The mechanics of aerobic exercise require that oxygen be brought in by the lungs transferred to the blood vessels. Oxygen rich blood is then pumped by the heart to the muscles. The muscles utilize oxygen for muscle contraction. Through routine aerobic activity, the body becomes more efficient at processing oxygen. Examples of aerobic activity include running, jogging, biking, rowing, walking. In fact any exercise that incorporates large muscle groups, raises the heart rate, breathing rate and body temperature is aerobic in nature.
- Increases cardiorespiratory and cardiovascular system outputs
- Strengthens heart
- Decreases resting heart rate
- Improves circulation by clearing out cholesterol buildup
- Body adapts to burn fat as primary fuel source
- Improves psychological disposition and reduces stress levels
- Raises basal metabolic rate
- Decreases blood pressure
- Reduces LDL blood cholesterol level
- Tones muscles
- Improved balance and posture
- Increases Blood Oxygen level
- Increases flexibility, reducing capability for injury
Weekly Requirements And Limitations
Fitness Level gains are determined by Frequency, Intensity and Duration of the Aerobic exercise. Each session (duration) should last from 20 to 60 minutes and be performed 3 to 5 days per week (frequency) at an intensity level measured by heart rate (60% - 90%) according to the American College of Sports Medicine (ACSM).
During the first 15 minutes of aerobic activity, glycogen or sugar within the muscles is used for energy. Fat metabolism for energy doesn't occur until about 15 to 20 minutes after beginning aerobic activity. This is why it's important that aerobic duration be at least 30 minutes. Aerobic sessions greater than 1 hour continue to burn fat but at not the same rate as during the first hour.
Additionally, sessions greater than 1 hour increase the risk of injury due to fatigue. Increasing aerobic frequency (greater than 5 times per week) does not give the body a chance to fully recover and can even reduce the body's capability to defend itself against illness. It is important to listen to what your body is trying to tell you. Rest, adequate sleep, proper diet all become more critical when demands are placed on our bodies above the normal everyday physical stress.
The type of fuel you put in a vehicle depends on the performance you expect out of it. The same is true of our body. Unlike weight training, aerobic training has two main goals. The first is to improve cardiovascular performance, the second to burn fat. Both of these goals can be realized during the same aerobic session.
If the goal is to simply improve cardiovascular strength then we need to target performance. Like weight training, we want to consume a complex carbohydrate snack before aerobics. A sugar snack will not provide the sustained energy and in fact may decrease performance. Excessive sugar intake before aerobic activity can work against the participant. When large amounts of sugar are ingested, the pancreas must secrete insulin to metabolize the sugar. Insulin levels in the blood inhibit the liver from metabolizing fat. Therefore little or no fat burning takes place during exercise. This includes sugary drinks as well like sport drinks which stay in the stomach much longer than ordinary cold water thereby inhibiting quick hydration. Therefore, if the goal is to burn fat, then water only should be consumed before aerobics.
In addition to their doctor's recommendations:
- Eat a small, easily digestible snack (such as crackers) prior to exercise.
- Drink plenty of water before, during and after exercise to prevent dehydration.
- Older populations lose their sensitivity to thirst and subsequently dehydrate easier.
- Wear loose, comfortable clothes to avoid movement restrictions.
Types Of Aerobic Activities
Anything that maintains the target heart rate 60% - 90% of the Maximum Heart Rate is considered aerobic. If the heart rate is lower, then aerobic levels have not been reached. If the heart rate is higher, then an anaerobic level has been reached. During anaerobic exercise (sprinting) protein is being consumed and energy is being produced without the benefit of oxygen.
High intensity, high impact aerobics is not necessary to burn fat. For example, running for 1 mile burns only 20% more fat than brisk walking for 1 mile. It's important to focus on the exercise and maintain the target heart rate. Watching TV, reading books or other similar activity tends to distracts the participant from monitoring the target heart rate. Use music with sufficient beats per minute to intensify the exercise session (120 - 140 bpm).
It is important to provide a period for cool-down. Abruptly stopping aerobic activity can cause blood pooling in your lower extremities or making you feel lightheaded.
During pregnancy, no exercise should be performed in the supine position after the fourth month. Target heart rate should not exceed 140 bpm. Avoid exercises that incorporate extreme flexed or extended joint positions. Joints are looser in the latter part of pregnancy. Also avoid jumping movements due to joint and tissue laxity. It is important to maintain the current fitness levels during pregnancy and not try to increase or improve the fitness level. The time to do this is before pregnancy not during. Keep Aerobic/Step moves basic and simple. High step heights can become dangerous due to the body's change in the center of gravity. Recommended step heights are 4 to 6 inches. Keep strenuous activities down to a duration of 15 minutes at a time. It is also very important to avoid the Valsalva maneuver (holding the breath) during exercise. It robs not only the baby of oxygen but oxygen starved muscles can cramp easily.
Rating Of Perceived Exertion (RPE)
Generally, if you can't talk during exercise, you're training to hard. However, a more accurate method of measuring exercise intensity is the Rating of Perceived Exertion. To put it simply, imagine a scale of 6 to 20 and try to determine where your intensity level is on that scale. That number will be very close to your heart rate. To simplify further, you can narrow the scale down when exercising to a scale of 10 to 18. This would correspond to a heart rate of 100 to 180. It is beneficial to become familiar with this method so that you are always aware of your heart rate when exercising. This allows you to constantly monitor your heart rate and adjust the intensity of your exercise to remain within the target zone. This method should not replace direct heart rate measurement due to inherent inaccuracy but serve as an adjunct to it.
Blood pressure readings consist of two numbers, systolic and diastolic pressures. The systolic pressure is a measurement of how forceful the heart is pumping blood when it contracts in the pumping stage. It is the vascular pressure created during the contraction of the left ventricle. If this reading is too high, then the heart is working too hard. The diastolic pressure is the measurement of the force existing within the relaxed arteries between heartbeats. If this number is high it could be indicative of clogged or constricted blood vessels.
Digital blood pressure monitors are available at many department and drug stores and provide an easy method of taking a reading. When a reading is taken in the doctors office, he first wraps the cuff around your arm and pumps it up with air effectively cutting off the circulation to the lower arm. As he pumps air into the cuff, a mercury pressure gauge provides an increasing reading of the pressure within the cuff. Listening through a stethoscope, he begins to slowly let the air out and the gauge begins to fall. At the moment he hears the pulse start back up, he records the level on the gauge. This is the systolic pressure. He continues to release air from the cuff. When he can no longer hear your pulse, he records that reading from the gauge. That is your diastolic pressure. A reading of 120/80 or lower is considered good. A reading of 140/90 or above is considered high blood pressure.
It is important to see a doctor to determine if medication is required if high blood pressure is indicated. Exercising with high blood pressure and without medication could cause serious consequences. Exercise raises the heart rate and associated cardiovascular pressures which can push a borderline reading to excessive levels. Certain foods can elevate blood pressure by constricting blood vessels or increasing heart rate.
The Valsalva maneuver or holding the breath while performing an exercise can increase blood pressure to extremely high and dangerous levels. Blood pressures of nearly 400/350 have been recorded during such actions. Existing aneurisms can burst, blood vessels in the eye can rupture and even retinas can tear (Valsalva Retinopathy). This is a common and dangerous practice. It is also the job of the trainer or spotter to recognize when the breath is being held and bring it to the exerciser's attention immediately.
Proper Attire For Specific Activity
Proper attire is just as important as all the other requirements for effective exercise. Running shoes provide the needed heel cushioning but lack in the side to side lateral support for required for aerobics. Aerobic shoes are generally available for women. However, men's aerobic shoes are scarce. A good cross trainer shoe provides all the necessary support for aerobics. Athletic shoes should fit properly. Break in period does not apply to athletic shoes they should fit comfortably from the beginning. Depending on the amount of use they get, insoles may wear out in before the shoes show signs of external wear.
It is important to wear clothing that allows the skin to breathe. The body utilizes sweating to regulate temperature. Clothes that restrict the cooling of the skin are not recommended. It's important to wear clothing that allows the body to ventilate. If evaporation does not occur, the wet clothing will continue to help radiate body heat. This can lead to loss of excess body heat after exercise when heat retention is important.
Cotton soaks up sweat readily, but stays wet. Wool, however, continues to provide body warmth even when wet. Nylon doesn't allow water to permeate through. Obviously, layers are important in cold weather environments. Layers allow you to remove and replace outer garments as the need arises. Hats are equally important in cold weather since a considerable amount of body heat can be lost through the head. In warm weather, wear loose clothing that allows sweat evaporation. Again, cotton drys slower than man-made materials. A combination of cotton and polyester combines the absorption and wicking qualities of each material.