Stretching: Pros and Cons

Researchers at the University of Sydney in Australia reviewed the world's literature and concluded that stretching does not prevent muscle soreness that follows vigorous exercise (1). Athletes train by taking a hard workout, feeling sore the next day, and then taking easy workouts for as many days as it takes for the soreness to go away. Since stretching does not reduce muscle soreness, it does not help you to recover faster from hard exercise. The best way to recover from exhausting competition is to move with little pressure on muscles, such as cycling on a stationary bicycle (2).

Stretching does not prevent injuries (3). Muscles and tendons tear when the force applied to them is greater than their inherent strength. Anything that makes a muscle stronger helps to prevent injuries, but stretching does not make muscles stronger or faster.

Even though most high school and college coaches have their athletes stretch before games or races (4), you should not stretch before competition because it decreases muscle strength (5) and impairs your ability to run fast (6).

However, stretching can make you a better athlete. Muscles attach to bones by long fibrous bands called tendons. Stretching lengthens tendons, and the longer the tendon, the greater the force a muscle can exert on a joint (7). So stretching a tendon to make it longer allows an athlete to exert more force around a joint to help him jump higher, run faster, lift heavier or throw further (8).

References:
(1) Cochrane Database of Systematic Reviews 2007, Issue 4
(2) American Journal of Physical Medicine & Rehabilitation, June 2007
(3) Clinical Journal of Sport Medicine, March 2005
(4) Clinical Journal of Sports medicine, May 2006
(5) Journal of Bodywork and Movement Therapies. April 2006
(6) Sports Science, May 2005
(7) Journal of Sports Science, February 2006
(8) The American Journal of Sports Medicine, February 2006

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Lose weight with diet?

A new study from Israel shows us once again that dieting without exercise does not work. The participants took off only 6 to 10 pounds in two years. No matter what diet they were on, most regained some of the weight they lost in the early months by the end of the study (NEJM, July 17, 2008). It didn't make any difference whether the overweight person was on a low-fat or low-carbohydrate diet, or diet that stresses fruits, vegetables, whole grains beans, seeds, nuts and seafood. However, their small weight loss did result in improved cholesterol and blood pressure readings.

If we really want to lose weight for good, we have to exercise. Appetite is controlled in a part of our brain called hypothalamus. If we try to lose weight just by eating less food, our hypothalamus makes us miserable when we see tasty food and know that we shouldn't eat it. If we exercise, we will eat more, but we will not increase our intake of food to equal the extra calories that we burn when we exercise. After we have been exercising for a few months, our muscles will be stronger, we will feel and sleep better and we can actually start to enjoy our new activity. Then we are set for a life-long pattern of burning up the calories that we take in.

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Heart at exercise

A healthy heart is so strong that it is never a cause of tiredness during exercise. Tiredness during exercise comes from our muscles, when they are running out of fuel or out of oxygen. Skeletal muscles use both fat and sugar for energy. When our muscles run out of their stored sugar supply, called glycogen, they cannot contract and function adequately. We will then feel tired, our muscles hurt and we will have difficulty coordinating them.

On the other hand, our heart muscle gets energy directly from fat and sugar in our blood and even from a breakdown product of metabolism called lactic acid. It is virtually impossible for the heart muscle to run out of fuel unless we are starving to death. It is also impossible for a healthy heart to run out of oxygen. Oxygen comes to the heart through arteries on its outside surface. If these arteries are not plugged up with plaques, they are large enough to supply all the oxygen that the heart can possibly need. However, fatty plaques in arteries can block the flow of blood. When the heart does not get enough blood, it will hurt and can start to beat irregularly.

Exercise can't hurt a healthy heart. If we develop heart pain during exercise, something is wrong and we need to check with a medical doctor immediately.

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Life starts at 30...

One of the most unique birthday cards that I had ever received was that from the gym that I first joined years ago. It was just a normal card in fact, nothing fancy. When I first received it, it read "A man's life starts at 30." I said to myself that I wasn't 30 years old, and thus didn't give it much of a thought. But when I looked further, the number "30" wasn't referred to the age but the waistline! Wow, I was impressed!

As years went by, this phrase has become my personal motto in fitness. Every time I workout, I always have it in mind. Some people drop out from exercising because they see no direction to where they are going. However, when we have a goal or direction in doing what we do, it'll keep us motivated and going, and combating, ha ha!!

Many of today's civilized diseases, or what we called "wealthy diseases" in life insurance, are caused by overweight or obesity. High blood pressure, diabetes, high cholesterol and triclycerides, almost all of these diseases can be avoided or reduced by watching our weight. These diseases are not fatal by themselves. For example, no one dies because of diabetes itself. However, it's because of diabetes, if not treated, people become blind, suffer kidney disease, undergo lower limb amputation, have nerve damage and suffer heart diseases and stroke. Any one of these complications requires long-term financial support. To stay alive, one has to take consistent and regular medication and supervision, and this involves money. That's why we sometimes call them as "wealthy diseases," for we need to be wealthy in order to live together with them.

Many people that we know are overweight or obese. Are they lazy people? Or are they immune to all these diseases? For me, I don't think so. Look at them. They work hard everyday in the office. When we are exercising in the gym or sleeping at night, they are probably still working in the office. To them, they have different priority in their life. They want to earn money, earn more money, and earn much more money. They say we don't work hard. We say them workaholics. Who is right? Who is wrong?

This is something that I personally think we should ponder from time to time. If you can't strike a balance between health and wealth, what good if you've lost your health and can no longer work for your wealth? Which company is so kind to employ a kidney failure patient who needs to go for dialysis 3 times a week and can thus work only limited hours in a week?

I've witnessed many cases where people work hard for more money, but at the end using that hard-earned money to pay their medical bills. Is that what we want? Is that why we work, working to pay future medical bills?

We are all lucky earthlings. There is no day in our life we ever need to worry if we have food to eat for that day. Rather, we are scratching our head as to what to eat everyday. We eat good. We eat sumptuously. But have we eaten right and balanced too?

Losing some weight is no longer a cosmetic issue. It's more of a health and well-being matter. I always say I'm fat because, well, because I'm fat. Yes, I'm fat and I'm fat, and I want to stay exercising.

I suddenly feel that this post sounds very heavy. I was supposed to make it read lively! My purpose of writing this post is to remind myself that being another year older is not an excuse to work lighter. And with you reading my humble blog, I know I don't walk alone on this road.

A little congratulation to myself for having a blog posting on my birthday at 12:00 midnight sharp, ha ha!

Fitness Basics

I believe nobody is born fit naturally and can remain fit without doing anything throughout his or her lifetime. Fitness requires persistent training and commitment. We will continue to enjoy the benefits of exercising if we stick to it. Once we stop, all the benefits will be gone. Age doesn't matter. It's never too late to start exercise.

If you've decided to start exercise now, or if you're new to exercise, here are some fitness basics that you might want to know:

• The best exercises for fitness are the ones that we can exercise continuously, those that are least likely to injure us and the ones we enjoy the most.

• We become fit by exercising vigorously enough to increase the circulation of blood. It makes no difference to our heart how we increase our circulation. We work harder at higher intensity, we become fitter.

• The best exercises for fitness use our legs because the blood vessels in our legs are so much larger and thus able to circulate far more blood to our body than other body parts. Arm exercises make us tire earlier because most people have weaker arms.

• Some exercises require a great level of fitness just to start. For example, to jump rope, we must spin the rope more than 80 times a minute to keep it from tangling. Many people can't jump 80 times a minute. So, choose exercises that we can take control of.

• For starters, the safest exercises are low-impact aerobics, walking, swimming and pedaling a stationary bicycle. Running causes lots of injuries, because the force of our feet striking the ground can be six times of our body weight, which can damage muscles and bones. (Read my post on Deep Impact on Knees for more information.) Choose appropriate exercise wisely.

• Exercises that don't keep us moving may be fun, but they won't make us fit. For example, the average tennis player spends 80 percent of their playing time waiting for the ball. (Read my post on Are all exercises the same? for more information.)

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Deep Impact on Knees

For those who have been joining my classes since last Friday, I did mention that my right knee actually hurt a little. Not sharp pain or persistent pain, just a little sting on and off. It alarmed me for the need to look after my joints and not to overwork. The pain is gradually subsiding now. If you have been checking every part of my blog, you would have noticed that at the bottom of the page, there is a section about my weekly calories burned. Because I'm fat, I want to make sure that I burn at least 800 Calories per day on average. This requires very strong discipline. Such as when I knew that I couldn't burn up at least 800 Calories on last week due to class cancellation, I ran on treadmill to make up the deficit. I suspected it was the run that hurt my knees. BodyCombat doesn't involve constant and prolonged running and jumping. And after doing BodyCombat for years, we have learnt how to avoid injury. So, the culprit that first came into my mind is the treadmill, ha ha!

In the post of Are all exercises the same?, we have learnt that exercises are different in terms of the capacity in conditioning our heart and lungs. Now, same question again but in different context: Are all exercises the same, this time in terms of the exertion of pressure or impact on our joints, especially the knees?

You have actually known the answer even without me telling. Yes, you are right: Different exercises or activities give different degree of impact or pressure on our knees. We know when we jump, our knees have to absorb more pressure than, say, climbing stairs. But have you ever wondered how strong is the impact actually? Or how much pressure are our knees absorbing?

Human body is such a marvelous thing. Our knees, being so small and look so fragile and vulnerable, have to support our full body weight when we are standing. And when we are moving, they have to, and are capable of absorbing pressures few times greater than that of our full body weight. Here are some examples on how many times our full body weight is put on our knees when we are performing different exercises:

^ Climbing: 3 times the body weight

^ Running: 6 times the body weight

^ Jumping: 9 times the body weight

For example, if we weight 50kg and we are running on the treadmill, our knees have to absorb 300kg (6 x 50kg) of pressure each time we stride! And when we jump and land, that pressure would become 450kg! Wow! Don't play play oh!

Now we know how much pressure our knees are taking with different exercises, we must then learn to appreciate them more. Give them good care and look after them properly. Know our own limits, and obey them whenever possible. Don't do things that will make us regret in the future. If we are overweight, do shred the extra weight off to give our knees lighter load. If we have knees problems, do engage in exercises that are more knee friendly. For me, I make sure myself exercise very regularly, so to maintain the body weight and body fat. What about you?

In a nutshell:

Our body can withstand pressures few times greater than our body weight. However, that doesn't mean we should take it for granted. The heavier we are, the higher the pressure and force our knees have to take. Do exercise some understanding on how hard our body is working, and do something to reduce its load in order to maintain better health and fitness in the long run.

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Are all exercises the same?

Many people do exercise. Some play badminton with their friends, some jog in the park or in their taman, some work out in the gym, and so on. All of these are exercises, as they involve moving our muscles. But, all they all the same? Do they give us the same benefits?

All exercises offer benefits, but different exercises produce different benefits to different body parts. Some types of exercise or activity will improve the condition of our heart and lungs if they are brisk, sustained and regular. The higher the intensity of the exercise, the more it conditions our heart and lungs. Low-intensity activities do not condition the heart and lungs much. But they can have other long-term health benefits.

The table below shows three types of sample activities and how they affect our heart and lungs:

Sample Exercises/Activities and Their Impact On Our Heart & Lungs

Column 1 - These vigorous exercises are especially helpful when done regularly. To condition our heart and lungs, work more than 50% of our maximum heart rate. These exercises can also burn up more calories than those that are not so vigorous.

Column 2 - These activities are moderately vigorous but still excellent choices. They burn lesser calories but still can condition our heart and lungs

Column 3 - These activities are not vigorous or sustained. They still have benefits - they can be enjoyable, improve coordination and muscle tone, relieve tension, and also help burn up some calories. These and other low-intensity activities - like gardening, yard- work, housework, dancing and home exercise - can help lower our risk of heart disease if done daily.

To know how often do we need to exercise in a week, check out my comment on How much calories can you burn?.

In a nutshell:

Different exercises provide different kind of benefits. Know what we want to achieve, and choose the appropriate type of exercise accordingly. Bottom line is, no matter what type of exercise do we choose, do it consistently.

How come some of us don't sweat during exercise?

Before someone asked me about this question, I actually used sweating as one of the indicators to see if we have worked out hard in class. Sometimes seeing people came into my class in dry outfit and walked out the class dry like a baby diaper (Errr… can I describe the scenario like this?), I really wandered if I had done my part for motivating them to work out harder and sweat a little bit more. My outfit was all wet and dripping in sweat, but how come some people could be so "sweatless" and dry?

Then someone left a comment, posted a question actually, in the posting on "Oh my sweat..." I did some research on it and found out the answer. It was then I realized that I was being ignorant on this issue all this time. Again, I realize the power of this blogging stuff again. I brush up my knowledge by sharing with you what I know, and I acquire new and more knowledge by you asking questions and giving comments. Thank you jeandesign for putting up this question and opened my eyes.

OK, sweating during exercise is an "enjoyable" thing. We generally feel very satisfy when we sweat a lot during workout, and often enough will have a sense of achievement for we have worked out hard. The more we sweat, the more we will feel that we have had a better and more productive workout. However, what if we didn't really sweat during the workout? Was that workout a failure? Had we not exercised hard enough for it to be a productive one? Had we wasted our time in the workout? Were our pores "jammed" or clogged and thus unable to perspire? Were we not fit physically anymore?

To clear all these confusions, we'll first look into why we sweat and later, what is going on when we exercise.

Our body is like an engine that never stops running. And like all engines, it produces heat. The more we move our muscles, the more heat is produced. If the body didn't have ways getting rid of the heat and keeping us cool, we would overheat and collapse within minutes. There are four methods how our body uses to keep us cool:

1. The first method is radiation, where heat radiates out of the skin if the air around us is cooler than our body. Factors important in radiant heat loss are the surface area and the temperature gradient or difference.
   
2. The second method is conduction, which is the transfer of heat by direct contact between our body with other objects, such as swimming in a pool of cold water where the water absorbs our body heat. The rate of conductive heat loss depends on the object(s) that the body has in contact with. Water conducts heat away from the body 25 times faster than air because it has a greater density (therefore a greater heat capacity). In other words, we loss body heat 25 times faster inside water than in dry air land. (Now we know why people like to go into water during those hot weather time.)
   
3. The third method is convection, where moving air cools us down, such like when we stand in front of a fan or when the wind blows. The rate of convective heat loss depends on the density of the moving substance (water convection occurs more quickly than air convection) and the velocity of the moving substance.
   
4. The last method is evaporation, where water from our blood absorbs the heat and rises to the surface of the skin through the sweat glands so it can evaporate creating a cooling effect. The heat loss is converting water from a liquid to a gas. Besides using sweat as a way to remove excessive heat from the body, respiration is another way where air is heated as it enters the lungs and is exhaled with an extremely high moisture content.
   

Methods of Body Heat Transfers

Our body produces heat at all time, even when we are sleeping. In colder conditions, we will not need to sweat as much due to the body using radiation to keep cool. In hotter conditions, sweating is the primary method of keeping us cool due to the surrounding air being hotter than our body. But if humidity presents, sweat cannot evaporate as well and that's why we will see sweat dripping off us. Since in these conditions sweat doesn't evaporate, radiation and convection (remember the moving air?) are used by our body to keep cool.

When we exercise in an air-conditioned room like that in our studio, some of us will not sweat as much because the cold air evaporates our sweat faster. It also sets our body up to use more of the radiation method, meaning our body can deal with the heat created by exercise more easily. It does not mean we are not burning as many calories, because caloric burn is determined by intensity and duration of our exercise, not how much we sweat. We are in fact sweating all the time, just that we just can't see it because it is always evaporating. We will sweat more when there are more people in the studio, or when the air ventilation system is poor.

If it were true that the more we sweat, the more calories we burn during exercise, then it would also be true that we would be burning more calories simply by sitting in a hot, humid room so as to build up a sweat. But this is obviously not the case as the sweat we would be seeing is due only to the conditions of the room not allowing for evaporation for cooling the body. That is, staying inside the sauna room and sweat heavily is because our sweat cannot evaporate and run dry, not because it is helping us to burn more calories. This also dehydrates our body.

Everyone has a different sweating pattern. Gender, age, fitness level and environment contribute to how much we sweat. Women seem to sweat less and start to sweat at higher temperatures than men. People tend to sweat less as they grow old and thus cannot take the heat as well as a younger person but declining fitness levels may have something to do with that. In laboratory experiments where both young and old people were of similar fitness levels, there was no notable difference in their sweating process. However, if given same exercise environment, same intensity level, same length of time for exercise, fitter people usually sweat more and start sweating at a lower body temperature. This is because the function of sweating is to cool the body. A physically fit body cools itself more efficient than one that is unfit.

For those of us who sweat a lot during exercise, it is crucial that we drink more water before, during and after the exercise to rehydrate ourselves. I personally consume about 250 ml water before class, 1,125 ml (the size of my water bottle) throughout a class, and another 250-500 ml after class. You guys know I sweat bullets.

In a nutshell:

Exercise helps to produce more heat; more heat produces more calorie expenditure. We produce the same amount of heat whether exercising in a cold environment or a hot one. Therefore, just because we don't sweat as much in the colder environment does not mean our exercise session was less productive. Remember, for more caloric burn, focus in our intensity (heart rate zones) and/or duration of exercise, not in the amount of sweat.

Ice ice water! Ice ice water!

You may or have not heard of it, but drinking ice water, or very cold or chilled water, can really help us to burn some extra Calories!

If you still can recall Physics in secondary school, a Calorie is a unit of energy. Scientifically, it is the amount of energy, or heat, taken to raise the temperature of 1 kilogram (kg) of water 1 degree Celcius (°C). So, when we drink ice water, our body has to heat up the temperate of the ice water to that of our body temperature. In other words, our body has to raise the temperature of the ice water, thus burning calories. If you have doubt, try to drink some ice water and then test the temperature of your urine. Does your urine feel cold or warm?

Now, let’s see how much calories can be burnt when we drink ice water:

• Assume the temperature of ice water at 0°C.
• Our body temperature is estimated at 37°C.
• A standard mug or glass holds approximately 250 millilitres (ml), or grams (g), of water.
• 250 g of water = 0.25 kg of water.
• It takes 1 Calorie to raise 1 kg of water 1°C.

Therefore, to raise 0.25 kg of the ice water from 0°C to 37°C, our body burns 0.25 x 37 = 9.25 Calories!

So, if we drink 8 glasses of ice water a day, which is equivalent to 8 glasses x 250 ml per glass = 2,000 ml = 2 litres = 2 kg of ice water, our body burns 2 x 37 = 74 Calories a day. This figure is actually not very impressive and significant, as it doesn’t even burn off the caloric intake of a tin can of Coca-Cola (143 Calories). Nevertheless, this small effort can contribute a little to enhance our daily caloric burning process. If one day we can burn 74 Calories extra, then that will be 518 Calories extra a week, and 2,220 Calories extra a month.

In a nutshell:

While we definitely shouldn't depend on ice water consumption alone to replace exercise or healthy diets, drinking cold water instead of warm water does burn extra Calories. Take it as an add-on process, not a whole process by itself.

How much calories can you burn?

One of the most popular questions that people like to ask when joining a fitness class is how much calories can the class help them to burn. Honestly speaking, although I would love to answer that question, I really can’t tell it off hand.

All of us are different individuals. We are different in terms of genetics, gender, age, height, weight, body fat, fitness level, metabolism rate, health condition, muscle mass, daily diet, to name just a few. If I tell you that you can burn X amount of calories after joining the class, I am just not painting you the whole picture. Unless you and I share all the same statistics, given the same period of workout time, we don’t burn the same amount of calories.

On the other hand, instead of knowing how much calories can the class help us to burn, maybe we should look into how much calories do we want to burn during our workout. The fact is, the harder we work, the more calories we burn. The question now is, how hard is hard?

To work harder is to work at higher intensity level. And one of the best indicators to know of the intensity level is by referring to our heart rate during the workout duration: More calories are expended, or burnt, at higher heart rate. The following table shows my personal average energy, or calories, expended at different heart rate zones:

My Current Energy Expenditure Table

Let say, for instance, I maintain my heart rate at 50-60% of my maximum during my workout. After one hour of exercise, I can burn about 499 Calories. If I raise my heart rate up to 70-80% of my maximum, then I can burn around 849 Calories for that hour. As you can deduce from the table above, at higher heart rate zone (HR zone), more calories are expended or burnt.

The bottom line is, if we want to burn more calories, we simply need to work at higher intensity level, or at higher HR zone. If we don't want to work too hard but still want to burn that much of calories, what we need to do then is to work for longer period of time. That is, in order to burn about 1,000 Calories, I need to exercise for nearly 2 hours while maintaining my heart rate at the 50-60% HR zone. If I want to burn the same amount of Calories within an hour, I’ll have to work myself harder at the 80-90% HR zone. Alternatively, I can also switch from one HR zone to another from time to time and make up the desired total energy expenditure. For example, I can workout in the 60-70% HR zone for an hour, and 23 minutes in the 70-80% HR zone. So, 674+[849*(23/60)]=999 kcal.

Note:

This Energy Expenditure table is that of my personal reference. It gives me an idea of how much energy, or calories, I’ll expend at each training intensity (in both kcal/min and kcal/hour). From there, I get to know how much to eat (energy intake) before/after the exercise session and find out my personal exercise intensities in HR%. The data in this table changes when I change my weight (in kg), HRmax (maximum heart rate, 220 minus current age) and VO₂max values. The higher the weight, the more calories can be expended. The higher the HRmax (or the younger the age), the more calories can be expended, The higher the VO₂max, the more calories can be expended too. Yours should be different from mine.

VO₂max (also maximal oxygen consumption, maximal oxygen uptake or aerobic capacity) is the maximum capacity of an individual's body to transport and utilize oxygen during exercise, which reflects the physical fitness of the individual. Higher the value, fitter is the person.