Category Archives: science

Cramps

A new study suggests that cramps during exercise have nothing to do with electrolytes or dehydration, but are simply due to muscle fatigue.8479719962_3208ac3c1e

For decades we have been told that cramps during long runs are due to dehydration and loss of electrolytes. It is tempting to think so indeed, as patients with disturbed electrolytes due to illness suffer from cramps. However, these patients are usually severely ill and have cramps all over their bodies. Runners on the other hand, typically have them in the working muscles and often only later in the race. Moreover, they might be tired but they are not ill!

Scientists now suspect that cramps in runners (or in any athlete) might be something different. Indeed, there is more and more evidence that cramps are due to muscular fatigue, and the latest study by Martin Hoffman and Kristin Stuempfle suggests this as well.

They studied 280 runners during a 161 km ultra-marathon by measuring their body weight before, during and after the race, and they determined their sodium and CK (= a measure of muscular damage) levels by a blood sample after the race. The runners also completed a questionnaire about cramping, “near” cramping (= controllable, not full blown), drinking strategies and the use of electrolyte supplements.

14% of the participants reported cramping, and 28% near cramping. There was no difference in changes in bodyweight or sodium levels between those suffering from cramping or near cramping and the others. Those who cramped or near cramped however, showed higher CK blood concentrations and were more likely to have suffered from them in the past.

The researchers concluded that cramping was associated with muscle damage, which confirms other studies suggesting that it is due to fatigue.

This is important for all of us, because if they are right, there is no need to take electrolyte supplements. It could then be more beneficial to review our training, build up our muscle strength and see if our technique needs improving.

References:

KW Braulick, KC Miller, JM Albrecht et al. Significant and serious dehydration does not affect skeletal muscle cramp threshold frequency. Br J Sports Med. 2013; 47(11): 710-4.

MD Hoffman and KJ Stuempfle. Muscle cramping during a 161 km ultra-marathon: comparison of characteristics of those with and without cramping. Sports Med Open. 2015; 1 (1):8.

MP Schwellnus, EW Denman and TD Noakes. Aetiology of skeletal muscle “cramps” during exercise: a novel hypothesis. J Sports Sci. 1997; 15(3):277-85.

MP Schwellnus. Cause of exercise associated muscle cramps (EAMC) — altered neuromuscular control, dehydration or electrolyte depletion? Br J Sports Med. 2009; 43(6):401-8.

 

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The best exercise for your health

Have you ever wondered which exercise would be best to keep you healthy as you get older? I guess the answer is “the one you like”, but Pedro Angel Latorre-Roman and his colleagues wanted to investigate this further and compared master long distance runners with athletes engaged in gym work and sedentary people.15308809285_249e075362

 

 

 

 

 

47 long distance runners and 49 bodybuilders from local clubs volunteered for the study, and were compared to 47 sedentary people. All the participants were male, and between 35 and 60 years old. They were divided in groups according to their age (35-40 year, 40-50 year and 50-60 year old).

The researchers calculated their BMI, measured their body fat percentage, and analysed their quality of life using a questionnaire. The participants performed countermovement jumps and had their hand grip measured to test their strength.

Unsurprisingly, the long distance runners as well as the bodybuilders maintained their strength much better throughout aging than the sedentary people, even though muscle mass was decreased in all the older participants compared to the younger ones. The runners showed healthier BMI values and body fat percentages, and scored better in the quality of life questionnaire than both other groups. However, they lost more muscle mass than the bodybuilders as they grew older.

This study confirms a previous study by Williams, which showed that running is much more effective in keeping your body fat percentage healthy than other sports. Williams compared the BMI and waist circumference of 33,374 runners with the kind and amount of exercise they were doing. Most runners do not only run, but are also engaged in a wide variety of different sports, such as cycling, walking, swimming… He noticed that those who ran more were leaner, even if the total amount of energy spent exercising was the same.

Both studies are off course observational, which means that they can only show an association between two findings. It does not mean that one leads to the other, as there might be a third factor which explains the association. For example, there is an association between lying in bed and dying, as most people die in bed, but this is explained by disease and injury.

It is also possible that lean people are more often tempted to take up running than other people.

The same could be true concerning the results of the quality of life questionnaire: are you happy because you are running, are you running because you are happy or is there another explanation?

References:

PA Latorre-Roman, JM Izquierdo-Sanchez, J Salas-Sanchez and F Garcia-Pinillos. Comparative Analysis between two models of active aging and its influence on body composition, strength and quality of life: long-distance runners versus bodybuilders practioners. Nutr Hosp. 2015; 31(4): 17-25.

PT Williams.  Non-exchangeability of running vs. other exercise in their association with adiposity, and its implications for public health recommendations. PLoSOne. 2012; 7(7): e36360. doi:10.1371/journal.pone0036360.Epub 2012 Jul 13.

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Exercise and mortality

5797534694_a36e9d8b0dExercising helps you to live longer, whatever the amount you are doing. If you exercise a little, your risk of an early death drops and if you exercise a lot, it drops even more. This is the conclusion of a study published on April 6th in the JAMA.

If you plot “benefits” against “dose” on a graph, most biological systems will show an inverted “U”. Take food for example: if you eat too little, you might die, but if you eat too much, you might also die. If you take a medicine, you have to take the right amount, as taking not enough will have no effect and taking too much is toxic.

Is the same true for exercise? Everybody agrees that you need a minimum of exercise to stay healthy, but some people believe that too much is bad for you. The recent cases of sudden deaths during competitions and the findings of heart rhythm disturbances in older endurance athletes have fuelled the debate.

To answer this question, Hannah Arem and her colleagues have looked at the mortality rates and physical activity levels of 661 137 men and women over 14.2 years.

Sure enough, they showed that having the recommended amount of exercise (a minimum of 150 min of moderate intensity, or 75 min of vigorous intensity endurance exercise per week) resulted in a 30% lower mortality risk compared to not exercising at all. However, any exercise is much better than none, as people who did less than the recommended amount already reduced their mortality risk by about 20%.

Working out more is even better, and exercising 2 to 3 times the recommended amount reduces your risk by 37%, while doing 3 to 5 times more leads to a 39% reduction.

The researchers noticed that those who exercise 10 times or more the recommended amount did not reduce their risk any further, but they could not observe any evidence of harm either.

Can I believe this?

This is very large study, which makes it trustworthy. Moreover, the results are the same for both genders and all BMI ranges.

On the other hand, it is based on questionnaires, and participants can easily over- or underestimate what they are doing or change their habits. However, most population studies about exercise and mortality suffer from these same limitations.

If Hannah Arem is right, concerning exercise, there cannot be too much of a good thing. Even though I have never met anybody running marathons or participating in triathlons for health reasons only, it is good to know we are not harming our bodies.

Keep going, but make sure that you avoid overtraining and injuries!

References

Arem H, Moore SC, Patel A et al. Leisure time physical activity and mortality: a detailed pooled analysis of the dose-response relationship. JAMA Intern Med 2015; DOI:10.1001/jamainternmed.2015.0533. (Abstract)

Photo

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“Aerobic” and “anaerobic” exercise are misnomers

1673932398_5b4211ff72Most people still use the terms “aerobic” and “anaerobic” exercise to name intensity levels, referring to the way your body produces the required energy. However, the way you produce energy is one big continuous chain of reactions, and categorizing exercise in this way can lead to misunderstandings.

In an article in March 2015, Kamir Chamari and Johnny Padulo suggest using the terms “explosive efforts”, “high intensity efforts” and “endurance intensity efforts”.

Energy production: a complex chain of reactions

When you exercise, your body transforms glycogen, glucose, fats or some proteins into a specialised molecule called ATP (adenosine triphosphate), which can then be used by your muscle fibres.

There is some ATP available for immediate use to perform very intensive bouts of exercise, e.g. sprinting, which we should call “explosive efforts”.  After about 6 sec however, it is gone and your body therefore immediately starts topping it up.

Glycogen or glucose is first broken down in the cytoplasm of the cells into pyruvic acid, producing about 3 molecules of ATP. This might not sound as very much, but the system is quick. It does not need any oxygen, even if oxygen is available, and it is therefore often called “anaerobic”. It is everything you need for short, intense bouts of exercise which Chamari and Padulo suggest calling “high intensity efforts”.

Pyruvic acid is then used by the mitochondria of your cells to produce about 32 molecules of ATP in a complex series of reactions. This part of the energy production chain is very productive but it is rather slow. As it requires oxygen, it is often called “aerobic” and the exercise intensity at which you rely most on it is “endurance intensity exercise”.

The bottle neck between high intensity and endurance intensity levels

As the first part of the chain is fast (up to pyruvic acid, without the need for oxygen) and the second slow, there will be a bottle neck between the two of them. If you go harder, the bottle neck will become bigger, and more of your energy will have to come from the first “anaerobic” part of the chain, even if there is plenty of oxygen available.13191313253_05274951ac

Whatever the intensity you are exercising at, you will always be using energy from both parts of the chain. The relative amounts will differ, obviously, but will be determined by the intensity of the effort and not by the presence or absence of oxygen. Labelling a workout as “aerobic” or “anaerobic” is therefore incorrect, and can lead to confusing and misunderstandings.

Lactic acid

If you are going hard, pyruvic acid will be accumulating in your cells due to the bottle neck. It changes then into lactic acid and moves out of the cell. As lactic acid can very easily change back into pyruvic acid, which can used to produce a lot of energy, it is eagerly taken up by other tissues. It is therefore not a waste product at all, but a very important molecule.

However, if you produce more lactic acid than your tissues can take up, the amount in your blood will increase. Your brain uses this rise as a signal that you are going a bit too hard and it will slow you down by making your muscles ache.

As you can have this feeling even if you are doing an endurance workout, it is clear that you are getting energy via every part of the chain.

References:

Chamari K and Padulo J. “Aerobic” and “anaerobic” terms used in exercise physiology: a critical terminology reflection. Sports Medicine- Open.  2015; 1:9. doi: 10.1186/s40798-015-0012-1.

Willmore JH, Costill DL and Kenney W L. Physiology of sports and exercise. Ed: Human Kinetics 2008.

Photo’s:

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Do you need to exercise if you are healthy?

14022436150_97d48f6579Exercise improves your health, even if you are fit.

What is the importance of exercise if you are young, fit and healthy? Researchers in Finland have tried to answer this question by studying male identical twins. As these brothers are identical at the gene sequence level, any difference should be due to lifestyle factors.

They recruited 10 healthy male identical twins between 32 and 36 years old, of which only one brother had been exercising regularly for the last three years. They then measured their body weight and fat percentages, assessed their glucose levels and insulin sensitivity, and calculated the volume of their brains’ grey matter using magnetic resonance imaging.

The active twins had a higher VO2max and less visceral fat than their sedentary brothers, even though their body weight was not that different. Their glucose levels were lower and their insulin sensitivity* was higher. They also had a higher volume of grey matter in those areas associated with motor control.

The researchers concluded that even among healthy young adults exercise makes a difference. This is important, as lower fitness levels, more visceral fat and poor glucose metabolism are associated with chronic diseases later in life. Obviously, the negative effects of being sedentary begin early!

You might wonder if you have taken up exercise because you have a more favourable genetic profile than sedentary people. If so, you would be healthier whatever you do. This study suggests that this is not the case and that exercise makes a real difference, since identical twins should have the same genetic profile. This does not mean that genes do not matter. They are very important indeed, but you can influence them by your lifestyle.

This is only a small study. It would be great to confirm it with larger ones, but it must be very difficult to find a large group of identical twins of the same sex and age group with different exercise habits.

* Insulin sensitivity = how sensitive the body is to insulin stimulation. Low sensitivity is associated with higher risk of diabetes type 2.

References:

Rottensteiner M, Leskinen T, Niskanen E et al. Physical acivity, fitness, glucose homeostasis, and brain morphology in twins. Med Sci Sports Exerc. 2015; 47(3): 509-518.

Picture:

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A happy brain makes you run better

Fatigue during endurance exercise is a weird and complex phenomenon, and scientists are still discussing what influences it. Samuele Marcora’s group has just published an article in Frontiers in Human Neuroscience reporting two experiments studying the effect of visual cues related to happiness and motivation. They showed that such cues can make your unconscious brain think you are working out less hard than you actually are, and that therefore you will keep going for longer.medium_1734834072

Samuele Marcora’s theory about fatigue states that the moment you stop exercising is determined by perceived effort (how hard you think you are working) and potential motivation (the maximal effort you are happy to deliver). This means that you will stop when you are judging that the effort required has become larger than the effort you want to make. This theory is called the psychobiological model of endurance performance. To delay fatigue you could therefore do two things: make the effort seem less important, or increase your motivation.

Our unconscious brain takes in much more information than we realise, especially visually. Only a tiny amount of this information makes it to our conscious attention, but we process all the information unconsciously and it therefore influences our behaviour. To study the impact of the unconscious brain on perceived effort, the researchers therefore set up a study during which they could give participants subliminal visual cues.

In their first experiment 13 participants cycled for as long as they could (i.e. to exhaustion) while looking at a computer screen. They were shown happy or sad faces on a regular basis during the effort, but the images came and went so quickly (in 16 msec) that they did not realise they were seeing them. Every participant performed the experiment twice: once with happy and once with sad faces.

In the second experiment, a well trained competitive endurance athlete cycled 12 times to exhaustion while looking at a screen showing words extremely quickly. The words were encouraging (action, go, lively, energy) during 6 workouts and discouraging (stop, toil, sleep tired) during the other workouts.

In both experiments, the participants cycled significantly longer when exposed to happy faces or encouraging words, and rated the effort as less strenuous. Their mood was not different however, proving that the information had not reached their conscious attention.

Samuele Marcora and his team concluded that these experiments confirm their theory. They also think they provide evidence against the central governor theory of Tim Noakes.

The central governor theory states that your pace, and therefore your fatigue, is determined by your unconscious brain which has to make sure that you get safely over the finish line. According to this theory your pace will thus be determined by “calculations” of your brain based on signals from your body, (e.g. working muscles, glycogen reserves), the environment (temperature, altitude…), but also on messages from your central nervous system, such as motivation, encouragement, knowledge about the course, etc…If you brain is not sure that you will get there safely, it will slow you down –or even stop you- by making you feel tired and reducing the number of muscle fibres you can use.

I am not so sure that the experiments contradict the central governor theory. Is it not likely that subliminal cues would also influence how your brain determines what you can do? Please let us know what you think!

Whatever you think about these theories, it is a good idea to surround yourself by positive images and words, and to smile to every runner you meet.

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Exercise and a family history of type 2 diabetes

© Kiankhoon | Dreamstime Stock Photos
© Kiankhoon | Dreamstime Stock Photos

Type 2 diabetes is more and more frequent in our Western world. It is probably the result of a complex and not- well-understood interaction of genes, lifestyle and obesity.

The disease starts with insulin resistance, which means that your tissues do not respond that well to stimulation by insulin. However, insulin is essential for the transfer of glucose from your blood into your tissues. As your tissues become resistant, you need more insulin to do the same job as before. If moreover the producing cells become dysfunctional, you will not be able to produce enough to keep your blood glucose levels normal and you will develop diabetes.

A family history of the disease is an important risk factor. Fortunately, you can lower your risk by exercising regularly. Working out will help you to normalise your glucose metabolism, as during exercise your muscles can take up glucose without insulin. It will also help you to keep your weight under control and reduce your risk of cardiovascular disease, which is diabetes’ major complication. Exercise is therefore a cornerstone of the prevention as well as of the treatment.

As exercise is so important for people at risk, the obvious question is: do people with and without a family history have different aptitudes for sport? To answer this, Antonio Bianco and his colleagues compared the aptitude for anaerobic performance of 33 elite athletes without a family history of type 2 diabetes with 13 elites with a family history.

The anaerobic metabolism is the pathway to produce energy without oxygen, as opposed to the aerobic metabolism. It is much quicker, but it is less economical than the aerobic metabolism, and your body will therefore use it for short, high intensity activities such as high intensity interval training and strength exercise.

The athletes performed squat jumps and a Wingate test*, which is the classical test to determine somebody’s peak anaerobic power.

As suspected, the athletes with a family history had a higher body mass than the others, but, surprisingly, their anaerobic performances were significantly better.

The majority of the studies showing the importance of regular workouts for diabetes used aerobic exercise. However, a mounting amount of evidence suggests that strength exercise is just as beneficial. If Bianco is right, his findings would be important for everybody who has a family history of type 2 diabetes, since it is likely that you will prefer an exercise discipline you are good at.

In other words: if you have a family history of type 2 diabetes, you might be better at sports that include shorter period of intense activity and/or power (e.g. most ball sports, gym work) than at endurance sports (e.g. distance running, walking). Maybe you would you therefore prefer them?

The most important thing is that you love your chosen form of exercise so much that you keep doing it!

*A Wingate test is performed on a specialised ergometer. After warming-up, the athlete starts pedalling as fast as possible. After three seconds the researcher adds a resistance corresponding to 75g/Kg of the athlete’s weight to the flywheel. The athlete continues to go as hard as possible for 30 seconds, and the researcher notes the peak power output.

Disclaimer: If you are new to exercising, please ask your doctor for advice first.This article is for general information only, and does not replace medical advice. It cannot be used to diagnose or guide treatment. If you have any concerns or questions, you should talk to a qualified health provider.

References and further reading:

A Bianco, F Pomara, M Raccuglia et al. The relationship between type 2 diabetes family history, body composition and blood basal glycemia in sedentary people. Acta Diabetol. 2014; 51(1): 79-84.

A Bianco, F Pomara, A Patti et al. The surprising influence of family history to type 2 diabetes on anaerobic performance of young male elite athletes. Springerplus. 2014; 3: 224. doi: 10.1186/2193-1801-3-224. eCollection 2014.

R Khardori, G T Griffing, B E Brenner et al. Type 2 Diabetes Mellitus. Medscape (Accessed on 5/10/2014).

R J Wood and E C O’Neill. Resistance training in type II diabetes mellitus: impact on areas of metabolic dysfunction in skeletal muscle and potential impact on bone. J Nutr Metab. 2012; doi:10.1155/2012/268197.  (Accessed on 5/10/2014).

Altitude training for endurance athletes

© Ichtor | Dreamstime Stock Photos
© Ichtor | Dreamstime Stock Photos

There is no doubt that if you want to compete at altitude, you will first have to acclimatize to the lack of oxygen. If not, you will probably not perform as well as you could and you will certainly put your health at risk. However, does training at altitude help you to perform better at sea level? The jury is still out…

Lorenzo Pugliese and colleagues have published the latest article about this question in the September issue of the Journal of Sports Science & Medicine. It is an observational study of two elite endurance athletes, a race walker and a marathon runner, who used altitude training as part of their preparation for the Athens Olympic Games (2004). As both of them obtained gold medals, it must have worked for them, even though we do not know for sure what would have happened if they had stayed at sea level.

Even though altitude training is popular between endurance athletes and coaches, it is still controversial between scientists. In theory it should work of course: as the air pressure is lower at altitude, your body learns how to use oxygen more effectively, what then allows you to perform better when you are back at sea level. The best known effect is an increase in red blood cells, and thus in haemoglobin mass, although there are also adaptations at the level of the muscles and the mitochondria. This increase is triggered by the hormone erythropoietin or EPO, which is produced by the kidneys. However, some people produce less EPO than others and there are therefore important inter-individual differences between the effects of altitude on athletes.

Training hard and altitude

If you want to win endurance races, you need to be able to train at fast paces. Running fast for a long distance is difficult to do at altitude when you are not used to it, as your muscles need more oxygen than you can deliver to them. This is even more so for elite athletes, whose muscles are trained to perform at an optimal level. If you do not train intensively enough for a period of a time, your muscles become detrained, and anything you might have gained by improving your oxygen metabolism will be useless.

While you are acclimatizing, you will face some other problems:

  • Sleeping can be difficult as you are short of breath.
  • As soon as you arrive at altitude, your plasma volume (=the water part of your blood) will decrease, as your body wants to increase the red blood cell concentration and producing new red blood cells takes some time.
  • The air is colder and drier which can easily lead to dehydration.
  • As your muscles cannot extract as much oxygen from your blood as they do at sea level, your VO2max is in effect reduced. Running at the same speed as at sea level will therefore mean working at a higher level of your VO2max, which will feel harder.
  • You are more vulnerable to infections.

All these factors will make it difficult to train at the required level during the acclimatization. Once you are used to the altitude the situation will improve, but in the meanwhile you might have lost valuable time and your legs might have lost speed.

Athletes and coaches have therefore developed live-high-and-train-low camps, whereby they live at altitude and train at lower level. Alternatively, they might do live-low-and-train high camps, whereby they perform some of their sessions at altitude to have an additional training stimulus.

 Olga Vasilkova | Dreamstime Stock Photos
Olga Vasilkova | Dreamstime Stock Photos

Reasons for the controversy

Studies about altitude training contradict each other, whatever formula they use (live-high-and-train-high, live-high-and-train-low or live-low-and-train-high). It is of course possible that athletes and coaches have noted some benefits that are too small to be measured by scientists. As major championships are won or lost by seconds, such very small benefits can make a big difference indeed.

It more likely that the controversy is due to a lack of control groups: in a good study you would compare similar athletes doing the same training at altitude as at sea level, and you would take into account that some people do not react as well as others. In practise such a study is very difficult and expensive to conduct. To complicate matters even further, there could be a placebo effect, as most athletes believe that altitude training is beneficial.

Lorenzo Pugliese’s athletes followed a live-high-and-train-high program. However, they were able to train at the same running/walking pace as at sea level and, according to Pugliese, this is the reason why the camp worked so well for them. Both of them had extensive altitude training experience and that might well have been the reason for their success. Maybe a three week camp so now and then is simply not enough, and you might need to live for a long time at altitude to reap the benefits? This would explain why so many top endurance athletes are born and/or live at altitude. Bad news for all of us who live at sea level though…

References

D M Bailey and B Davies. Physiological implications of altitude training for endurance performance at sea level: a review. Br J Sports Med. 1997; 31:183-190.

L Pugliese, FR Serpiello, GP Millet et al. Training dairies during altitude training camp in two Olympic champions: an observational case study. J Sports Sci Med. 2014; 13(3):666-672. eCollection 2014.

Strength after endurance or endurance after strength training?

All endurance athletes (runners, cyclists, cross-country skiers…) need some strength training. Personally, I prefer to train for endurance and strength on separate days, but for many of us it is more time-effective to combine the two in one session. If that is your case, what do you do first?

© Phil Date | Dreamstime Stock Photos
© Phil Date | Dreamstime Stock Photos

This is an important question, as research has shown that endurance and resistance training lead to different adaptations. Strength training leads to increased muscle mass, while endurance training will allow you to use the available energy and oxygen more effectively and exercise for longer. If you combine both in one session, you will not have any recovery between them and it might be impossible for your body to benefit fully from both. If so, the order in which you do them (first endurance and then strength or the other way around) is important.  Getting it wrong could make a big difference.

Most, if not all, runners I know will start by endurance exercise, and according to Moktar Chtara and his colleagues that is indeed the right thing to do. They divided 48 young men in five groups. The first group performed endurance training only, the second strength training only, the third endurance plus strength and the fourth strength plus endurance workouts. The fifth group did not train and served as a control group. After 12 weeks the endurance plus strength group outperformed every other group during a 4 km run time trial, and their VO2max had improved most.

In the September issue of Medicine & Science in Sports and Medicine however, Moritz Schumann and colleagues published a study suggesting that this does not matter for cyclists. They divided 34 young men in two groups, one of which performed endurance plus strength workouts and the other strength plus endurance. The endurance part of the sessions consisted of cycling, and the strength part of exercises for all the major muscle groups but mainly for the legs.

Both groups improved in strength, VO2max and time to exhaustion, but after 24 weeks there were no significant differences between the groups. The researchers concluded that as endurance cycling is biomechanically similar to many of the strength exercises, they could enhance each other’s effect. Running is of course different.

Surprisingly, Schumann could not notice any significant reduction in body or visceral fat, or in cholesterol levels. Studies whereby the participants perform strength and endurance workouts on separate days on the other hand, typically do show improvements.  The researchers could not really explain this discrepancy: did the participants not train frequently enough (as they did two sessions worth in one go)? Only further studies can figure this out…

In the meanwhile, I’m going to continue planning my endurance and strength workouts in separate days.

References

M Chtara. K Chamari, M Chaouachi et al.  Effects of intra-session concurrent endurance and strength training sequence on aerobic performance and capacity. Br J Sports Med. 2005; 39:555-560.

GA Nader. Concurrent strength and endurance training: from molecules to man. Med Sci Sports Exerc. 2006; 38(11):1965-1970.

 M Schumann, M Kuusmaa, RU Newton et al.  Fitness and lean mass increases during combined training independent of loading order. Med Sci Sports Exerc. 2014; 46(9): 1758-1768.

Do we snack because we are bored?

Several studies have shown that television watching makes you snack more, which is very dangerous for your waistline, while others have found no effect. Could this discrepancy be due to the content of the programmes? If so, choosing your programs wisely would help you to keep your weight under control.

© Kmitu | Dreamstime Stock Photos
© Kmitu | Dreamstime Stock Photos

It is possible that your mood, in particular your level of boredom, could influence how much you are eating. To check this out, Colin Chapman and his colleagues compared how much 18 normal-weight women snacked when watching an engaging comedy program, with what they ate looking at a boring lecture or reading a boring text. The snacks consisted of grapes and M&M chocolates.

The women snacked significantly less during the engaging television program than during the boring one or while reading the boring text. There was no real difference between the amount snacked while reading or watching something boring.

Previous studies have already shown that obese people tend to eat more when bored, but now more and more researchers think that everybody does so. Moreover, if Colin Chapman is right it would mean that being bored by other means than television watching (in this experiment: reading) is just as bad.

The researchers also noted that when bored the women snacked more on grapes than on chocolates. When captivated however, they had relatively more chocolate. They suppose that when the women had more time to choose, they went for the healthy option. Even so, they took in more calories than when they were captivated.

Of course, this experiment was conducted in a lab and the women might behave otherwise when at home. The researchers did not check what the women ate after the experiment and we therefore do not know if there was any effect on the size of their meal.

We do not know either what the women were used to do. Habits are powerful, and if you are used to snack while watching television or if you associate snacking with having a good time, you will find it harder to control it.

Even so, if you want to keep your snacking under control, you should avoid boring stuff… Alternatively, you could make sure that there are no snacks available when you have boring things to do, which is probably a more realistic solution.

References

CD Chapman, VC Nilsson, HA Thune et al. Watching TV and food intake: the role of content. PLoSOne. 2014; 9(7): e100602. doi: 10.1371/journal.pone.0100602. eCollection 2014.