1. ACE Personal Trainer Manual 5th Edition
Chapter 11: Cardiorespiratory Exercise: Programming and Progressions
Lesson 11.2

2. After completing this session, you will be able to:
LEARNING OBJECTIVES
After completing this session, you will be able to:
Interpret general guidelines for intensity of cardiorespiratory exercise for health, fitness, and weight loss
Interpret general guidelines for duration of cardiorespiratory exercise for health, fitness, and weight loss
Interpret general guidelines for exercise progression of cardiorespiratory exercise for health, fitness, and weight loss

3. INTENSITY
Exercise intensity – the most important element of the exercise program to monitor
Methods for monitoring exercise intensity:
Heart rate [% maximum heart rate (MHR); % heart-rate reserve (HRR)]
Ratings of perceived exertion (RPE)
VO2 or metabolic equivalents (METs)
Caloric expenditure
Talk test/first ventilatory threshold (VT1)
Blood lactate and second ventilatory threshold (VT2)
Exercise intensity is also the most difficult element to present quantitatively.

4. INTENSITY: HEART RATE
Using percentage of MHR or HRR is the most widely used approach for programming and monitoring intensity:
Accuracy requires knowledge of the individual’s MHR
Given the risk of a maximal-effort test, MHR is normally determined via mathematical formulas (e.g., 220 – age)
Numerous variables impact MHR:
Genetics
Exercise modality (e.g., MHR varies between running and cycling)
Medications
Body size – MHR higher in smaller clients due to smaller heart and stroke volume
Altitude – lowers MHR reached due to a client’s inability to train at higher intensities
Age – MHR varies significantly among people of the same age
Smaller heart and chamber size – generally explains why females often have higher resting heart rates (RHR) than males.

5. INTENSITY: HEART RATE Concerns with 220 – age formula:
Tends to overestimate MHR in younger adults
Underestimates MHR in older adults
This may lead to over- or underestimating exercise intensities:
Overtraining – risk of injury and a potentially negative experience
Undertraining – potential boredom and insufficient challenge
Risk of cardiovascular complications – strongly related to inappropriately high exercise intensities
Guiding exercise on the basis of estimated age-based MHR is discouraged
ACSM suggests formulas with standard deviations closer to 7 bpm:
206.9 – (0.67 x age)
208 – (0.7 x age)

6. INTENSITY: HEART RATE

7. RECOMMENDED EXERCISE INTENSITY

8. KARVONEN METHOD
The Karvonen formula – or heart-rate reserve (HRR) – should be based on measured MHR measured to yield the most accurate results.
HRR considers potential RHR differences by determining a HRR from which training intensities are calculated.
This reduces discrepancies in training intensities between individuals with different RHR and accommodates the training adaptation that lowers RHR, therefore expanding HRR.
While the HRR model does reduce the error in estimation, it still has limitations regarding its accuracy and appropriateness. There is some debate over the body position in which RHR is measured. This formula was created measuring true RHR, taken in the morning in a reclining position. RHR varies by approximately five to 10 beats when a person transitions from lying to standing, thereby altering the size of the HRR. Given the concern with some inconsistencies with clients measuring their own HR, ACE recommends measuring RHR in the body position in which the client will exercise. This may necessitate the need for two sets of training zones, one for seated/recumbent positions and another for standing activities.

9. KARVONEN METHOD

10. USE OF KARVONEN METHOD
Figure 11-3 Use of the Karvonen formula for a 20-year-old man (average shape; resting heart rate = 70 bpm)
Note: bpm = Beats per minute; MHR = Maximum heart rate; HRR = Heart-rate reserve; RHR = Resting heart rate

11. RATINGS OF PERCEIVED EXERTION
RPE – a subjective numbering system shown to be capable of defining the ranges of objective exercise intensity
There are two versions of the RPE scale:
The classical (6 to 20) scale
The contemporary category ratio (0 to 10) scale
RPE ratings of moderate to hard span the range of recommended exercise training intensities.
The RPE system works well for approximately 90% of people.
With practice, clients can usually learn to use the scale fairly effectively.
A rating of “moderate” on the RPE scale is more or less equivalent to 70% of HRR.
A rating of “somewhat hard” is more or less equivalent to 80% of HRR.
A rating of “hard” is more or less equivalent to 85% of HRR.
Very sedentary individuals often find the RPE scale difficult to use, as they find any level of exercise fairly hard.
However, in the very sedentary, even a small amount of low-intensity exercise is effective in terms of producing some exercise training benefits and improved health outcomes.
At the other end of the continuum, individuals who have high levels of muscular strength may under-rate the intensity of exercise if they focus on the muscular tension requirement of exercise rather than on the breathing elements.

12. SESSION RPE
How does the concept of “session RPE” expand your understanding of intensity?
Use this technique to monitor the intensity of your own workouts and develop multiple scenarios that will help you reach a weekly RPE goal.

13. INTENSITY: VO2 OR METABOLIC EQUIVALENTS
Due to the inaccuracy of estimating %VO2max or %VO2reserve (VO2R), a program based on metabolic or ventilatory responses is better.
METs – multiples of an assumed average metabolic rate at rest of 3.5 mL/kg/min:
Very easy and intuitive to understand (e.g., at 5.0 METs, they are working five times harder than resting)
RMR is not exactly 3.5 mL/kg/min in every individual, or even in the same person at all times
The utility of using METs rather than directly measured VO2 is so substantial that it more than makes up for any imprecision
Light (<3 METs)
Moderate (3–6 METs)
Vigorous (>6 METs)
There are minimal improvements in VO2max if the intensity of training is below a threshold of 40/50% of VO2max or VO2R. While acknowledging that lower-intensity exercise can result in improvements in aerobic capacity in very sedentary or unfit individuals, there does seem to be a lower-limit intensity below which exercise is of minimal benefit.
Although experimental evidence is lacking, this lowest effective training intensity at which adaptations might be provoked is probably better defined in terms of the first ventilatory threshold (VT1). Although training below this threshold may have some benefit, it is highly probable that training very much below this threshold will yield minimal cardiorespiratory fitness benefits. It is arguable that very extensive low-intensity training is important in terms of expending energy in programs designed for weight loss, although there does appear to be a lower limit of exercise intensity that is critical when training for cardiorespiratory fitness.
Training programs based on %VO2max or %VO2R depend on a maximal exercise test to be accurate, or on some estimate of VO2max derived from a submaximal test. Given that maximal tests are rarely available, and that equations for estimating VO2max are not exceedingly accurate, particularly if any handrail support is allowed during treadmill testing or training, recommending exercise on the basis of this “gold standard” technique probably is much less useful than is widely assumed.
In cases where VO2 is not directly measured during either testing or training, an alternative method for expressing exercise intensity is in terms of METs.

14. MET VALUES

15. INTENSITY: CALORIC EXPENDITURE
When the human body burns fuel, oxygen (O2) is consumed, which yields calories to perform work.
The number of calories produced per liter of O2 consumed varies according to the fuel utilized:
4.69 kcal per liter of O2 for fats
5.05 kcal per liter of O2 for glucose
A value of 5 kcal per liter of O2 is sufficiently accurate
Caloric expenditure – calculated in terms of the gross or absolute VO2 during an activity:
The measured or estimated total quantity of O2 consumed per minute x 5 kcal/liter O2
A relative VO2 of 40 mL/kg/min for a 220-lb (100-kg) individual is converted to gross or absolute terms as follows:
If this individual consumes 40 mL/kg/min, then his or her entire body consumes 40 mL x 100 kg = 4,000 mL/min, or 4.0 L/min (1,000 mL = 1 L)
Most pieces of commercial cardiovascular exercise equipment provide estimates of caloric expenditure in this same manner. While they may not always be 100% accurate, they calculate caloric expenditure by estimating gross or absolute VO2 based on the amount of work being performed (i.e., speed, grade, and watts).
If direct measurement of VO2 during activity is not available, the trainer can use published MET estimates for a variety of activities (see Table 11-6). Online caloric-expenditure calculators are available for a variety of physical activities on the ACE website (
If the quantity of O2 consumed is provided or measured in relative terms (i.e., mL/kg/min), this value must first be converted to gross or absolute terms to determine the total amount of O2 consumed before the caloric value can be calculated.

16. Then ask, “Can you speak comfortably?”
INTENSITY: TALK TEST
At about the intensity of VT1, the increase in ventilation is accomplished by an increase in breathing frequency – it is no longer possible to speak comfortably.
Ask clients to recite something familiar, such as the Pledge of Allegiance.
Then ask, “Can you speak comfortably?”
If yes, the intensity is below the VT1.
If less than an unequivocal “yes,” the intensity is probably right at VT1.
If “no,” the intensity is probably above or nearer to VT2.
The talk test is based off an individual’s unique metabolic or ventilatory responses.
2nd option:
Compare the number that an individual can count to during the expiration phase of one breath during exercise against the number that can be counted to during the expiration phase at rest.
Normally, when the number that can be counted to during exercise drops to about 70% of the number that is possible at rest, the intensity is approximately equal to the VT1. For example, if an individual can count to 14 during the expiration phase at rest, 70%—the indicator of VT1—represents the exercise intensity at which he or she can no longer count past 10.
For most people, training at intensities at which the answer to the question, “Can you speak comfortably?” becomes less than an unequivocal “yes” may represent the ideal training intensity marker. Therefore, the talk test is an appropriate marker to use for many individuals, especially for those seeking to lose weight or develop their aerobic efficiency. At VT1, fats continue to contribute significantly to the number of calories burned (caloric quality). Additionally, training at or near this intensity (unique to the individual’s own metabolism) increases the likelihood of a better exercise experience. Higher-intensity training for those individuals with performance goals can be regulated in terms of the VT2.

17. BLOOD LACTATE AND VT2
Lactate – produced at a higher rate as exercise intensity increases
At approximately 50% power output during incremental exercise, the ability to remove lactate becomes limited, and a net accumulation of lactate in the blood begins
Lactate threshold – the point when lactate production becomes greater than lactate removal, resulting in an initial rise in blood lactate values
VT1 and the increase in blood lactate occur at about the same intensity
VT2 – the point at which high-intensity exercise can no longer be sustained given the accumulation of lactate that begins to overwhelm the blood’s buffering system
Defined as the onset of blood lactate accumulation (OBLA) and represents the “shutdown” point; the HR turnpoint (HRTP)
Exercise immediately below this OBLA marker represents the highest sustainable intensity.
Considered an excellent marker of performance – usually lasting 20–30 minutes in duration
Because of the need to prevent the accumulation of lactate from causing disturbances in the blood pH balance of the body, the acid associated with lactate is buffered by the bicarbonate buffering system in the blood. This produces extra carbon dioxide (CO2), which causes a subsequent increase in the amount of breathing (VT1) and the subsequent challenge to talking continuously. At higher intensities, when the buffering mechanism cannot keep up with the extra acid production, and the pH of the blood begins to fall (due to accumulating lactate), the respiratory center is strongly stimulated, and there is yet another increase in breathing (VT2). This is usually associated with a blood lactate concentration of about 4 mmol/L – equivalent to the OBLA. This point represents the intensity at which the body can no longer sustain an activity, given the accumulation of lactate, and begins to shut down. In most healthy people, this marker is associated with a flattening of the HR response to increasing intensity, referred to as the HR turnpoint (HRTP).
OBLA technically refers to the point at which lactate levels begin to rise exponentially due to an accumulation within the blood and an inability to buffer the influx of acid.
What researchers define as the OBLA is commonly referred to as the anaerobic or lactate threshold by athletes and fitness professionals. This intensity represents the “shutdown” point—what many fitness professionals call the LT. The LT technically refers to the point at which lactate production becomes greater than lactate removal, resulting in an initial rise in blood lactate values.

18. VENTILATORY RESPONSE TO INCREASING INTENSITY

19. THRESHOLD DETECTION
Schematic of the detection of the first and second thresholds based on increases in ventilation (VT1 and VT2), on lactate (LT and 4 mmol/L), and on the non-linearity of the HR increase
This provides for the possibility of three effective training zones based on two thresholds.

20. THREE-ZONE TRAINING MODEL
VT1 and VT2 provide an easy way to divide intensity into training zones that are determined without any use of MHR:
Zone 1 reflects heart rates below VT1
A client can talk comfortably
Zone 2 reflects heart rates from VT1 to just below VT2
The client is not sure if he or she can talk comfortably
Zone 3 reflects heart rates at or above VT2
The client definitely cannot talk comfortably
VT1 and VT2 can be based on respiratory responses or blood lactate responses.

21. DURATION
Exercise duration – the amount of time spent performing the physical activity
Can also be expressed as exercise quantity
Benefits gained from exercise and physical activity are dose-related:
Greater benefits are derived from greater quantities of activity
Activity expending ≤1,000 kcal/week generally produces improvements to health
Greater quantities expending ≥2,000 kcal/ week promote effective weight loss and significant improvements to overall fitness

22. CONSIDERATIONS FOR DURATION
Exercise quantity may be performed:
As one continuous bout, or
Intermittent bouts
Accumulated throughout the day lasting a minimum of 10 minutes each
Trainers must place the needs and abilities of their clients first:
Assess current conditioning levels, tolerance, and availability
Select suitable durations and progressions
Aspire only to attain the recommendations when appropriate

23. EXERCISE DURATION GUIDELINES
Moderate-intensity exercise for at least 30 minutes a session, a minimum of 5 days per week for a total of 150 minutes per week, or
Vigorous-intensity exercise for at least 20–25 minutes a session, a minimum of 3 days per week for a total of 75 minutes per week, or
A combination of both
Those seeking to manage or lose weight:
50–60 minutes of moderate-intensity exercise or activity each day, 5–7 days a week, for a total of 300 minutes, or
A total of 150 minutes of vigorous exercise or activity per week, performed a minimum of three days a week, or
These exercise guidelines are from U.S. Department of Health & Human Services, 2008.
Trainers must bear in mind that beginner exercisers will generally not be able to complete 30 minutes of moderate-intensity cardiorespiratory exercise, nor will they be capable of achieving the recommended frequency. Exercise can be performed in multiple sessions of 10 or more minutes to accumulate the desired duration and volume of exercise per day. Very deconditioned individuals can benefit from exercise bouts of less than 10 minutes.

24. PRINCIPLES OF EXERCISE PROGRESSION
Overload – when additional timely, appropriate stresses are placed on the organs or systems, physiological adaptations and improvements occur.
The rate of progression depends on:
The individual’s current conditioning level
Program goals
Tolerance for discomfort associated with raising training load or volume
Specificity – physiological adaptations made within the body are specific to demands placed upon that body
Often called the SAID principle – specific adaptations to the imposed demands
A training program should progress to mimic the demands of that activity to provide the specific stimuli that elicit appropriate adaptations.

25. EXERCISE PROGRESSION
Exercise duration – initially the most appropriate variable to manipulate
Start with developing adherence:
Build exercise sessions by 10%, or
5–10 minutes every week or two over the first 4–6 weeks
Increase frequency, then intensity, keeping progressions consistent with the client’s goals
To limit the risk or burnout or orthopedic injury from overuse:
Include multiple modalities
Cross-training, walking, cycling, elliptical training, etc.
Include multiple variations within a modality
Steady-state exercise, interval training, Fartlek training, etc.
While exercise needs to be an enjoyable and positive experience for clients, the trainer will need to determine how to progress each client’s program.
Fartlek running involves varying the pace throughout the run, alternating between fast segments and slow jogs.

26. SUMMARY
Exercise intensity is arguably the most important element of the exercise program to monitor.
At the same time, it is the most difficult element to present quantitatively and there are numerous methods by which a trainer can program.
Benefits gained from exercise and physical activity are dose-related, in that greater benefits are derived from greater quantities of activity.
Ultimately, exercise needs to become an enjoyable and positive experience and the rate of progression must be taken into consideration.