Swimming: A Step Toward Healthy Aging
Author(s): Kathrotia R, Rao P, Shah C, Shukla P, Trivedi D, Oommen E
Vol. 5, No. 4 (2008-09 - 2008-10)
Review Article
Kathrotia R, Rao P, Shah C, Shukla P, Trivedi D, Oommen E
Dr Rajesh Kathrotia, Dr Dhananjay Trivedi, and Dr Oommen Elvy, Department of Physiology, Medical College, Baroda; Dr Pinkesh Rao and Dr Chinmay Shah are from Department of Physiology, Medical College, Bhavnagar; and Dr Shukla Pranav is from the Department of Physiology, Dental College, Visnagar
Abstract
Swimming is generally considered to be a healthy leisure activity for both the young and the old. Increasing age is associated with increasing disability and functional impairments and reduction or postponement of such a decline can increase longevity. PEFR which reflects respiratory muscle strength is a strong predictor of mortality in elderly. So we tried to study and compare the effects of short and long duration of swimming on PEFR with increase in age.
A total of 228 male subjects participated in the study; these comprised of 158 swimmers divided in to two groups: Ls (swimming practice of six months to one year) and Ss (swimming practice of 4-6 weeks), and 70 sedentary controls. All were grouped according to age into young (20-34years), middle aged (35-49years) and the old (≥50years). Results showed that PEFR is significantly higher in swimmers as compared to non-swimmers. PEFR increases significantly with duration of swimming and it is highest in Ls swimmers in old age group (545.55±32.05 l/min). PEFR declines after 50 years in controls (440±26.45 to 358.75±30.9 l/min, p<0.001) and in swimmers (Ss) with short duration of swimming practice (531.64±32.93 to 471.03±74.65 l/min, p<0.001) but not in swimmers (Ls) with long duration of swimming practice (535±47.76 and 545.55±32.05 l/min, p=0.46).
Age-related decline in lung function as assessed from PEFR can be reduced or prevented with regular swimming practice for a long duration. Swimming not only helps to maintain the health but also postpones onset of disability in the elderly thereby delaying the morbidity till near death. Thus, swimming can be a very important component of successful aging.
Key words: swimming, PEFR, elderly
Introduction
Advancing age is associated with increasing disability and functional impairments which may be contributed by functional decline in cardiovascular, pulmonary, musculoskeletal, and other systems1. Even hospitalizations due to complications are increased with increasing age. Reduction or postponement of this functional decline may not only reduce premature death and increase longevity but, more importantly, may also decrease the period of illnesses so that people can remain healthy until near death.
The Peak Expiratory Flow Rate (PEFR) reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. Studies have shown PEFR to be a predictor of mortality in the elderly2. PEFR is also a predictor of mortality in various diseases like asthma, COPD3, ischemic heart disease4, cardiovascular disease5, diabetes6, even in patients hospitalized for orthopedic operations7 or COPD deteriorations.8 PEFR, in fact, can predict recovery or mortality. PEFR is also believed to be related to development of atherosclerotic plaques9. Various such studies have suggested that measuring lung function is useful in assessing the prognosis in elderly populations.
Furthermore, PEFR not only correlates well with FEV1, the duration of this maneuver is shorter, less cumbersome and requires infrequent repletion. Therefore PEFR has a definite edge over vital capacity measurement in field conditions, since it eliminates the risk of inducing bronco- spasm in subjects with unknown history of obstruction. Measurement of the peak expiratory flow may be easier than measurement of the forced expiratory volume (FEV) in elderly people10.
Swimming is generally considered to be a healthy leisure activity for both the young and the old. This exercise has a greater impact on lung function than any other sport11,12. However what duration of swimming can improve lung function in the elderly is yet to be established. So we tried to study and compare the effects of short and long duration of swimming on PEFR with increase in age.
Materials and Methods
The study was carried out at local swimming clubs of Baroda city. Swimmers were defined as those who were involved in regular swimming practice of covering a distance of about 2000m to 4000m, 5 days in a week. Healthy male swimmers in the age group of 20-34 years (young), 35-49 years (middle aged) and ≥50 years (old) were selected for the study. As PEFR is affected maximally by height only those whose height was between 160 and 170 cm were included in the study. Smokers and those with present history or clinical examination suggestive of any active respiratory disorder were excluded.
Swimmers in each age group were further sub-grouped according to the duration of swimming—swimming practice of 4-6 weeks (Ss) and swimming practice of six months to one year (Ls).
Age- and height-matched sedentary controls (leisure-time physical activity done for less than 20 minutes or fewer than 3 times per week) were selected for each group from medical college staff and the students.
After informed consent, PEFR was measured using Wright’s Peak Flow Meter in standing position after at least 5 minutes of rest. PEFR readings were taken with at least 2 minutes gap between each reading and the best of the three reading was considered. All the readings were taken between 6 am to 9 am. BMI was calculated form anthropometric measurements of height and weight.
Unpaired students ‘t’ test was applied to test the significance of difference between groups and p<0.05 was considered statistically significant.
Results
A total of 228 subjects participated in the study of which 70 were controls and 158 were swimmers of different age groups.
There was no significant difference between the mean age and height of swimmers and non-swimmers, however, the average weight and BMI was significantly higher in the middle aged and the elderly compared to the young, in both controls and swimmers.
Table 1: Mean age and height (all values are mean ± SD).
Age (yrs)
Ls
Ss
Ns
Young (n=125)
27.63±1.57 (n=36)
27.62±1.59 (n=45)
27.34±0.56 (n=44)
Middle-aged (n=57)
40.16±5.54 (n=12)
38.16±5.8 (n=31)
38.44±6.42 (n=14)
Old (n=46)
57.22±9.76 (n=13)
61.31±9.29 (n=21)
63.62±10.52(n=12)
Height (cm)
Young (n=125)
163.97±2.61 (n=36)
164.26±2.76 (n=45)
166.12±2.94(n=44)
Middle-aged (n=57)
165.33±1.87 (n=12)
166.08±2.81 (n=31)
165.88±2.52(n=14)
Old (n=46)
166.77±2.81 (n=13)
163.79±3.22 (n=21)
165.5±3.7 (n=12)
Ls – Swimming practice of six months to one year duration.
Ss- Swimming practice of 4-6 weeks duration.
Ns – Non-swimmer controls.
Table 2: Mean weight in swimmers and controls (values are mean ± SD).
Weight (kg)
Age Group</th>
Ls
Ss
Ns
Young
54.09±9.43
54.51±9.2
56.03±10.75
Middle aged
72.16±11.59٭٭
73.7±9.45٭٭
77.66±7.14٭٭
Old
69.83±10.08٭٭
69.41±10.5٭٭
72.25±13.32٭٭
٭٭p < 0.001 middle and old compared to young
Graph 1: Comparison of mean BMI between young, middle and old aged.
٭p<0.01 middle and old compared to young
Graph 2: Intergroup and Intragroup Comparison of PEFR
PEFR (L/min) is significantly higher in swimmers as compared to nonswimmers irrespective of the duration of swimming in each age group.
PEFR increases significantly with the duration of swimming; it is highest in Ls swimmers in the old age group (545.55±32.05 l/min, p<0.01). Whereas in the young (496±46.54 vs 498.05±42.81 l/min, p=0.23) and the middle-aged (531.64±32.93 vs 535±47.76 l/min, p=0.31) there is no significant increase in PEFR with increase in swimming practice from short (Ss) to long (Ls) duration.
PEFR declines after 50 years in the controls (440±26.45 to 358.75±30.9 l/min, p<0.001) and in swimmers (Ss) with short duration of swimming practice (531.64±32.93 to 471.03±74.65 l/min, p<0.001) but not in swimmers (Ls) with long duration of swimming practice (535±47.76 & 545.55±32.05 l/min, p=0.46).
Discussion
Irrespective of the duration of swimming practice, PEFR was found to be significantly higher in swimmers compared to the non-swimmer controls. Studies by Mehrotra et al, De et al and others have demonstrated the beneficial effect of sports like swimming on lung functions13,14,15,16.
Although the mean PEFR did not significantly differ with increase in swimming practice in the young and middle-aged groups16, in the older groups (≥50 years) the mean PEFR increased significantly with increase in swimming practice from 4-6 weeks to six months to one year. The age-related decline in lung function seems to be nullified by regular swimming practice of more than 6 months1. Pherwani et al demonstrated a significant increase in PEFR with 2 to 5 year of swimming practice which he attributed to the hypertrophy of diaphragm.
The mean PEFR was comparable in the young and middle-aged individuals in both swimmers and the non-swimmer controls. Further, PEFR showed a decline from middle age to old age in non-swimmers and in swimmers with short duration of swimming practice. However, such decline was not found in swimmers with long duration of swimming practice suggesting that swimming has a protective effect on lung function in the elderly. A longitudinal study is required to confirm these findings.
In conclusion, swimming is a very good exercise for all age groups, but more so in the elderly as assessed from PEFR1. Long duration of swimming seems to benefit elderly (≥50 years) more than other groups. Swimming will surely help to maintain the health and postpone disability among the elderly, thereby delaying the morbidity till near death. Thus, swimming can be considered to be a very important component of active aging.
References
- Kay-Tee Khaw. Healthy aging. BMJ 1997;315:1090-1096.
- Cook NR, Denis A. Evans, Paul A. Scherr, Frank E. Speizer, James O. Taylor and Charles H. Hennekens. Peak Expiratory Flow Rate and 5-Year Mortality in an Elderly Population Am J Epidemiol 1991; 133 (8): 784-794
- Hansen EF, Jørgen Vestbo, Klaus Phanareth, Axel Kok-Jensen, and Asger Dirksen Peak Flow as Predictor of Overall Mortality in Asthma and Chronic Obstructive Pulmonary Disease. Am J Resp Crit Care Med 2001, 163 (3): 690-693.
- Simons LA, McCallum J, Simons J, Friedlander Y. Relationship of peak expiratory flow rate with mortality and ischaemic heart disease in elderly Australians. Med J Aust. 1997 ;166(10):526-9.
- Persson, C, C. Bengts son, L. Lapidus, E. Rybo, G.Thinnger and H. Wedel. Peak expiratory flow and risk of cardiovascular disease and death: a 12-year follow-up of participants In the population study of women in Gothenburg, Sweden. Am J Epldemlol 1988; 124:942–8.
- Klein BEK, Scot E. Moss, Ronald Klein and Karen J. Cruickshanks. Peak Expiratory Flow Rate: Relationship to Risk Variables and Mortality The Wisconsin Epidemiologic Study of Diabetic Retinopathy. Diabetes Care 2001;24:1967-1971.
- Galasko CS, Rushton S, Sylvester BS, Steingold RF, Noble J, Boston DA. The significance of peak expiratory flow rate in assessing prognosis of elderly patients undergoing operations on the hip. Injury. 1985;16(6):398-401.
- de la Iglesia F, Diaz JL, Pita S, Nicolas R, Ramos V, Pellicer C, Diz-Lois F. Peak expiratory flow rate as predictor of inpatient death in patients with chronic obstructive pulmonary disease. South Med J. 2005; 98(3):266-72.
- Zureik M; Francine Kauffmann, Pierre-Jean Touboul, Dominique Courbon, BS; Pierre Ducimetière. Association Between Peak Expiratory Flow and the Development of Carotid Atherosclerotic Plaques. Arch Intern Med. 2001;161:1669-1676.
- Reijo Tilvis, Jaakko Valvanne, Sirpa Sairanen, Anssi Sovijärvi. Peak expiratory flow is a prognostic indicator in elderly people BMJ 1997;314:605.
- Mehrotra PK, Varma N, Tiwari S, Kumar P. Pulmonary functions in Indian sportsmen playing different sports. Ind J Physiol Pharmacol. 1998;42(3):412-6.
- Doherty M, Lygeri Dimitriou. Comparison of lung volume in Greek swimmers, land based athletes, and sedentary controls using allometric scaling. Br J Sports Med 1997;31:337-341.
- Mehrotra PK, Verma N, Yadav R, Tewari S, Shukla N. Study of pulmonary functions in swimmers of Lucknow city. Ind J Physiol Pharmacol. 1997;41(1):83-6.
- De AK. Peak expiratory flow rate in adolescent male swimmers of all India rural swimming meet. Ind J Physiol Pharmacol. 1992;36(2):118-20.
Indian Journal for the Practising Doctor Vol V (4) September October 2008
- De AK, Roy AS, Ray A, Debnath PK. Simple anthropometry and peak expiratory flow rate in elite South Asian athletes. J Sports Med Phys Fitness. 1991;31(4):596-8.
- Pherwani AV, Desai AG, Solepure AB. A study of pulmonary function of competitive swimmers. Ind J Physiol Pharmacol. 1989;33(4):228-32.
Review Article
Kathrotia R, Rao P, Shah C, Shukla P, Trivedi D, Oommen E
Dr Rajesh Kathrotia, Dr Dhananjay Trivedi, and Dr Oommen Elvy, Department of Physiology, Medical College, Baroda; Dr Pinkesh Rao and Dr Chinmay Shah are from Department of Physiology, Medical College, Bhavnagar; and Dr Shukla Pranav is from the Department of Physiology, Dental College, Visnagar
Abstract
Swimming is generally considered to be a healthy leisure activity for both the young and the old. Increasing age is associated with increasing disability and functional impairments and reduction or postponement of such a decline can increase longevity. PEFR which reflects respiratory muscle strength is a strong predictor of mortality in elderly. So we tried to study and compare the effects of short and long duration of swimming on PEFR with increase in age.
A total of 228 male subjects participated in the study; these comprised of 158 swimmers divided in to two groups: Ls (swimming practice of six months to one year) and Ss (swimming practice of 4-6 weeks), and 70 sedentary controls. All were grouped according to age into young (20-34years), middle aged (35-49years) and the old (≥50years). Results showed that PEFR is significantly higher in swimmers as compared to non-swimmers. PEFR increases significantly with duration of swimming and it is highest in Ls swimmers in old age group (545.55±32.05 l/min). PEFR declines after 50 years in controls (440±26.45 to 358.75±30.9 l/min, p<0.001) and in swimmers (Ss) with short duration of swimming practice (531.64±32.93 to 471.03±74.65 l/min, p<0.001) but not in swimmers (Ls) with long duration of swimming practice (535±47.76 and 545.55±32.05 l/min, p=0.46).
Age-related decline in lung function as assessed from PEFR can be reduced or prevented with regular swimming practice for a long duration. Swimming not only helps to maintain the health but also postpones onset of disability in the elderly thereby delaying the morbidity till near death. Thus, swimming can be a very important component of successful aging.
Key words: swimming, PEFR, elderly
Introduction
Advancing age is associated with increasing disability and functional impairments which may be contributed by functional decline in cardiovascular, pulmonary, musculoskeletal, and other systems1. Even hospitalizations due to complications are increased with increasing age. Reduction or postponement of this functional decline may not only reduce premature death and increase longevity but, more importantly, may also decrease the period of illnesses so that people can remain healthy until near death.
The Peak Expiratory Flow Rate (PEFR) reflects the strength and condition of respiratory muscles and the degree of airflow limitation in large airways. Studies have shown PEFR to be a predictor of mortality in the elderly2. PEFR is also a predictor of mortality in various diseases like asthma, COPD3, ischemic heart disease4, cardiovascular disease5, diabetes6, even in patients hospitalized for orthopedic operations7 or COPD deteriorations.8 PEFR, in fact, can predict recovery or mortality. PEFR is also believed to be related to development of atherosclerotic plaques9. Various such studies have suggested that measuring lung function is useful in assessing the prognosis in elderly populations.
Furthermore, PEFR not only correlates well with FEV1, the duration of this maneuver is shorter, less cumbersome and requires infrequent repletion. Therefore PEFR has a definite edge over vital capacity measurement in field conditions, since it eliminates the risk of inducing bronco- spasm in subjects with unknown history of obstruction. Measurement of the peak expiratory flow may be easier than measurement of the forced expiratory volume (FEV) in elderly people10.
Swimming is generally considered to be a healthy leisure activity for both the young and the old. This exercise has a greater impact on lung function than any other sport11,12. However what duration of swimming can improve lung function in the elderly is yet to be established. So we tried to study and compare the effects of short and long duration of swimming on PEFR with increase in age.
Materials and Methods
The study was carried out at local swimming clubs of Baroda city. Swimmers were defined as those who were involved in regular swimming practice of covering a distance of about 2000m to 4000m, 5 days in a week. Healthy male swimmers in the age group of 20-34 years (young), 35-49 years (middle aged) and ≥50 years (old) were selected for the study. As PEFR is affected maximally by height only those whose height was between 160 and 170 cm were included in the study. Smokers and those with present history or clinical examination suggestive of any active respiratory disorder were excluded.
Swimmers in each age group were further sub-grouped according to the duration of swimming—swimming practice of 4-6 weeks (Ss) and swimming practice of six months to one year (Ls).
Age- and height-matched sedentary controls (leisure-time physical activity done for less than 20 minutes or fewer than 3 times per week) were selected for each group from medical college staff and the students.
After informed consent, PEFR was measured using Wright’s Peak Flow Meter in standing position after at least 5 minutes of rest. PEFR readings were taken with at least 2 minutes gap between each reading and the best of the three reading was considered. All the readings were taken between 6 am to 9 am. BMI was calculated form anthropometric measurements of height and weight.
Unpaired students ‘t’ test was applied to test the significance of difference between groups and p<0.05 was considered statistically significant.
Results
A total of 228 subjects participated in the study of which 70 were controls and 158 were swimmers of different age groups.
There was no significant difference between the mean age and height of swimmers and non-swimmers, however, the average weight and BMI was significantly higher in the middle aged and the elderly compared to the young, in both controls and swimmers.
Table 1: Mean age and height (all values are mean ± SD).
| Age (yrs) | |||
|---|---|---|---|
| Ls | Ss | Ns | |
| Young (n=125) | 27.63±1.57 (n=36) | 27.62±1.59 (n=45) | 27.34±0.56 (n=44) |
| Middle-aged (n=57) | 40.16±5.54 (n=12) | 38.16±5.8 (n=31) | 38.44±6.42 (n=14) |
| Old (n=46) | 57.22±9.76 (n=13) | 61.31±9.29 (n=21) | 63.62±10.52(n=12) |
| Height (cm) | |||
| Young (n=125) | 163.97±2.61 (n=36) | 164.26±2.76 (n=45) | 166.12±2.94(n=44) |
| Middle-aged (n=57) | 165.33±1.87 (n=12) | 166.08±2.81 (n=31) | 165.88±2.52(n=14) |
| Old (n=46) | 166.77±2.81 (n=13) | 163.79±3.22 (n=21) | 165.5±3.7 (n=12) |
Ls – Swimming practice of six months to one year duration.
Ss- Swimming practice of 4-6 weeks duration.
Ns – Non-swimmer controls.
Table 2: Mean weight in swimmers and controls (values are mean ± SD).
| Weight (kg) | |||
|---|---|---|---|
| Age Group</th> | Ls | Ss | Ns |
| Young | 54.09±9.43 | 54.51±9.2 | 56.03±10.75 |
| Middle aged | 72.16±11.59٭٭ | 73.7±9.45٭٭ | 77.66±7.14٭٭ |
| Old | 69.83±10.08٭٭ | 69.41±10.5٭٭ | 72.25±13.32٭٭ |
٭٭p < 0.001 middle and old compared to young
Graph 1: Comparison of mean BMI between young, middle and old aged.
٭p<0.01 middle and old compared to young
Graph 2: Intergroup and Intragroup Comparison of PEFR
PEFR (L/min) is significantly higher in swimmers as compared to nonswimmers irrespective of the duration of swimming in each age group.
PEFR increases significantly with the duration of swimming; it is highest in Ls swimmers in the old age group (545.55±32.05 l/min, p<0.01). Whereas in the young (496±46.54 vs 498.05±42.81 l/min, p=0.23) and the middle-aged (531.64±32.93 vs 535±47.76 l/min, p=0.31) there is no significant increase in PEFR with increase in swimming practice from short (Ss) to long (Ls) duration.
PEFR declines after 50 years in the controls (440±26.45 to 358.75±30.9 l/min, p<0.001) and in swimmers (Ss) with short duration of swimming practice (531.64±32.93 to 471.03±74.65 l/min, p<0.001) but not in swimmers (Ls) with long duration of swimming practice (535±47.76 & 545.55±32.05 l/min, p=0.46).
Discussion
Irrespective of the duration of swimming practice, PEFR was found to be significantly higher in swimmers compared to the non-swimmer controls. Studies by Mehrotra et al, De et al and others have demonstrated the beneficial effect of sports like swimming on lung functions13,14,15,16.
Although the mean PEFR did not significantly differ with increase in swimming practice in the young and middle-aged groups16, in the older groups (≥50 years) the mean PEFR increased significantly with increase in swimming practice from 4-6 weeks to six months to one year. The age-related decline in lung function seems to be nullified by regular swimming practice of more than 6 months1. Pherwani et al demonstrated a significant increase in PEFR with 2 to 5 year of swimming practice which he attributed to the hypertrophy of diaphragm.
The mean PEFR was comparable in the young and middle-aged individuals in both swimmers and the non-swimmer controls. Further, PEFR showed a decline from middle age to old age in non-swimmers and in swimmers with short duration of swimming practice. However, such decline was not found in swimmers with long duration of swimming practice suggesting that swimming has a protective effect on lung function in the elderly. A longitudinal study is required to confirm these findings.
In conclusion, swimming is a very good exercise for all age groups, but more so in the elderly as assessed from PEFR1. Long duration of swimming seems to benefit elderly (≥50 years) more than other groups. Swimming will surely help to maintain the health and postpone disability among the elderly, thereby delaying the morbidity till near death. Thus, swimming can be considered to be a very important component of active aging.
References
- Kay-Tee Khaw. Healthy aging. BMJ 1997;315:1090-1096.
- Cook NR, Denis A. Evans, Paul A. Scherr, Frank E. Speizer, James O. Taylor and Charles H. Hennekens. Peak Expiratory Flow Rate and 5-Year Mortality in an Elderly Population Am J Epidemiol 1991; 133 (8): 784-794
- Hansen EF, Jørgen Vestbo, Klaus Phanareth, Axel Kok-Jensen, and Asger Dirksen Peak Flow as Predictor of Overall Mortality in Asthma and Chronic Obstructive Pulmonary Disease. Am J Resp Crit Care Med 2001, 163 (3): 690-693.
- Simons LA, McCallum J, Simons J, Friedlander Y. Relationship of peak expiratory flow rate with mortality and ischaemic heart disease in elderly Australians. Med J Aust. 1997 ;166(10):526-9.
- Persson, C, C. Bengts son, L. Lapidus, E. Rybo, G.Thinnger and H. Wedel. Peak expiratory flow and risk of cardiovascular disease and death: a 12-year follow-up of participants In the population study of women in Gothenburg, Sweden. Am J Epldemlol 1988; 124:942–8.
- Klein BEK, Scot E. Moss, Ronald Klein and Karen J. Cruickshanks. Peak Expiratory Flow Rate: Relationship to Risk Variables and Mortality The Wisconsin Epidemiologic Study of Diabetic Retinopathy. Diabetes Care 2001;24:1967-1971.
- Galasko CS, Rushton S, Sylvester BS, Steingold RF, Noble J, Boston DA. The significance of peak expiratory flow rate in assessing prognosis of elderly patients undergoing operations on the hip. Injury. 1985;16(6):398-401.
- de la Iglesia F, Diaz JL, Pita S, Nicolas R, Ramos V, Pellicer C, Diz-Lois F. Peak expiratory flow rate as predictor of inpatient death in patients with chronic obstructive pulmonary disease. South Med J. 2005; 98(3):266-72.
- Zureik M; Francine Kauffmann, Pierre-Jean Touboul, Dominique Courbon, BS; Pierre Ducimetière. Association Between Peak Expiratory Flow and the Development of Carotid Atherosclerotic Plaques. Arch Intern Med. 2001;161:1669-1676.
- Reijo Tilvis, Jaakko Valvanne, Sirpa Sairanen, Anssi Sovijärvi. Peak expiratory flow is a prognostic indicator in elderly people BMJ 1997;314:605.
- Mehrotra PK, Varma N, Tiwari S, Kumar P. Pulmonary functions in Indian sportsmen playing different sports. Ind J Physiol Pharmacol. 1998;42(3):412-6.
- Doherty M, Lygeri Dimitriou. Comparison of lung volume in Greek swimmers, land based athletes, and sedentary controls using allometric scaling. Br J Sports Med 1997;31:337-341.
- Mehrotra PK, Verma N, Yadav R, Tewari S, Shukla N. Study of pulmonary functions in swimmers of Lucknow city. Ind J Physiol Pharmacol. 1997;41(1):83-6.
- De AK. Peak expiratory flow rate in adolescent male swimmers of all India rural swimming meet. Ind J Physiol Pharmacol. 1992;36(2):118-20. Indian Journal for the Practising Doctor Vol V (4) September October 2008
- De AK, Roy AS, Ray A, Debnath PK. Simple anthropometry and peak expiratory flow rate in elite South Asian athletes. J Sports Med Phys Fitness. 1991;31(4):596-8.
- Pherwani AV, Desai AG, Solepure AB. A study of pulmonary function of competitive swimmers. Ind J Physiol Pharmacol. 1989;33(4):228-32.