Ageing Arteries and Aerobic Exercise: Bridging Evidence and Innovation in Vascular Health Open Access

Dear Editor,

Arterial stiffness (AS) represents a significant biomarker and modifiable risk factor for cardiovascular disease, directly linked to ageing and lifestyle factors [1, 2]. Aerobic exercise (AE) has emerged as a cornerstone intervention, offering promising pathways to mitigate vascular stiffening [3]. However, variability in individual responses and the interplay of systemic factors demand a nuanced exploration. These considerations form the basis for our response to the insightful review “De-Stiffening the Aged Aorta with Regular Aerobic Exercise in Humans: Fact or Fallacy?” by Pierce et al. [4] published in your highly regarded journal. AS reflects the complex interactions between vascular ageing, systemic inflammation, and the physiological adaptations to exercise. We commend the authors for their detailed analysis and conclusions, particularly regarding the frequency-dependent benefits of aerobic activity. However, we believe this topic warrants more insights that are expansive and identify challenges that may open the debate about the nuances of exercise interventions, challenges, and the integration of complementary strategies to address AS comprehensively.

Pierce et al. [4] emphasized the importance of performing AE 4 to 5 times weekly to achieve meaningful reductions in AS. This recommendation is supported by studies such as those by Keijzer et al. [5] who verified the inverse relationship between cardiorespiratory fitness and AS, and Kobayashi et al. [6] who showed the efficacy of intermittent AE in reducing brachial-ankle pulse wave velocity during postprandial hyperglycaemia in older adults. While these findings are robust, they also reveal significant variability in individual responses to exercise interventions, influenced by baseline fitness levels, genetic predispositions, comorbidities, and age. Personalized exercise prescriptions that consider these factors are essential for optimizing outcomes. Stratified analyses of group participants by demographic and physiological characteristics could help identify subpopulations that benefit most from specific exercise regimens [7]. For instance, sedentary older adults may respond best to gradually increasing intensity, while younger individuals with metabolic disorders might derive greater benefits from higher intensity programs [8]. The discussion on high-intensity interval training (HIIT) in the review of Pierce et al. [4] is particularly intriguing. While HIIT has demonstrated significant benefits in improving aerobic fitness, compared to moderate-intensity continuous training, its effects on AS may vary depending on the measurement approach [9]. Recent reports demonstrated that carotid-femoral pulse wave velocity, which assesses central AS, might not always show pronounced reductions following HIIT, whereas brachial-ankle pulse wave velocity, which captures stiffness across both central and peripheral arteries, has been shown to improve in various populations. These variations could be influenced by differences in vascular adaptation, regional arterial compliance, and the specific methodology used to assess AS [10, 11]. Further research is needed to better understand how HIIT differentially influences various segments of the arterial tree and the underlying physiological mechanisms driving these effects. Acute hemodynamic stresses induced by HIIT may counteract its vascular benefits, particularly in populations with pre-existing conditions. Combined exercises that blend HIIT and moderate-intensity continuous training could offer a balanced approach, maximizing fitness gains while minimizing potential adverse effects on vascular health [12]. Furthermore, intermittent AE characterized by shorter, high-frequency sessions has emerged as a promising alternative for individuals with time or mobility constraints.

One critical limitation of the current literature, as noted by Pierce et al. [4], is the relatively short duration of most studies, which typically span weeks to months. This limited timeframe often fails to capture the cumulative benefits of sustained physical activity. Long-term adherence to regular AE has been shown to significantly attenuate AS, as demonstrated by Shibata et al. [13], whose work highlights the advantages of consistent exercise over decades. Implementing periodized training models, where intensity and duration are progressively increased, could enhance sustainability and maximize vascular adaptations. Additionally, research exploring the minimum effective dose of exercise for populations with physical limitations or chronic conditions remains an area of critical importance. Systemic inflammation is a well-established contributor to AS, and AE’s ability to reduce inflammatory markers is a significant advantage. However, combining exercise with anti-inflammatory dietary interventions could further amplify its benefits [14]. Diets enriched with omega-3 fatty acids, polyphenols, and nitric oxide precursors have been shown to enhance vascular function and reduce oxidative stress, as highlighted by Wiest et al. [15]. Future trials should focus on the synergistic effects of dietary strategies and structured exercise regimens, exploring how timing, composition, and frequency of meals influence vascular outcomes.

Pierce et al. [4] also briefly mentioned non-exercise interventions such as inspiratory muscle training and passive heat therapy, which are particularly relevant for individuals unable to engage in traditional AE. Inspiratory muscle training enhances nitric oxide bioavailability and reduces systemic inflammation, while passive heat therapy promotes vasodilation and improves endothelial function. These modalities have shown promise in improving arterial compliance and could serve as complementary strategies for managing AS [16]. Combining non-exercise interventions with AE could expand the range of therapeutic options available to diverse populations, particularly those with mobility or endurance limitations.

Notably, the integration of technology into exercise interventions represents an exciting frontier. Wearable devices capable of monitoring vascular biomarkers such as PWV and heart rate variability offer the potential for real-time feedback and personalized adjustments to exercise regimens [17]. In conclusion, Pierce et al. [4] provided a comprehensive and insightful review of AE’s role in mitigating AS. The interconnected molecular pillars of vascular ageing, including mitochondrial dysfunction, inflammation, and cellular senescence, require a multifaceted approach involving exercise and dietary strategies. Building on their findings, we underscore the importance of addressing individual variability, integrating complementary strategies such as diet, pharmacology, and leveraging emerging technologies to enhance precision and adherence. We commend Pierce et al. [4] for their valuable contribution and hope this commentary inspires further research and innovation in managing AS.