EFFECTS OF INTENSITY AND DURATION OF EXERCISE ON TOTAL LEUKOCYTE COUNT IN NORMAL SUBJECTS

Shaukat Ali, Farman Ullah, Habib Ullah*

Department of Physiology and *Department of Medicine, Gomal Medical College, DI Khan

Background: Leucocytes the mobile units of the protective system of the body, may circulate freely in the blood, adhere to the vascular endothelium in sites where blood flow is relatively slow and then once again re-enter the circulation in a process of continuous exchange. This process of continuous exchange of leucocytes is influenced by proper stimulation such as exercise. This study was done to observe the effects of intensity and duration of exercise on total leucocyte count. Methods: Two groups of normal healthy male adult subjects were exercised on treadmill. Group-I performed exercise by running for a duration of 2-3 minutes, at 7% grade (4 degree inclination) and at constant speed ranging from 7.5 to 9 Km/hour while group-II walked on treadmill for a duration of 7-10 minutes at zero grade and at constant speed ranging from 5 to 6 Km/hour. Blood sample was drawn before exercise, immediately after exercise and after 30 minutes of rest after the exercise. Total leukocyte count was then done by improved Neubauer haemocytometer. Results: The mean of pre-exercise total leucocyte count of Group-I subjects (n=15) was 9750 384.47/l, while immediately after exercise the mean total leucocyte count increased to 17856.66 1213.24/l and after 30 minutes rest, it came down to 10396.67 648.35/l. Whereas, the mean of total leucocyte count of group-II subjects (n=15) was 10266.66 307.60/l pre-exercise, 16336.66 866.30/l immediately post-exercise and 1162.33 718.85/l at 30 minutes post-exercise. The total leucocyte count increased significantly immediately after exercise and it significantly decreased after 30 minutes of rest but was still higher than the pre-exercise count in both the groups Conclusion: It is clearly reflected by this study that the magnitude of exercise-induced leucocytosis is higher in exercise of more intensity and less duration.


INTRODUCTION

Sedentary individuals of all ages will achieve significant improvements in physical working capacity by performing appropriate type of exercise at the proper intensity, duration and frequency1. The ability of exercise to alter the immune system of adults has been well documented in the literature2. The leucocytes are the mobile units of the protective system of the body3. The well known phenomenon of leucocytosis is induced by exercise4. The change in peripheral leucocyte number is assumed to be diagnostically informative and may be a prognostic marker, reflecting organ damage and restoration after strenuous physical exercise5. The intensity of leucocytosis is proportional to the intensity of work and duration of exercise6, independent of gender and subject fitness level7.  

MATERIALS AND METHODS

This study was conducted at the Department of Physiology, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi. Thirty  subjects were selected from the students, staff and residents of JPMC, Karachi according to the following criteria:

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 Normal healthy male adult subjects with no disease or positive clinical findings.

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 Age ranging from 18 to 45 years.

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 Weight ranging from 50 to 85 kilograms.

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 Non-smokers.

All of the experiments in this study were performed between 9:00 A.M. and 1:00 P.M., to avoid possible circadian fluctuations in the blood concentrations of leucocytes. On the experimental day, a general physical examination of each volunteer was made.

The procedure of treadmill exercise was explained to all the study participants prior to exercise. A continuous monitoring of treadmill belt velocity was observed throughout the test8.

The selected subjects were divided into two groups and the subjects of each group were exercised on the treadmill, AR-160A (Minato Medical Science Company, Japan), as follows:

Group-I (n=15): The treadmill exercise was performed by running for a duration of 23 minutes, at 7% grade (4 degree inclination) and at constant speed ranging from 7.5 to 9 Km/hour.

Group-II (n=15): The treadmill exercise was performed by walking for a duration of 7-10 minutes at zero grade and at constant speed ranging from 5 to 6 Km/hour.

Each subject was allowed a 30 minutes rest period before taking pre-exercise blood sample. After taking the first sample, each subject was asked to do exercise on treadmill (as mentioned above). Second sample of blood was taken immediately after exercise. Then the subject was comfortably seated in a chair to have rest for 30 minutes and finally third sample of blood was taken at 30 minutes post-exercise. Total leucocyte count was determined manually using an improved Neubauer haemocytometer. The results were statistically evaluated.

RESULTS

The pre exercise and post exercise total leucocyte counts of both the groups are given in tables 1 and 3, while tables 2 and 4 show the differences, percent variation and significance of these differences.

Table-1: Total leucocyte count in Group-I (treadmill running )

Pre-exercise (Cells/ml)

Immediately post-exercise  (Cells/ml)

30 minutes post-exercise (Cells/ml)

9750

384.477

17856.667

1213.240

10396.670 648.356

Values are expressed as Mean S.E.M.                (n = 15)

Table-2: Mean of differences S.E.M, % variation and p value of total leucocyte count in group I (treadmill running)

 

Immediately post-exercise

Vs

pre-exercise

30 minutes post-exercise vs

 pre-exercise

30 minutes post-exercise

vs

immediately post-exercise

Mean of Differences

SEM

8106.667

1022.642

646.667

14.719

-7460

16.035

%Variation

+83.145

+6.633

-76.513

P-value

< 0.001

< 0.001

< 0.001

(n=15)     = Decrease                + =Increase.

DISCUSSION

In our results total leucocyte count was significantly increased, immediately after exercise in both groups (P<0.001) but the increase is more in group-I (83.145%) than in group-II (59.746%) as reported by Kayashima et al5 and McCarthy et al6, who observed an increase of 90% and 115%, respectively. The increase in total leucocyte count reported by these researchers was slightly more because the exercise stress was more severe than the present study.

Table-3: Total leucocyte count in Group-II (treadmill walking)

Pre-exercise

(Cells/ml)

Immediately post-exercise

(Cells/ml)

30 minutes post-exercise (Cells/ml)

10266.667 307.602

16336.667 866.301

11623.33 718.8551

Values are expressed as Mean SEM.                (n = 15)

Table-4: Mean of differences S.E.M, % variation and p value of total leucocyte count in group II (treadmill walking)

 

Immediately post-exercise

 Vs

pre-exercise

30 minutes post-exercise

vs

pre-exercise

30 minutes post-exercise

vs

immediately post-exercise

Mean of differences SEM

6110.00

746.03

1396.667

612.635

-4713.33

634.779

%Variation

+59.746

+13.657

-46.089

P-value

< 0.001

< 0.001

< 0.001

(n = 15)   = Decrease                + = Increase.

Gabriel and Kindermann9 reported that moderate exercise elicits lower changes in cell concentration than strenuous exercise. The total leucocyte count was then decreased significantly (P<0.001) after 30 minutes rest, by 76.513% in group-I subjects and 46.089% in group-II subjects. In a study done by Iversen et al8 the total leucocyte count had returned to pre-exercise level after 30 minutes of completion of exercise. In the present study, although, total leucocyte count had significantly decreased after 30 minutes rest but was still 6.633% (P<0.001) and 13.657% (P<0.001) higher than pre-exercise count in group-I and group-II subjects, respectively.  Nieman et al10 have reported that exercise-induced leucocytosis was evident even after three hours of recovery while Suzuki et al11 observed the persistence of exercise induced leucocytosis for one hour after termination of exercise.

CONCLUSION

By studying the effects of exercise on leucocyte count in two groups of subjects, who were exercised for different durations and intensities. The present study has clearly indicated that the magnitude of exercise-induced leucocytosis depends upon the intensity and duration of exercise (higher in exercise of more intensity and less duration). Precautions must be taken while drawing blood samples for such routine investigations as total leucocyte count. It is suggested that if the patient is exerted, a 3060 minutes rest, depending upon the degree of exertion, must be allowed before taking the blood sample.

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8.        Iversen PO, Arvesen BL, Benestad HB. No mandatory role for the spleen in the exercise induced leucocytosis in man. Clin Sci 1994; 86: 505-510.

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11.     Suzuki K, Naganuma S, Totruka M, Suzuki KJ, Mochizuki M, Shiraishi M, et al. Effects of exhaustive endurance exercise and its one week daily repetition on neutrophil count and functional status in untrained men. Int J Sports Med 1996; 17(3): 205-212.

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Address for Correspondence and Reprints:

Dr. Shaukat Ali, Department of Physiology, Gomal Medical College, DI Khan, Pakistan.

Email: drfarmanwazir@hotmail.com