Three Energy Systems = One Fine Machine

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Hello everyone,

Today we will be looking at the three energy systems we use for our daily activities (this will be a very general look at the systems. If you’d like more info on anything, please leave a comment so I can follow-up). Today’s article will not have much of a practical component to it, but more educational. We’ll apply this education to next week’s applicable article.
Let’s get right into it!

ATP
Adenosine Triphosphate is the molecule that our body uses as energy. One of the three phosphate (P) molecules breaks off; resulting in an adenosine diphosphate (ADP) molecule, a phosphate ion, and energy. It is this energy we use for nearly all the processes in our body.

Aerobic System – Our highly efficient but slower system
We’ll start with the aerobic system. Even though it is the most complex, it is the easiest to sum up, because most of us have a general sense of what’s involved. “Aerobic” implies that oxygen is required to produce energy from this system. Once oxygen is brought into the equation, our cells have to work harder to create the energy, thus resulting in a longer amount of time before that energy is available. Along with the oxygen, our aerobic system uses fats and carbohydrates to create the ATP (adenosine triphosphate) our cells need for energy. Our aerobic system is like highway driving. It takes a while to get up to speed, but once we’re there, we are moving as efficiently as possible. The aerobic system may take a couple minutes to become fully operational during exercise, but it’s capacity lasts as long as there is oxygen and glucose available.

Anaerobic Lactic System – Our mid-capacity system
The anaerobic systems do not make use of fat breakdown, thus avoiding the need of oxygen. This results in less chemical processes, and quicker access to energy. The lactic system breaks down glucose molecules to produce ATP, supplying our muscles with faster energy than the aerobic system. However, a trade-off for this quicker energy is the production of lactic acid. The problem with lactic acid is that it releases hydrogen ions into our muscles and bloodstream, creating an acidic environment which causes that burning feeling when you’re exercising at high intensities. If too many hydrogen ions are present in our cells, we have to decrease our intensity to a point where we can tolerate/remove the hydrogen ions.

Anaerobic Alactic System – Our instantaneous but short lived system
This system doesn’t breakdown fats or carbohydrates for energy. In fact, everything this system needs is already stored within our muscles in the form of stored ATP and creatine phosphate (CP). During the initiation of intense exercise, the stored ATP within our muscle is used for instantaneous energy. As mentioned before, this results in many ADP molecules sitting in our muscles. This ADP is converted back to ATP by borrowing the phosphate ion from the stored CP. These processes are very fast, allowing us to give maximal efforts for an all-out bout of 10-15 seconds.

One Fine Machine
These three systems work together at all times; allowing us to run four blocks to catch the bus (lactic), sprint after the bus as it pulls away from the stop (alactic), and jog 20 minutes to get home using our own two feet (aerobic). The intensity of the activity determines which system predominates, but rest assured they are all working to some degree. In next week’s article, we will use this knowledge to look at the marketed “fat burning zones” on treadmills; and whether slow is better for “burning fat”.

-Stuart

 

“What is the Best Exercise for Losing Weight” – Part III

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This is the last addition to this three part article. Today we will be talking about practical applications, specific exercises and resources, you can use to increase your fitness level, create a net caloric defict (resulting in weight loss), and decrease your risk for many chronic diseases.

The Guidelines for Health Benefits
The Canadian Society for Exercise Physiology (CSEP) is Canada’s gold standard for physical activity recommendations, health and fitness research, and fitness professional certifications. In January of 2011, CSEP released new physical activity guidelines broken down into age groups. The guidelines can be found on the CSEP website, or MORFit’s Resources page. For adults, CSEP advises: “To achieve health benefits, adults aged 18-64 years should accumulate at least 150 minutes of moderate- to vigorous-intensity aerobic physical activity per week, in bouts of 10 minutes or more.”
Ideally this would be spread over 4-6 days of the week, and not just one full-on bout of 2.5 hours. Keep in mind this is to achieve health benefits, which will reduce your risk for things like cardiovascular disease, diabetes, hypertension, and other diseases. If you’re looking to lose weight, this may not be enough.

How Much is Enough for Weight Loss?
The American College of Sports Medicine (ACSM) advises: “Overweight and obese adults may benefit from progression to approximately 250-300 min/week or 50 to 60 min on 5 days/week”. Research suggests this volume of activity (>2,000 kcals/week) enhances long-term weight loss maintenance. They recommend targeting a 5-10% reduction in body weight over the initial 3-6 months. This may not sound like much, and many diets/progams out there claim to lose that much in half the time. The difference here, is that we’re trying to adopt a sustainable lifetsyle that will continue to deliver results over the long term, to avoid the yo-yo effect.
In addition to the physical activity, the ACSM recommends reducing caloric energy intake by 500-1000 kcal/day to achieve weight loss. Dietary fat should account for <30% of total energy intake.

Making the Numbers Fit
Just how much physical activity equates to 2,000 kcals? Below is a list of kcal/min burnt during different activity intensities. From this table, we can see that a female exercising “lightly” (3.4 Kcal/min), would need to exercise for just under ten hours to burn 2,000 kcals in a week. This should help illustrate the importance of balancing the intensity and duration discussed in part II.

Men                                         Women
Level               Kcal/min             Level               Kcal/min
Light               2.0-4.9               Light               1.5-3.4
Moderate         5.0-7.4               Moderate         3.5-5.4
Heavy             7.5-9.9                Heavy             5.5-7.4
Very Heavy      10.0-12.4            Very Heavy      7.5-9.4

There are other ways to determine more accurately how much energy is being used during exercise. A fitness professional can help you determine these numbers based on your weight/age/etc.

Still Waiting for the Exercises
Now that we have a general idea of how much exercise we should be targeting, let’s talk about types of exercises. As mentioned in part II, we get the greatest benefit from useing several large muscle groups while weight bearing. Treadmills, rowers, and ellipticals are good examples to choose from in a gym. Running, cycling, stairs, skipping, and multi-muscle exercises (aerobics, burpees) are great if you’re at home. Sports, boot camps, spin classes, running groups are very social and effective outlets in the community.
This list is certainly not exhaustive. The bottom line is to find activities that you enjoy doing, and making sure that you’re engaging in the activities with sufficient intensity and duration to experience the benefits you’re seeking.

In fture articles, we’ll get more specific about tracking intensities with heart rates and RPE’s. For now, I encourage you to set a goal of finding activities you can adopt into your lifestyle, and start working towards dedicating 150 minutes per week to those activities.
I wish you all the best!

-Stuart

“What is the Best Exercise for Losing Weight” – Part II

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Welcome to part II of our quest to find an answer to that universal question, “What is the best exercise for losing weight?”. Part I touched on some basic physiology of kCals in our bodies; today we will explore some fundamentals that pertain to diet, exercise and lifestyle. Let’s get started!

#1 – Every Little Bit Counts
Let’s make a brief distinction between scheduled acitivities and unscheduled activities of daily living (ADL’s). Scheduled activities include going to the gym, your morning runs, playing on the softball team Tuesday nights, etc. ADL’s include everything else you do throughout the day that increases your heart rate and burns calories above your resting metabolism. Both these forms of activity are important in creating a net energy deficit, and ultimately contributing to weight loss. Scheduled activities (moderate to very heavy intensity) will burn anywhere from 2-6 times more kCals than most light ADL’s. However, if your scheduled activities account for only one hour of your day, you have another ~15 hours of awake time to fit in your lighter ADL’s. Now we can see the importance of taking the stairs instead of the elevator, sneaking a walk in over lunch hour, and carrying your groceries instead of using a cart.

Key Point: Any activity that increases your heart rate or breathing rate is burning extra energy. The more often you engage in these activities, the greater the daily energy expenditure will be, and your body will become more accustomed to these increased demands.

#2 – Move What Your Mamma Gave You
The last point highlighted the importance of performing light to moderate activities throughout the day. Now we’ll discuss the importance of maximizing efficiency of the limited time you have for scheduled activites. Due to my profession, I will be using the gym as my example of scheduled activity. Many of us only have 30-60 minutes in a day to dedicate to the gym. This is still enough time to experience significant benefits, if you’re taking advantage of your time. There are two key components to consider during your workouts: Duration & Intensity. If weight loss is your goal, you will need to balance these two variables to result in an adequate kCal expenditure (specific kCal values for common activities will be discussed in another article). If you’re pressed for time, try cranking up the intensity of your workout. If you don’t like working your body into a pile of sweat and lactic acid burn, then burn your kCals at a moderate intensity over a longer period of time.
The more muscles you have working, the more oxygen your body needs to fuel those muscles, and the more kCals you will burn. You will have to work at a higher percieved intensity on a bike to achieve the same energy output compared to a treadmill, for the same duration. A good indicator of which exercises require more muscles: Weight-bearing activities, and exercises requiring you to move more limbs are more effective than weight-supported activities.
My Question of the Day to the Reader: Considering this last point, how do sit-ups sound as an exercise to lose that belly fat?

Key Point: Increase your intensity or duration to burn more energy in your workouts. Exercises requiring the use of more muscles also require more energy. So try getting on the treadmill, elliptical or rower. The bike is weight-supported and lower body only; but can be a great tool if your intensity/duration are high enough.

#3 – The Diet
The nemesis of millions. Our diet has the ability to send us in either direction of the weight management spectrum, regardless of level of physical activity. You can workout religiously every day of the week, and still gain weight if your diet is not managed. Conversely, many people have eaten their way from obese to a “healthy” weight without changing their level of physical activity. How is this possible? It comes down to education, practice, and discipline. It’s important to have a general understanding of the foods you typically eat, and an understanding of how much activity and food are required to progress towards your goals. Then you’ll probably go through a period of trying different strategies that are compatible with your goals and your lifestyle. Finally, it’s a matter of turning new practices into habits that become second-nature.
There’s a reason why fad diets come and go. They will work for some people, but not everyone. There’s nothing wrong with trying one strategy for managing your diet, and not having it work for you. This is not a reflection on your ability to reach your goals. This simply wasn’t the right strategy for you.

Key Point: Don’t underestimate the influence of your diet. Try not to get discouraged if you run into setbacks or “bad days”. EVERYBODY experiences these, multiple times. If you have the right intentions in mind, and are making changes to manage your diet, then you’re on the right track.

 

That’s it for part II. Next week, part III will get into some applicable examples of exercise and diet strategies to take your weight loss by the horns. Thanks again for reading, please feel free to leave your comments below.

-Stuart