Regular Article
Exercise intensity: Platelet function and platelet–leukocyte conjugate formation in untrained subjects

https://doi.org/10.1016/j.thromres.2007.08.018Get rights and content

Abstract

Introduction

Strenuous and exhaustive exercise intensifies platelet activity as shown in the literature but effects of moderate exercise are still in discussion. The present study investigated effects of two different standardised exercise intensities controlled by individual anaerobic threshold (IAT) on platelet function and conjugate formation.

Methods

20 healthy male non-smokers underwent two exercises at 80% (moderate) of IAT which corresponded to about 57% of peak oxygen consumption (peak VO2) in our subjects and 100% (strenuous) of IAT, corresponding to about 69% peak VO2. Blood samples were taken after 30 min rest and immediately after exercise. CD62P expression and differentiated platelet–leukocyte conjugates (CD45, CD14, CD41) as well as microparticles and platelet–platelet aggregates were detected flow cytometrically with and without TRAP-6-stimulation.

Results

CD62P expression and the number of aggregates were increased (P  0.05) after exercise in the TRAP-stimulation experiment independent of exercise intensity. The number of platelet–granulocyte (rest 5.7 ± 1.8 to post 8.1 ± 1.7 (80%) vs. 6.2 ± 1.9 to 10.3 ± 2.0 (100%)), platelet–monocyte (5.3 ± 3.6 to 8.5 ± 3.7 (80%) vs. 7.4 ± 3.5 to 11.7 ± 4.8 (100%)), and platelet–lymphocyte conjugates (4.4 ± 1.2 to 6.4 ± 1.3 (80%) vs. 4.6 ± 1.7 to 7.8 ± 1.8% positive cells (100%)) were also higher after both exercises but increased significantly weaker (P  0.05) after moderate exercise. These results were confirmed by the TRAP-stimulation experiment.

Conclusion

Although moderate exercise led to an increase in platelet reactivity and platelet–leukocyte conjugate formation the changes in conjugate formation were significantly weaker compared to strenuous exercise. Therefore it is recommended that submaximal endurance performance should be individually developed in order for everyone to be able to carry out normal daily activities and also to exercise well below the IAT.

Introduction

It has been confirmed in different studies that physical exercise influences platelet function and platelet leukocyte interaction as well as blood coagulation and fibrinolysis [1], [2], [3], [4]. Studies have pointed to an association between exercise and a risk of cardiovascular events [5], [6], often however without a clear differentiation of the types of exercise done. Because duration as well as intensity are the main factors which define a type of exercise, more precise descriptions of the particular exercise intervention is mandatory. Although only few studies have investigated platelet function after different types of exercise, in particular, the investigations of Wang et al. have demonstrate the diverse effects of different exercise intensities on platelet function [7], [8], [9]. These studies have shown that strenuous exercise enhances platelet activity while moderate exercise suppresses platelet function. However, these specific effects of moderate exercise have not yet been confirmed in other studies [3], [10], [11], [12], [13], [14]. Different factors complicate a convenient comparison of the available results. For example, various methods are used to control the exercise program. In addition, different methods are used to measure platelet function with a wide range of multiple laboratory analyses from use of in vivo markers such as β-thromboglobulin and platelet factor 4, to aggregation and adhesion tests, to various other techniques such as the flow cytometry. The reason is, that clear and accepted standards for the evaluation of platelet function, to enable convenient comparability of the different methods are still lacking. Therefore the results of these different laboratory methods are not always in line, making the interpretation more complex.

The aim of the present study was to investigate platelet function and platelets leukocyte interaction as well as changes in microparticles and aggregates after standardised exercises at 80 and 100% of the individual anaerobic threshold (IAT) for 60 min which corresponds approximately in our case with 57 and 69% of the peak oxygen consumption (peak VO2) in mean. These exercise intensities correlate to a strenuous (100%) and a moderate exercise (80%); moderate exercise is recommended for prevention or rehabilitation training. This part of the study, focussing on platelet function, should help to clarify the following: (a) does moderate exercise increase platelet function or not, (b) platelet leukocyte interaction and (c) the number of microparticles or aggregates in comparison with strenuous exercise in healthy untrained participants. For the investigation of these questions a standardised flow cytometric technique was used to analyse platelet function on their direct surface in whole blood avoiding any artificial effects during the preparation of the platelets as much as possible.

Section snippets

Subjects

Twenty-five healthy untrained non-smoking males were included in the study. Two participants did not take part in the second test and three discontinued the second test before 45 min. Three subjects ended their second trial between 45 and 60 min whereas the other participants finished both exercises precisely after 60 min and these 20 were included to the study group which was further investigated. The main characteristics, anthropometric and performance data of the 20 subjects are shown in

Exercise performance, heart rates, metabolic and control data

Performance, heart rate and metabolic data are shown in Table 1. These data underline the diverse effects of the different exercise intensities on the cardiac and metabolic system. The exercise intensities of 80 and 100% of the individual anaerobic threshold corresponded to 57 and 69% of the peak VO2 of this intervention group on average, which can be defined as a moderate, and strenuous, exercise. The norepinephrine concentration was intensity dependent increased after exercise whereas the

Discussion

Physical exercise can increase the risk of cardiovascular events as described in several publications, yet on the other hand is also recommended to prevent such events [5], [6]. Numerous authors have suggested the importance of the exercise intensity in this respect. However which intensity level may be borderline dangerous and which intensity is most optimal for prevention and rehabilitation training remains to be clarified. There are currently only few studies on this topic including

Conclusion

It can be summarized from our study, that a) moderate exercise enhances platelet activity and reactivity, b) yet moderate exercise intensity results in a significantly lower increase in conjugate formation compared to strenuous exercise, and that c) aggregates are enhanced after both exercises after TRAP stimulation.

Based on these results, it is recommended that the IAT should be improved in order for everyone to be in the position to carry out daily activities and also to exercise well below

Acknowledgements

The authors thank Mrs. B. Tauch, Mrs. S. Hörnlein and Mr. M. Soßdorf for their excellent assistance, and the management of POM (Planet of motion) for the support of the study.

References (29)

  • J.S. Wang et al.

    Moderate-intensity exercise suppresses platelet activation and polymorphonuclear leukocyte interaction with surface-adherent platelets under shear flow in men

    Thromb Haemost

    (2004)
  • J.S. Wang et al.

    Effects of short-term exercise on female platelet function during different phases of the menstrual cycle

    Arterioscler Thromb Vasc Biol

    (1997)
  • T. Hilberg et al.

    Platelet activity, reactivity and platelet–leukocyte conjugate formation before and after exhaustive or moderate exercise in patients with IDDM

    Platelets

    (2004)
  • T. Hilberg et al.

    Blood coagulation and fibrinolysis after long-duration treadmill exercise controlled by individual anaerobic threshold

    Eur J Appl Physiol

    (2003)
  • Cited by (0)

    View full text