Isometric exercise at 70% versus 0% maximal voluntary contraction prior to muscle metaboreflex activation increased the average real variability of diastolic blood pressure (P=0.0024).
RCT (n=10)
Randomized order
Does isometric exercise of different intensities alter blood pressure variability during muscle metaboreflex activation in healthy young adults?
Diastolic blood pressure average real variability is higher and coefficient of variation is lower during muscle metaboreflex activation following higher intensity isometric exercise in healthy young adults, indicating larger oscillations in diastolic blood pressure.
p-value: p=0.0024
During exercise, blood pressure (BP) increases to ensure adequate perfusion of active skeletal muscles. BP variability (BPV) provides important information about BP control and can be assessed on a beat-to-beat basis. While beat-to-beat BPV has been examined at rest in different populations and following isometric handgrip exercise in healthy young adults, BPV during muscle metaboreflex activation (MMA), a common component of the exercise response, has not been investigated. Therefore, the aim of this study was to examine BPV during isolated MMA following isometric exercise of different intensities in healthy young adults. It was hypothesized that BPV would be greater during isolated MMA following isometric exercise of higher intensities in healthy young adults. Ten healthy young adults (7M/3F, 22±3y) completed four trials in a randomized order over four visits. Each trial consisted of a 5-minute baseline (BL) period, with a cuff around the right thigh inflated to 200mmHg 10s before the end of BL to cause lower-limb circulatory occlusion. Next, participants performed 90s of 30%, 50%, or 70% maximal voluntary contraction (MVC) isometric right calf exercise or continued to rest (0% control trial). Participants then stopped exercising and rested or continued to rest with maintained limb circulatory occlusion for 3.5 minutes to induce MMA after exercise performance. Beat-to-beat systolic (SBP), diastolic (DBP), and mean arterial (MAP) BPs were measured via photoplethysmography. BPV parameters of standard deviation (SD), range, interquartile range (IQR), coefficient of variation (CoV), and average real variability (ARV) were calculated for SBP, DBP, and MAP, respectively. Normality of data was assessed using the Shapiro-Wilk test, and two-way repeated measures analysis of variance with Šídák’s post-hoc tests was used to determine statistical differences. Data are presented as mean±SD with statistical significance set to P< 0.05. ARV of DBP (occlusion 1.20-1.85 vs. BL 1.15-1.62mmHg, P=0.0021) and MAP (occlusion 1.37-1.91 vs. BL 1.34-1.79mmHg, P=0.0027) were higher during the period after the rest/exercise phase when MMA was present following exercise performance compared to BL, whereas CoV of SBP (occlusion 5.1-5.6 vs. BL 5.6-6.6mmHg, P=0.0002), DBP (occlusion 4.9-6.1 vs. BL 5.2-6.8mmHg, P=0.0119), and MAP (occlusion 4.5-5.3 vs. BL 4.9-6.1mmHg, P=0.0029) was lower. ARV (0% 0.85-1.52 vs. 70% 1.06-2.47mmHg, P=0.0024) and CoV (0% 2.47-7.19 vs. 70% 4.11-8.88mmHg, P=0.0182) of DBP were higher during trials involving exercise of greater intensities. SD, range, and IQR of DBP and MAP were higher during trials involving exercise of greater intensities (all P< 0.05). In conclusion, DBP ARV is higher, and CoV is lower during MMA following isometric exercise of greater intensities in healthy young adults. With ARV representing variations in successive beats, these results indicate that there are larger oscillations in DBP during MMA following isometric exercise of greater intensities in healthy young adults. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Oliver et al. (2026) conducted an RCT in Healthy young adults (n=10). Isometric calf exercise with limb circulatory occlusion vs. 0% control trial (rest with occlusion) was evaluated on Average real variability (ARV) of diastolic blood pressure (p=0.0024). Isometric exercise at 70% versus 0% maximal voluntary contraction prior to muscle metaboreflex activation increased the average real variability of diastolic blood pressure (P=0.0024).