The effect of post-exercise heat exposure (passive heat acclimation) on endurance exercise performance: a systematic review and meta-analysis.

Background: "Active" heat acclimation (exercise-in-the-heat) can improve exercise performance but the efficacy of "passive" heat acclimation using post-exercise heat exposure is unclear. Therefore, we synthesised a systematic review and meta-analysis to answer whether post-exercise heat exposure improves exercise performance.

Methods: Five databases were searched to identify studies including: (i) healthy adults; (ii) an exercise training intervention with post-exercise heat exposure via sauna or hot water immersion (treatment group); (iii) a non-heat exposure control group completing the same training; and (iv) outcomes measuring exercise performance in the heat (primary outcome), or performance in thermoneutral conditions, V̇Omax, lactate threshold, economy, heart rate, RPE, core temperature, sweat rate, and thermal sensations.

Rapid Creation of Knowledge-Balanced Student Groups Using ChatGPT4.

We demonstrated use of ChatGPT4 for efficient group formation in undergraduate medical education. ChatGPT4 created balanced groups considering students' backgrounds in microbiology, physiology, genetics, and immunology considerably faster than manual efforts. Manual refinements included gender balance and discipline distribution.

Human visceral and subcutaneous adipose stem and progenitor cells retain depot-specific adipogenic properties during obesity.

Abdominal obesity associates with cardiometabolic disease and an accumulation of lipids in the visceral adipose depot, whereas lipid accumulation in the subcutaneous depot is more benign. We aimed to further investigate whether the adipogenic properties where cell-intrinsic, or dependent on a depot-specific or obesity-produced microenvironment. We obtained visceral and subcutaneous biopsies from non-obese women ( = 14) or women living with morbid obesity ( = 14) and isolated adipose stem and progenitor cells (ASPCs) from the stromal vascular fraction of non-obese ( = 13) and obese ( = 13).

Immediate post-breakfast physical activity improves interstitial postprandial glycemia: a comparison of different activity-meal timings.

The optimal timing between meal ingestion and simple physical activity for improving blood glucose control is unknown. This study compared the effects of physical activity on postprandial interstitial glucose responses when the activity was conducted either immediately before, immediately after, or 30 min after breakfast. Forty-eight adults were randomized to three separate physical activity interventions: standing still (for 30 min), walking (for 30 min), and bodyweight exercises (3 sets of 10 squats, 10 push-ups, 10 lunges, 10 sit-ups).

Targeting Postprandial Hyperglycemia With Physical Activity May Reduce Cardiovascular Disease Risk. But What Should We Do, and When Is the Right Time to Move?

Physical inactivity and excessive postprandial hyperglycemia are two major independent risk factors for type 2 diabetes and cardiovascular-related mortality. Current health policy guidelines recommend at least 150 min of physical activity per week coupled with reduced daily sedentary behavior by interrupting prolonged sitting with bouts of light activity every 30-min. This evidence-based strategy promotes health and quality of life.

Skeletal Muscle to Pancreatic β-Cell Cross-talk: The Effect of Humoral Mediators Liberated by Muscle Contraction and Acute Exercise on β-Cell Apoptosis.

Context: Mechanisms explaining exercise-induced β-cell health are unknown.

Objective: This study aimed to define the role of muscle contraction and acute exercise-derived soluble humoral mediators on β-cell health.

Design: In vitro models were used.

The effects of age and dietary restriction on the tissue-specific metabolome of Drosophila.

Dietary restriction (DR) is a robust intervention that extends lifespan and slows the onset of age-related diseases in diverse organisms. While significant progress has been made in attempts to uncover the genetic mechanisms of DR, there are few studies on the effects of DR on the metabolome. In recent years, metabolomic profiling has emerged as a powerful technology to understand the molecular causes and consequences of natural aging and disease-associated phenotypes.

Association between cardiorespiratory fitness and the determinants of glycemic control across the entire glucose tolerance continuum.

Objective: Cardiorespiratory fitness (VO2max) is associated with glycemic control, yet the relationship between VO2max and the underlying determinants of glycemic control is less clear. Our aim was to determine whether VO2max is associated with insulin sensitivity, insulin secretion, and the disposition index, a measure of compensatory pancreatic β-cell insulin secretion relative to insulin sensitivity, in subjects representing the entire range of the glucose tolerance continuum.

Research Design And Methods: A cohort of subjects (N = 313) with heterogeneous age, sex, BMI, and glycemic control underwent measurements of body composition, HbA1c, fasting glucose, oral glucose tolerance (OGTT), and VO2max.

Determining pancreatic β-cell compensation for changing insulin sensitivity using an oral glucose tolerance test.

Plasma glucose, insulin, and C-peptide responses during an OGTT are informative for both research and clinical practice in type 2 diabetes. The aim of this study was to use such information to determine insulin sensitivity and insulin secretion so as to calculate an oral glucose disposition index (DI(OGTT)) that is a measure of pancreatic β-cell insulin secretory compensation for changing insulin sensitivity. We conducted an observational study of n = 187 subjects, representing the entire glucose tolerance continuum from normal glucose tolerance to type 2 diabetes.

The miRNA plasma signature in response to acute aerobic exercise and endurance training.

MiRNAs are potent intracellular posttranscriptional regulators and are also selectively secreted into the circulation in a cell-specific fashion. Global changes in miRNA expression in skeletal muscle in response to endurance exercise training have been reported. Therefore, our aim was to establish the miRNA signature in human plasma in response to acute exercise and chronic endurance training by utilizing a novel methodological approach.

Muscle specific miRNAs are induced by testosterone and independently upregulated by age.

Age dependent decline in skeletal muscle function leads to impaired metabolic flexibility in elderly individuals. Physical activity and testosterone treatment have proven efficient strategies for delaying this condition. However, a common molecular pathway has not been identified.

Different immunological phenotypes associated with preserved CD4+ T cell counts in HIV-infected controllers and viremic long term non-progressors.

Background: HIV-infected controllers control viral replication and maintain normal CD4+ T cell counts. Long Term Non-Progressors (LTNP) also maintain normal CD4+ T cell counts, but have on-going viral replication. We hypothesized that different immunological mechanisms are responsible for preserved CD4+ T cell counts in controllers and LTNP.

Daily marathon running for a week--the biochemical and body compositional effects of participation.

Although long-distance running, such as ultramarathons and multistage races, is increasingly popular, it maybe potentially harmful to health, despite sparse evidence. We studied 8 experienced recreational runners participating in a multiple-marathon running event in which 7 marathons were completed on consecutive days. Fasting blood chemistry and body composition were assessed before and 20-24 hours after the race.

Lack of exercise is a major cause of chronic diseases.

Chronic diseases are major killers in the modern era. Physical inactivity is a primary cause of most chronic diseases. The initial third of the article considers: activity and prevention definitions; historical evidence showing physical inactivity is detrimental to health and normal organ functional capacities; cause versus treatment; physical activity and inactivity mechanisms differ; gene-environment interaction (including aerobic training adaptations, personalized medicine, and co-twin physical activity); and specificity of adaptations to type of training.

Increased shelterin mRNA expression in peripheral blood mononuclear cells and skeletal muscle following an ultra-long-distance running event.

Located at the end of chromosomes, telomeres are progressively shortened with each replication of DNA during aging. Integral to the regulation of telomere length is a group of proteins making up the shelterin complex, whose tissue-specific function during physiological stress is not well understood. In this study, we examine the mRNA and protein levels of proteins within and associated with the shelterin complex in subjects (n = 8, mean age = 44 yr) who completed a physiological stress of seven marathons in 7 days.

Lifetime sedentary living accelerates some aspects of secondary aging.

Lifetime physical inactivity interacts with secondary aging (i.e., aging caused by diseases and environmental factors) in three patterns of response.

LIF is a contraction-induced myokine stimulating human myocyte proliferation.

The cytokine leukemia inhibitory factor (LIF) is expressed by skeletal muscle and induces proliferation of myoblasts. We hypothesized that LIF is a contraction-induced myokine functioning in an autocrine fashion to activate gene regulation of human muscle satellite cell proliferation. Skeletal muscle LIF expression, regulation, and action were examined in two models: 1) young men performing a bout of heavy resistance exercise of the quadriceps muscle and 2) cultured primary human satellite cells.

Muscle specific microRNAs are regulated by endurance exercise in human skeletal muscle.

Muscle specific miRNAs, myomiRs, have been shown to control muscle development in vitro and are differentially expressed at rest in diabetic skeletal muscle. Therefore, we investigated the expression of these myomiRs, including miR-1, miR-133a, miR-133b and miR-206 in muscle biopsies from vastus lateralis of healthy young males (n = 10) in relation to a hyperinsulinaemic–euglycaemic clamp as well as acute endurance exercise before and after 12 weeks of endurance training. The subjects increased their endurance capacity, VO2max (l min−1) by 17.

Mitochondrial dysfunction precedes insulin resistance and hepatic steatosis and contributes to the natural history of non-alcoholic fatty liver disease in an obese rodent model.

Background & Aims: In this study, we sought to determine the temporal relationship between hepatic mitochondrial dysfunction, hepatic steatosis and insulin resistance, and to examine their potential role in the natural progression of non-alcoholic fatty liver disease (NAFLD) utilising a sedentary, hyperphagic, obese, Otsuka Long-Evans Tokushima Fatty (OLETF) rat model.

Methods: OLETF rats and their non-hyperphagic control Long-Evans Tokushima Otsuka (LETO) rats were sacrificed at 5, 8, 13, 20, and 40 weeks of age (n=6-8 per group).

Results: At 5 weeks of age, serum insulin and glucose and hepatic triglyceride (TG) concentrations did not differ between animal groups; however, OLETF animals displayed significant (p<0.

Changes in skeletal muscle mitochondria in response to the development of type 2 diabetes or prevention by daily wheel running in hyperphagic OLETF rats.

The temporal changes in skeletal muscle mitochondrial content and lipid metabolism that precede type 2 diabetes are largely unknown. Here we examined skeletal muscle mitochondrial fatty acid oxidation (MitoFAOX) and markers of mitochondrial gene expression and protein content in sedentary 20- and 40-wk-old hyperphagic, obese Otsuka Long-Evans Tokushima fatty (OLETF-SED) rats. Changes in OLETF-SED rats were compared with two groups of rats who maintained insulin sensitivity: age-matched OLETF rats given access to voluntary running wheels (OLETF-EX) and sedentary, nonobese Long-Evans Tokushima Otsuka (LETO-SED) rats.

Changes in visceral adipose tissue mitochondrial content with type 2 diabetes and daily voluntary wheel running in OLETF rats.

Using the hyperphagic, obese, Otsuka Long-Evans Tokushima Fatty (OLETF) rat, we sought to determine if progression to type 2 diabetes alters visceral white adipose tissue (WAT) mitochondrial content and if these changes are modified through prevention of type 2 diabetes with daily exercise. At 4 weeks of age, OLETF rats began voluntary wheel running (OLETF-EX) while additional OLETF rats (OLETF-SED) and Long-Evans Tokushima Otsuka (LETO-SED) rats served as obese and lean sedentary controls, respectively, for 13, 20 and 40 weeks of age (n = 6-8 for each group at each age). OLETF-SED animals displayed insulin resistance at 13 and 20 weeks and type 2 diabetes by 40 weeks.

Cessation of daily wheel running differentially alters fat oxidation capacity in liver, muscle, and adipose tissue.

Physical inactivity is associated with the increased risk of developing chronic metabolic diseases. To understand early alterations caused by physical inactivity, we utilize an animal model in which rats are transitioned from daily voluntary wheel running to a sedentary condition. In the hours and days following this transition, adipose tissue mass rapidly increases, due in part to increased lipogenesis.

Cessation of daily exercise dramatically alters precursors of hepatic steatosis in Otsuka Long-Evans Tokushima Fatty (OLETF) rats.

The purpose of this study was to delineate potential mechanisms initiating the onset of hepatic steatosis following the cessation of daily physical activity. Four-week-old, hyperphagic/obese Otsuka Long-Evans Tokushima Fatty rats were given access to voluntary running wheels for 16 weeks to prevent the development of hepatic steatosis. The animals were then suddenly transitioned to a sedentary condition as wheels were locked (wheel lock; WL) for 5 h (WL5), 53 h (WL53) or 173 h (WL173).