You get what you give: localized vascular changes are apparent following long‐term exercise training

With the increase in sedentary behaviour in today's fast paced world, cardiovascular disease (CVD) has emerged as the leading cause of death worldwide (Perez-Terzic, 2012). Increasing the likelihood of CVD is a comprehensive list of risk factors that include high blood pressure, high cholesterol, overweight/obesity and lack of physical activity (Perez-Terzic, 2012). A readily modifiable health behavior that has been extensively studied regarding its impact on CVD is exercise. Numerous studies have demonstrated that regular exercise is associated with decreases in CVD risk factors in both primary and secondary prevention settings (Perez-Terzic, 2012). However, risk factor improvements do not account for the full magnitude of CVD risk reduction. The remaining explanation can be found in the direct effect of exercise on both vascular morphology and vascular function (Green et al. 2008). Unfortunately, research pertaining to the effects of exercise on the vascular system in healthy asymptomatic subjects is not as well documented. Obtaining a more comprehensive understanding of the effects of exercise on the vascular system will assist in creating improved intervention tools to combat CVD. In a recent issue of The Journal of Physiology, Spence et al. (2013) investigated the impact of separate endurance and strength training protocols on conduit artery morphology and function in young healthy males. The specific focus of the present research effort was to determine the distinct impacts of endurance versus strength exercise training on vascular measures following 24 weeks of training. Briefly, the results revealed that both exercise protocols improved vascular function, as measured by flow-mediated (FMD) and glyceryl trinitrate-mediated (GTN) dilatation. Specifically, the endurance training group had more pronounced lower limb adaptations present within the femoral artery while the strength training group had more pronounced upper limb adaptations present within the brachial artery. A strong aspect of the present research was the use of an extended training protocol duration coupled with a longitudinal study design. Previous longitudinal work within this area has focused primarily on shorter training protocol durations ranging from 4 to 12 weeks. On the other hand, studies utilizing extended training protocol durations (24+ weeks) have been limited to cross-sectional study designs. With both of the aforementioned experimental designs, numerous questions surrounding vascular adaptations to training remain unanswered, as differing underlying subject pools often confound conclusions gained from these investigations, while shorter training stimuli leave one to wonder about chronic implications. The present study design allowed for valuable insight into vascular adaptations as a result of training while being able to speak to the chronic effects. A caveat of any training study is the design and implementation of exercise programmes that are well matched to the research outcomes. In the present study, Spence et al. (2013) designed both an aerobic training programme and a resistance training programme. The desire to use commonly used training programmes was a noteworthy design by the researchers, as this would allow research results to be easily transferred and applied in a real world setting. The presently prescribed aerobic training protocol, although not described in detail, was available from a previous publication, was well designed with monitored intensity progressions and was aligned with the notion of commonly used aerobic exercise. This was a combination of walking, jogging and running with progressive increases in the prescribed intensity throughout training based on subjects’ measured . In contrast to the well-designed aerobic training programme, the strength training programme appeared to be more advanced and did not align with the authors’ description of commonly used strength exercises. The prescription consisted of numerous exercises that resulted in a full body training experience; however, Olympic lifts, dead lifts, front squats and back squats may be quite challenging for the general population to perform correctly. These types of exercises require impeccable form to prevent the occurrence of training-related injuries while similar machine-orientated exercises are able to stimulate the same muscles with less risk. It is important to note that the appropriate lifting techniques were developed during the initial few weeks of training and all training sessions were supervised to eliminate training injuries. With this information in mind, an area for future research would be a more generally accessible strength programme. The American College of Sports Medicine (ACSM) guidelines could be utilized to develop a programme that is both readily accepted and endorsed for healthy individuals within a population as well as those potentially suffering from or at risk for CVD and are applicable as a general common training modality (Pollock et al. 2000). The primary outcome measures of the present study were vascular morphology and function in response to exercise training. In more detail, this study demonstrated that endurance and strength training exercise prescriptions result in an increase in baseline artery diameter, decreases in arterial wall thickness and improvements in endothelial-dependent vasodilatation in both the brachial and the femoral arteries. Endothelial-dependent vasodilatation was measured using the gold standard technique: FMD. Although FMD is a valid approach to assess arterial function via nitric oxide bioavailability, combining this measure with pulse wave velocity (at both the brachial and the femoral arteries), the gold standard for evaluating arterial distensibility, would add another level of validity to the research findings. By completing pulse wave velocity measurements, in addition to FMD, the results from Spence et al. (2013) would be able to speak directly to the influence of differing exercise modalities on arterial distensibility and endothelial health/endothelial dysfunction. It is clear that there were localized vascular responses dependent upon the exercise training modality, such that endurance training positively impacted primarily the femoral artery and strength training positively influenced primarily the brachial artery. Upon closer investigation of Spence et al.'s (2013) figures 1 and 2, the results revealed that this observation was not explicitly present in every individual. In fact, it is clear that there were differing individual responses present between subjects within each training group with respect to their outcome variables. With the potential of ‘responders’ and ‘non-responders’ present in the current experiment, additional analyses with this categorization would provide insight into the rationale behind such differences. One potential explanation for the observed responder groups might be previous exercise experience, as this was not controlled for in the present research paper. The intention of the present study was to identify the occurrence of vascular adaptations to a longer training stimulus (i.e. >12 weeks). That being said, measurements of vascular function and morphology at key time points (i.e. the length of prior studies investigating vascular adaptations to exercise training that helped form the background context for Spence et al. (2013)) should have been obtained. Throughout the 24 week training protocol subjects were committed to supervised training sessions, making additional vascular measurements at key time points highly accessible. Previous research has shown that changes to vascular function of conduit arteries, measured through flow-mediated dilatation, can occur as soon as 2 weeks into an exercise training programme (Tinken et al. 2008). With this in mind, an extension of the present study would be to obtain serial measurements of vascular adaptations to training. A similar approach could be applied to detraining to garner a better understanding of both vascular morphology and vascular function as they relate to CVD risk factors. In closing, Spence et al. (2013) provide important information regarding the vascular adaptations in response to either aerobic or strength training exercise regimes. The study results demonstrate that both exercise modalities improve vascular function and by extension reduce the risk of CVD. Future studies building on the work completed by Spence et al. (2013) can focus on implementing a more accessible strength training programme in accordance with the ACSM guidelines while exploring the effect of exercise training on vascular adaptations by monitoring these adaptations over the course of the study rather than just before and after.

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.