Effects of detraining on left ventricular mass in endurance-trained individuals: a systematic review and meta-analysis.

AIMS: Detraining refers to a loss of training adaptations resulting from reductions in training stimulus due to illness, injury, or active recovery breaks in a training cycle and is associated with a reduction in left ventricular mass (LVM). The purpose of this study was to conduct a systematic review and meta-analysis to determine the influence of detraining on LVM in endurance-trained, healthy individuals. METHODS AND RESULTS: Using electronic databases (e.g. EMBASE and MEDLINE), a literature search was performed looking for prospective detraining studies in humans. Inclusion criteria were adults, endurance-trained individuals with no known chronic disease, detraining intervention >1 week, and pre- and post-detraining LVM reported. A pooled statistic for random effects was used to assess changes in LVM with detraining. Fifteen investigations (19 analyses) with a total of 196 participants (ages 18-55 years, 15% female) met inclusion criteria, with detraining ranging between 1.4 and 15 weeks. The meta-analysis revealed a significant reduction in LVM with detraining (standardized mean difference = -0.586; 95% confidence interval = -0.817, -0.355; P < 0.001). Independently, length of detraining was not correlated with the change in LVM. However, a meta-regression model revealed length of the detraining, when training status was accounted for, was associated with the reduction of LVM (Q = 15.20, df = 3, P = 0.0017). Highly trained/elite athletes had greater reductions in LVM compared with recreational and newly trained individuals (P < 0.01). Limitations included relatively few female participants and inconsistent reporting of intervention details. CONCLUSION: In summary, LVM is reduced following detraining of one week or more. Further research may provide a greater understanding of the effects of sex, age, and type of detraining on changes in LVM in endurance-trained individuals.

In healthy, endurance-trained individuals, detraining results in significant reductions in left ventricular mass. When accounting for training status, the length of the detraining period is positively associated with reductions in left ventricular mass. Limited research on this topic hinders the ability to assess sex differences or the impact of the type of detraining (i.e. only activities of daily living vs. reduced training load) on the response to detraining.

Three-Dimensional-Derived Echocardiographic Left Ventricular Structure and Function and Indices from the 12-Lead Electrocardiogram across the Menstrual Cycle in Healthy Physically Active Females: An Exploratory Study.

Background: The impact of the menstrual phases on left ventricular (LV) structure and function using 3D echocardiography and resting electrocardiogram (ECG) in healthy, eumenorrheic, and physically active females has not been investigated. Methods: sixteen females (20 y ± 2) underwent 3D echocardiography and an ECG at three time points in the menstrual cycle phases (follicular, ovulation, luteal). LV end-diastolic volume (LVEDVi), LV ejection fraction (LVEF), LV mass allometrically indexed to height2.7 (LVMi), torsion, and global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS) were evaluated. ECG data of the P and QRS waves were presented as well as axis deviation, chamber enlargement, and any rhythm abnormalities. Results: LVMi was significantly higher in the luteal phase (36.4 g/m2.7 ± 3.3) compared to the follicular (35.0 g/m2.7 ± 3.7) and ovulation (34.7 g/m2.7 ± 4.3) phases (p = 0.026). There were no differences in other indices of LV structure and function or ECG variables across all phases of the menstrual cycle or evidence of arrhythmia. Conclusions: In physically active females, there is a small but significantly higher LVMi associated with the luteal phase of the menstrual cycle with no concomitant change in LV function or ECG parameters. These findings are important to consider when conducting clinical or research serial assessments.