This document discusses objective and subjective measures of exercise intensity. Objectively, it describes VO2 max and how it is measured via ergospirometry to determine cardiorespiratory fitness. It provides normal VO2 max values for Indians and how VO2 max relates to different activities' energy costs. Maximum heart rate is also discussed as related to VO2 max and used to prescribe training intensities via the Karvonen formula. Subjectively, the Rating of Perceived Exertion scale is presented as an easy way to gauge exertion levels, especially for those who can't monitor heart rate. Both objective and subjective measures have limitations but provide ways to prescribe and monitor exercise intensity.

1. Objective and subjective measures of exercise
intensity
By,
DR. Susan Jose

2. VO2 max
• VO2max can be defined as the maximal volume of oxygen
uptake by the muscles during physical exertion.
• VO2 max is directly proportional to the capacity of the
– pulmonary
– cardiovascular
– muscular systems
• Measurement- by an ergospirometer test
• In this procedure, the subject breathes through a low-resistance
valve with his nose occluded while performing a maximal
exercise testing
– Flow volume loops
– expired fractions of oxygen (O2) and carbon dioxide (CO2)
– heart rate
are measured that is used for the computerized calculation of
Vo2 max.

3. Activity Resting Horizontal
Component
Vertical
Component/
Resistance
Component
Limitations
Walking 3.5 0.1 speed 1.8 speed x
grade
Most accurate for
speeds of 1.9–3.7
min/h
Running 3.5 0.2 speed 0.9 speed x
grade
Most accurate for
speeds > 5 min/h
Stepping 3.5 0.2 steps/min 1.33 (1.8 step
Height x steps
min)
Most accurate for
stepping rates of
12–30 steps /min
Leg cycling 3.5 3.5 (1.8 work rate)/
body weight
Most accurate for
work rates of 300–
1,200 kg /m/ min
Arm cycling 3.5 (3 work rate)/
body weight Most accurate for
work rates between
150–750 kg /m
/Min
Vo2 max = Resting + Horizontal + Vertical
ACSM Predictive Vo2 Max Equations

4. • Normal values at rest in India population:
– Healthy male - 4.7.56±8.37 L/kg/min
– Healthy female – 3.7.62±7.40 L/kg/min
Uses-
• Test improvements endurance during a training season
• Objective measure of exercise intensity prescription
• To analyze the progress in cardio respiratory fitness following
an exercise training.

5. MAXIMUM HEART RATE
• Maximal heart rate (HR max.)is the peak heart
rate that an individual can achieve without any
cardiovascular problems at maximal physical
exertion and it is age dependant.
• Its is calculated using the FOX EQUATION=
220-AGE
WHY IMPORTANT?
• HR max - important due to its relation to
maximum oxygen consumption (VO2max).
• HR max Inversely proportionally to Vo2max.

6. Use-
• For prescription of exercise intensity in Endurance training.
• Karvonen’s formula= (HR max—HR rest)× 50-85% +RHR
The target heart rate during exercise can be continuously monitored
by using validated chest straps and wrist watches.
Disadvantage-
 Not reliable in patients on beta blockers.
 In relative contraindicated conditions such as controlled
arrhythmias, partial conduction blocks.
INTENSITY MILD MOD HIGH
Target heart
rate
50- 63% 64- 76% 77-93%
Oxygen
consumption
20-39% of vo2
max.
40-59% of vo2
max.
60-84% of vo2
max.

7. Subjective measure of exercise intensity

8. Rate of Perceived Exertion
Perceived exertion is how hard you feel like your body is
working. It is based on the physical sensations a person
experiences during physical activity, including increased heart
rate, increased respiration or breathing rate, increased
sweating, and muscle fatigue.
• There are various scales to measure the Perceived Exertion
such as
– Borg Rating of Perceived Exertion (RPE),
– Talk Test
– Feeling Scale
– OMNI Scales

9. • Modified Borg RPE scale (0-10)- measures the level of bodily
exertion and breathlessness during physical activity.
• It is usually used in clinicals and home setups after a
submaximal exercise test or during / after the aerobic training.
• It can be of good value in patients who have difficulty in self
monitoring of the pulse rate during training.
• Visual display of the scale is beneficial to improve the
reliability of the self-reported exertion measure.

11. • 0.5 - 2 on modified Borg's = warm up and cool down
exercises
• Training at 3-4 on modified Borg's = moderate
intensity training
• 5-10 on modified Borg's = High intensity training.
• Although, it is easy to use but it cannot be considered
as the first choice for intensity prescription.

12. Uses-
• Patients on beta blockers.
• Patients with the a heart transplantation as the
autonomic nervous system is disrupted.

13. REFERENCES
1. ROY S, MCCRORY J. Validation of Maximal Heart Rate Prediction Equations
Based on Sex and Physical Activity Status. Int J Exerc Sci. 2015 Oct
1;8(4):318–30.
2. MAXIMUM HEART RATE MEASURED VERSUS ESTIMATED BY DIFFERENT
EQUATIONS DURING THE CARDIOPULMONARY EXERCISE TEST IN OBESE
ADOLESCENTS [Internet]. [cited 2020 Apr 21]. Available from:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6202885/
3. Karvonen method [Internet]. Oxford Reference. [cited 2020 Apr 22].
Available from:
https://www.oxfordreference.com/view/10.1093/oi/authority.201108101
05207569
4. Rate Perceived Exertion as a Measure of Exercise Intensity [Internet].
[cited 2020 Apr 22]. Available from:
//www.nursingcenter.com/journalarticle?Article_ID=4388376&Journal_ID
=2695880&Issue_ID=4388241
5.ACSM GUIDELINES 2019

14. THANK YOU