Cardiorespiratory responses to moderate exercise and determination of aerobic power in first year medical students

Subha Kavundapadi Chandrasekaran, Rajkumar Devaraj


Background: Cardiovascular and metabolic disorder has become common in individuals leading a sedentary life. Exercise stress tests are carried out as part of the investigations for determining the individual fitness level. Aerobic power or VO2max which involves a full functional support from cardio respiratory and metabolic pathways is an appropriate test to study cardio pulmonary fitness. The main objective of the study is to find out the normal cardiopulmonary responses to exercise and their aerobic power among untrained 1st year medical students by Astrand 6 minute cycle test.

Methods: All participants who were not undergone any physical training was taken for the study. Students with history of any respiratory or cardiovascular disorders, any lower limb surgery, smoking and drinking alcohol were excluded. Cardiorespiratory changes associated with exercise were studied using bicycle ergometer. VO2max was determined from the heart rate noted at the end of 6 minutes cycling by using Astrand-Rhyming nomogram.

Results: Heart rate, systolic blood pressure and respiratory rate increased with exercise, while diastolic pressure recorded a fall. VO2max   in male students mean 2.973±0.245, in female students mean 2.665±0.305. The VO2maxis thebest physiological indicator of a person’s capacity to continue the severe physical work. From this we can set a norm in assessing physical fitness and the test can be used as screening measures before joining in a job or sports training.

Conclusions: Aerobic power or VO2max or physical work capacity which involves a full functional support from cardiorespiratory and metabolic pathways is an appropriate test to study cardiopulmonary fitness. Implication:  Astrand 6 minutes cycle test  can be used for screening measures before joining in a job or sports training where physical fitness is needed.



Bicycle ergometer, Astrand-Rhyming nomogram, VO2max

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Wasserman K, Hansen JE, Sue JY, Casaburi R, Whipp BJ. Principles of Exercise Testing and Interpretation 3rd edition.

Saper CBC. Convergence of autonomic and limbic connection in the insular cortex of the rat. J Comp Neural. 1982;210(2):163-73.

Fagraeus L, Linnarsson D. Autonomic origin of Heart rate fluctuations at the onset of muscular exercise. Journal of Applied physiology. 1976;40(5):679-82.

McCloskey DI, Mitchell JH. Reflexes cardiovascular and respiratory originating from exercising muscle. J. Physiol. 1972;224(1):173-86.

Chapman CB, Fisher JN and Sproule BJ. Behaviour of stroke volume at rest and during exercise in human beings. J. Clin. Inves. 1960;39(8):1208-13.

Plotnick GD, Becker LC, Fisher ML, Gerstenblith G, Renlund DG, Fleg JL et al. Use of Frant starling mechanism during sub maximal versus maximal upright exercise. Am J. Physiol. 1986;251(6Pt 2):H1101-5.

Thadani U, Parker Jo. Haemodynamics at rest and during supine and sitting bicycle exercise in normal subjects. AM . Cardiol. 1978;41:52-9.

Gledwill N, Cox D, Jamnik R. Endurance athlete’s stroke volume does not plateau major advantage is diastolic function”. Med Sci Sports Exer. 1994;26:1116-21.

Stickland MK, Welsh RC, Petersen SR, Tyberg JV, Andersons WD, Jones RL, et al. Does fitness level modulate the Cardiovasular hecomodynamic response to exercise of Apool. Physiol. 2006;100:1895-901.

Zhou, B, Conlee RK, Jensan R, Fellingham GW, Georges JD and Fisher AG. Stroke volume does not plateau during graded exercise in elite male distance runners. Med. Sci. Sports Exer. 2001;33:1849-54.

Thompson WR. ACSM’S Guideline’s for exercise Testing and Prescription. 8th edition. 2010.

Krogh A, Lindhard J. The regulation of respiration and circulation during the initial stages of muscular work Journal of physiol (Lond). 1913;47(1-2):112-36.

Comroe JHJR, Schmidt CF. The hyperpnea of muscular exercise. Physiol Rev. 1943;138:536-47.

Grodins FS. Analysis of factors concerned in regulation of breathing in exercise. Physiol. Rev. 1950;30,220.

Bannister RG, Cunningham DFC. The effects on the respiration and performance during exercise of adding oxygen to the inspired air. J. Physiol (Lond). 1954;125(1):118-37.

Filley GF, Gregoire F, Wright GW. Alveolar and arterial O2 tension and the significance of the alveolar – arterial oxygen tension difference in normal men. Journal Clin – Invest. 1954;33(4):517-29.

Saltin B, Rowell LB. Functional adaptations to physical activity and inactivity. Federation Proceeding. 1980;39(5):1506-13.

Jackson AS, Beard EF, Wier LT, Ross RM, Stuteville JE, Blair SN. Changes in aerobic power of men, ages 25-70 yr. Med Sci sports Exercise. 1995;27(1):113-20.

Jackson AS, Wier LT, Ayers GW, Beard EF, Stutevile JE, Blair SN. Changes in aerobic power of women, ages 20-64 yrs. Med Sci Sports Exercise. 1996;28(7):884-91.

Saltin B, Nazar K, Costill DL, Stein E, Jansson E, Essen B, Golnick D. The Nature of the training response; peripheral and central adaptations of one legged exercise. Acta Physiol Scand. 1976;96(3):289-305.

Green HJ, Jones S, Balt Burnett M, Farrance B, Ranney D. Adaptations in muscle metabolism to prolonged voluntary exercise and training. J Appl Physiol. 1995;78(1):138-45.

Kraemer WJ, Duncan ND, Volek JS. Resistance training and elite athletes: adaptations and program considerations. J Orthop Sports Phys Ther. 1998;28(2);110-9.

Kraemer WJ, Patton JF, Gordon SE, Harman EA, Deschenes MR, Reynolds K, et al. Compatibility of high intensity strength and endurance training on hormonal and skeletal muscle adaptation. J Appl Physiol. 1995;78(3):976-89.