours: incredible personal achievement. 

Score: 4 (out of 5)

Pros: get to know the AT; landscapes; ultrarunning camaraderie

Cons: we never get really empathic with Meltzer´s efforts

Extras: In 2017 Joe McConaughy, 26, set a new record in the AT of 45 days and 12 hours, hiking it self-supported and carrying a backpack. This record was beaten again in 2018 by Belgian Karel Sabbe, 28, who completed the AT running in an incredible 41 days and 7 hours.

Appalachian Mountains


With the recent marathon world record (WR) of Eliud Kipchoge, which stopped the watch in 2.01.39 in the last Berlin marathon, much has been talked about how long it will take to break the 2 hours barrier in the marathon. He had already run the marathon distance faster, in the Nike sponsored and failed attempt to break the 2 hours barrier in Monza in 2017 (2.00.25). 

His running shoes in both occasions, the Nike´s Zoom Vaporfly Elite in Monza, and the Vaporfly 4% prototype in Berlin, have been a matter of discussion, as whether technical improvements on running shoes will be determinant on achieving new WR, or if these technical modifications should be limited somehow in the future. This reminds of what happened with the revolutionary Speedo swimsuits that appeared in 2008, that were decisive in breaking 93 (!) world records, until the International Swimming Federation ruled a new set of regulations.

Predictions about WR evolution in marathon has been the subject of numerous studies over the years, with hypothesis in recent articles about breaking the 2h barrier going from the year 2022 to the year 2100, or as far as saying that human limit for running a marathon was 2.00.43.

As already mentioned in other entry, running economy is one of the three main determinants in running performance (the other two being the maximal VO2 and lactate threshold). Footwear will be a key factor, as reducing the running energetic cost will be determinant in achieving a sub 2h marathon.

When comparing different types of footwear, and also the barefoot option, among the main characteristics to consider we could point out to shoe mass, cushioning, stiffness, motion control, drop height or comfort. As for the shoe mass, there is a higher metabolic cost when running with heavy shoes (more than 440g) than with light shoes (less than 440g) or barefoot, although there was no difference if using light shoes or running barefoot. Not considering footwear mass, minimalist shoes were also more economical than normal shoes.

More shoe cushioning, and consequently comfort, were also associated with small improvements in running economy, although it also implied more shoe mass, and therefore a higher energetic cost. A benefit on one side (cushioning), can be a risk on another (shoe mass).

Considering the sole, for identical shoe mass, there was no difference in running economy between hard and soft shoes. As for the longitudinal shoe stiffness, it was associated with a small improvement in running economy.

A new batch of running shoes have been recently developed trying to bring together every positive effect on running economy: low shoe mass, highly compliant midsole material and a stiff embedded plate. Using these prototype shoes, as the ones used by Kipchoge, it was found a 4% reduction in the running energetic cost when comparing with previous marathon running shoes, as the Nike Zoom Streak 6 and the Adidas Boost 2 that had been used to run some of the best marathon times previously. This improvement in running economy has proved crucial in establishing the new marathon WR.

A new generation of running shoes, in addition with ideal weather conditions, careful pacing (that lacked in the second half of Berlin marathon) and new energy drinks and supplements, will surely get an athlete below the 2h barrier. Any prediction on when this will happen? And more important: who will run it?



The Effect of Footwear on Running Performance and Running Economy in Distance Runners

Fuller, J.T., Bellenger, C.R., Thewlis, D. et al.

Sports Med (2015) 45: 411


A Comparison of the Energetic Cost of Running in Marathon Racing Shoes

Hoogkamer, W., Kipp, S., Frank, J.H. et al.

Sports Med (2018) 48: 1009


How Biomechanical Improvements in Running Economy Could Break the 2-hour Marathon Barrier

Hoogkamer, W., Kram, R. & Arellano, C.J.

Sports Med (2017) 47: 1739


MARATHON OLYMPIC CHAMPIONS (V) – Stockholm 1912: KEN McARTHUR (1881-1960)

Start of the 1912 Marathon

“I went out to win or die, and it was worth two and a half years working and waiting for.”

Ken McArthur

Some countries did their first appearance in these Olympics, with Japan becoming the first Asian country, and first and last appearance of Serbia as an independent country until the 2008 Games. It was the last occasion where individuals could entry as private instead of being selected by a country.

As for the marathon, it would start in the Olympic stadium, go to the Sollentuna town, and come back to the stadium. Among the runners, world most renowned ones were present, with the North-Americans favourites, with the 1911 (Clarence DeMar) and 1912 (Mike Ryan) Boston marathon winners and the bronze medal at London Olympics 4 years earlier (Joe Forshaw). Kenneth McArthur entered for South Africa, and although little known outside his country he was undefeated in the distance, having won his three previous marathon races.

McArthur was born in Ireland (Ballymoney), and known as “Big Ken” because of his bulky frame. There he worked as a postman, usually running his rounds and racing against trains. In 1900 he moved to South Africa to become a policeman, and only then started to compete, winning many cross-country national championships. In 1908 he won Johannesburg marathon, and the following year Cape Town and Durham, when he finished 5 seconds shy of the standing world record (2.44.31).

Once again hot conditions were present in an Olympic marathon, with an estimated temperature of 32°C in the shade, and 68 runners of 19 countries present. In the early stages the Finnish Tatu Kolehmainen was leader, but at the turn around point South African Chris Gitsham took the lead, with a few more runners less than 1 minute behind him. Kolehmainen caught Gitsham, and they run together for a few miles, until Kolehmainen definitively dropped behind around mile 21. McArthur got to his teammate, and when he stopped for a drink, pulled away, being able to win the marathon in 2.36.54, with Gitsham less than a minute behind, and North American Strobino in third place. It is the only time that the same country has won gold and silver in the Olympic marathon.

Among the anecdotes of the marathon, the Japanese Kanakuri Shizō went missing when he stopped at a party to drink, and decided to quit the race. He took a train back to Stockholm, and without notifying any official, left the country on the following day. Invited again by Swedish authorities 50 years later, he managed to complete the race, with an unofficial time of 54 years. Sadly, this marathon also had the first fatality in the Olympic Games in the figure of Francisco Lázaro, a Portuguese marathon runner that decided to cover his body with fat to prevent sunburn and avoid transpiration. At the mile 19 he collapsed with a body temperature of 41°C, and nothing could be done to prevent his death. Before the race he had said: “Either I win, or I die”.

As for McArthur, about one year after his victory and already back in South Africa, a foot injury ended his running efforts. Once retired from the police, he moved briefly back to Ireland with his wife and settled on a family farm, although they eventually returned to South Africa, where he would die of old age in 1960.

Sourced from:

Pictures in the public domain used under Creative Commons Licence

Silver - Gitsham (South Africa)
Bronze- Strobino (United States)
McArthur crossing the finish line
Gold - McArthur (South Africa)

Vías Verdes Plazaola Marathon (16/09/18 – 69)

St Martin church (Andoain)

After a summer with holidays, weeks going easy on training, and some short races during July, this marathon was the comeback after more than 100 days, and on the day that Eliud Kipchoge set an astonishing new world record in Berlin, in 2.01.39, that may remain for a long time.

Marathon 69 was supposed to be Valtiendas, near Segovia, returning in mid-August after a long hiatus. Already registered, in early July I got an email announcing its cancellation because of the low number of registrants. With my entry price returned, I decided to register for the Plazaola marathon instead. I had already registered in 2017, but because of difficulties to sort out travel and accommodation, I finally decided to cancel my entry and run the inaugural Ribera Run Race ultra that took place in Peñafiel, near my hometown.

Vías Verdes marathons ( are races that take place in old abandoned rail tracks, restored as pathways. Nowadays there are 4 of them, and Plazaola was the last in the calendar, and would become my first experience with them.

With also a short 26k edition available, the marathon would run from Lekumberri, in Navarra, to Andoain, in Guipuzcoa. With easy train access from central Spain, and good combinations from the near San Sebastian, it looked as a good marathon option in an otherwise quiet September. I booked one-night accommodation in Andoain, and the bus available from the organization at the time of registration (6€), to go from Andoain at 7.30 to the start in Lekumberri. At the time of registration there also some offers including two nights’ accommodation and transport to the start, that could be a good opportunity to do some tourism in the area and know the nearby San Sebastian.

Lekumberri is a small village in a hilly area. From there is 26 miles to Andoain, after passing Leitza (where is located the start for the shorter race), going from the 560m at the start to the 80m at the arrival. Without cloakroom facilities at the race start, was better to wear something to keep us warm until the 9.00 start, although the weather was so good that it was almost unnecessary.

Only a few more than 100 participants take the start, and after a short lap in the roads of Lekumberri we take the Vías Verdes route. From that point on the whole course follows the old train paths, in a greenish scenario with many tunnels, the longest about 1.5 miles in length. In the rules was specified the need of frontal light, and although some of the tunnels are short or partially lighted, it was useful to avoid the water patches and occasional potholes in the dark areas.

The beautiful scenario, well provided refreshment points, good weather and mostly shaded areas make for a fun race, where miles start going by unnoticed. I feel with energy, although considering the lack of long sessions during the last few weeks, I decide to save energy and enjoy the views, losing a few positions. I cross the half marathon in 1.47.37 without effort, while keeping a stable pace and doing the stops in the refreshment points as short as possible I start overtaking some runners. Feeling well I push in the last 5 miles to get to the finish line in 3.36.45, my best time of the year by more than 7 minutes. Finally, good body sensations, helped by the nice downhill course, and probably an unusual long period away from competition.

A marathon that deserves a slot in my next year calendar, and the entry race for a more demanding autumn season. With the Grand Slam (12 marathons in a calendar year) planned for 2018 getting closer, I start thinking about going a bit further (13, 14…?).

What are your racing plans for the remaining months of the year?


Score: 5 (out of 5)

Pros: green scenery; good organization; hoodie in the runner bag; free lunch post-race

Cons: no answer to any of my emails asking for information

Finish area
Race medal


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Guatemala national flag

We get an early morning call, at 2.30am, to get from Antigua to Guatemala City airport, and the 6.30am flight to Flores. It is a short duration flight of 1h in a small airplane. Our travel package included one-night stay in Tikal, although many tourists are doing the 1-day tour, and will return on the evening. They don´t have to carry all their luggage with them, but it must be a more tiring trip, as they have to get back later to Flores airport on the evening to fly back to Guatemala.

View of Tikal from the top

We leave our luggage in the hotel, in the lake shore of Lago Petén, from where we can see the small peninsula of Flores, and start our day trip to Tikal, that is about 40 miles north, taking a bit more than 1h to get to the entrance, where our guide buys the tickets for us (20$ for foreigners). Weather is considerably hot already at 10am, and it looks like the perfect time to cover ourselves with sun protection and strong anti-mosquito repellent. Tikal was the first archaeological site recognised as World Heritage by UNESCO, as far back as 1979. The tour gives us an insight of the amazing Mayan town of Tikal, and even when only a tiny fraction of its buildings is restored, you can imagine the amount of people that used to walk and live here centuries ago, with an estimated population of around 50 thousand inhabitants. Most of the buildings are still hiding under the jungle, while only a small percentage of the town is open to the public. Imagination, and especially recent new laser techniques, have allowed to see what lies beneath the vegetable cover. As we were explained the costs of restoration and maintenance are very high, and the number of tourists still insufficient to proceed with extensive excavation campaigns. We are given some free time in the central square, useful to explore some back alleys far from tourist crowds. After a picnic lunch, we get back to the buses and our hotels, after an exhausting day, but with a very rewarding visit that will stay on our memories for years to come. Still time for a visit to Flores, a nice touristy spot, overcrowded with swallows at sunset.

Pyramid half covered in vegetation
Ceiba tree
Covered pyramid
Tikal buildings
Tikal central square

Next day we get an optional tour to the Blue Crater, in Sayaxché, where we arrive after one and a half hours in a boat following the river Pasión, where we can see the local population using the river resources and plenty of birds (sadly crocodiles were not on sight). We get on a small affluent when water turns from green to transparent, to finally arrive to the crater. It is a small lagoon, with crystalline clean waters and a depth of 5-7 metres in its centre, that offers a perfect swim and the possibility of seeing the river bed. The peace of the spot is ruined when some noisy North-American tourists arrive in their boat with the music at high volume. Possibly one of those places that tourism will ruin before long. The return boat trip offers a last view of the wildness, as we return to Flores airport and back to Guatemala City, where we will spend our last night in Guatemala.

Río Pasión
Cráter Azul waters
River shore
Cráter Azul

Next morning there is only time to do some souvenirs shopping and a short city tour in the same bus that will get us to the airport to catch our return flights home. We only have the chance to leave the bus for a short walk inside the Cathedral, and from there head back to the airport, where we will finally arrive with just enough time to do our check in and pass the security controls because of the heavy traffic. And here it finishes the 1-week tour to Guatemala, for a rewarding first experience in Central America.

Ciudad de Guatemala Cathedral
San Simón image


      No Comments on GUATEMALA (1/2)

Guatemala gets to be this year summer holidays destination, as I found a relatively cheap package in an agency near home, including flights, accommodation, circuit and a visit to Tikal with internal flights. Whole package is going to be 9 days and 7 nights. There are longer packages, but probably 1 week looks as the choice to go for and get a taste of what this country has to offer. The Fuego volcano that caused several dead and disappeared a few weeks earlier, finally didn´t jeopardize the planned holidays.

Flight is not direct from Madrid, and after a short scale in Varadero (Cuba), where most of the passengers leave the airplane, a short flight gets the remaining passengers to Ciudad de Guatemala. There is only time to go to the nearby hotel, get a shower and go to sleep. No much for a first day spent arriving to our destination.

View from the airplane

Next morning, we depart towards Lago de Atitlán, with a brief stop at the Iximché Mayan archaeological site, where we do a short visit and have the chance of witnessing a traditional Mayan offering. As we continue our journey and get closer to the lake, we can appreciate its beautiful views surrounded by 3 impressive volcanoes, Atitlán, Tolimán y San Pedro, all of them above 3000 metres. We arrive to Panajachel, where we will spend the night, just in time to enjoy a wonderful sunset.

Iximché pelota court
Lago Atitlán view
Mayan ritual
Sunset in Panajachel

On the next day, we manage to get a very early boat tour of the lake, visiting the small village of San Juan de la Laguna, that lies on the opposite lake shore, where we visit some traditional shops of coffee and jade. Back in Panajachel, and already behind the original scheduled plan we get onto the bus to the traditional market of Chichicastenango, with their packed and coloured streets, and the interesting church of Santo Tomas, that offers an interesting blending of catholic and Mayan rituals under the same roof, and where pictures were strictly forbidden. From Chichicastenango we get again onto the bus and head towards Antigua, a World Heritage site by UNESCO, that was the country capital until the end of the XVIII century, when a series of earthquakes destroyed most of the town. This will become our sleeping quarter for 3 nights.

San Juan de la Laguna
Sto Tomás Church (Chichicastenango)
Atitlán lake shore
Market section (Chichicastenango)

Next day we have a trip to visit Ciudad Vieja, that was the country capital before Antigua itself, and a visit to the ecological Valhalla macadamia nuts plantation. Going back to Antigua we stop briefly in the Cerro de la Cruz, a spot offering a wonderful view overlooking the whole of Antigua, with its linear outline and the Agua volcano on the background.

Valhalla Plantation
Macadamia nuts
Ciudad Vieja view
Antigua view from Cerro de la Cruz

On the following day, and although there is an optional hike to the Pacaya volcano, some of us decide to spend the day in Antigua, as we didn´t have time to walk its streets and visit some of its countless churches, many of them in ruins, and the traditional linear streets covered with cobblestones. For the first time in our trip we have the chance to experience the force of a rainy season storm and catch one of the many tuk-tuks available to get back to the hotel. Time to go to sleep early, as next day is our flight to Tikal.

San José Cathedral
Santa Catalina Arch

To be continued…

SPORT DRINKS (2/2): formulations and future directions

Nowadays there are many available sport drinks formulations in the market, with various percentages of carbohydrates, flavours, colours and so on. It is usually accepted that a mixture of fructose and maltodextrin in similar proportions gets higher assimilation rates than a glucose only drink. As for the replenishment levels, is generally advised to get between 30 and 60g carbohydrates every hour for exercises lasting more than 1h. Concentrations vary, as there are formulations depending on the chronology, with hypotonic drinks before (4-6% carbohydrates and 0.5-0.7g sodium per litre), isotonic during (6-9% carbohydrates and 0.5-0.7g sodium per litre, or 0.7-1.2g sodium in hot conditions) and generally hypertonic drinks after the exercise (9-10% carbohydrates and 1.0-1.5g sodium per litre). As carbohydrates concentration are higher, there is an increased chance for gastrointestinal problems.

Among drinks that could also be considered we find the milk and liquid yogurt, that are usually beneficial after exercise, as they provide high quality proteins and amino acids, recommended for the recovery of muscle fibres, and are rich in carbohydrates.  Chocolate milkshake could be your perfect hydrating and recovery drink after long trainings. As for juices, they are mainly rich in carbohydrates, and they could be useful for replenishing liquid losses after training, but, as with the milk-based drinks, with caution of side effects if consuming during the exercise. Regarding energy drinks, although they will have their own entry, they usually add extra nutrients, whose inclusion is not always scientifically justified (taurine, caffeine, guarana…), so caution should be exerted before recurring to their use.

A new field of sport drinks is on the rise, based on hydrogels and alginate. Alginate is a seaweed derived polymer, with several uses in the pharmaceutical industry (cartilage regeneration and wound healing among others). At low levels of pH, as in the stomach (because of the gastric acids used for the digestion), forms a hydrogel, capable of encapsulating the carbohydrates. When this “capsule” abandons the stomach towards the intestine, with a higher pH, loses its shape, releasing the carbohydrates. This unique property allows for higher quantities of carbohydrates consumption, impossible with the usual formulations (due to its slow gastric emptying), and higher levels of water intake. In preliminary studies with athletes running 25k at a 3:48min/k pace it was possible to increase the amount of carbohydrates to 300g carbohydrates/L without side effects, an amount considerably higher than in usually available commercial drinks. A clear evidence of the new popularity of these drinks is that already in 2016 winners of all World Marathon Majors (Berlin, Chicago, NY, Tokyo, Boston and London) were using some kind of alginate hydrogels, a trend that has only continued.

Additional benefit of this new hydrogels is the possibility of delivering other nutrients and supplements that could otherwise not be so well tolerated by the stomach. On top of this, there is a consensus that the common use of drinks and gels, even at elite level, are detrimental for the dental health, as most use flavourings, such citric acid, that contribute towards an acidic pH. The alginate gels on the contrary are pH neutral, and therefore could contribute to maintain a healthier teeth.

Also worth mentioning the use of the new technologies in the recent field of “smart bottles”. These technologically interconnected devices, with sensors capable of sending information to computer applications are useful in patients that need accurate control of liquid intake. The use of these so called smart bottles in sports is warranted, as they would allow a perfectly timed control of liquid intake.



Sports Drinks on the Edge of a New Era

Sutehall SMuniz-Pardos BBosch ANDi Gianfrancesco APitsiladis YP.

Current Sports Medicine Reports: April 2018 – Volume 17 – Issue 4 – p 112–116


Accuracy of daily fluid intake measurements using a “smart” water bottle

Borofsky MSDauw CAYork NTerry CLingeman JE.

Urolithiasis. 2017 Oct 4.


Hydration and chemical ingredients in sport drinks: food safety in the European context

Urdampilleta AGómez-Zorita SSoriano JMMartínez-Sanz JMMedina SGil-Izquierdo A.

Nutr Hosp. 2015; 31(5):1889-1899


Fluid replacement and performance during the marathon

Cheuvront SNMontain SJSawka MN.

Sports Med. 2007; 37(4-5):353-7.

SPORT DRINKS (1/2): hydration and thermoregulation

Until 1923 with the research of AV Hill there was no information about the importance of fluid consumption during sports. He was the first who found that blood supply was important to keep muscles and heart at work during the exercise. His seminal work laid the ground for the cardiovascular model of thermoregulation, which explained the importance of good hydration during exercise practice.

Summarising, water loss, mainly through sweating, reduces the plasma volume in the body. The heart has to increase its output to maintain the blood flow to muscles and skin. If exercise continues without proper hydration there is a point in which heart is unable to maintain the stroke volume. The next step of protection from the body is to increase the vascular resistance, in other words, to contract blood vessels, and consequently the blood supply, to the skin. This would affect the thermoregulatory ability of the body to dissipate the heat, leading to an increase in the body temperature. When body temperature reaches 39°C there is a dramatic decrease in the physical performance, with also neurophysiological effects. Without treatment it would cause a heat stroke, fatal in many occasions.

It is still unclear which is the trigger limiting physical outcome, if dehydration or body overheating. In some studies the fastest athletes were the most dehydrated, maybe because they were able to keep dissipating heat during competition, and running economy was better (lowering of body weight), but it is impossible to know if their performances had been better if they had been properly hydrated.

It was generally advised that athletes should match fluid intake and fluid loss through sweating, as prevention for the negative effects of dehydration. Only in 2007 the American College of Sports Medicine (ACSM) started talking about a “tolerable dehydration”, where a fluid loss below 2% of body mass didn´t affect physical performance. In this regard is usual to have a deficit of 0.4-0.6L for every hour doing exercise, as liquid intake and nutrition are somehow more limited. For elite marathon runners competing in warm weather, an intake of 1L/h would be enough to keep dehydration at a 1.7%, still in the tolerable margin, while in cooler conditions a drinking rate of 0.5L/h could be enough. For more recreational runners, with marathon times around 4h, a rate of 0.5L/h would be insufficient to keep dehydration on bay (unless in a light runner of about 50kg weight). Fluid needs are variable among marathon runners, and affected by weather conditions, performance intensities and duration, and conditions in laboratory studies are never like those found in actual races.

It was only in 1970 that Costill studied the effect of water against a carbohydrate+electrolytes drink in a group of athletes, and although they found similar ability to keep body temperature constant, the group drinking the prepared beverage was able to keep electrolyte balance and carbohydrates metabolism.  It opened a new research topic, and therefore a new commercial field, that we will follow in our next entry.



Muscular Exercise, Lactic Acid, and the Supply and Utilization of Oxygen

AV Hill and H Lupton

QJM: An International Journal of Medicine, Volume 16, Issue 62, 1 January 1923, Pages 135-171


Fluid Ingestion During Distance Running

David L. Costill PhD, Walter F. Kammer MD & Ann Fisher MA

1970, Archives of Environmental Health: An International Journal, 21:4, 520-525

THE BARKLEY MARATHONS: The race that eats its young (2014, 89min, A Iltis & TJ Kane)


Gary “Lazarus Lake” Cantrell lights a cigarette to signal the start of the Barkley Marathons (Photo by Michael Hodge, used under a Creative Commons License)



“If you’re going to face a real challenge it has to be a real challenge. You can’t accomplish anything without the possibility of failure.”

Gary Catrell, ultra-runner and race director of the Barkley Marathon


This documentary chronicles the 2012 Barkley Marathon, a race I didn´t know about until I came across the film a couple of years ago in a streaming platform, and that I recently watched again.

The Barkley Marathon is an ultra-marathon race that takes place since 1986 in the Frozen Head State Park, in Tennessee, over a distance of 100 miles (although it is said to be closer to 130 miles, but no GPS are allowed), and a completion time limited to 60 hours. The course, that changes slightly every year, consists of 5 loops, each of them approximately 20 miles long, with 12000ft climb and descent through a dense forest, that start and end at a yellow gate.

Registration is 1.60$, a car licence plate from their town/country for first-timers, and another object (from a white shirt to a pair of socks, depending on race director necessities) for previous runners. The number of runners is limited to 40, with an obscure registration process involving some kind of motivation letter and a set of complicated rules.

Completing 3 loops achieves a “fun run”. The first 2 loops are done clockwise, and the next 2 counter-clockwise. For the 5th loop, if there is still any runner on the track, the first one can choose the direction to follow, with subsequent runners alternating directions. From more than 1000 starts over the years, the full distance have only been completed 18 times (by 15 different runners).

The film introduces us with some of the participants, as they arrive to base camp. The start is in a 12h window, from midnight to midday, and runners are only informed 1h in advance. We get the feeling of some runners and their preparations. They are not given any course map. Some books are distributed along the course, and each runner has to take the page number according with their race number in each of them, working as checking points. There is also animated and intercalated information about its origin and course, along the film, giving useful bits of information. We get also introduced to who could be defined as one of the central characters of the film, race director Gary Cantrell (aka Lazarus Lake), whose funny quotes are for me one of the highlights of the film. He probably deserves most of the credit for this race happening. We are also introduced to some of the runners, although I will make a note of the subsequent 3 finishers:

  • Brett Maune, finisher and winner of the 2011 edition, that will revalidate his title and be the first runner ever to complete the Barkley twice, as he eventually does, establishing a still lasting record of 52.03.08 (and breaking the previous record by more than 3h).
  • Jared Campbell, who will also complete successfully the marathon in 56.00.16. Running with Brett from loops 2 to 4, and a last loop in opposite direction and hard competition with Maune, adds a welcome tension to keep the plot interest (later to become the first runner to complete 3 Barkleys).
  • John Fegyveresi, who will become the third finisher of the 2012 Barkley, finishing shy of the time limit, in the first Barkley with 3 finishers.

After witnessing the feat of finishing such a race, we are also given an insight with the end credits of 2013 and 2014 race results.

A funny film, where you can feel the tension, sweat, blood and every bit of effort involved. After watching the film you will only want to grab your shoes and go running crazy in the woods.

Score: 5 (out of 5)

Pros: fun and close look to the ultra-running world; the race director, a true character

Cons: that some of these races may be out of bounds for mortal runners