The findings of this study suggest sport-specific cardiac adaptations.
- Prolonged QT dispersion derived from electrocardiograms has been used as an indicator of abnormal ventricular repolarization for several cardiac diseases.
- An increased QT dispersion has been documented in patients with arterial hypertension and left ventricular hypertrophy.
- In addition to clinical environments, left ventricular hypertrophy is observed in athletes completing regular training.
- This left ventricular hypertrophic cardiac response serves as a reactive mechanism to compensate for volume overload experienced during endurance training or pressure overload experienced during resistance training.
- Although athletes develop impressive left ventricular tissue growth, it is unknown whether this exercise-induced left ventricular hypertrophy is associated with increased QT dispersion as observed in patients with hypertensive myocardial hypertrophy.
- Despite evidence suggesting that cardiac remodeling varies in response to pressure overload (concentric hypertrophy) or volume overload (eccentric hypertrophy)...
...there is limited research on comparing QT dispersion and echocardiographic parameters across athletes competing in different sports varying in terms of the predominant type of overload imposed.
- In this way, sports may be classified according to the mechanical demands they elicit based on the peak static components (expressed as relative intensity of voluntary muscular contraction across three levels [A, B, C])...
...and the peak dynamic components (expressed as percentage of maximal oxygen uptake across three levels [I, II, III]) undertaken by athletes.
- This study aimed to compare QT dispersion and echocardiographic parameters between athletes competing in different sports and sedentary controls and assess the associations between QT dispersion and echocardiographic parameters among them.
- Advanced left ventricular hypertrophy, predominantly concentric in nature, induced by pressure overload, accompanied with an increased QT dispersion was observed in athletes predominantly completing static exercise (powerlifters and bodybuilders).
"These structural parameters we observed in powerlifters and bodybuilders represent remodeling adaptations in response to training that fall within a 'grey zone'...
"...where extreme expressions of athlete’s heart and mild morphological forms of hypertrophic cardiomyopathy may overlap...
"...Although these likely remodeling adaptations in powerlifters and bodybuilders mimic pathological hypertrophic cardiomyopathy, their LV end-diastolic diameters (~ 52–53 mm) were within clinically accepted partition values for the general population (45–55 mm)...
"...which is a useful and sensitive marker in distinguishing an athletic heart from hypertrophic cardiomyopathy diagnosis."
- On the other hand, mild left ventricular hypertrophy (toward the upper threshold of the normal reference range) induced by volume overload that was accompanied with a reduced QT dispersion was observed in long-distance runners, volleyball athletes, and football athletes.
"In addition to LV structural parameters, LV systolic indicators were also within clinically accepted reference ranges for the general population...
"...further supporting adaptive (rather than maladaptive) physiological cardiac remodeling in athlete groups predominantly undertaking dynamic (long-distance runners, football athletes, and volleyball athletes) or static exercise (powerlifters and bodybuilders)."
Sport-related differences in QT dispersion and echocardiographic parameters in male athletes (open access)
The findings of this one in mice and humans do not support the involvement of brain-derived neurotrophic factor (BDNF) in the potential cognitive benefits of β-OHB supplementation.
- This study conducted parallel human and rodent trials to characterize the effect of exogenous ketone supplementation on indices of brain health.
- First, the study aimed to investigate the effect of an acute dose of an exogenous ketone monoester supplement on circulating BDNF and cognition in adults with type 2 diabetes.
The findings of this one suggest that exercise training, especially high-intensity exercise, may reduce the inflammatory potential of dendritic cells and macrophages.
- Exercising regularly promotes health, but these benefits are complicated by acute inflammation induced by exercise.
- A potential source of inflammation is cell-free DNA, yet the cellular origins, molecular causes, and immune system interactions of exercise-induced cell-free DNA are unclear.
This one indicates low-carb diets may not impair exercise performance and that minimal carbohydrate supplementation (10g/h) during exercise can eliminate exercise-induced hypoglycemia and improve performance during strenuous time-to-exhaustion (70%⩒O2max) tests.
- Leveraging a randomized crossover design, this study evaluated performance during strenuous time-to-exhaustion (70%⩒O2max) tests in trained triathletes following 6-week high- (380g CHO/day) or low-carbohydrate diets (40g CHO/day) to determine:
* If adoption of the low-carbohydrate diet impairs time-to-exhaustion performance.
The findings of this systematic review and meta-analysis suggest that only 300 MET-minutes per week (half of the WHO's recommended minimum) of low- to moderate-intensity exercise is sufficient to improve frailty in older adults.
- This study explored the dose-response relationship of exercise prescriptions for improving frailty in older adults, based on the 2024 Older Adult Compendium.
- A total of 16 eligible randomized controlled trials comprising 2,716 older adults were included.
This one found that even trained individuals can experience consequential muscle growth and strength adaptations just by maintaining their previous weekly set number above a certain, moderate, weekly set volume threshold, provided a high level of effort is sustained.
- This study investigated the effects of increasing previous resistance training weekly set volume by 30% and 60% on muscle hypertrophy and strength.
- Fifty-five resistance-trained men were randomly allocated to the experimental groups, while 29 completed the study, as follows:
Here, a 4-week detraining period decreased the HIIT-induced increase in whole-body oxidative metabolism in insulin-resistant individuals, but this did not affect improvements in hepatic insulin sensitivity, hepatic lipid content, and glycemia.
- The aim of this study was to compare the sustainability of metabolic effects induced by a long-term HIIT intervention between people with different degrees of whοle-body insulin sensitivity and people with overt type 2 diabetes upon detraining.
- In this study, men with (20) and without type 2 diabetes (12 insulin-sensitive, 10 insulin-resistant) underwent hyperinsulinemic-euglycemic clamps, spiroergometry, ectopic lipid quantification and muscle biopsies at baseline, after 12-week HIIT and after 4-week detraining.