Physical Activity/Aerobic Exercise
Aerobic exercise is generally exercise that is done over a long period of time, typically 20 minutes or more. It is used to tone the body, make it leaner, and improve endurance by keeping the cardiovascular system healthy. Although getting any exercise is healthy, getting at least 20 minutes of sustained aerobic exercise about 3 times a week, along with a good diet, will generally keep a person healthy.
Technically, aerobic exercise is exercise that mainly uses energy from the cells in the muscles of the body doing aerobic respiration. Aerobic respiration of a cell is when the cell uses oxygen to burn energy (aerobic means "requiring air (or oxygen)"), unlike anaerobic respiration where the cell does not use oxygen when it burns energy. Cellular aerobic respiration can potentially be 18 times more efficient than anaerobic respiration, and aerobic respiration produces less toxins in the cell. Because of this, the cell will try to do aerobic respiration whenever it can, but it will do anaerobic respiration to get energy when it lacks oxygen.
Exercises that are less intense but last longer allow the body to give the muscles oxygen as they are using it up, and keep them doing aerobic respiration. More intense exercises use up the oxygen in the cells faster than it can be replaced, so the cells divert to anaerobic respiration to get the energy they need.
What Happens to the Body During Aerobic Exercise?
A lot of energy is not used during aerobic exercise, so the body will burn fat by converting it into sugar for the cells to use as energy. If aerobic exercise is sustained for more than 20 minutes, it is especially healthy because the body will continue to burn fat for several hours afterward.
Aerobic exercise requires a lot of oxygen, so many things in the body do change. The heart rate increases, and the volume of blood per heart beat increases, to circulate the oxygen in the blood to the muscles faster, and remove toxins from the cell faster. This increases the blood pressure. To get more oxygen into the bloodstream, and get toxins out, the breathing rate increases, and the lungs expand and contract more.
Lactic acid is produced and will cause a burning sensation in the muscles. The body will try to get oxygen to the muscles as fast as it can, but it is not always able to give the muscles all the oxygen they need. When this happens, the muscles will shift to anaerobic respiration until they can get the oxygen they need. This usually happens during any aerobic workout, if the person is trying to push him or herself. When it does happen, the muscles will produce many toxins that are created during anaerobic respiration, and then the liver will try to cleanse those toxins as fast as it can. When the liver cannot remove the toxins as fast as they are created, they build up. When a person experiences pain in their muscles because of working out, it is usually because of lactic acid building up (unless the person has pulled a muscle or damaged something).
One good benefit of getting aerobic exercise is the release of endorphins, which are chemicals in the brain that reduce the feeling of pain and make a person feel better. They are sort of like the body's natural pain medicine, and they make a person feel good. Sustained aerobic exercise for a long period of time, like during a marathon, can be euphoric because of endorphins. They are released to reduce the pain a person feels during aerobic exercise.
A person who regularly does aerobic exercise will develop a healthier and stronger body. Their heart will be stronger, and pump more blood per heartbeat, making it more efficient, to handle the increased blood circulation required for aerobic exercise. This will allow the person to have a lower heart rate when resting, and make them feel better. The lung capacity and efficiency at transferring material between the air and the bloodstream will increase to handle the extra oxygen required during aerobic exercise. This will allow the person to breathe less when resting, making them feel better. The arteries, veins, and capillaries will become more efficient to handle the increased blood circulation. The muscles will increase their efficiency and more blood vessels will be created in the muscles. Coordination will increase. The person will feel better because of having more endorphins in their brain. The muscles, bones, organs, and other tissue will become stronger to handle the impact that exercise will give to them. Burning more energy will require eating more, but even if a person eats more, the person can more easily lose fat by working out.
Types of exercises
- Climbing Stairs (sustained for 20 minutes or more)
- Team Sports
- Chopping Wood (sustained for 20 minutes or more)
- Cross Country Skiing
Method: Using heart rate as guide
|Use at your own discretion. This is NOT medical advice. Any change in lifestyle involving massive change in physical activity should be under doctors supervision.|
When we start conditioning, at first, our heart beat goes up to high levels even with very moderate forms of exercise. The reason for this is that our cardiovascular system and our respiratory system are not conditioned. In other words, they are not very effective for a person who has not exercised for years. But once we start exercising, these systems keep on becoming more and more effective and conditioned. Our heart becomes stronger and our lungs become stronger. Our body is able to supply more oxygen to the muscles in an easier fashion.
Similary, the muscular system becomes more efficient. Our muscles are able to produce more work by using more energy. A fit and conditioned individual can work more through his muscles than a deconditioned person. His muscles are stronger and better adapt at working.
So, as we train, our body can supply more oxygen, more easily, and the muscles can use that extra oxygen to do more work more easily.
Therefore, no matter if you are a fit individual or some one who has been living a sedentary lifestyle for the past many years, you can use heart rate as an effective guide line for your exercise intensity. Your heart rate will tell you how comfortable your body is while exercising. It is one measure that is tailored to your body's ability to perform. Other methods like your speed or inclination or resistance etc. are not tailored to your ability. An unconditioned individual might be struggling at a speed, at which a trained individual is barely breaking a sweat. However, the heartbeat will tell a different story.
Here is the theory behind using heart beat as a guide:
The maximum heart rate is your heart's response to increased oxygen demand and your body's attempt to oxygenate (meaning supply your body with oxygen). It declines with age variably and there is an interindividual variability as well. Here is a rough approximation for the maximum heart rate for an individual:
Maximum Heart Beats Per Minute = 220 - (age in years)
This is a very raw approximation but it doesn't matter that much. Better approximation can be achieved for an individual by putting on a good heart rate monitor and running as fast as possible for at least 2 minutes in an untrained individual to see how high his/her heart beat goes.
Now, by exercising at heart beat about 70% - 80% of maximum heart beat, a person successfully improves his body, while remaining in a comfortable zone.
Even 65% - 70% bpm of max, is a good conditioning zone that is very comfortable and produces constant bodily improvement.
There is no need to push too much. Remain at 70% - 80% : it is very comfortable and gives huge improvements.
For example, I am 25. My maximal heart beat is ~195 (220 - 25).
- 70% of maximal heart beat is 136 bpm.
- 75% of maximal heart beat is 146 bpm.
- 80% of maximal heart beat is 156 bpm.
- 85% of maximal heart beat is 166 bpm.
- (These are all approximations).
During exercise, if I keep my heart beat at about 70% - 80%, I will have significant benefits. If I want, I can push it to 75% - 85% (85% is the upper limit). It is usually sufficient to remain around 70-75%. As an alternative to measure the heart rate run and try to talk at the same time. If you can do this without significant shortness to breath will have reached approximately 70% of your maximal heart beat.
Note that, for an untrained individual, even very moderate exercise will bring his/her heart beat pumping really fast. That means that they can easily remain very comfortable and get significant health improvements. Very soon they will find that their heart beat does not rise that sharply.
Invest in a good heart rate monitor. I think, polar makes excellent heart rate monitors. Buy the ones that have a chest strap. Many professional treadmills can read the heart rate readings from the chest strap - so you don't need to carry the wrist watch with you (that comes with the chest strap). I found the chest strap heart rate monitors to be much more accurate.
Energy output analysis
- Deconditioned individual - maximum energy output = 6-7 times resting energy expense
- Conditioned individal - max. energy output = 10 - 12 times resting energy expense
A person can only sustain about 20% of maximum energy output throughout the day, without getting fatigued over time.
- Deconditioned Individual can spend about 20% of 7 = 1.4 times what he would spend sitting/lying whole day.
- Conditioned Individual can spend about 20% of 10 = 2 times what he would spend sitting/lying whole day.
Considering that sitting/lying whole day (basal metabolic rate) is about 2000-3000 calories for most people, a difference of .6 (2 - 1.4) times basal metabolic rate is
- 1200 - 1800 extra calories per day that a fit individual can spend compared to a deconditioned individual. Do you have any idea how much difference these 1200-1800 calories can make!
Base line - become fit.
Aerobic exercise, Running for example, is a pleasure and it gives the best feeling in the world to run. Don't overdo it and give your body time to slowly increase in efficiency and capacity.
As heart and respiratory systems become stronger, the body's peak capacity as well as endurance increase. As muscles become stronger and more effective, body's peak capacity and endurance increase further. The whole body becomes more powerful and stronger.
Warming up and cooling down
It is very important to warm up before suddenly increasing the intensity of your exercise. It is equally (if not more) important to slowly cool off. These two things prevent injury. When warming up, you slowly bring your body into the correct state for more intense exercise, without this warm-up phase the body's muscles and tendons are tight and prone to injury thus it's important to warm up to prevent injury. The cool down is important for recuperation of your body. If you don't allow for a proper cool down, lactic acid more readily and easily builds and stays in your muscles. This acid slows down the healing process and makes you sore. Generally, 5-10 minutes to warm up and about 5 minutes to cool down is sufficient. During the cool down, it is a good idea to write down your daily exercises.
After both the cool down and warm up phase, 5-10 minutes of stretching should follow. This also prevents injury, helps in recuperation, and helps to alleviate lactic acid buildup.
Specific exercise tips
I found treadmill to be an excellent machine for aerobic exercise. I have always loved running and treadmill makes it so easy.
Running on a treadmill, lessens chances of injury. This is because you don't need to be careful of the terrain (road, bumps on the road, foot path etc.), or vehicles or other things. No problems with weather. Also, most good treadmills absorb the shock, making the running more comfortable for your legs.
Also, most treadmills have excellent programs built into them. These programs have been designed by experts and use contemporary exercise theories. Programs like heart rate based programs, can use your heart rate monitors to adjust the inclination etc.
One thing to note is to accurately simulate running outside, you should set the treadmill at at least a 1% grade or higher. With the higher grade, you will be pushing more against the treadmill than the treadmill will be pushing your feet along.
Important Tip: Don't ever forget to clip the stop button to your self. You never know when you might lose a step or something and end up falling. The last thing you want is the belt burning your back or increasing your injury by throwing you around. Always, clip that stop button to your clothes. This is extremely important if you are going to run at a fast pace.
Heart Rate Monitor Guide: I think most treadmill heart rate monitors lack precision. A good heart rate monitor would be a good investment if you plan on exercising seriously.
Biking is another excellent aerobic exercise, besides being immensely entertaining.
Tips about buying a bike and accessories
- Get special biking shoes. If your pedals have the lock-in mechanism, get matching shoes. The shoes can be "clipped" into the pedals. The term 'clipless' refers to the older mechanism that locked your foot, which was a cage like system, the clip. Pedals without this system but that offer the possibility to lock your foot are called clipless. That allows you to pull the pedals up in addition to the usual push down. That allows you to complete a full rotation instead of each leg just completing a partial rotation. In addition to using more muscle groups you can, with practice, develop a smoother pedal cycle with greater stability and thus allowing higher cadence. Higher cadence is essential for cardiovascular stress and training. Note that, some basic practice is needed to be able to easily unlock and lock your feet and to immediately unlock your feet in case of emergency.
- Don't buy a very expensive bike. I made this mistake and I don't think that my bike justifies the expenditure. It does not matter that you bike is 1 lb. lighter. It will pinch you for long if you belong to the category that most of us belong to.
- Tire pressure is essential for optimum performance. Correct tire pressure will yield a sufficiently low rolling resistance of the tire and a minimal risk of flats. Under-inflating will result in a softer ride but also increases the risk of 'pinch flats' caused by squeezing the tire between the ground and the rims when hard cornering. Also, rolling resistance is significantly increased resulting in less then optimal speeds. Over-inflation only reduces the rolling resistance marginally but creates some other issues such as easy puncture flats and bouncing behavior, compromising bike stability. The pressure required is a variable depending on driver weight, the kind of tire and ride circumstances.
- The choice depends on the kind of bike. There are specific tires for each kind of bike. The difference is in tire width and profile. The wider the tire, the higher the rolling resistance because of larger contact area, but also the higher the grip on the surface. Profile refers to the tire surface, this can be smooth (slicks) or heavy profile like on mountain bikes. The heavier the profile the more drag and grip it has on loose surfaces such as mud and sand. There is absolutely no point in any profile when the only surface you ride on is asphalt (road). With this in mind, a road bike has a thin smooth tire with the lowest rolling resistance and a mountain bike will have a wide tire with heavy profile for optimum grip on rough surfaces. City bikes, cyclo-cross bikes or other models may choose for something intermediate.
- Other Accessories
- Accessories are optional but can be useful. The use of a helmet is heavily debated and a little out of the scope of this article. Cycling gloves may offer protection against RSI (repetitive stress injuries) from leaning on the handlebars by means of the padding in them. They can also offer extra comfort when riding rough surfaces. Most professional cyclists wear them but the choice remains yours. Glasses provide you with cover for dust and bugs but may also provide a hinder during heavy weather. Cycle clothing has several uses but may dramatically improve riding comfort, especially when riding for greater distances. Cycling shorts are essential in preventing shearing injuries from leg action under sweaty circumstances. The jerseys are in a fabric that allows sweating while still keeping warm. Basically the lycra allows for a more optimal thermoregulation, in addition they provide back pockets. Another good accessory - heart rate monitor. Its fun to see your heart rate once in a while. Another good accessory - an electronic speedometer, mileage computer. They are cheap and it's a pleasure to see how many miles you did today and the total number of miles so far.
Benefits of bicycling
- Very Entertaining - Biking is probably one of the most entertaining exercises out there. Although, every exercise gives pleasure and has a unique fun attached to it, riding a bike is like gliding. You feel the fresh air brushing your face and body. You get to see many places. Biking is really fun.
- Fresh Air - Cycling is something that gives you an opportunity to catch a breath of fresh air, literally.
- Low Impact - Cycling is easier on your bones than running.
- Hiking while Biking! You can literally go places on your bike. It is not too hard to bike 30 miles in a day (even if you are not very trained, although, your muscles might be a bit sore the next day). You can see parks, cities, neighborhoods on your bike.
- Practical - You can commute to work / school on a bike to save money on gas.