Energy Demands of Muscles During Exercise!

Filed under :Exercise

All forms of exercise require the activation of skeletal muscles.  To contract muscle fibers require many physiological conditions, such as energy, oxygen, and removal of lactic acid.

For very brief periods, the energy for muscle contraction can be provided by the energy stored within the muscle itself in molecules such as ATP, creatine phosphate (you may have heard of the supplement Creatine), glucose, and glycogen (storage form of glucose).

More prolonged activity requires increased delivery of oxygen and metabolic fuels (such as glucose and fatty acids) to the muscle from other sources.

Contracting muscle cells produce heat and metabolites, including lactic acid and carbon dioxide, which must be carried away in order for the muscle to continue functioning.  If these metabolites are not removed, muscle pain and fatigue can result.

The proportional use of fuels (carbohydrate, fat, and even protein) during exercise depends on the intensity and duration of the activity.  This means that mix fuels used at the beginning is different than the mix used later on (notice I say “mix fuels” because many have the assumption that during exercise we use either glucose, or fat as energy, in reality we use both but at different proportions depending on the duration and intensity of the exercise).

In a very high intensity, short durations, exercise such as sprints the main source of energy is ATP and glucose these are two sources of energy that can be called on quickly-that is, it does not require oxygen.  With longer durations of exercise a greater proportion of ATP is generated through the breakdown of fat (fatty acids)-involves oxygen.

If you are trying to burn more fat when exercising it is usually recommended to do aerobic activities longer than one hour in a moderate intensity.  The reason behind this is if the intensity is too high you will be using a greater proportion of glucose (from blood, muscle, or liver) rather than fatty acids.  In moderate intensity you will be using greater proportion of fatty acids, sparing glucose.  You should do cardio longer than one hour because the longer you work out the greater will be the switch from using glucose as energy to fatty acids.

After a prolonged aerobic activity you should always consume a high glycemic food (refer to my previous post “Sugar Rush”) to recover glycogen stores in the muscles.  By doing so, you will decrease muscle fatigue, as well as you will have more energy for the next time you exercise!

The “Soy Scare”

Filed under :Food Hypes

You may love it, hate it, or be scared of it.  I will try to make some sense out of this product to make it more clear for all the people out there that enjoy it, or would love to try it, feeling safe doing it.

When you search the web with the keyword “soy” in your search engine you will get numerous articles, forums, and recipes.  Many of these articles may say that soy is one of those super foods, while others will disappoint you with their negativity and bad reputation of soy.

The truth is that soy is not horrible; instead it is a great product.  Some soy products that you may be familiar with are: soy milk, tofu, soy sauce, edamame. It may be also added to many other foods.

One of the biggest assumptions of soy products is that they contain molecules that mimic the female hormone, and therefore men may be scared of it (“may grow breasts”) while women feel like it will disrupt their menstrual cycles.

Estrogen is one of the female sex hormones.  Isoflavones are compounds found in plants that act like estrogens.  Soy is one of those plants that contain isoflavones.  In one study conducted on 34 healthy women (median age 36) the portions were randomized to 40mg or 140mg isoflavones daily for each woman through one menstrual cycle. The result of this study was that they didn’t find any estrogenic effect (Nutrition & cancer, 2009).  The bottom line is that if you occasionally eat soy products (not in a very concentrated form) they will most likely not alter your menstrual cycle and men will not start growing breast tissue.

Due to its high protein and low cholesterol content, soy can be used as a meal replacement or dietary component in weight loss.  There are many studies that support the association of soy consumption and lower body weight.  One study assessed lifetime soy consumption and body mass index (BMI) among 1,418 women.  This 5 year study concluded that higher soy consumption in adulthood was related to lower BMI (European Journal of Nutrition, 2007). It is not clear though whether the source of dietary protein plays a role in the regulation of food intake and body weight, or other potential mechanisms (reduction of appetite, increase in satiety, or glycemic control).

There are actually international soy conferences in which scientists from around the world come together to review their research and new finding about soy.  Some clinical evidence for the health benefits of soy that they mention are: helps lower cholesterol (now a well known fact), cognitive function, anti-cancer properties, anti-inflammatory effects, as well as many other benefits.

When you do your web search you may find all kinds of posts about soy, much of it warnings about its horrible consequences for the thyroid, the brain – you name it. What you won’t find is much of anything resembling solid proof for these claims. There may be some negative aspects to soy, such as allergies (as can be with many other foods) or other compounds that may play a small role on the body, but working some of it into your diet is probably okay, particularly if it’s replacing red meat. Swapping soy-based foods for meat means trading a source of saturated fat and cholesterol for one with polyunsaturated fat, fiber, and some healthful vitamins and minerals almost always a good nutrition deal.  But as with anything, you should not over do it, always remember to keep a well balanced diet, with a variety of foods!

Can EGCG Enhance Exercise Performance?

Filed under :Green Tea - EGCG

In recent years, the chemical composition of green tea has been determined.
EGCG (Epigallocatechin Gallate) is viewed as the most significant active component.
There has been a lot of research looking at the effects of green tea and numerous medical conditions such as cancer and cardiovascular health.

In the search for strategies to enhance athletic performance, researchers began looking at EGCG in the last decade.

There have been several studies done on the effects of EGCG on mice, but only one study done with humans.
  • One study looked at the anti-obesity effect of EGCG in a mouse model of diet-induced obesity – control animals gained twice as much body weight during a 4-week treatment as animals supplemented with 1% EGCG in the diet (International Journal of Obesity, 2005).
  • Another study conducted on mice investigated the effects of long-term intake of EGCG in combination with regular exercise on the development of obesity in mice – This study had found that long term intake of EGCG together with regular exercise decreased body weight gain by 33% on a high fat diet (International Journal of Obesity, 2006)
  • A study done on male cyclists investigated the effects of EGCG consumption on fat oxidation at rest, during sub maximal exercise, and on endurance performance – the study found little benefit in consuming green tea extract on fat oxidation or cycling performance (International Journal of Sport Nutrition & Exercise Metabolism, 2009).

It has been determined that it is safe to consume ~800mg of the green tea extract EGCG per day.  Some side effects that are reported are considered very mild events which include: excess gas, upset stomach, nausea, heartburn, stomach ache, abdominal pain, dizziness, headache, and muscle pain.  More research is needed though for higher dosages, and long term consumption.

The bottom line is that many studies done on mice show positive results for Green Tea-EGCG supplementation, while the only study conducted on human subject showed little to no results to enhance endurance performance.  Currently there is no data investigating the effect of EGCG on resistance training. In conclusion, more research is needed to investigate the effects of supplementing with EGCG and exercise performance.

Timing of eating and working out…

Filed under :Exercise, Health promoting

Exercising in the early hours of the day – There are many benefits to exercising in the morning.  In the morning your body and mind are fresh, after a long day at work you are more likely to find excuses or make other plans rather than exercise.  By working out in the morning you will wake up faster, and be more mentally alert for the rest of the day.

The big question here is whether you should eat breakfast before a morning workout or is it better to go on an empty stomach?

It is supported by many research studies that consuming a pre-exercise meal is the right way to go! The goals of a pre-exercise meal are to supply the body with glucose for use during exercise, and to minimize fatigue during exercise. It is recommended to consume the pre-exercise meal 2-4 hours before the exercise; yet it can be safely eaten as late as 1 hour before exercise.

The meal should be small, easy to digest, and familiar to the individual.  The pre-exercise meal should be: high in carbohydrates, moderate in protein, low in fat and fiber, and moderate in size.  People engaging in early morning activities may want to schedule a very early morning snack or carbohydrate beverage (e.g. fruit juice) instead of skipping everything all together.  The timing and amount of food consumed depends on individual preferences and on the type, intensity, and duration of the workout.

Exercising in the afternoon – Research suggests that your maximum body temperature occurs between 2 – 4 pm, therefore the muscle strength is at its peak and you are going to be less likely to injure yourself. It’s also a time when people are most awake and alert.

You should eat a low glycemic meal 2 – 4 hours before the workout.  You can also consume a high glycemic food about an hour before the workout with some water to maximize energy stores and energy during the workout (refer to my previous post “Sugar Rush” for explanation about glycemic foods).

Exercising in the evening – Research suggests that exercising in the evenings will produce better sleep as well as lower daytime sleepiness for the whole day!  Here again, it is recommended to eat a low glycemic meal 2 – 4 hours before the workout.


Whether you exercise in the morning, afternoon, or evening; you must eat after the workout to replenish muscle glycogen and refuel the body.  It is important to consume both carbohydrates as well as proteins post-exercise.  Many believe they should consume only proteins after a workout which is incorrect; protein and carbohydrates are equally important.

Carbohydrates help replenish the muscle glycogen stores, while protein helps rebuild muscle tissue.  Carbohydrates actually help protein absorption.  It is recommended to eat small frequent meals throughout 2 hours post-exercise (rather than one big protein shake, or one big meal.)

So, what is the best time of the day for a workout? It depends on the individual!  Do you need an extra push in the morning to wake up, do you have your energy peak in the afternoon, or do you need a better sleep and need to reduce fatigue during the day – choose the best time for you.  Always remember to eat before and after the workout! This is a very important part of being physically active, which many tend to ignore or just uncertain about.

If you have any additional questions, concerns, or comments – please let me know 😉

Exercise and Brain Health!

Filed under :Exercise

It is immediately recognized that exercise promotes good health of the cardiovascular, muscular, and skeletal systems; however the field of exercise and cognitive function is not as familiar.

Studies in ageing humans show that endurance exercise is protective against cognitive decline; especially in planning and memory.

It was once believed that the adult brain was incapable of producing new neurons. It is now known that neurogenesis (the process by which neurons are generated) is continuous in adults as well. Moreover, now it is believed that exercise stimulates the production of new nerve cells in the brain.

Research suggests that aerobic exercise in children is associated with higher measures of responsiveness, faster cognitive processing speed, and better academic performance (Medical Science and Sports Exercise, 2008).  Even though level of physical activity can be confounded by other factors such as IQ, social, or economic statues, these finding are very consistent and convincing.

Exercise has also been recently shown to increase brain volume in healthy exercising adults.  In one study researches used magnetic resonance imaging (MRI) to examine brain volume.  People aged 60–79 were randomly assigned to aerobic or non-aerobic exercise groups (1 hour three times a week for 6 months). Adults exercising aerobically showed increased brain volume in frontal lobe regions implicated in higher order processing, attention control and memory (Journal of Gerontology, 2006).

It is believed that in most societies today people are less active than in previous generations.  This could affect the next generations’ cognitive development.  Much research suggests that exercise has an affect on cognitive development, and improvement.  Physical activity during childhood may optimize cognitive development promoting lasting changes in brain structure and function.

Just another great reason for you to exercise; for overall body and brain health!

“Health Logic”

Filed under :Health promoting

In this post I will reverse from my scientific knowledge and focus on the psychological, as well as sociological aspects of lifestyle (as they are equally important).

For instance, there are many different reasons why people eat. Some reasons may be: you might have smelled something cooking that stimulated your appetite; or saw an advertisement of a food that you like; could be of social reasons; maybe you looked at the clock and decided it’s time to eat; and finally perhaps you are actually hungry?  There are many possibilities… If fact, we have so many different motivations for eating that it is easy to forget that the ultimate reason – obtaining nutrition – is a biological necessity (Food is our sole source of energy and raw materials from which our bodies are made.)

Although, our need for food is driven by biological necessity our eating patterns vary and are influenced by other factors (social, emotional, daily routine, etc).  Other behaviors such as smoking and physical activity may be influenced in the same manner.

Recently I have come across an interesting article, “Health logic and health-related behaviors.” The author of this article emphasizes the concept of the “Health logic”, which he defines as the judgmental way that health-related behaviors in everyday activities are understood.  In his article the four behaviors: smoking, eating, drinking alcohol, and exercise are classified as health-behavior related. It is so because they can enhance or damage health as everyday activities, since they are practiced by people as they go about their day-to-day lives.  In other words, people are responsible for their own health in the way they behave on everyday basis.

This takes into account the psychological aspect of eating as well as the other three factors (smoking, alcohol consumption, and exercise).  Many people may focus on “science based” factors of gaining weight or exercise such as: metabolic rate or the genetic aspect of weight gain. Many do not consider the psychological aspect of this issue, which in my opinion plays a very important role in our daily lives.

It is important to take a step back in our day-to-day lives (that are very much a routine for most of us) look at what we are doing right and wrong and maybe ask ourselves some questions – e.g. why am I eating right now? Am I really hungry? Why do I even smoke? By making small modifications for a healthier lifestyle we can make great impact in the long run, and even as soon as tomorrow!

Lactose Intolerance…

Filed under :Health promoting

Most nutrient molecules in our body must be broken down by enzymes in the digestive system before they can be absorbed.

Lactose, “milk sugar”, must be broken down into glucose and galactose (refer to my previous post “Confusion over sugar”) in order to be absorbed in the small intestine. The enzymes that perform this task are found on the surface of the small intestine, they are called lactase.

In certain individuals with a condition known as lactose intolerance, however, this is not the case.  Lactose intolerance develops when the body stops producing the enzyme lactase.  When this occurs a person begins to have trouble digesting lactose and thus, cannot absorb it.

The problem with this is that lactose remains in the intestine, serving as a nutrient for bacteria that normally live there.  Lactose stimulates bacterial growth and the resultant production of gas and other waste products.  These substances irritate the lining of the intestine and cause bloating, discomfort, and diarrhea.

Lactose intolerant individuals experience these symptoms after drinking milk or eating other daily products and therefore eventually learn to avoid them.

Lactose intolerance has a genetic basis and is more prevalent among certain people.  It has been estimated that this condition affects over 50% of adults worldwide.

Although there is no cure, new commercial products that allow affected individuals to indulge their taste for dairy products include pills containing enzymes that can break down lactose, as well as lactose-free milk.

Night Munchies…

Filed under :Health promoting

The simple lifestyle phenomenon of night eating defined as ‘getting up at night to eat’ is a habit that many may possess.

In a recent study, researchers examined the association between the habit of eating at night, and the 5-6 year preceding subsequent weight changes in a middle-aged population.

This research found that women with night eating habits experienced an average 6 year weight gain of 5.2 kg (11.5 lb), whereas only 0.9 kg (2 lb) average weight gain was seen among women who did not get up at night to eat.

Night eating and weight change were not associated among men (very surprising to me).

Eating at night is generally not recommended, and I personally consider it to be a bad habit.  The night eating behavior often results in “morning anorexia” (minimal or no calorie intake at breakfast), evening hyperphagia (at least 50% of daily calorie intake after the evening meal) and insomnia.

As any bad habit, night eating is possible to change with small effort and lots of will-power.  This small lifestyle change is beneficial in the long run. Preventing wait gain (especially in women), “promoting” breakfast, as well as eliminating random night time awakening, giving you a better sleep!

The chronically dieting women…

Filed under :Exercise, Health promoting

For most healthy women, “going on a diet” for a designated time should present few, if any, nutritional or long-term health problems.  However, serious health problems may arise for active females who chronically diet or restrict energy intake while expending high amounts of energy in exercise.

If an active female constantly restricts energy intake, it is almost impossible to get adequate nutrients (protein, carbohydrate, fats, vitamins, and minerals).  For example, If not eating enough protein, the body will not be able to maintain and repair muscle tissue and to cover the cost of any protein used for energy during exercise.

Many active females avoid fat either for weight loss or because they think fat is bad for their health.  If fat intake is too low (<10-15% of energy intake), the intake and absorption or the fat-soluble vitamins and essential fatty acids may also be low.

With poor energy intake, many complain of fatigue, frequent injuries, irritability, etc. In this situation, you should either increase total daily energy intake and/or decrease total energy expenditure (less exercise).

Chronic energy restriction can result in decreased bone density, impaired immune response, menstrual dysfunction, anemia, poor exercise performance, and increased recovery time from injury.

Another effect of constant dieting is that it lowers the metabolism rate (more accurately, resting metabolic rate).  This means that the total daily energy expenditure is reduced in people who chronically restrict energy intake.  This decrease is compounded when heavy physical activity is combined with low energy intakes.

It is important to keep healthy energy statues.  An adequate intake of macronutrients is important as well as micronutrients for optimal health and fitness.

Dietary supplements-Vitamins and minerals…

Filed under :Food Hypes, Health promoting

Dietary supplements – a very confusing and mysterious subject for many.  People might use supplements for a number of different reasons.  Some top reasons may be to: improve overall health, prevent/cure a disease, or because they heard about it from family/friend/media, etc. Majority of people believes that even if they are not using dietary supplements now they should start using them. The reason behind this is that people think that supplements are a part of a healthy lifestyle, or are necessary to maintain good health. However, this kind of philosophy is not very accurate.

The following are some reasons why you should be using dietary supplements: if you are trying to conceive, are pregnant, have a food restriction (e.g. vegetarian, don’t eat milk products, restricting calorie intake, etc), or are an elderly person. For healthy adults who eat a healthy diet with a variety of foods there should be no need to be consuming dietary supplements. I personally see it as a pure waste of money.

As an example, let’s look at vitamin C.  Did you know you can get your daily recommended dosage of vitamin C from eating just one orange (as well as many other fruits or veggies)?  Vitamin C is a water soluble vitamin; therefore any extra that your body doesn’t need it will dispose of through urine (the same applies to the B-complex vitamins). Too much vitamin C (over 10,000mg in one serving) can actually be toxic to the body and have a free radical-like effect.

The dietary supplements are not evaluated by the U.S. Food and Drug Administration (FDA) – therefore, there is basically no regulation of the manufacturing and the claims that are made on the supplements.  If you decide to use a dietary supplement after all, always choose one that has been at least tested by a “Third Party Evaluation” (independent testing to evaluate quality control issues such as: labeling accuracy, purity, strength, and ability to dissolve). Here are some reliable links to “Third Party Evaluation” (much of the information found online is misleading and incorrect, however these are authoritative sources).

If your body is deficient in a certain vitamin or mineral it will have a tendency to absorb it even better (from the food you eat).  If you are already getting all the necessary vitamins and minerals that your body needs (from food) it will usually decrease absorption of these substances.  Therefore, by taking extra vitamins and minerals in the form of dietary supplements there is a great chance that your body will not absorb all those exaggerated quantities. As a side note, when these supplements are made in factories the manufacturers try to compress as much as possible into one pill to make it as small as possible in order to make it easier for a consumer to swallow. This compression decreases the likelihood that the pill will dissolve in the stomach and get absorbed in the intestine. Alternatively, consuming vitamins and minerals from natural sources will result in better absorption by your body.

In conclusion, you should really focus on eating a healthy diet, including all the “food groups” and trying to get at least 5 servings of fruits and veggies per day (different colors will give you diverse nutrients).  You should only start supplementing your diet if your health care provider or dietitian suggested you to do so. If you still choose to use supplements, use ones that have been evaluated by a third party and never think that you can substitute a good, healthy diet with supplements. Good diet, sufficient sleep, and regular exercise – are still your best sources for optimal health!

This was just a very general supplement discussion, if you have a question about a specific vitamin, mineral, ergogenic aid, or supplement – please let me know and I will be happy to discuss it.