Obesity blunts insulin sensitivity improvements and attenuates strength gains following resistance training in nondiabetic men.

PURPOSE: Impaired insulin sensitivity is central in the etiology of type 2 diabetes in people with obesity. The effectiveness of resistance training (RE) alone in improving insulin sensitivity in people with obesity is undetermined. This study aimed to determine the influence of obesity on insulin sensitivity responses to RE. METHODS: Nineteen sedentary men were allocated to Lean (BMI 22.7 ± 2.5 kg m-2; n = 10) or Obese group (BMI 33.2 ± 3.2 kg m-2; n = 9). Participants were evaluated before and after a 10-week supervised progressive RE (3 sets of 10 repetition maximum (RM), 3 d/wk) for insulin sensitivity indexes using an oral glucose tolerance test, body composition using anthropometrics, and strength using 1RM. RESULTS: Groups were matched at baseline for all variables except for body composition and absolute strength. Body fat was not changed in both groups. Matsuda insulin sensitivity index, hepatic insulin resistance, and insulin area under the curve improved by 64.3 ± 61.9 unit, - 58.2 ± 102.9 unit, 2.3 ± 4.1 unit, and - 721.6 ± 858.2 µU/ml, respectively, only in the Lean group. The increased 1RM% for leg press was greater in the Lean (49.5 ± 18.7%) than in the Obese (31.5 ± 13.9), but not different for bench press (18.0 ± 9.1% vs. 16.4 ± 6.0%, respectively). CONCLUSION: Sustained obesity precludes insulin sensitivity improvements and attenuates strength gains in response to progressive RE. Additional strategies such as caloric restriction might be necessary for RE to improve insulin sensitivity, particularly at high levels of obesity.

Using artificial intelligence for exercise prescription in personalised health promotion: A critical evaluation of OpenAI's GPT-4 model.

The rise of artificial intelligence (AI) applications in healthcare provides new possibilities for personalized health management. AI-based fitness applications are becoming more common, facilitating the opportunity for individualised exercise prescription. However, the use of AI carries the risk of inadequate expert supervision, and the efficacy and validity of such applications have not been thoroughly investigated, particularly in the context of diverse health conditions. The aim of the study was to critically assess the efficacy of exercise prescriptions generated by OpenAI's Generative Pre-Trained Transformer 4 (GPT-4) model for five example patient profiles with diverse health conditions and fitness goals. Our focus was to assess the model's ability to generate exercise prescriptions based on a singular, initial interaction, akin to a typical user experience. The evaluation was conducted by leading experts in the field of exercise prescription. Five distinct scenarios were formulated, each representing a hypothetical individual with a specific health condition and fitness objective. Upon receiving details of each individual, the GPT-4 model was tasked with generating a 30-day exercise program. These AI-derived exercise programs were subsequently subjected to a thorough evaluation by experts in exercise prescription. The evaluation encompassed adherence to established principles of frequency, intensity, time, and exercise type; integration of perceived exertion levels; consideration for medication intake and the respective medical condition; and the extent of program individualization tailored to each hypothetical profile. The AI model could create general safety-conscious exercise programs for various scenarios. However, the AI-generated exercise prescriptions lacked precision in addressing individual health conditions and goals, often prioritizing excessive safety over the effectiveness of training. The AI-based approach aimed to ensure patient improvement through gradual increases in training load and intensity, but the model's potential to fine-tune its recommendations through ongoing interaction was not fully satisfying. AI technologies, in their current state, can serve as supplemental tools in exercise prescription, particularly in enhancing accessibility for individuals unable to access, often costly, professional advice. However, AI technologies are not yet recommended as a substitute for personalized, progressive, and health condition-specific prescriptions provided by healthcare and fitness professionals. Further research is needed to explore more interactive use of AI models and integration of real-time physiological feedback.

Acute Exercise Promptly Normalizes Myocardial Myosin Heavy-Chain Isoform mRNA Composition in Diabetic Rats: Implications for Diabetic Cardiomyopathy.

Background and Objectives: The acute effects of exercise on the myosin heavy-chain (MHC) isoform mRNA expression and the upstream transcription factors in diabetic and non-diabetic hearts remain unexplored. We aimed to determine the acute effect of a single exercise session on the expression of left ventricular MHC, MHC-α and MHC-ß, and thyroid receptor (TR), TR-α1 and TR-ß, isoform mRNA in diabetic and non-diabetic rats. Materials and Methods: Sprague-Dawley rats were assigned to four groups: non-diabetic control (CS), diabetic exercise (DIEX), sedentary diabetic (DIS), and non-diabetic exercise (CEX). Diabetes was induced via streptozotocin injection (55 mg/kg). DIEX and CEX rats performed an exercise session (60 min at 50 m/min and 0% grade) 6-7 weeks after diabetes induction. Results: MHC-α mRNA was lower in DIS (p = 0.03) and not different in DIEX (p = 0.1) relative to CS. DIS showed higher MHC-ß mRNA than the non-diabetic rats, CS and CEX (p = 0.02 and p = 0.009, respectively). MHC-ß mRNA in DIEX was normalized to non-diabetic levels in CS (p = 0.3). TR-α1 was higher in DIS and not different in DIEX relative to CS and CEX (p = 0.03 and p = 1.0, respectively). In CEX, exercise did not change MHC-α, MHC-ß, and TR-α1 relative to CS (p = 1.0). TR-ß was not different between groups. Conclusion: In conclusion, exercise appears to acutely normalize the myocardial MHC and TR isoform mRNA expression only in the diabetic heart. These responses may induce therapeutic mechanisms other than changing the MHC isoform composition.

Synergistic Beneficial Effects of Resveratrol and Diet on High-Fat Diet-Induced Obesity.

Introduction: Despite decades of research, obesity and its related medical complications remain a major health concern globally. Therefore, novel therapeutic strategies are needed to combat obesity and its numerous debilitating complications. Resveratrol (RES) has a potential therapeutic effect in obesity and diabetes by improving oxidative metabolism and insulin signaling. Background and Objectives: The aim of this study was to investigate the effect of RES treatment on weight loss and glucose and fatty acid metabolism. Methods: Obesity was induced in 24 mice by exposure to a high-fat diet (HFD) for 8 weeks. Mice were randomly assigned to one group of either: group 1: control, non-treated low-fat diet (LFD) for 12 weeks (n = 8), group 2: non-treated high-fat diet (HFD) for 12 weeks (n = 8), group 3: RES-treated HFD (HFD + RES) (n = 8), or group 4: RES-treated and switched to LFD (HFD-LFD + RES) (n = 8). HFD + RES mice were first fed an HFD for 8 weeks followed by 4 weeks of RES. The HFD-LFD + RES group was first fed an HFD for 8 weeks and then treated with RES and switched to an LFD for 4 weeks. Results: After 12 weeks, group 2 mice had significantly higher body weights compared to group 1 (23.71 ± 1.95 vs. 47.83 ± 2.27; p < 0.05). Group 4 had a significant decrease in body weight and improvement in glucose tolerance compared to mice in group 2 (71.3 ± 1.17 vs. 46.1 ± 1.82 and 40.9 ± 1.75, respectively; p < 0.05). Skeletal muscles expression of SIRT1, SIRT3, and PGC1α were induced in group 3 and 4 mice compared to group 2 (p < 0.01), with no changes in AMP-activated protein kinase expression levels. Furthermore, combination of RES and diet ameliorated skeletal muscle intermediate lipid accumulation and significantly improved insulin sensitivity and secretion. Conclusions: The results of this study suggest a synergistic beneficial effect of LFD and RES to lower body weight and enhance glucose and fatty acid metabolism.

Changes in myocardial myosin heavy chain isoform composition with exercise and post-exercise cold-water immersion.

This study investigated the changes in myocardial myosin heavy chain (MHC) isoforms, MHC-α and MHC-ß composition in young healthy rodents following endurance training, with and without post-exercise cold-water immersion (CWI). Male rats were either trained on a treadmill for 10 weeks with (CWI) or without (Ex) regular CWI after each running session, or left sedentary (CON). Left ventricular mRNA of MHC-α, MHC-ß, thyroid receptor α1 (TR-α1) and ß (TR-ß) were analyzed using rt-PCR and semiquantitative PCR analysis. MHC isoform protein composition was determined using SDS-PAGE electrophoresis. MHC-α isoform protein was predominant in all groups. The relative expression of MHC-ß (%MHC-ß) protein was not different between groups (CWI 34.7 ± 6.9%; Ex 32 ± 5.3%; CON 35.5 ± 10%; P = 0.7). MHC-ß mRNA was reduced in Ex (0.7 ± 0.3-fold) compared to CWI (1.3 ± 0.2-fold; P < 0.001) and CON (1.01 ± 0.2-fold; P = 0.03). TRα1 mRNA was lower in CWI (0.4 ± 0.05-fold) than Ex (1.02 ± 0.3-fold) and CON (1.01 ± 0.2-fold) (P < 0.001 for both). CWI exhibited greater %MHC-ß mRNA (56.8 ± 4.1%) than Ex (44.4 ± 7.7%; P = 0.001) and CON (48.5 ± 7.8%; P = 0.03). Neither exercise nor post-exercise CWI demonstrated a distinct effect on myocardial MHC protein isoform composition. However, CWI increased the relative expression of MHC-ß mRNA compared with Ex and CON. Although this implicates a potential negative long-term impact of post-exercise CWI, future studies should include measures of cardiac function to better understand the effect of such isoform mRNA shifts following regular use of CWI.

The contribution of noradrenergic nerves to the vasoconstrictor response during local cooling of leg and forearm skin in humans.

This study investigated the noradrenergic contribution during the cutaneous vasoconstrictor response to local cooling in the leg and forearm. On each limb, one site was perfused with Yoh/Prop to block the postsynaptic adrenoceptors and another with Lactated Ringer's (control) using microdialysis. Blood flow was measured by Laser-Doppler flowmetry (LDF). Cutaneous vascular conductance (CVC) was calculated as LDF units divided by the mean arterial pressure. After baseline measures, skin was locally cooled to 24°C. Basal CVC was similar at all sites in the leg and forearm (all p > 0.1). During the first 10 min of local cooling, CVC was reduced in the leg (p < 0.005) and unchanged in the forearm control sites (p = 0.2). Yoh/Prop induced an increased CVC in the leg and forearm to a similar level (39.2 ± 11.5, and 41.3 ± 3.3%CVC, respectively; p < 0.35). Late during local cooling, the vasoconstriction was attenuated in the leg and forearm at Yoh/Prop (-38.2 ± 5.3 -37.1 ± 5.3%CVC, respectively; p = 0.5) compared to control sites (-69.1 ± 5.8 vs. -54.5 ± 6.4%CVC, respectively; p < 0.005). Noradrenergic contribution was greater in the leg than the forearm during the late vasoconstrictor response (p = 0.006). These data indicate that the leg skin can induce greater vasoconstriction than forearm during local cooling, possibly via higher noradrenergic sensitivity in the leg skin.

The Counter Effect of Exercise on Cisplatin-Induced Cognitive and Proliferation Impairments.

Background Cisplatin, a widely used chemotherapeutic agent, offers therapeutic benefits for cancer treatment but often leads to adverse effects on neurogenesis and oxidative stress, causing cognitive impairment. Concurrent physical activity has been proposed as a potential strategy to counteract these side effects. This study aimed to investigate the impact of physical exercise on cisplatin-induced cognitive impairment in a mouse model. Methods Adult male mice (n=45) were divided into three groups: control, cisplatin-treated (2.3 mg/kg), and exercise/cisplatin. Cisplatin was administered intraperitoneally over one month, while the exercise/cisplatin group underwent moderate-intensity exercise alongside cisplatin treatment. Spatial memory was evaluated using the novel object recognition (NOR) task, and hippocampal proliferation and oxidative stress were examined using Ki-67 and glutathione peroxidase (GPx) immunohistochemistry (IHC) staining, respectively. Statistical analyses were performed using the GraphPad Prism 4.0 software (GraphPad Software, San Diego, CA). Results The cisplatin-treated mice exhibited significantly lower preference index (PI) scores in the NOR task compared to the control (p<0.001) and exercise/cisplatin (p<0.001) groups. IHC staining revealed impaired hippocampal proliferation and increased oxidative stress in the cisplatin-treated group relative to the control and exercise/cisplatin groups. The introduction of a moderate-intensity exercise protocol appeared to mitigate the decline in hippocampal proliferation and oxidative damage induced by cisplatin. Additionally, cisplatin-treated mice experienced weight loss, while exercise attenuated this effect. Conclusion Cisplatin treatment resulted in decreased memory, hippocampal proliferation, and weight loss in mice. Concurrent moderate-intensity exercise seemed to alleviate these effects, suggesting a potential role for physical activity in ameliorating cisplatin-induced cognitive decline. This study underscores the importance of incorporating exercise as a complementary strategy to enhance cognitive outcomes in cancer patients undergoing cisplatin treatment.

The relationship between quality of life, sleep quality, mental health, and physical activity in an international sample of college students: a structural equation modeling approach.

Objective: We assessed the direct and indirect relationships between sleep quality, mental health, and physical activity with quality of life (QOL) in college and university students. Methods: In a cross-sectional design, 3,380 college students (60% females; age = 22.7 ± 5.4) from four continents (Africa: 32%; America: 5%; Asia: 46%; and Europe: 15%; others: 2%) completed the Pittsburgh Sleep Quality Index (PSQI); Insomnia Severity Index (ISI); Epworth Sleepiness Scale (ESS); the Depression, Anxiety, and Stress Scale 21 (DASS); the International Physical Activity Questionnaire short-form (IPAQ); and the World Health Organization Quality of Life-BREF (WHOQOL-Brief). Results: We showed that sleep quality, insomnia, and depression had direct negative effects on the physical domain of QOL (ß = -0.22, -0.19, -0.31, respectively, p < 0.001). There was a strong negative direct association between depression and the psychological domain of QOL (ß = -0.60, z = -22.21, p < 0.001). Both stress and PSQI had direct effects on social relationships QOL (ß = 0.11; z = 4.09; and ß = -0.13; z = -7.40, respectively, p < 0.001). However, depression had the strongest direct impact on social relationships QOL (ß = -0.41, z = -15.79, p < 0.001). Conclusion: The overall QOL of university students is associated with their sleep quality, mental health, and physical activity warranting further interventional studies aiming at improving students' quality of life.

Lockdown Duration and Training Intensity Affect Sleep Behavior in an International Sample of 1,454 Elite Athletes.

Objective: To investigate the effect of 1) lockdown duration and 2) training intensity on sleep quality and insomnia symptoms in elite athletes. Methods: 1,454 elite athletes (24.1 ± 6.7 years; 42% female; 41% individual sports) from 40 countries answered a retrospective, cross-sectional, web-based questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: 1) Pittsburgh sleep quality index (PSQI); 2) Insomnia severity index (ISI); bespoke questions about 3) napping; and 4) training behaviors. The association between dependent (PSQI and ISI) and independent variables (sleep, napping and training behaviors) was determined with multiple regression and is reported as semi-partial correlation coefficient squared (in percentage). Results: 15% of the sample spent < 1 month, 27% spent 1-2 months and 58% spent > 2 months in lockdown. 29% self-reported maintaining the same training intensity during-lockdown whilst 71% reduced training intensity. PSQI (4.1 ± 2.4 to 5.8 ± 3.1; mean difference (MD): 1.7; 95% confidence interval of the difference (95% CI): 1.6-1.9) and ISI (5.1 ± 4.7 to 7.7 ± 6.4; MD: 2.6; 95% CI: 2.3-2.9) scores were higher during-compared to pre-lockdown, associated (all p < 0.001) with longer sleep onset latency (PSQI: 28%; ISI: 23%), later bedtime (PSQI: 13%; ISI: 14%) and later preferred time of day to train (PSQI: 9%; ISI: 5%) during-lockdown. Those who reduced training intensity during-lockdown showed higher PSQI (p < 0.001; MD: 1.25; 95% CI: 0.87-1.63) and ISI (p < 0.001; MD: 2.5; 95% CI: 1.72-3.27) scores compared to those who maintained training intensity. Although PSQI score was not affected by the lockdown duration, ISI score was higher in athletes who spent > 2 months confined compared to those who spent < 1 month (p < 0.001; MD: 1.28; 95% CI: 0.26-2.3). Conclusion: Reducing training intensity during the COVID-19-induced lockdown was associated with lower sleep quality and higher insomnia severity in elite athletes. Lockdown duration had further disrupting effects on elite athletes' sleep behavior. These findings could be of relevance in future lockdown or lockdown-like situations (e.g., prolonged illness, injury, and quarantine after international travel).

Ramadan Observance Exacerbated the Negative Effects of COVID-19 Lockdown on Sleep and Training Behaviors: A International Survey on 1,681 Muslim Athletes.

Objective: Disrupted sleep and training behaviors in athletes have been reported during the COVID-19 pandemic. We aimed at investigating the combined effects of Ramadan observance and COVID-19 related lockdown in Muslim athletes. Methods: From an international sample of athletes (n = 3,911), 1,681 Muslim athletes (from 44 countries; 25.1 ± 8.7 years, 38% females, 41% elite, 51% team sport athletes) answered a retrospective, cross-sectional questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: (i) Pittsburgh sleep quality index (PSQI); (ii) insomnia severity index (ISI); (iii) bespoke questions about training, napping, and eating behaviors, and (iv) questions related to training and sleep behaviors during-lockdown and Ramadan compared to lockdown outside of Ramadan. The survey was disseminated predominately through social media, opening 8 July and closing 30 September 2020. Results: The lockdown reduced sleep quality and increased insomnia severity (both p < 0.001). Compared to non-Muslim (n = 2,230), Muslim athletes reported higher PSQI and ISI scores during-lockdown (both p < 0.001), but not pre-lockdown (p > 0.05). Muslim athletes reported longer (p < 0.001; d = 0.29) and later (p < 0.001; d = 0.14) daytime naps, and an increase in late-night meals (p < 0.001; d = 0.49) during- compared to pre-lockdown, associated with lower sleep quality (all p < 0.001). Both sleep quality (χ2 = 222.6; p < 0.001) and training volume (χ2 = 342.4; p < 0.001) were lower during-lockdown and Ramadan compared to lockdown outside of Ramadan in the Muslims athletes. Conclusion: Muslim athletes reported lower sleep quality and higher insomnia severity during- compared to pre-lockdown, and this was exacerbated by Ramadan observance. Therefore, further attention to Muslim athletes is warranted when a circadian disrupter (e.g., lockdown) occurs during Ramadan.