The Best Cardio (2/3)
2. The Respiratory System in Response to Exercise
The respiratory system provides oxygen to be transported through the blood to the exercising muscles as well as eliminating carbon dioxide. In addition, the respiratory system helps buffer the metabolic acids as they build up during intense exercise.
During exercise, acid is produced and body temperature increases as oxygen is removed from hemoglobin into muscle.
During intense exercise, much more lactic acid and carbon dioxide is produced which then is buffered. This buildup of lactic acid and carbon dioxide further stimulates respiration.
Low to moderate exercise engages the “aerobic” metabolism and continues doing so as oxygen is available. However, as the exercise becomes more intense, the ability of the cardiorespiratory system to provide oxygen becomes less effective and the “anaerobic” metabolic systems are activated to supply the muscles with energy using glucose and lactic acid as fuel sources.
Engaging in physical exercise disrupts homeostasis. The more intense the exercise, the greater the disruption in homeostasis. The brain, the respiratory system, the heart and blood vessels, the muscles all respond profoundly to the intensity of the exercise for the primary purpose of delivering oxygen and nutrients to the working muscles.
The overload principle — the Specific Adaptation to Imposed Demands — provides the validation for all exercise training adaptations, that is, if you continually overload a system it will respond and adapt.
But the response is specific; only the system or body part repeatedly stressed will adapt to the continual overload. The more muscle groups involved the more training adaptations will be made. Only those muscles involved will adapt, no others. If the cardiorespiratory system is continually imposed upon, there will be a specific reaction to improve the cardiorespiratory function and so, better adaptation of the system to the next challenge.
The rate of oxygen utilized is represented by VO2. The V indicates the volume of oxygen consumed. The measure of the maximum oxygen consumed is the gold standard for assessing a person’s cardiovascular fitness. It is measured by exercising to exhaustion.
VO2 increases linearly as exercise intensity is increased until a VO2 max is reached. Over time with regular vigorous workouts, VO2max increases because improvements in oxygen delivery, cardiovascular adaptations, and improvements in muscle mitochondrial oxygen utilization have improved.
The “aerobic” exercises — the jogging, distance cycling, are such that the systems are not stressed enough to be demanding a specific response. These “aerobic” exercises do not improve VO2max. To improve VO2max the body has to be engaged enough to shift into anaerobic metabolism, ultimately reaching and sustaining exercise past the Anaerobic Threshold.
Therefore, it is essential to exceed your maximum heart rate to gain the metabolic effects of exercise, and in particular, the cardiorespiratory system, to improve blood pressure, circulation, and increased VO2max.
To do this type of maximum intensity exercise it is far safer and more beneficial to exercise on the Myoride Exercise Machine: engaging the most muscle groups, through their entire range of motion, under moderate resistance, to complete body exhaustion. No other exercise will exert the amount of anaerobic metabolism or improve the cardiorespiratory system as this type of exercise provides.
We know that maximum intensity training is 2½ times as effective in improving cardiorespiratory function as medium intensity training.
Simple measurements such as the careful monitoring of heart rate recovery will provide adequate ways of knowing when to stop exercising before overstressing the cardiorespiratory system.
Three to six bursts of output of 30-90 second intervals, with enough rest in between to allow enough oxygenation and lactic acid removal, while heart rate recovery is carefully monitored — provides all the benefits of exercise, while giving a clear, objective indicator of when it is time to quit exercising for the day.
Heart Rate Recovery
Heart rate is a window into the body and describes how your physical and mental systems are processing. Heart rate is a way to measure physiological output.
The intensity of the heart rate is the same whether you are fit or if you’re a person who doesn’t exercise at all. However, in a fit person, the size of the heart chamber has increased so that more blood is pumped per stroke making the heart more efficient. The heart increases in size and is able to deliver more blood to the body per heartbeat.
After exercise, your heart rate will recover to resting levels slowly or quickly depending on your fitness level. A slow heart rate recovery after an intense exercise interval indicates that the heart is not as responsive to the demands placed on it. A rapid heart rate recovery is indicative of a well-functioning heart, able to supply the demands placed on it.
Heart Rate Recovery
Phase 1 is the first minute after exercise in which the heart rate drops rapidly.
Phase 2 is the longer heart rate recovery which occurs from 30 minutes to several hours depending on fitness level and intensity of workout.
Determining Heart Rate Recovery
Step 1: Exercise intensely until fatigue and then stop.
Step 2: Exactly 60 seconds after the bout of intense exercise, note the pulse.
Step 3: Rest interval until ready to continue the next exercise interval.
Step 4: Repeat steps 1, 2, and 3 until the heart rate does not recover as effectively.
Interpretation: It may be the third, fourth, or fifth interval that the heart rate, after 60 seconds, does not return to the previous heart rate recoverings, say 12 points higher. This is the time to stop exercising as more exercise will place more demands on the cardiorespiratory system than it can adapt to.
Never extend exercise beyond what your body can respond to! You are asking for trouble. Going beyond the point of over-training will do catabolic damage to the heart and oxidative damage to the arteries.
A Normal Pulse Rate
A well-conditioned heart that has had the benefits of Maximum Intensity Interval Training, functions at rest with a pulse of between 70-74 beats per minute. When the body engages in an intense exercise interval, the pulse increases rapidly at the onset of exercise, then recovers very quickly at the end of exercise. The fast recovery is the key to cardiac strength and the resting pulse of around 72 is the indicator of healthy myocardial physiology.
A slow pulse indicates a heart that is overly stressed. Prolonged long-term endurance training results in non-physiological changes in autonomic control of the heart such that parasympathetic activity dominates and sympathetic control is reduced. The parasympathetic stress and sympathetic weakness results in a decreased heart rate at rest, in response to low to moderate exercise.
High intensity interval exercise, even at 80-90% maximum, is superior to moderate intensity exercise for increasing aerobic capacity and VO2max is nearly 2½ times as effective in improving cardiovascular function as medium intensity training at 50-60% of VO2max.
Do not waste your time and energy on long-term low to moderate exercise. If you are not engaging your muscles, through their complete range of motion, under moderate resistance, to complete exhaustion, you are not only wasting your time and energy, you may be damaging your health.
The increase in intensity will more than double your health benefits, increasing your physical performance and cardiac function far better than continuous “aerobic” exercise. Not only that, but REDUCING the volume (the total amount of exercise) and INCREASING the intensity to maximum will increase your speed, your endurance, improve your heart function and energy metabolism and decrease the catecholamine stress hormone levels.
The Myoride Exercise Machine is the best way to engage in full body, complete range of motion, low-impact, Maximum Intensity Interval Training.