Metabolic intensity and energy cost of Pilates exercises: an exploratory systematic review and meta-analysis of limited and heterogeneous evidence

Although Pilates exercises are widely practiced worldwide, the available evidence regarding their metabolic intensity and energy cost remains limited and inconsistent. This study aimed to explore the metabolic equivalent (MET) and energy cost of Pilates exercises. As a secondary objective, we examined other measures commonly used in professional practice to monitor exercise intensity, such as heart rate and the rating of perceived exertion (RPE). A systematic search was conducted in PubMed, CENTRAL, Embase, Web of Science, SPORTDiscus, and CINAHL (May 2024). The methodological quality of the studies was assessed using the Rosendal scale. For the meta-analysis, weighted averages were calculated for the following outcomes: METs, energy cost (kcal·min⁻ 1 ), oxygen consumption (V̇O 2 , ml·kg⁻ 1 ·min⁻ 1 ), heart rate (bpm), and RPE (Borg 6–20). The certainty of the evidence was assessed using the GRADE approach. Six studies met the inclusion criteria. Very low- to low-certainty evidence suggests that a typical Pilates session elicits, on average, 3.7 (95% CI: 3.1–4.3) METs, 3.8 (95% CI: 3.1–4.5) kcal·min⁻ 1 , V̇O 2 of 10.3 (95% CI: 8.1–12.6) ml·kg⁻ 1 ·min⁻ 1 , heart rate of 108.6 (95% CI: 104.1–113.0) bpm, and RPE of 10.6 (95% CI: 9.3–12.0). However, sensitivity analyses excluding two studies with high risk of bias and without indirect calorimetry yielded lower and more conservative estimates of 3.0 (95% CI: 2.3–3.6) METs and 2.9 (95% CI: 2.3–3.6) kcal·min⁻ 1 , which should be considered the most methodologically reliable estimates available to date. The rest interval between sets and exercises emerged as a potential moderator, with durations ≤ 60 s associated with higher metabolic intensity. Within the limits of the current and highly heterogeneous evidence base, Pilates appears to elicit light-to-moderate metabolic intensity. These conclusions are exploratory, and the estimates require confirmation through future well-controlled primary studies. Prospero registration number: CRD42022370937.