Cardio Exercise / HR Training "Fundamentals"

Cardio Description: 
"Cardio" is today’s catch-all term for "Cardio Respiratory Fitness" regularly used in the context of endurance fitness activity.  Cardio fitness exercises your heart, lungs and circulatory system with the primary function of supplying oxygen (and removal of lactic acid cellular waste) to skeletal muscles during sustained physical activity.  Cardio is generally used in reference to exercise in the presence of oxygen; this activity is referred to as aerobic exercise.

Aerobic means "with oxygen", and refers to the use of oxygen in muscles’ energy-generating process. Aerobic exercises typically include those performed at moderate levels of intensity for extended periods of time and that maintain an increased heart rate. With Cardio exercise, oxygen is used to "burn" fats and glucose (a simple sugar and the most important carbohydrate) in order to produce ATP (adenosine triphosphate), the basic energy carrier for all cells.  Aerobic exercise improves the respiratory system by increasing the amount of oxygen that is inhaled and distributed to body tissues.

Anaerobic means "without oxygen", and refers to the energy exchange in living tissue that is independent of oxygen. Anaerobic exercise is brief, highly intense activity where energy supplies (ATP) is available in limited quantity within the muscle cells.  Examples of anaerobic exercise include weight lifting, sprinting, and jumping.

Exercises / Activities:
There are many ways to get a good ‘Cardio’ workout.  Activities need to be greater than 20 minutes duration and involve effort (intensity) above normal ‘daily’ living intensity to attain physical benefits. It is generally believed that if the duration of the cardio activity is longer than 90 minutes, consuming additional carbohydrates during the activity to provide extra calories (energy) is physiologically wise.  Some common activities that evoke a cardio response are the following:  running/jogging/power walking, bicycling, swimming, cross-country skiing, aerobic exercise (group / DVD), dance, skating, soccer, basketball, and any continuous movement sport. 

Frequency / Intensity / Time (FIT) = Results
Results from ‘Cardio’ exercise are always dictated by Frequency, Intensity and Time.

Frequency:  Days per week exercise is accomplished. Generally believed that a minimum of 3 days/week is needed to experience positive physiological adaptation and 6 days per week at varying degrees of intensity is max.

Intensity:  Is the sum of speed + workload. This is the wild card with ‘Cardio’ fitness programs.  De-conditioned and/or individuals just beginning a cardio program need to start at a light intensity level and slowly (over weeks of training) increase their intensity, allowing their bodies to adapt to the new demands being made on it (it is recommended that one consult with their doctor prior to beginning any fitness program). With increased degrees of individual ‘Cardio’ fitness, variations of frequency, duration, and load can be implemented to better achieve specific results.

Time:  Duration of exercise activity. The aerobic energy system really kicks in after 5 minutes of continuous effort and this system’s conversion of calorie to energy can last for several hours (depending on the ‘cardio’ condition of the individual). 

Cardio Exercise Benefits:
A ‘Cardio’ fitness program affords many positive results with your overall health, both physically and mentally.  Some of the more recognized benefits are as follows:

Heart Rate (HR) Training

Description:
Personal wellness is not one single element, but a continuum based on Health, Fitness and Performance.  Individually, we strive for specific aspects of health at different times of our lives.  Scientific research has proven that to reach particular fitness goals exercising at the correct individual intensity is vital. For the general population, the best barometer of exercise intensity is our individual heart rates (measured in beats/minute). Understanding and tailoring the degree of training intensity (zones) to maximize one’s physiological response and adaptation is simple and easily accomplished with the use of a heart rate monitor (HRM).  HRM’s are the most sophisticated and powerful fitness tool available to fitness enthusiast today.

Degree of Intensity (zones):
Best described as:  Speed + Workload (calorie cost) of a workout.  Interestingly, different levels of intensity tax one’s cardio/energy systems differently and produce results specific to the effort.  There are no hard and fast borders defining every individual’s exact intensity levels or zones, but a general rule can be used to understand how and when one’s system might respond.  Using the Wellness continuum mentioned above, the following training levels (expressed as a percent of one’s ‘max heart rate’) seem generally applicable:

General Training Ranges:

50-65%            Health
Functional Fitness, Daily Health and Well-being
Major Benefits:  Lower body fat, positive changes in BP, improved cholesterol levels, enhanced immune function, muscle strengthening, minimize fatigue, heighten wellness and energy

65-80%            Fitness
This level causes significant cardio respiratory / pulmonary adaptation and should be gradually worked into a fitness program as conditioning improves. 
Major Benefits:  Positive changes in oxygen utilization, lactate waste removal, energy system efficiencies, VO2 max. This intensity level has the best fat calorie utilization for required energy needs. 

80-100%          Performance
Athletes and highly-conditioned Sport/Fitness Enthusiasts wanting to “elevate their game”.  Often achieved with high intensity / interval training workouts
Major Benefits: Performance, endurance and recovery improvement.  Push anabolic threshold up. Improve efficiencies of all energy systems.

Specific Training HR Range

50 – 60%         Start Up, Basic Wellness
Goal:  Maintain current state of health and begin the “getting fit” process.
Exertion Level:  Warm-up / Easy pace; Slight sweating; No difficulty to converse; Increase heart rate slightly above normal for a sustained duration.

60 – 70%         Health Enhancement
Goal:  Gradually improve upon current health condition.
Exertion Level:  Moderate and comfortable pace; mild sweating; little difficulty to converse, but breathing becomes more rapid and HR obviously faster and stronger.

70 – 80%         Fat Burning / Base Fitness
Goal:  Maximized stored fat as calorie / energy source during workout and improved base cardio-respiratory health.
Exertion Level:  Moderate, sustainable intensity; full sweat; some difficulty to converse; breathing is somewhat labored and HR is strong

80 – 90%         Cardio Conditioning
Goal:  Improve fitness and cardio condition level. 
Exertion Level:  High, not sustainable over long duration; heavy sweat; difficulty to converse; breathing is labored and HR is fast, strong and evident.

90 – 100%       Anaerobic / Interval Training
Goal:  Push anaerobic threshold up toward max HR. Improve cardio conditioning and recovery time; minimize fatigue and muscular lactic acid build up. 
Exertion Level:  Max – All Out, sustainable in only limited durations or short bursts.  Breathing and HR are close to or at max; muscle burn.

Resting HR:
This is the rate your heart beats after a good night’s sleep, just after you awaken and before you rise out of bed.  This should be the heart’s lowest rate of the day, although it is not a good indication of good health unto itself as it is somewhat unique to the individual.  However, you can improve (slow) your resting HR with better overall fitness. This is called the ‘Training Effect’.  A rise in one’s resting HR may indicate ‘over-training’ and if this is suspected, one should take a rest or active rest (low intensity) day of activity.

Max HR:
Interestingly, this is a specific number unique to the individual and genetically determined. It cannot be increased with training, and cannot be achieved when in a de-conditioned state.  One’s HR has everything to do with heart size and total blood volume pumped per beat.  It is the maximum number of contractions per minute your heart can make.  When achieved in a real-life situation, it is done so through short-burst, high intensity activity.  This rate cannot be sustained for more than several seconds, as the energy required (ATP) cannot keep up with demand. 

Max HR is best determined with a professional’s guidance or doctor’s supervision, but there are formulas that provide a relatively accurate measure.  Heart Rate Training Levels (zones) are most often referred to as a percent of one’s max HR. Note, if you are de-conditioned, you do not want to take a Max HR test designed to bring you to your actual max; always consult a doctor prior to starting a fitness program. Instead, these formulas are much easier, and accurate enough, for you to use to begin training.

Generally Accepted Max HR calculation:
Max HR               = 220 – Age
Training Level     = Max HR x Intensity Level (as a % of maxHR) x 1.10

                           OR

210 – (1/2 current age) – (5% x body wt in lbs) + 4 (males only, female add nothing)

Karvonen Formula = Target Training HR
(establish)    Max HR
(subtract)     Age
(subtract)     Resting HR
(multiply)      Desired Training Level (specific %, i.e. 85%)
(add)            Resting HR
(result)         Target Training HR

*Note: All these formulas are for general reference only.  They have margins of error and are best used for general orientation of one’s maximum HR, only.

Talk Test (supports General Training Range)
This is a subjective measurement of cardio intensity and measures “perceived exertion.”  When exercising in a social group, these estimates are broad enough to often include most of the participants with the designated, desired intensity level.

50-65%:      Breathing is only slightly above normal ‘daily-living’ level.  Conversation is easy and only slightly labored, but full use of complete sentence is not an issue.

65-80%:      Breathing is significantly more strenuous than at rest. The participant
Is still able to talk, but finds it difficult to speak in full sentences.

80-100%:    Breathing is deep and may become labored.  Speaking becomes increasingly difficult with participant only able to converse in short, abbreviated sentences.  As intensity is increased, the ability to converse becomes very difficult.

High Intensity Training

The fundamental principles are intensity, duration, and frequency. Exercises performed with a high level of intensity (effort), are intended to stimulate the physiological adaptation with an outcome of increased muscular strength (resistance training) or cardio energy efficiencies (aerobic or anaerobic). Advocates believe this type of training is superior as it demands the greatest amount of physiological adaptation in the shortest amount of time.  Cardio exercise, high-intensity training is best accomplished with the inclusion of Interval Training Workouts. 

Interval Training Workouts

Interval training consists of a period of high intensity exercise followed by a period of rest (usually active rest).  Several bouts or reps of interval training are usually linked one after another, causing each ensuing rep to become more exhausting and causing greater physiological adaptation (benefit). The degree and speed of recovery between reps plays a significant role with intensity of the rep set (number of reps to be completed).  Also, Intervals create variety in the workout and help avoid training plateaus. There are generally three types (duration) of Interval workouts:

Sprint - Short, max anaerobic effort, 30 seconds or less
Intermediate - Sub max, intense aerobic effort, up to 5 mins.
Endurance - Cardio rigorous, sustainable but not desirable, up to 10 mins.

Anabolic Threshold

This level of exercise intensity is actually the aerobic energy system ceiling.  The anaerobic threshold (AT) is the point at which lactate (cellular waste) starts to accumulate in the blood. This happens when it is produced faster than it can be removed, sometimes referred to as the lactate threshold.  This buildup interferes and obstructs ATP production and thus, quickly impedes continued high-intensity activity.  When exercising below the AT level, any lactate produced by the muscle is removed by the body without it building up.  The AT is a useful measure for deciding exercise intensity and can be greatly increased with specific training.