Your Body on a Run
I often think about the myriad processes that go on inside of me while I’m running. So I decided to give it a look on the old interwebs, and found out some pretty fascinating stuff.
In truth, every change we notice (and don’t notice) while running is actually aimed at one purpose: keeping your muscles active. The reason your heart beats faster is so that it can supply more oxygen rich blood to your muscles. This also explains why you breathe heavily.
Oxygen is what fuels muscles (through the creation and subsequent use of ATP, which you might remember from grade school).
In the process of using up this energy, muscles generate waste. Much like a car expels fumes when it is in use, muscles excrete lactic acid and heat when you use them to run. Lactic acid build-up is, in fact, what makes your muscles burn during a hard workout.
The fuel-burning process happens in stages:
1. Phosphagen System: The limited amount of ATP naturally present in your muscles is used up within 8-10 seconds.
2. Anaerobic/Glycogen and Lactic Acid System: Before your body has begun using oxygen (hence “anaerobic), anaerobic metabolism splits up glucose molecules (present in Carbohydrates) to make ATP for fuel. This process can only last around 90 seconds due to the large amount of lactic acid it generates as a by-product.
3. Aerobic: With oxygen present, the body more efficiently breaks down glucose molecules, using glycogen sources from the muscles, the liver, or food (also sometimes fatty acids, though that seems to be a last resort).
A number of other crazy things happen to power your run.
Vasodilation: Blood vessels that lead to the muscles expand to allow for increased blood flow.
Vasoconstriction: Blood vessels that lead to other bodily organs constrict to decrease blood flow to those organs and thereby increase the blood available your muscles.
Cardiac Output: The amount of heart beats combined with the volume of blood the heart ejects with each beat is your cardiac output. During strenuous running, total cardiac output is between 20-25 liters per minute.
Respiration: All that lactic acid in your blood signals your nervous system to stimulate your respiratory system to accommodate the need for more oxygen.
Adrenaline Release: The adrenal glands release adrenaline (epinephrine) to dull your response to pain. It helps to remember that running used to serve us well for fleeing from predators and chasing down food-so it would make sense that our body would distract us from pain that would cause us to slow down or stop.
This is by no means an exhaustive description of what is a very complex process. But I love knowing how incredibly my body is, and taking that information with me on a run.
[Information Credit: Discovery Health Online]
Alcohol & Training
Today I wondered: how does consuming alcohol affect training, muscle growth and fat loss? Everyone knows that alcohol contain empty calories and can make your judgement on what to eat less than perfect, but what about how your body is affected biochemically? Read on…
Work that liver!
We all know that alcohol is a toxin, and our bodies respond to it as such. Our liver and other metabolising organs go hell for leather to ensure that the alcohol is removed as soon as possible, before it does any damage. This is clearly a good thing, but at the same time it does mean that foods that you have eaten that day do not get metabolised as quickly as they usually would do. In essence? This means that more fat is stored/synthesised while your body attempts to get rid of the alcohol in your system
This does also mean that any nutrients in the foods you ate prior to or with your booze probably won’t won’t get broken down or absorbed as fully as they would have done if your body wasn’t working hard to break down the alcohol. Another negative…
Hormone hell
Alcohol is a clever little bugger, and often touted as good for you in moderation due to its phytochemical resveratrol (some studies have shown that this chemical can combat diabetes and heart disease). Unfortunately resverstrol is also a phytoestrogen, which essentially means that it mimics excess oestrogen in the body. Why is this bad? Oestrogen is a hormone that promotes increased fat storage, so if you’re looking to lose fat you don’t want your body producing any more than is necessary. Nor do you want any chemicals that mimic it floating round your blood stream!
As well as this, alcohol disrupts the production of HGH (human growth hormone) and testosterone (a key player in muscle growth), both important hormones needed for muscle building. HGH production (which happens mostly during slumber) can be affected by alcohol consumption (drinking alcohol can disrupt your sleep - mostly the quality of restful/repairing sleep that you have) and HGH production can be decreased by up to 70% when sleep is disturbed. Testosterone production drops in the presence of the hormone cortisol, which is a hormone released when the liver processes alcohol. All in all this is a hormone mix that is best avoided if you want to shed fat and gain muscle…
ATP - easy as 1, 2, 3…
The production of adenosine triphosphate (also known as ATP - your body’s main energy store) is also negatively affected by alcohol consumption (due to the changes in water potential inside muscle cells that alcohol brings), leading to less energy available for exercise on the days following your drinking. As well as this glycogen synthesis is slowed. Why is that important? Glycogen is the way that your muscles store glucose, and it is used when you need energy (to sprint, lift hard, whatever). Glycogen is stored in your muscles immediately after exercise, but this will not happen if your body is still working off any alcohol you may have consumed recently. This leads to excess glucose in your system being converted to the much-less-useful compound fat instead of being stored as glycogen. Again, a real negative if you are looking to maximise fat loss.
So there you go. A little alcohol won’t harm you in moderation, but it is always pretty interesting to know how it might affects your training/fat loss/muscle growth goals.
What exactly is the big deal with breathing? Why do we breathe? Always. It must be pretty important….so important that most of the time our body does it automatically. Respiration (a fancy-pants word for breathing) is more than just breathing in oxygen and breathing out carbon dioxide. The nutrients (sugars, proteins and fats) that you eat travel through the circulatory system to the cells and are broken down and their energy converted into ATP (adenosine triphosphate) through stacks of complicated processes that go under the banner cellular respiration. ATP is kind of like the universal energy currency of cells. Australia has the dollar, Europe the euro and cells have ATP. Most things that happen inside cells (like moving, replicating and making things) have a cost that is paid in ATP. Each cell even has its own money mints to print the ATP – the mitochondria.
The sugar glucose is the major energy source of most animals and plants. Carbon dioxide and water and produced as wastes when it is broken down. While excess water can be removed via the urinary system (peed out), getting rid of the carbon dioxide waste can be a bit more problematic. In liquids like blood, or cellular fluids, carbon dioxide combines with water to form carbonic acid. Our body (and other vertebrates) has a system (bicarbonate buffer) in place can stop small increases in carbonic acid in the bloodstream from being harmful. But cellular respiration is happening constantly so ultimately the carbon dioxide needs to be removed from the body so that the cells (and blood) don’t become more and more (and more) acidic. Changes in the acidity of the blood (and cells) can stuff up lots of important things (like moving, replicating and making things) and even make things fall apart (change protein conformation). So, the carbon dioxide is transported to the lungs (or gills, or skin or however the particular animal/plant does this) in the blood (buffered by the bicarbonate system in vertebrates) and breathed out.
But when we breathe, we breathe in oxygen….right? What does oxygen have to do with anything? Find out Friday.
