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An international consensus seems to have developed in educational research--and among educational planners and policymakers--during the last 10-15 years proclaiming that learning is, and must be, a visible phenomenon. This paper questions this predominant view and serves an assemblage of points offering educational scientists at least four profound perspectives to reflect upon. First of all, learning is not immediately visible to the learning subject. It demands and deserves a qualitative lifelong perspective and--not to be underestimated--autonomous reflections to come to know and acknowledge what learning is and can be in an existential perspective. For the individual, it is always worth asking the question whether or not the things 'learned' in the first place were worth learning. Secondly, no one can examine the complex synaptic wiring process in the changeable and 'learning' brain (i.e., human neuroplasticity); the body-phenomenological depths and growth of a human being; or the manifold processes constituting the totality of historical social interactions surrounding the learning process and reduce them to something simple and already 'known' (a figure, a score, an effect, an answer in a test, an evaluation statement, etc). Thirdly, so-called visible learning for teachers has to be differentiated from both conscious and unconscious learning for pupils and students. The attempts to objectify and sometimes even instrumentalize learning risk running into obvious problems and fostering serious mistakes. Besides, the teacher and the 'learner' do not share the same perspectives and they often also have different interests. Fourthly, the concept of learning is not a value-neutral term and should only be used with an awareness of its historical development as a concept. I will argue that character formation--edification of character ("Bildung"), in light of the rich German "geisteswissenschaftliche" tradition--and the capability to think and become a vivid language user and creator demand much more than learning. Moreover, teaching is much more than a method to 'produce' learning, and to reproduce learning goals, and the purpose of education must transcend a teleological implementation of strategic national and international learning goals. In this paper, the revitalized concept of "Bildung" both serves as a critique of the visible learning paradigm and as a take-off of an alternative and more fertile way to conceptualize the task and possibilities of education. The line of the argument and ambition of the paper is to depict how blindness seems to be an inevitable part of educational seeing. The thesis is that powerful scientific and political adherents of learning cannot see what they cannot see--neither when they see what they (think they) see, nor when they do not see what they do not (want to) see.

Adipose tissues, particularly beige and brown adipose tissue, play crucial roles in energy metabolism. Brown adipose tissues' thermogenic capacity and the appearance of beige cells within white adipose tissue have spurred interest in their metabolic impact and therapeutic potential. Brown and beige fat cells, activated by environmental factors like cold exposure or by pharmacology, share metabolic mechanisms that drive non-shivering thermogenesis. Understanding these two cell types requires advanced, yet broadly applicable in vitro models that reflect the complex microenvironment and vasculature of adipose tissues. Here we present mouse vascularized adipose spheroids of the stromal vascular microenvironment from inguinal white adipose tissue, a tissue with 'beiging' capacity in mice and humans. We show that adding a scaffold improves vascular sprouting, enhances spheroid growth, and upregulates adipogenic markers, thus reflecting increased adipocyte maturity. Transcriptional profiling via RNA sequencing revealed distinct metabolic pathways upregulated in our vascularized adipose spheroids, with increased expression of genes involved in glucose metabolism, lipid metabolism, and thermogenesis. Functional assessment demonstrated increased oxygen consumption in vascularized adipose spheroids compared to classical 2D cultures, which was enhanced by β-adrenergic receptor stimulation correlating with elevated b-adrenergic receptor expression. Moreover, stimulation with the naturally occurring adipokine, FGF21, induced Ucp1 mRNA expression in the vascularized adipose spheroids. In conclusion, vascularized inguinal white adipose tissue spheroids provide a physiologically relevant platform to study how the stromal vascular microenvironment shapes adipocyte responses and influence activated thermogenesis in beige adipocytes. [ABSTRACT FROM AUTHOR]

Introduction: Liver fat (LF) and visceral adipose tissue (VAT) content decreases with training, however, this has mainly been investigated in sedentary obese or healthy participants. The aim of this study was to investigate the effects of repeated prolonged exercise on LF and VAT content in well‐trained older men and to compare baseline LF and VAT content to recreationally active older men. Method: A group of five well‐trained older men were tested before and after cycling a total distance of 2558 km in 16 consecutive days. VAT content and body composition was measured using DXA before a bicycle ergometer test was performed to determine maximal fat oxidation (MFO), maximal oxygen consumption (VO2max$$ {\mathrm{VO}}_{2_{\mathrm{max}}} $$), and the relative intensity at which MFO occurred (Fatmax). LF content was measured on a separate day using MRI. For comparison of baseline values, a control group of eight healthy age‐ and BMI‐matched recreationally active men were recruited. Results: The well‐trained older men had lower VAT (p = 0.02), and a tendency toward lower LF content (p = 0.06) compared with the control group. The intervention resulted in decreased LF content (p = 0.02), but VAT, fat mass, and lean mass remained unchanged. VO2max$$ {\mathrm{VO}}_{2_{\mathrm{max}}} $$, MFO, and Fatmax were not affected by the intervention. Conclusion: The study found that repeated prolonged exercise reduced LF content, but VAT and VO2max$$ {\mathrm{VO}}_{2_{\mathrm{max}}} $$ remained unchanged. Aerobic capacity was aligned with lower LF and VAT in older active men. [ABSTRACT FROM AUTHOR]

Insulin deficiency in type 1 diabetes (T1D) leads to an impairment of glucose metabolism and mitochondrial function. Actovegin is a hemodialysate of calf blood, which has been shown to enhance glucose uptake and cell metabolism in healthy human skeletal muscle. The objectives of this study were to determine the effects of Actovegin on skeletal muscle mitochondrial respiration and functional aerobic capacity in a T1D mouse model. Effects on the expression of mitochondrial proteins, body mass, and food and water consumption were also investigated. Streptozotocin-induced T1D male C57B1/6 mice (aged 3–4 months) were randomized to an Actovegin group and a control group. Every third day, the Actovegin and control groups were injected intraperitoneally with (0.1 mL) Actovegin and (0.1 mL) physiological salt solution, respectively. Oxidative phosphorylation (OXPHOS) capacity of the vastus lateralis muscle was measured by high resolution respirometry in addition to the expression levels of the mitochondrial complexes as well as voltage-dependent anion channel. Functional aerobic capacity was measured using a rodent treadmill protocol. Body mass and food and water consumption were also measured. After 13 days, in comparison to the control group, the Actovegin group demonstrated a significantly higher skeletal muscle mitochondrial respiratory capacity in an ADP-restricted and ADP-stimulated environment. The Actovegin group displayed a significantly lesser decline in functional aerobic capacity and baseline body mass after 13 days. There were no significant differences in food or water consumption between groups. Actovegin could act as an effective agent for facilitating glucose metabolism and improving OXPHOS capacity and functional aerobic capacity in T1D. Further investigation is warranted to establish Actovegin's potential as an alternative therapeutic drug for T1D. [ABSTRACT FROM AUTHOR]

Background The aim of this study was to investigate the effect of prolonged endurance exercise on adipose tissue inflammation markers and mitochondrial respiration in younger and older men. Methods "Young" (aged 30 years, n = 7) and "old" (aged 65 years, n = 7) trained men were exposed to an exercise intervention of 15 consecutive days biking 7 to 9 hours/day at 63% and 65% of maximal heart rate (young and old, respectively), going from Copenhagen, Denmark to Palermo, Italy. Adipose tissue was sampled from both the gluteal and abdominal depot before and after the intervention. Mitochondrial respiration was measured by high-resolution respirometry, and adipose inflammation was assessed by immunohistochemical staining of paraffin embedded sections. Results An increased number of CD163+ macrophages was observed in both the gluteal and abdominal depot (P <.01). In addition, an increased mitochondrial respiration was observed in the abdominal adipose tissue from men in the young group with complex I (CI p) stimulated respiration, complex I + II (CI+II p) stimulated respiration and the capacity of the electron transport system (ETS) (P <.05), and in the older group an increase in CIp and CI+II p stimulated respiration (P <.05) was found. Conclusion Overall, we found a positive effect of prolonged endurance exercise on adipose tissue inflammation markers and mitochondrial respiration in both young and old trained men, and no sign of attenuated function in adipose tissue with age. [ABSTRACT FROM AUTHOR]

It is well known that exercise efficiency declines at intensities above the lactate threshold, yet the underlying mechanisms are poorly understood. Some have suggested it is due to a decline in mitochondrial efficiency, but this is difficult to examine in vivo. Therefore, the aim of the current study was to examine how changes in temperature and pH, mimicking those that occur during exercise, affect mitochondrial efficiency in skeletal muscle mitochondria. This study was performed on quadriceps muscle of 20 wild-type mice. Muscle tissue was dissected and either permeabilized (n = 10) or homogenized for isolation of mitochondria (n = 10), and oxidative phosphorylation capacity and P/O ratio were assessed using high-resolution respirometry. Samples from each muscle were analyzed in both normal physiological conditions (37℃, pH 7.4), decreased pH (6.8), increased temperature (40℃), and a combination of both. The combination of increased temperature and decreased pH resulted in a significantly lower P/O ratio, mirrored by an increase in leak respiration and a decrease in respiratory control ratio (RCR), in isolated mitochondria. In permeabilized fibers, RCR and leak were relatively unaffected, though a main effect of temperature was observed. Oxidative phosphorylation capacity was unaffected by changes in pH and temperature in both isolated mitochondria and permeabilized fibers. These results indicate that exercise-like changes in temperature and pH lead to impaired mitochondrial efficiency. These findings offer some degree of support to the concept of decreased mitochondrial efficiency during exercise, and may have implications for the assessment of mitochondrial function related to exercise. [ABSTRACT FROM AUTHOR]

Hepatic lipid metabolism is highly dynamic, and disruption of several circadian transcriptional regulators results in hepatic steatosis. This includes genetic disruption of the glucocorticoid receptor (GR) as the liver develops. To address the functional role of GR in the adult liver, we used an acute hepatocyte-specific GR knockout model to study temporal hepatic lipid metabolism governed by GR at several preprandial and postprandial circadian timepoints. Lipidomics analysis revealed significant temporal lipid metabolism, where GR disruption results in impaired regulation of specific triglycerides, nonesterified fatty acids, and sphingolipids. This correlates with increased number and size of lipid droplets and mildly reduced mitochondrial respiration, most noticeably in the postprandial phase. Proteomics and transcriptomics analyses suggest that dysregulated lipid metabolism originates from pronounced induced expression of enzymes involved in fatty acid synthesis, β-oxidation, and sphingolipid metabolism. Integration of GR cistromic data suggests that induced gene expression is a result of regulatory actions secondary to direct GR effects on gene transcription. [ABSTRACT FROM AUTHOR]

Background: Statin therapy has shown pleiotropic effects affecting both mitochondrial function and inflammatory status. However, few studies have investigated the concurrent effects of statin exposure on mitochondrial function and inflammatory status in human subcutaneous white adipose tissue. Objectives: In a cross-sectional study, we investigated the effects of simvastatin on mitochondrial function and inflammatory status in subcutaneous white adipose tissue of 55 human participants: 38 patients (19 females/19 males) in primary prevention with simvastatin (> 40 mg/d, > 3 mo) and 17 controls (9 females/8 males) with elevated plasma cholesterol. The 2 groups were matched on age, body mass index, and maximal oxygen consumption. Methods: Anthropometrics and fasting biochemical characteristics were measured. Mitochondrial respiratory capacity was assessed in white adipose tissue by high-resolution respirometry. Subcutaneous white adipose tissue expression of the inflammatory markers IL-6, chemokine (C-C motif) ligand 2 (CCL2), CCL-5, tumor necrosis factor-α, IL-10, and IL-4 was analyzed by quantitative PCR. Results: Simvastatin-treated patients showed lower plasma cholesterol (P < .0001), low-density lipoprotein (P < .0001), and triglyceride levels (P = .0116) than controls. Simvastatin-treated patients had a lower oxidative phosphorylation capacity of mitochondrial complex II (P = .0001 when normalized to wet weight, P < .0001 when normalized to citrate synthase activity [intrinsic]), and a lower intrinsic mitochondrial electron transport system capacity (P = .0004). Simvastatin-treated patients showed higher IL-6 expression than controls (P = .0202). Conclusion: Simvastatin treatment was linked to mitochondrial respiratory capacity in human subcutaneous white adipose tissue, but no clear link was found between statin exposure, respiratory changes, and inflammatory status of adipose tissue. [ABSTRACT FROM AUTHOR]

Objectives: Traditional jumping–dance rituals performed by Maasai men involve prolonged physical exertion that may contribute significantly to overall physical activity level. We aimed to objectively quantify the metabolic intensity of jumping–dance activity and assess associations with habitual physical activity and cardiorespiratory fitness (CRF). Methods: Twenty Maasai men (18–37 years) from rural Tanzania volunteered to participate in the study. Habitual physical activity was monitored using combined heart rate (HR) and movement sensing over 3 days, and jumping–dance engagement was self‐reported. A 1‐h jumping–dance session resembling a traditional ritual was organized, during which participants' vertical acceleration and HR were monitored. An incremental, submaximal 8‐min step test was performed to calibrate HR to physical activity energy expenditure (PAEE) and assess CRF. Results: Mean (range) habitual PAEE was 60 (37–116) kJ day−1 kg−1, and CRF was 43 (32–54) mL O2 min−1 kg−1. The jumping–dance activity was performed at an absolute HR of 122 (83–169) beats·min−1, and PAEE of 283 (84–484) J min−1 kg−1 or 42 (18–75)% when expressed relative to CRF. The total PAEE for the session was 17 (range 5–29) kJ kg−1, ~28% of the daily total. Self‐reported engagement in habitual jumping–dance frequency was 3.8 (1–7) sessions/week, with a total duration of 2.1 (0.5–6.0) h/session. Conclusions: Intensity during traditional jumping–dance activity was moderate, but on average sevenfold higher than habitual physical activity. These rituals are common, and can make a substantial contribution to overall physical activity in Maasai men, and thus be promoted as a culture‐specific activity to increase energy expenditure and maintain good health in this population. [ABSTRACT FROM AUTHOR]

Background: Adjuvant chemo‐ and radiotherapy cause cellular damage to tumorous and healthy dividing cells. Chemotherapy has been shown to cause mitochondrial respiratory dysfunction in non‐tumorous tissues, but the effects on human peripheral blood mononuclear cells (PBMCs) remain unknown. Aim: We aimed to investigate mitochondrial respiration of PBMCs before and after adjuvant chemo‐ and radiotherapy in postmenopausal patients with early breast cancer (EBC) and relate these to metabolic parameters of the patients. Methods: Twenty‐three postmenopausal women diagnosed with EBC were examined before and shortly after chemotherapy with (n = 18) or without (n = 5) radiotherapy. Respiration (O2 flux per million PBMCs) was assessed by high‐resolution respirometry of intact and permeabilized PBMCs. Clinical metabolic characteristics and mitochondrial DNA (mtDNA) content of PBMCs (mtDN relative to nuclear DNA) were furthermore assessed. Results: Respiration of intact and permeabilized PBMCs from EBC patients significantly increased with adjuvant chemo‐ and radiotherapy (p = 6 × 10−5 and p = 1 × 10−7, respectively). The oxygen flux attributed to specific mitochondrial complexes and respiratory states increased by 17–43% compared to before therapy initiation. Similarly, PBMC mtDNA content increased by 40% (p = 0.002). Leukocytes (p = 0.0001), hemoglobin (p = 0.0003), and HDL cholesterol (p = 0.003) concentrations decreased whereas triglyceride (p = 0.01) and LDL (p = 0.02) concentrations increased after treatment suggesting a worsened metabolic state. None of the metabolic parameters or the mtDNA content of PBMCs correlated significantly with PBMC respiration. Conclusion: This study shows that mitochondrial respiration and mtDNA content in circulating PBMCs increase after adjuvant chemo‐ and radiotherapy in postmenopausal patients with EBC. Besides the increased mtDNA content, a shift in PBMC subpopulation proportions towards cells relying on oxidative phosphorylation, who may be less sensitive to chemotherapy, might influence the increased mitochondrial respiration observed iafter chemotherapy. [ABSTRACT FROM AUTHOR]

This review provides an overview of the evidence regarding mtDNA and valid biomarkers for assessing mitochondrial adaptions. Mitochondria are small organelles that exist in almost all cells throughout the human body. As the only organelle, mitochondria contain their own DNA, mitochondrial DNA (mtDNA). mtDNA-encoded polypeptides are subunits of the enzyme complexes in the electron transport chain (ETC) that are responsible for production of ATP to the cells. mtDNA is frequently used as a biomarker for mitochondrial content, since changes in mitochondrial volume are thought to induce similar changes in mtDNA. However, some exercise studies have challenged this "gene-dosage theory", and have indicated that changes in mitochondrial content can adapt without changes in mtDNA. Thus, the aim of this scoping review was to summarize the studies that used mtDNA as a biomarker for mitochondrial adaptions and address the question as to whether changes in mitochondrial content, induce changes in mtDNA in response to aerobic exercise in the healthy skeletal muscle. The literature was searched in PubMed and Embase. Eligibility criteria included: interventional study design, aerobic exercise, mtDNA measurements reported pre- and postintervention for the healthy skeletal muscle and English language. Overall, 1585 studies were identified. Nine studies were included for analysis. Eight out of the nine studies showed proof of increased oxidative capacity, six found improvements in mitochondrial volume, content and/or improved mitochondrial enzyme activity and seven studies did not find evidence of change in mtDNA copy number. In conclusion, the findings imply that mitochondrial adaptions, as a response to aerobic exercise, can occur without a change in mtDNA copy number. [ABSTRACT FROM AUTHOR]

Questions of "quality" in the use of technology with children with learning disabilities are discussed, focusing on the need for basic pedagogical considerations; the impact of the computer on the learning process relative to factors of learner control, motivation, feedback type, graphics, and screen design; and use of computerized speech feedback in remediating reading problems. (Author/PB)

Myalgia and new-onset of type 2 diabetes have been associated with statin treatment, which both could be linked to reduced coenzyme Q10 (CoQ10) in skeletal muscle and impaired mitochondrial function. Supplementation with CoQ10 focusing on levels of CoQ10 in skeletal muscle and mitochondrial function has not been investigated in patients treated with statins. To investigate whether concomitant administration of CoQ10 with statins increases the muscle CoQ10 levels and improves the mitochondrial function, and if changes in muscle CoQ10 levels correlate with changes in the intensity of myalgia. 37 men and women in simvastatin therapy with and without myalgia were randomized to receive 400 mg CoQ10 daily or matched placebo tablets for eight weeks. Muscle CoQ10 levels, mitochondrial respiratory capacity, mitochondrial content (using citrate synthase activity as a biomarker), and production of reactive oxygen species were measured before and after CoQ10 supplementation, and intensity of myalgia was determined using the 10 cm visual analogue scale. Muscle CoQ10 content and mitochondrial function were unaltered by CoQ10 supplementation. Individual changes in muscle CoQ10 levels were not correlated with changes in intensity of myalgia. CoQ10 supplementation had no effect on muscle CoQ10 levels or mitochondrial function and did not affect symptoms of myalgia. [ABSTRACT FROM AUTHOR]

Aim & Methods: Extreme endurance exercise provides a valuable research model for understanding the adaptive metabolic response of older and younger individuals to intense physical activity. Here, we compare a wide range of metabolic and physiologic parameters in two cohorts of seven trained men, age 30 ± 5 years or age 65 ± 6 years, before and after the participants travelled ≈3000 km by bicycle over 15 days. Results: Over the 15‐day exercise intervention, participants lost 2–3 kg fat mass with no significant change in body weight. V̇O2max did not change in younger cyclists, but decreased (p = 0.06) in the older cohort. The resting plasma FFA concentration decreased markedly in both groups, and plasma glucose increased in the younger group. In the older cohort, plasma LDL‐cholesterol and plasma triglyceride decreased. In skeletal muscle, fat transporters CD36 and FABPm remained unchanged. The glucose handling proteins GLUT4 and SNAP23 increased in both groups. Mitochondrial ROS production decreased in both groups, and ADP sensitivity increased in skeletal muscle in the older but not in the younger cohort. Conclusion: In summary, these data suggest that older but not younger individuals experience a negative adaptive response affecting cardiovascular function in response to extreme endurance exercise, while a positive response to the same exercise intervention is observed in peripheral tissues in younger and older men. The results also suggest that the adaptive thresholds differ in younger and old men, and this difference primarily affects central cardiovascular functions in older men after extreme endurance exercise. [ABSTRACT FROM AUTHOR]

Objectives: The agro‐pastoralist Maasai of East Africa are highly physically active, but their aerobic fitness has so far only been estimated using heart rate (HR) response to submaximal exercise and not directly measured. Thus, we aimed to measure aerobic fitness directly using respiratory gas analysis in a group of Maasai, and habitual physical activity energy expenditure (PAEE) as explanatory variable. Methods: In total, 21 (10 rural, 11 semi‐urban) of 30 volunteering Tanzanian Maasai men were eligible to participate. Respiratory gas exchange was measured during a graded exercise test until exhaustion on a stationary bicycle to determine aerobic fitness. Maximal effort criteria were at least two of the following (1) leveling off, (2) respiratory exchange ratio (RER) >1.10, and (3) maximum HR within 10 bpm of age‐estimated maximum HR. Habitual PAEE was estimated using combined accelerometry and HR monitoring. Anthropometry, biochemistry, blood pressure, resting HR, and dietary intake information were collected for background information. Results: Mean age was 43.2 (range 26–60) years, and hemoglobin was higher in the rural versus semi‐urban Maasai (16.9 vs. 15.4 g/dl, p =.02). Mean aerobic fitness (34.4 vs. 33.3 mlO2/min/kg, p =.79), and mean PAEE (58.5 vs. 52.9 kJ/day/kg, p =.64) were similar in rural and semi‐urban Maasai, respectively. Conclusions: Aerobic fitness was low to moderate in male rural and semi‐urban Maasai. This may be explained by relatively low PAEE in comparison to previous objectively measured activity levels in Maasai, which indicates recent lifestyle changes. [ABSTRACT FROM AUTHOR]

We aimed to investigate how assimilation of nutrients affects the postprandial responses of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) and to evaluate the effect of pancreatic enzyme substitution (PES) on insulin secretion in patients with chronic pancreatitis (CP) and pancreatic exocrine insufficiency (PEI). Eight male patients with CP and PEI were studied. Blood was sampled frequently on two separate days after ingestion of a liquid meal with and without PES, respectively. Eight healthy male subjects served as a control group. [beta]-Cell responsiveness was estimated as changes in insulin secretion rates in response to changes in postprandial plasma glucose (PG). There was no difference in the PG incremental area under curve (AUC) for patients with and without PES [406 [+ or -] 100 vs. 425 [+ or -] 80 mM * 4 h (mean [+ or -] SE), P = 0.8]. The response of total GLP-1 was higher after PES (AUC: 7.8 [+ or -] 1.2 vs. 5.3 [+ or -] 0.6 nM * 4 h, P = 0.01), as was the response of total GIP (AUC: 32.7 [+ or -] 7.5 vs. 21.1 [+ or -] 8.3 nM * 4 h, P = 0.01). Concurrently, both plasma insulin, plasma C-peptide, and total insulin secretion increased after PES (AUC: 17.7 [+ or -] 4.2 vs. 13.6 [+ or -] 2.9 nM * 4 h, P = 0.02; 237 [+ or -] 31.4 vs. 200 [+ or -] 27.4 nM * 4 h, P = 0.005; and 595 [+ or -] 82 vs. 497 [+ or -] 80 pmol * [kg.sup.-1] * 4 h, P = 0.01, respectively). [beta]-Cell responsiveness to glucose was not significantly different on the two study days for patients with CP. These results suggest that the secretion of GLP-1 and GIP is under influence of the digestion and absorption of nutrients in the small intestine and that PES increases insulin secretion. pancreatic exocrine insufficiency; glucagon-like peptide-1; glucose-dependent insulinotropic polypeptide

Introduction: Decreased fasting and oral glucose-stimulated incretin hormone concentrations following moderate-intensity continuous endurance training interventions have been reported in glucose-tolerant people, however results are conflicting. The effect of more time-efficient, very low-volume, high-intensity interval training (HIT) on circulating incretin hormone levels has never been studied. Materials and methods: Ten sedentary and overweight-to-obese participants (4 women and 6 men; age 43 ± 6 years (mean ± SD); BMI 30.2 ± 3.2 kg∙m−2; HbA1c 35 ± 5.1 mmol∙mol−1 (5.3 ± 0.3%); VO2max 30 ± 5 ml∙min−1∙kg−1) from the Copenhagen cohort of the METAPREDICT trial underwent 6 weeks of supervised low-volume HIT (3 sessions per week: 7 × 1 min at ∼100% VO2max separated by 1 min of active recovery). We measured glucose, insulin, C-peptide, glucagon, GLP-1 and GIP concentrations during a frequently sampled 75 g oral glucose tolerance test as well as VO2max and body composition before and after the intervention. Results: Training compliance was 100%. Relative VO2max improved after the intervention (median 2.69 ml∙min−1∙kg−1, IQR [0.43; 3.14], p = 0.037) while there were no significant effects on body weight and composition. No significant effects on oral glucose-stimulated glucose and hormone responses or estimates of insulin sensitivity and β-cell function were observed. Conclusion: Low-volume HIT improved aerobic fitness, but neither affected glucose tolerance nor oral glucose-stimulated incretin hormone responses in sedentary and overweight-to-obese people. Highlights Ten sedentary, overweight-to-obese, glucose-tolerant participants underwent 6 weeks of supervised, very low-volume HIT. Aerobic fitness improved. Fasting and oral glucose-stimulated incretin hormone concentrations were not affected. [ABSTRACT FROM AUTHOR]