If exercise is medicine, where is the dose? A call to improve reporting and monitoring of exercise interventions in fibromyalgia research

Exercise is widely recognized as a cornerstone non-pharmacological therapy for managing pain and other core symptoms of fibromyalgia. Current guidelines, including those from the American College of Sports Medicine (ACSM), frame exercise prescription through the FITT principles-frequency, intensity, time, and typeproviding a structured approach to defining exercise dose in this population (Ligouri, 2021). When these parameters are implemented with high compliance (i.e., when at least 70% of the ACSM-recommended exercise dose is met), exercise interventions are associated with greater improvements in pain, sleep quality, and fatigue, as supported by recent meta-analytic evidence in fibromyalgia (Niu et al., 2024). However, only about half of the analyzed exercise interventions achieved high compliance with ACSM guidelines, highlighting substantial variability in exercise prescription across fibromyalgia trials (Niu et al., 2024).Despite this growing body of evidence, two complementary perspectives continue to coexist in both research and clinical practice. On one hand, public health recommendations emphasize that any physical activity is preferable to none, particularly in populations with a high symptom burden and low activity levels (Bull et al., 2020;Ekelund et al., 2026). On the other hand, research increasingly seeks to identify specific exercise doses, operationalized through FITT parameters, that maximize therapeutic benefit. We argue that these perspectives do not represent opposing views, but rather reflect different positions along a dose-response continuum (Figure 1). This continuum ranges from reducing the detrimental effects of sedentary behavior in individuals with fibromyalgia (Segura-Jiménez et al., 2020), to achieving a minimum effective dose for meaningful clinical improvement, and ultimately to defining outcome-specific optimal exercise doses (Núñez-cortés et al., 2025). Within this framework, the message "move more and sit less" provides a simple, evidence-based recommendation easily understood by most patients; however, in clinical practice it must be translated into individualized exercise prescriptions to maximize benefits (Warburton and Bredin, 2016). Recent meta-analyses provide important insights into the exercise dose-response relationship in fibromyalgia, particularly regarding pain reduction and overall disease impact (Albuquerque et al., 2022;Couto et al., 2022;Rodríguez-Domínguez et al., 2024;Casanova-Rodríguez et al., 2025;Guachizaca Moreno et al., 2025;Núñez-cortés et al., 2025;Wang et al., 2025). While this literature reflects progress in FITT-based exercise prescription, dose-response interpretation remains limited by persistent methodological shortcomings, including heterogeneous interventions, incomplete reporting of FITT parameters, limited monitoring of performed exercise, high dropout rates, and poor adherence documentation. Consequently, conclusions often rely on intended or reported FITT criteria (when available) rather than on the exercise dose actually delivered and executed by participants.To establish exercise as a true therapeutic intervention in fibromyalgia, intended adherence to FITT principles alone is insufficient. Given the disease's fluctuating nature and the need for symptom-driven adaptations, exercise dose must be precisely defined, actively monitored, and transparently reported based on what is actually executed, including internal and external load, session-level modifications, and adherence over time. In this Opinion article, we outline four critical areas requiring improvement arguing that fibromyalgia research must move beyond "prescribing a program" toward the deliberate administration of exercise as a therapeutic dose. These concepts are summarized in Figure 2, which illustrates exercise dose as a dynamic, multilevel process-from planned to executed dose within a real-world clinical context. Each level of this framework is discussed in detail in the following sections. Accurate and clinically meaningful reporting therefore requires structured descriptions of FITT principles. Mind-body exercise modalities commonly used in fibromyalgia, such as yoga or Tai Chi, are defined as practices integrating physical movement with mental focus and breath regulation. In this context, the FITT framework should be expanded to 'FITT-M' to incorporate the Mindfulness (or mental) component-including attentional focus, breathing control, and mind-body integration-as a core dimension of the therapeutic dose. Although this component is inherently more difficult to quantify than traditional FITT parameters, its inclusion is essential to more accurately reflect the multidimensional nature of these interventions. This is further supported by recent evidence indicating that mind-body exercise therapies are a beneficial adjunctive approach for improving a range of symptoms in fibromyalgia (Zhang et al., 2026).The Consensus on Exercise Reporting Template (CERT) (Slade et al., 2016) provides a 16-item checklist covering key domains of exercise delivery and is strongly recommended to improve reporting completeness, reproducibility, and clinical translation (Subialka et al., 2025). Complementary frameworks, such as PRIRES for resistance exercise interventions (Lin et al., 2023), may provide additional modality-specific guidance alongside CERT. Table 1 summarizes Beyond its role as a reporting tool, applying CERT principles prospectively during exercise protocol design may further improve intervention fidelity and clinical interpretability by requiring explicit definition of key intervention components before implementation. In line with this perspective, the framework proposed here (Table 1) emphasizes the use of CERT as a guiding tool during the design and planning stages, focusing on the key domains.A common limitation in exercise trials is the discrepancy between prescribed and executed exercise dose. In the al-Ándalus randomized controlled trial (n=244), participants with fibromyalgia generally trained at lower heart rate intensities than those prescribed (Gavilán-Carrera, 2020). This finding illustrates a recurrent scenario in both fibromyalgia research and clinical practice: even when exercise prescriptions are well defined, the delivered dose frequently diverges as a result of real-time session adjustments and clinical decision-making.Although highly relevant, this gap is rarely documented in sufficient detail. Most trials focus on the intended intervention, providing limited insight into how and why exercise dose is modified in practice or into the clinical decision-making processes underlying such modifications. In fibromyalgia, where symptom fluctuations and variable tolerance are inherent, these decisions are central to the safe and effective delivery of exercise.Failure to report the rationale for adaptations to disease-related variability compromises the interpretation of dose-response relationships and limits opportunities to inform and improve clinical practice. Moreover, systematically identifying the factors driving dose modifications and documenting how these adaptations are implemented would enhance both mechanistic understanding and clinical applicability.Selected CERT items can be expanded to capture this clinical decision-making process (Table 1). Item 7a allows reporting of predefined decision rules guiding progression or dose modification, item 14b documents ongoing individual tailoring, and item 16b provides a framework to report clinically justified deviations from the planned intervention. Explicit use of these items would improve transparency, clarify how exercise dose is modified in fibromyalgia trials, and enhance clinical relevance and reproducibility. From a research perspective, incorporating executed-dose data would improve interpretation of dose-response relationships and strengthen future meta-analyses. As illustrated in Figure 2, systematic monitoring may also support more refined definitions of minimal and optimal exercise doses for improving health in fibromyalgia.In this framework, adherence primarily refers to consistent attendance to prescribed exercise sessions, while the effective exercise dose is captured through systematic monitoring of the executed internal and external load. Adherence is a critical, yet frequently underreported, component of exercise interventions. High dropout rates and missing data-common in exercise research and particularly prevalent in fibromyalgiacompromise outcome validity and limit interpretability. Reporting only the planned or executed exercise dose, even when accompanied by descriptions of clinical decisionmaking, is insufficient; understanding adherence patterns and the factors that shape them is essential to accurately quantify the stimulus that is ultimately delivered.Several barriers have been consistently associated with reduced exercise participation in fibromyalgia, including low fitness levels, reduced self-efficacy, and fear of symptom worsening (Vancampfort et al., 2024). Screening for psychological barriers such as kinesiophobia-using tools such as the Tampa Scale for Kinesiophobia-11 (TSK-11;Woby et al., 2005)-may help identify patients at greater risk of poor adherence.Conversely, appropriate supervision, lower body mass index, and lower symptom severity appear to positively influence adherence (Vancampfort et al., 2024). Together, these findings highlight that adherence is not merely a matter of attendance, but reflects complex psychological and contextual mechanisms that influence engagement with exercise over time. However, many of these key determinants, as well as others such as kinesiophobia (Vancampfort et al., 2024) Adherence is inherently dynamic, shaped by symptoms, motivation, expectations, and program structure. In fibromyalgia, predefined flare-up management strategies that allow temporary adjustment of exercise dose may help maintain participation during symptom exacerbations. Detailed reporting of session attendance, reasons for non-adherence, and resulting protocol adaptations provides the most realistic estimate of the effective exercise dose. Our proposed reporting approach is summarized in item 5 of Table 1. From a clinical perspective, adherence is fundamental: even highly efficacious exercise protocols have limited real-world value if patients cannot realistically follow them. Consequently, defining an "optimal" exercise dose is only meaningful when adherence is achievable and sustained.Exercise prescription in fibromyalgia must move beyond the exclusive focus on planned