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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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Do you eat before or after your run?

Many long distance runners perform at least some of their long runs in a fasted state (for example before breakfast, without taking anything), hoping that this will teach their bodies to become more effective at using fats for energy production. Even though it is not sure that it helps on race day, studies have shown indeed that you become better at burning fats if you train your body to do so.

© Mikhail Shifrin | Dreamstime Stock Photos
© Mikhail Shifrin | Dreamstime Stock Photos

The next question is then: would it help you to lose weight? In other words: would you lose more fatty tissue when you exercise in a fasted state than after a meal? Brad Schoenfeld and his colleagues have investigated this and concluded that it does not seem to make a difference. They published their study in the Journal of the International Society of Sports Nutrition in November 2014.

They divided 24 young female volunteers in two groups. One group exercised in a fasted state and the other after consuming a meal replacement shake. They all worked out on a treadmill three times a week at 70% of their maximal heart rate and followed the same diet with the aim to slim down. The women who started by exercising had their shake immediately after the workout.

After four weeks, all the women had lost weight, but there were no differences between the groups concerning amount of weight lost, waist line, lean or fat mass.

The researchers therefore concluded that it does not matter whether you exercise before or after a meal.

Schoenfeld explains the findings by citing previous research showing that our bodies change what they use as fuel, depending on what is available. If you burn more fats for a while, you will use more carbohydrates later in the day, and you have therefore to look at much longer periods than just a few hours.

You might understand their findings better if you think about the First Law of Thermodynamics, which states that energy does not get destroyed or created, but only changes from one form into another. What matter is therefore to get rid of the excess energy, whatever the form it is in.

A study with a negative result?

It is true that reading a study with a negative result is always slightly disappointing, and that is why in the past they did not get published. It is great that this now changing, because it might avoid repeating the same studies over and over again and it might also help us (I hope!) to avoid doing useless things.

Disclaimer: this article is for general information only, and does not replace medical or coaching advice. It cannot be used to guide treatment or training. If you have any concerns or questions, you should talk to a qualified health provider.

References:

Schoenfeld B J, Aragon A A, Wilborn C D et al. Body composition changes associated with fasted versus non-fasted aerobic exercise. J Int Soc Sports Nutr. 2014; 11 (1):54.

Spriet L L. New insights into the interaction of carbohydrate and fat metabolism during exercise. Sports Med. 2014; 44( Suppl 1): 87.

Stannard S R. Ramadan and its effect on fuel selection during exercise and following exercise training. Asian J Sports Med. 2011; 2(3):127.

Van Proeyen K, Szlufcik K, Nielens H et al. Beneficial metabolic adaptations due to endurance exercise training in the fasted state. J Appl Physiol (1985). 2011; 110(1):236.

Could exercising make you eat more?

Many people exercise in order to lose weight or to keep it under control, but does this make sense? It is beyond doubt that regular exercise will improve your health and well-being, but could it make you hungrier, and therefore make you eat more? If so, it would not make any difference for your waistline…

© Andre Maritz | Dreamstime Stock Photos
© Andre Maritz | Dreamstime Stock Photos

In the November 2014 issue of Nutrients, Stephanie Howe and her colleagues published a review article discussing what we know today about this subject. There are still plenty of questions left, especially concerning women, as most studies have been done on men. Studies on women are indeed much more difficult to conduct since oestrogen influences appetite, and researchers therefore have to control for the menstrual status.

Stephanie Howe and her colleagues explain how hormones influence our appetite, and how exercise influences these hormones. They then discuss several studies which have investigated this problem, and finally they look at the impact of diet.

They come to the conclusion that if you are sedentary, an acute bout of exercise is likely to make you overeat. However, as you become well-trained, your body becomes better and better at matching your energy intake with your expenditure.

They also note that as intense exercise suppresses your appetite more, you have to pay attention to what you are having after hard workouts: you could be tempted to eat too little or too late, which will delay your recovery.

Their article is free for all to read, and I will just try to make a summary in lay terms.

What determines your appetite?

Appetite is very complex and influenced by a long list of factors, such as gastric motility, the status of your energy reserves, temperature, dehydration… Your brain receives all this information via hormonal and neural signals, integrates them and then stimulates or suppresses your appetite.

The involved hormones can roughly be divided into two types: tonic circulating and episodic hormones.

The tonic circulating ones reflect your energy reserves and suppress your appetite when your energy stores are full, and are thus more involved with long term regulation. The best known ones are insulin and leptin.

The episodic hormones on the other hand are involved in short term appetite. Most of them are gut hormones and are released when you are eating or just before a meal. They suppress appetite, except for ghrelin, which makes you feel hungry. As their levels depend on what you are eating, it is easy to see why some diets make you feel fuller than others. Foods rich in fibres for example, will allow you to take in fewer calories without feeling hungry.

As mentioned earlier, oestrogen and progestogen also influence appetite, which explains why many women tend to gain weight during the menopause.

All these hormones act on the hypothalamus (an organ in your brain), which integrates the information and controls your appetite. Despite this sophisticated system, other factors, such as the sight and smell of food, cultural and social elements or the time of the day, also influence your desire to eat and can even override the hormonal influences.

Working Up Sweat (ID: 74747)
© Vlad | Dreamstime Stock Photos

Studying appetite

Researchers who want to study the influence of exercise on appetite therefore have to measure the amount of the appetite hormones in your blood as well as your desire to eat. The first can easily be done by a blood test, and the latter is often done using a visual analogue scale (VAS) or by measuring what the participants eat at a buffet in the research centre. A visual analogue scale typically consists of a series of numbered boxes (e.g. from 1 to 10), where the first and the last ones correspond to the extremes (e.g. “I’ve never been so hungry” and “I couldn’t eat anything at all”). You can then mark the box that corresponds best with how you are feeling.

Appetite hormones and exercise

A bout of aerobic exercise decreases your appetite by influencing your gut hormones. This effect is more pronounced in weight baring and more metabolic demanding exercise, such as running, than in non weight baring exercise.

Intense exercise influences the hormones more than moderate exercise. This suppression is only temporarily, but it can be enough to interfere with your next meal, and therefore with your recovery. This explains why it is so hard to eat anything solid after a race!

Resistance exercise on the other hand, does not seem to have an influence.

Are you really eating less?

It is not because your hormones are suppressing your appetite that you will eat less. As I am sure you know by experience, you can override your appetite if the food looks nice or if you believe you have good reasons to eat (e.g. I have spent a lot of calories, I need some comfort after all this hard work…).

© Ragne Kabanova | Dreamstime Stock Photos
© Ragne Kabanova | Dreamstime Stock Photos

Most studies looking into energy intake after exercise do so by measuring what the participants eat at a buffet offered by the researchers. This does not necessarily simulate real life and might therefore lead to false conclusions. Even so, there is evidence that trained people are able to match their energy intake to what they have spent, and can therefore maintain a healthy weight. Sedentary people however, are more likely to overeat after an acute bout of exercise.

Diet

Most athletes are health conscious and will choose a diet rich in fruit, vegetables, whole grains etc…Such a diet will contain fewer calories per volume than an unhealthy one. It will also make you feel full much earlier. For the vast majority of us this is excellent news, but the combination of a low calorie diet, intense exercise and appetite suppression can become a trap for some athletes. It can lead to a chronic negative energy balance, and is more often seen in women engaged in sports for which being lean is an advantage, such as long distance running. It can lead to menstrual disorders with all their complications: poor bone health, injury, illness…

Recovery

If you want to recover quickly, you have to refuel as soon as you can. This can be difficult if your appetite is suppressed. Other factors such as fatigue, dehydration, an elevated core body temperature or gastrointestinal problems can make things even trickier. A good recovery drink can help you out though, as drinking is much easier than eating.

 

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.

Choose chewier food to eat less

A mounting amount of evidence shows that eating with smaller bites and keeping your food for longer in your mouth makes you take in fewer calories. However, as all these studies have been done under standardised conditions in labs, it is not clear how you could do this in daily life. How can you keep taking smaller bites and keeping food in your mouth for longer while chatting or watching television?

© Max Blain | Dreamstime Stock Photos
© Max Blain | Dreamstime Stock Photos

In her latest article on the subject, Dieuwerke Bolhuis suggests choosing harder foods, which will need more chewing, to achieve just that without having to think about it.

Bolhuis and her colleagues asked 50 volunteers to have a meal of harder foods and one of softer foods for lunch on two different days. The volunteers ate as much as needed to feel “pleasantly full” while the researchers filmed them to determine their bite size and the time it took them to chew and swallow the food. The volunteers were invited for dinner on the same day as they had lunch. They could again eat as much as needed, and the researchers calculated the amount of energy they were taking in.

Eating harder foods indeed forced the volunteers to take smaller bites and chew longer, and led to a 13% lower energy intake. They did not compensate for this at dinner, which means that had eaten substantially less over the day without noticing any difference.

Click here to see the results as a graph: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3973680/figure/pone-0093370-g002/

If you could keep having about 13% less energy a day, you would quickly lose weight indeed. Moreover, the harder or chewier foods are often the healthier ones as well, as they are likely to be less processed or to contain more fibre. Unfortunately we do not know yet whether this can go on day after day: would your body end up compensating by eating more?

Anyway, it is certainly something to try out.

Disclaimer: 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:

DP Bolhuis, CG Forde, Y Cheng et al. Slow food: sustained impact of harder foods on the reduction in energy intake over the course of the day. PloS One 2014; 9(4): e 93379. doi: 10.1371

Low volume, high intensity interval training

sprint

Keeping fit or becoming fitter by regular exercise is important if you want to stay healthy. The usual advice is to perform at least 150 min of exercise a week, but could shorter, more intense workouts be just as good or even better? This is an important question, as for most people lack of time is a real issue.

Competitive athletes of all levels use interval training, -together with continuous workouts-, as it improves their fitness more and quicker than continuous endurance exercise. It is also less time consuming. Interval training sessions consists of bursts of intense exercise (e.g. 3 to 5 min at 85 to 90% of your maximal heart rate) followed by short periods of easy exercise.

Low volume, high intensity interval training or HIIT takes the idea of saving time a step further. It consists of 3 or 4 bursts of 30 sec “all out” exercise at your absolute maximum, with about 4 min of easy exercise after each burst. This session is typically repeated 3 times a week. Even though each HIIT session is preceded by a thorough warming-up and followed by a cooling down, it would typically take only about 3 x 25 to 30 min = 75 to 90 min a week, and it could therefore be a solution for sedentary people who are short of time.

However, there is a problem: going all out for 30 sec is much harder than you imagine. In labs, volunteers usually require plenty of encouragement and most of them feel nauseous or light headed. Moreover, it is likely to put you at a higher risk of injuries, and it is not sure yet if it is safe for people with health problems. Scientists have therefore wondered if a longer exercise burst at a slightly lower intensity would be easier to manage.

Low volume HIIT sessions are usually performed in labs, using specialised material. It is therefore not clear yet if these sessions could also be done without equipment, e.g. by running in your local park.

Helen Lunt and her colleagues have investigated just that, and published their results in January 2014.

English: Fitness trail station, North Bay Park...

49 previously sedentary volunteers were divided in 3 groups. One group, called “walk”, performed 30 minutes of continuous endurance exercise by walking. Another group, “ait” undertook an interval training session by jogging or running for 4 minutes at 85- 95% of their maximal heart rate followed by 3 minutes of easy walking. They repeated this 4 times per session. The last group, “mvit”, ran all-out for 30 sec up a slope at maximal volitional intensity, followed by a 4 min of easy walking. They started off by doing this exercise burst 3 times, and tried to increase the number of repetitions per session. All the participants warmed up before their workout and cooled down afterwards, and performed 3 workouts a week. All the sessions were hold at a public park and supervised by the researchers. The aim was to keep going for 12 week and to compare the VO2max of the participants before and after this period. VO2max is a measure of your aerobic fitness, and higher values are indeed linked to better health and longevity, even in overweight or obese people.

Unfortunately, 1 participant of the walk group, 3 of the ait and 4 of the mvit group had to drop out because of injuries related to the exercise.

At the end of the 12 weeks, the ait group had improved their VO2max more than the walk and mvit groups. The walk group had experienced the least adverse effects, as only one the participants had to stop.

The researchers concluded that interval training can help you to improve your fitness without spending as much time as you would if you performed continuous endurance training, but it comes at a price: your risk of being injured is greater. The results of the mvit group were disappointing, but this might be due to the fact that so many of them dropped out. Moreover, the time gained was not that important: in practice the walk group ended up by working out for 116 min week, the ait group 74 min and the mvit 46 min.

Could interval training help me if I’m sedentary?

Interval training can indeed improve your fitness quicker than continuous training, but it comes at a price: it is much harder work. Moreover, it might not be safe for people with health problems, and you should therefore first check with your doctor to see if it is ok for you. As it is hard work, it is better to do it under supervision by a fitness professional, who can make sure that you work out at the right level and who will encourage you.

Is low volume HIIT useful even if I’m used to training?

Most athletes are reluctant to change a training schedule that works, and there are therefore not many studies evaluating low volume HIIT. Moreover, as they do many different sessions, it is difficult to find out if improvements are due to the low volume HIIT or to another part of their training schedule.

If you are a competitive athlete, you are probably used to interval training. A proper low volume HIIT session however, is very hard, and might be too hard to do without continuous verbal encouragement from your coach. As always, everybody is different, and you have to find out what is best for you.

Disclaimer: this article is for general information only, and does not replace professional 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:

A P Bacon, R E Carter, E A Ogle et al. VO2max trainability and high intensity interval training in humans: a meta-analysis. PlosOne. 2013; doi 10.1371/journal pone.0073182

M J Gibala, J P Little , M J MacDonald et al. Physiological adaptations to low-volume, high-intensity interval training in health and disease. J Physiol. 2012; 590(Pt5): 1077-1084.

H Lunt, N Draper, H C Marshall et all. High intensity interval training in a real world setting: a randomized controlled feasibility study in overweight inactive adults, measuring change in maximal oxygen uptake. PLoSOne. 2014; 9(1): e83256.

 

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