Effects of moderate and low frequency recreational football on cardiovascular risk: a dose-response study

Introduction. Physical inactivity ranks fourth as a risk factor for global mortality. World Health Organisation (WHO) physical activity guidelines recommend at least 150 min/wk of moderate or 75 min/wk of vigorous intensity aerobic physical activity for “substantial health benefits”. Lack of time and motivation are often a barrier to meeting these recommendations. Aims. There is abundant evidence that recreational football (RF) at moderate and high frequency is effective to improve cardiovascular health, however, data are scarce regarding the effects of low frequency training (once a week).The aims of the present study were to: 1) compare the effects of low and moderate RF training volume (1 and 2 times a week for 12 weeks) on cardiovascular risk factors, 2) assess changes in inflammatory status after RF training, and 3) determine what cardiac and peripheral adaptations occur. The study population was 40 healthy, sedentary men (age range 35 - 55 years). Study 1. We compared the outcome of 12 weeks RF training in three groups: moderate frequency group (MFG, training twice a week), low frequency group (LFG, training once a week), and control group (CG, no training). As compared with the CG, the fat mass was decreased in both the LFG and the MFG, whereas body mass and body-mass index (BMI, weight in kg divided by height in meters squared) were decreased only in the MFG. Maximal oxygen consumption was higher in both the LFG and the MFG. Arterial blood pressure and blood lipid profile remained unchanged. Study 2. Endothelial function impairment and atherosclerosis are precursors of many cardiovascular events. Despite the consistent body of literature on inflammatory markers and their relationship with physical exercise, it is not clear how RF influences them. We measured inflammatory markers white blood count (WBC), neutrophil-lymphocyte ratio (NLR), and C-reactive protein (CRP). No differences among the three groups were found at 12 weeks. Comparison of CG with the merged LFG and MFG groups (FG), revealed differences only for WBC. This difference probably had no remarkable meaning. Study 3. To better understand the adaptations that lead to improvement in cardiovascular risk factors, we evaluated microvascular responsiveness by near-infrared spectroscopy (NIRS) and cardiac function and structure by echocardiography. At 12 weeks we recorded changes in area under the curve (AUC) and increased hyperaemia reserve in the MFG and the LFG, respectively, versus the CG. This increase was also noted when the FG was compared versus the CG, suggesting a possible improvement in hyperaemic response. Echocardiography showed an increase in cardiac dimensions in both the LFG and the MFG versus the CG. Cardiac function parameters remained unchanged, except for a difference in right ventricular systolic function between the FG and the CG. Conclusion. The main, novel finding of these studies is that low frequency RF training produces beneficial effects on some cardiovascular risk factors in sedentary, healthy, and untrained middle-aged men. No beneficial effects on inflammatory conditions (CRP, WBC, NLR) were noted. In addition, echocardiographic assessment showed ventricular remodelling in the FG, as demonstrated by increased left and right ventricular diameters and left ventricular mass. Diastolic function remained unchanged, indicating that low frequency RF training for 12 weeks was not sufficient to further improve normal diastolic function in this healthy sample. Finally, a small positive effect on endothelial function was detected, but further investigations are needed to explain this observation.