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ORIGINAL ARTICLE
Year : 2020  |  Volume : 47  |  Issue : 2  |  Page : 85-88

Protocols for moderate-intensity and vigorous-intensity exercise for undergraduate practical teaching


1 Department of Physiology, Bhima Bhoi Medical College and Hospital, Balangir, Odisha, India
2 Department of Physiology, Raiganj Government Medical College and Hospital, Raiganj, West Bengal, India
3 Department of Physiology, Fakir Mohan Medical College and Hospital, Balasore, Odisha, India

Date of Submission17-Apr-2020
Date of Acceptance05-Jun-2020
Date of Web Publication11-Sep-2020

Correspondence Address:
Dr. Himel Mondal
Department of Physiology, Bhima Bhoi Medical College and Hospital, Balangir - 767 002, Odisha
India
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/jss.JSS_25_20

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  Abstract 


Background: In academic teaching, we need exercise protocols with moderate and vigorous intensity for observing cardiorespiratory changes in different grades of exercise. Aim: We aimed to formulate exercise protocols with moderate- and vigorous-intensity for apparently healthy adult subjects for undergraduate practical teaching to be used in the observation of cardiorespiratory changes in different grades of exercise. Methods: We hypothesized that 50 m brisk walking (to and fro, four times in a clinical physiology classroom) is moderate-intensity exercise and spot jogging with full effort and verbal encouragement for 1 min is vigorous-intensity exercise. We measured heart rate (HR) immediately after moderate-intensity and vigorous-intensity exercise and compared it with the standards where attainment of 50%–70% of maximum achievable HR (HRmax) is moderate-intensity exercise and 71%–85% of HRmaxis vigorous-intensity exercise. Results: Data of 85 participants (male = 59, female = 26) with mean age 19.56 ± 1.13 years were analyzed. The percentage of HRmaxachieved in the moderate-intensity exercise was 58.19 ± 7.55, and vigorous-intensity exercise was 78.19 ± 8.48. About 85.88% of participants were within 50%–70% of HRmaxin the moderate-intensity exercise and 72.94% of participants were within 71%–85% of HRmaxin the vigorous-intensity exercise. Conclusion: A brisk walking for a distance of 50 m can be considered as moderate-intensity and a spot jogging with full effort for 1 min can be considered as a vigorous-intensity exercise for observing cardiovascular changes in different grades of exercise. These protocols can be used for physiology practical teaching in a small practice room without using any instrument in resource-limited settings.

Keywords: Curriculum, exercise, exercise intensity, heart rate, jogging, walking


How to cite this article:
Mondal H, Mondal S, Das D. Protocols for moderate-intensity and vigorous-intensity exercise for undergraduate practical teaching. J Sci Soc 2020;47:85-8

How to cite this URL:
Mondal H, Mondal S, Das D. Protocols for moderate-intensity and vigorous-intensity exercise for undergraduate practical teaching. J Sci Soc [serial online] 2020 [cited 2020 Sep 20];47:85-8. Available from: http://www.jscisociety.com/text.asp?2020/47/2/85/294791




  Introduction Top


The intensity of physical activity or exercise is the magnitude of the effort a person applies for that particular task. According to the World Health Organization, the intensity of physical activity is divided into two categories – moderate-intensity and vigorous-intensity. Metabolic equivalents (METs) are commonly used to express intensity. One MET refers to the energy consumed by the body in sitting quietly and it is equivalent to 1 kcal/kg/h. Moderate-intensity exercise requires approximately 3–6 METs and vigorous-intensity exercise requires >6 METs.[1],[2] METs can also be expressed in terms of oxygen consumption by the individual. One MET is equivalent to the oxygen consumption of 3.5 ml/kg/min.[3] Hence, either measurement of the heat or oxygen intake can be used to quantify the METs and then to comment on the exercise intensity. These methods require costly instruments that may not be available in resource-limited settings. Another relatively easier method to quantify the grades of exercise is to measure the heart rate (HR) during or immediately after the exercise. If the intensity of the exercise is moderate, then the HR would raise 50%–70% of the maximum achievable heart rate (HRmax) of an individual, and if the intensity is vigorous, the HR would raise 71%–85% of HRmax.[4]

In academic teaching in practical physiology, we observe cardiorespiratory changes (e.g., pulse, blood pressure [BP], respiratory rate [RR]) in different grades of exercise. For that, we record the resting cardiorespiratory parameters (e.g., resting HR [HRrest], BP, and RR) and the subject exercises with moderate-intensity and then vigorous-intensity (Competency number: PY5.12; core competency in “skill” domain with “show how” capability).[5] The parameters are measured again during or immediately after the exercise. Now the question arises – what mode and extent of the exercise are moderate or vigorous for students? To quantify the grades, at least, we need to check the raise in HR and if it becomes 50%–70% or 71%–85% of the HRmax, then the exercise will be considered as moderate-intensity and vigorous-intensity, respectively. However, if we would like to observe the changes in HR in different grades of the exercise, then we need a prefixed protocol for moderate-intensity and vigorous-intensity exercise.[6]

With this background, we aimed to formulate exercise protocols for apparently healthy young adults which would be of moderate- and vigorous-intensity. Furthermore, we aimed to develop the protocol that can be practiced with minimal instruments in a small practical classroom.


  Methods Top


Subjects

This study was conducted with 85 (male = 59, female = 26) apparently healthy adult sedentary undergraduate medical students. The only inclusion criterion was providing written consent for participation. Subjects with any acute or chronic diseases, as declared or detected by the physical activity readiness questionnaire, were excluded from the study.[7] The study was conducted in full accordance with the Declaration of Helsinki, updated in 2013.

The hypothesis of the exercise protocol

We hypothesized that a “50 m brisk walking” would be moderate-intensity exercise and “spot jogging with full effort and verbal encouragement for 1 min” would be the vigorous-intensity exercise.[8],[9] For designating those protocols of exercise to be moderate-intensity or vigorous-intensity, the raise in HR should be 50%–70% and 71%–85% of the HRmax in moderate- and vigorous-intensity exercise, respectively.

Design

This is an observational study conducted in December 2019 in the departmental teaching laboratory for undergraduate medical students. The study includes noninvasive checking of systemic arterial pulse rate before and immediately after the hypothesized exercise protocol of moderate- and vigorous-intensity.

Execution of the exercise protocol

We measured the length of the laboratory and found that to and fro walking for four times from one end to the other end of the room completes 50 m distance. HRrest was recorded by palpating radial pulse after a 5-min rest in sitting posture. Immediately, after the completion of brisk walking, the subjects sat on the stool and radial pulse rate was recorded for 15 s and multiplied by four to get HR in moderate-intensity exercise (HRme). Similarly, immediately after completion of the vigorous-intensity exercise, the radial pulse rate for vigorous-intensity exercise (HRve) was recorded. [Figure 1] demonstrates the process at a glance.
Figure 1: Observation of heart rate in resting state, moderate-intensity, and vigorous-intensity exercise

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Calculation and statistical analysis

HRmax was calculated from the formula: 208 − (0.7 × age).[10] Change in HR (ΔHR) in moderate-intensity exercise and vigorous-intensity exercise was calculated by subtracting HRrest from the HRme and HRve. In the calculated value, a positive sign indicates a raise in HR. The percentage of change in HR in comparison to HRrest was also calculated. The percentage of HRmax reached in each type of exercise was calculated by comparing achieved HR (i.e., HRme and HRve) and HRmax.

Data were expressed in mean and standard deviation. Data of male and female participants were compared by unpaired t-test. Subject achieving the target HR is expressed in number and percentage, and it was compared with a lower and higher than target range by Chi-square test. For the entire statistical test, a P < 0.05 was considered statistically significant. We used Microsoft Excel 2010 and GraphPad Prism 6.01 (GraphPad Software, CA, USA) for the calculation and statistical analysis.


  Results Top


We analyzed data of 85 participants (male = 59, female = 26) with mean age 19.56 ± 1.13 (male = 19.81 ± 1.14, female = 19 ± 0.89) years.

The mean HRrest was 76.73 ± 7.88 bpm. After moderate-intensity and vigorous-intensity exercise, the HR was 113.07 ± 14.73 and 151.93 ± 16.54 bpm, respectively. The percentage of HRmax used in moderate-intensity and vigorous-intensity exercise was 58.19 ± 7.55 (range: 39.92–77.32, 95% CI: 56.56–59.82) and 78.19 ± 8.48 (range: 47.25–96.356, 95% CI: 76.36–80.02), respectively [Table 1].
Table 1: Heart rate (bpm) in rest, after 50 meter brisk walking (moderate-intensity exercise), and after 1 min spot jogging with full effort (vigorous-intensity exercise)

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Number of the participant within the target HR range was 85.88% (below the range 11.77%, above the range 2.35%) (χ2: 106.8, P < 0.001) and 72.94% (below the range 9.41%, above the range 17.65%) (χ2: 60.89, P < 0.001) in moderate-intensity and vigorous-intensity, respectively. [Figure 2] shows the frequency distribution of the achieved percentage of HRmax.
Figure 2: Frequency distribution of achieved percentage of maximum heart rate in moderate-intensity (red triangle) and vigorous-intensity (blue square) exercise

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  Discussion Top


Major finding

To formulate moderate-intensity and vigorous-intensity exercise protocol for apparently healthy young adult students, we have observed that “50 m brisk walking” and “spot jogging with full effort and verbal encouragement for 1 min” can be considered as moderate- and vigorous-intensity respectively.

Implication

The effect of exercise on different cardiorespiratory parameters is a common topic in exercise physiology.[11] Several research-grade instruments can be used to find cardiorespiratory changes in different grades of exercise. However, many resource-limited settings in developing countries may not afford those instruments for teaching purposes. In contrast, the protocol we described in this study can be applied in a small teaching room with minimal instruments. If we conduct a session to observe the effect of exercise on pulse rate, only a wristwatch is sufficient. If we conduct a session to observe the effect of exercise on BP, a sphygmomanometer is sufficient. Furthermore, this protocol can also be applied in a field-level experiment.

For the practical physiology for undergraduate medical students, we prepared an objective structured practical examination guideline for observation of changes in HR in moderate-intensity and vigorous-intensity exercise [Annexure 1].



Limitation

There are several limitations of the study. The calculated HRmax may be different from the actual HRmax.[12] The maximal effort which the subjects supposed to use is affected by motivation. Although we used verbal encouragement, this may not be uniform for all the subjects. This limitation is extended to all exercise-related researches. We used the HR to designate the exercise to be moderate- or vigorous-intensity as our laboratory is not equipped with instruments to measure METs during exercise. Hence, the result of this study should be interpreted with caution.

Any centers may replicate a similar study for finding the suitability of this protocol for their students as environmental and ethnic factors varies across different geographical areas.


  Conclusion Top


For observation of cardiorespiratory changes in exercise, “50 m brisk walking” and a “spot jogging with full effort with verbal encouragement for 1 min” can be considered moderate-intensity and vigorous-intensity exercise, respectively. This protocol is specially developed for teaching undergraduate medical and paramedical students. The protocol does not require any costly instruments. Hence, it can be used in any resource-limited teaching institutions. Furthermore, it can be practiced in both indoor and outdoor.

Acknowledgment

We thank the first-year medical students (2019-2020 batch) of Fakir Mohan Medical College and Hospital, Balasore for their active participation in this study.

Financial support and sponsorship

Nil.

Conflicts of interest

All the authors are medical teachers who teach human physiology to undergraduate medical and paramedical students. According to the curriculum, they teach a “Demonstration - Observation - Assistance – Performance” session on “Record BP and pulse at rest and in different grades of exercise and postures in a volunteer or simulated environment”.



 
  References Top

1.
WHO. Intensity of Physical Activity. Geneva: WHO. Available from: https://www.who.int/dietphysicalactivity/physical_activity_intensity/en/. [Last accessed on 2020 Apr 12].  Back to cited text no. 1
    
2.
Mendes MA, da Silva I, Ramires V, Reichert F, Martins R, Ferreira R, et al. Metabolic equivalent of task (METs) thresholds as an indicator of physical activity intensity. PLoS One 2018;13:e0200701.  Back to cited text no. 2
    
3.
Sanghvi S. Cardiac rehabilitation. In: Porter SB, editor. Tidy's Physiotherapy. 15th ed. United Kingdom: Churchill Livingstone; 2013. p. 147-68.  Back to cited text no. 3
    
4.
Exercise Intensity: How to Measure it. USA: Mayo Clinic. Available from: https://www.mayoclinic.org/healthy-lifestyle/fitness/in-depth/exercise-intensity/art-20046887. [Last accessed on 2020 Apr 13].  Back to cited text no. 4
    
5.
Competency Based Undergraduate Curriculum. Medical Council of India. Available from: https://www.mciindia.org/CMS/information-desk/for-colleges/ug-curriculum. [Last accessed on 2020 Apr 13].  Back to cited text no. 5
    
6.
Burton DA, Stokes K, Hall GM. Physiological effects of exercise. Contin Edu Anaesth Crit Care Pain 2004;4:185-8.  Back to cited text no. 6
    
7.
Adams R. Revised physical activity readiness questionnaire. Can Fam Physician 1999;45:992, 995, 1004-5.  Back to cited text no. 7
    
8.
Murtagh EM, Boreham CA, Murphy MH. Speed and exercise intensity of recreational walkers. Prev Med 2002;35:397-400.  Back to cited text no. 8
    
9.
Zhang HJ, He J, Pan LL, Ma ZM, Han CK, Chen CS, et al. Effects of moderate and vigorous exercise on nonalcoholic fatty liver disease: A randomized clinical trial. JAMA Intern Med 2016;176:1074-82.  Back to cited text no. 9
    
10.
Roy S, McCrory J. Validation of maximal heart rate prediction equations based on sex and physical activity status. Int J Exerc Sci 2015;8:318-30.  Back to cited text no. 10
    
11.
Ramsbottom R, Kinch RF, Morris MG, Dennis AM. Practical application of fundamental concepts in exercise physiology. Adv Physiol Educ 2007;31:347-51.  Back to cited text no. 11
    
12.
Sarzynski MA, Rankinen T, Earnest CP, Leon AS, Rao DC, Skinner JS, et al. Measured maximal heart rates compared to commonly used age-based prediction equations in the Heritage Family Study. Am J Hum Biol 2013;25:695-701.  Back to cited text no. 12
    


    Figures

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