Response In Healthy Men Research Articles

Head–neck cooling effects on central and peripheral fatigue, motor accuracy, and blood markers of stress in men with multiple sclerosis and healthy men: A randomized crossover study

BackgroundThe present study aimed to investigate whether head and neck cooling (at 18 °C next to the skin) and fatiguing submaximal exercise at a thermoneutral ambient temperature can induce peripheral and central responses in healthy men and those with multiple sclerosis (MS). MethodsA local head–neck cooling (at 18 °C next to the skin) intervention in men with a relapsing-remitting form of MS (n = 18; age 30.9 ± 8.1 years) and healthy men (n = 22; age 26.7 ± 5.9 years) was assessed. Men in both groups performed 100 intermittent isometric knee extensions with 5 s contractions and 20 s of rest. The primary variables were measured before exercise, after 50 and 100 repetitions, and 1 h after recovery. The central activation ratio, maximal voluntary contraction, electrically induced force, electromyography, contractile properties, blood markers, muscle temperature, and perception of effort were measured. ResultsCompared with noncooled conditions, head and neck cooling increased the central capacity to activate exercising muscles but resulted in greater exercise-induced peripheral fatigue in men with MS (p < 0.05). Local cooling did not affect motor accuracy or the amplitude of electromyography signals; however, these factors were related to the intensity of the motor task (p > 0.05). The changes in central and peripheral fatigability induced by local cooling during submaximal exercise were more pronounced in men with MS than in healthy men (p < 0.05). ConclusionHead and neck cooling enhances central activation of muscles during exercise, leading to improved exercise performance compared with noncooled conditions in men with MS.

Acute hypoxic conditions preceding endotoxin administration result in an increased proinflammatory cytokine response in healthy men.

Tissues often experience hypoxia at sites of inflammation due to malperfusion, massive immune cell recruitment, and increased oxygen consumption. Organisms adapt to these hypoxic conditions through the transcriptional activation of various genes. In fact, there is significant crosstalk between the transcriptional responses to hypoxia and inflammatory processes. This interaction, named inflammatory hypoxia, plays a crucial role in various diseases including malignancies, chronic inflammatory lung diseases, and sepsis. To further elucidate the crosstalk between hypoxia and inflammation in vivo and assess its potential for innovative therapies, our study aimed at investigating the impact of acute hypoxic conditions on inflammation-induced immune responses. To this end, we exposed healthy human subjects to hypoxia either before (hypoxia priming) or after a single intravenous (i.v.) injection of 0.4 ng/kg LPS. Our data show that hypoxia exposure prior to LPS injection (hypoxia priming) amplified the proinflammatory response. This was reflected by an increase in body temperature, plasma noradrenaline levels, and the production of proinflammatory cytokines (i.e., IL-6 and TNF-α), compared with LPS control conditions. These effects were not observed when participants were exposed to hypoxia after LPS administration, demonstrating that the interaction between hypoxia and inflammation highly depends on the timing of both stimuli. Our findings suggest that acute hypoxia (i.e., hypoxia priming) modulates transient inflammation, leading to an enhanced proinflammatory response in healthy human subjects. This highlights the need for further investigations to understand the pathology of various hypoxia-inducible factor (HIF)-associated inflammatory diseases and to develop suitable, innovative therapies.NEW & NOTEWORTHY To our knowledge, this is the first in vivo study investigating the effects of hypoxia preceding (hypoxia priming) or following LPS administration on the endotoxin-induced inflammatory response in healthy human subjects. The data show that hypoxia priming amplified the proinflammatory response, reflected by an increased body temperature, increased plasma noradrenaline levels, and higher production of proinflammatory cytokines (i.e., IL-6 and TNF-α) compared with LPS control conditions.

Effect of Backpack Loads on the Timing of Cardiopulmonary Response in Healthy Men

The backpack used commonly affects posture and physical performance, resulting in increased oxygen uptake and energy expenditure. The purpose of this study is to confirm the effect of the chest loads on the reaching time of the cardiopulmonary response. Seventeen healthy men participants were monitored for cardiopulmonary function continuously during walking exercise with the Ramp protocol and recorded the time taken to reach THR, VO2 peak, RR Difference, maximal METs, maximal FECO2, and minimum FEO2. During the exercise test, subjects were instructed to carry a backpack loaded at no load, 5%, 10%, and 15% body weight in random order. There was a significant difference in the time to reach the THR, the oxygen intake peak time, the maximum metabolic equivalent time, the respiratory rate increase, the minimum oxygen amount, and the maximum carbon dioxide amount at no load and more than 5% load. However, no significant difference was found between the loads. It is thought that even a 5% backpack load of one's body weight can impose on cardiopulmonary energy costs, and this is thought to help improve training programs with a gradual increase in mechanical chest load.

Conditioning of the Cortisol Awakening Response in Healthy Men: Study Protocol for a Randomized Controlled Trial.

The hormone cortisol plays important roles in human circadian and stress physiology and is an interesting target for interventions. Cortisol varies not only in response to stress but also as part of a diurnal rhythm. It shows a particularly sharp increase immediately after awakening, the cortisol awakening response (CAR). Cortisol can be affected by medication, but it is less clear whether it can also be affected by learning. Animal studies have consistently shown that cortisol can be affected by pharmacological conditioning, but the results in humans have been mixed. Other studies have suggested that conditioning is also possible during sleep and that the diurnal rhythm can be conditioned, but these findings have not yet been applied to cortisol conditioning. The objective of our study was to introduce a novel avenue for conditioning cortisol: by using the CAR as an unconditioned response and using scent conditioning while the participant is asleep. This study investigates an innovative way to study the effects of conditioning on cortisol and the diurnal rhythm, using a variety of devices and measures to make measurement possible at a distance and at unusual moments. The study protocol takes 2 weeks and is performed from the participant's home. Measures in week 1 are taken to reflect the CAR and waking under baseline conditions. For the first 3 nights of week 2, participants are exposed to a scent from 30 minutes before awakening until their normal time of awakening to allow the scent to become associated with the CAR. On the final night, participants are forced to wake 4 hours earlier, when cortisol levels are normally low, and either the same (conditioned group) or a different (control group) scent is presented half an hour before this new time. This allows us to test whether cortisol levels are higher after the same scent is presented. The primary outcome is the CAR, assessed by saliva cortisol levels, 0, 15, 30, and 45 minutes after awakening. The secondary outcomes are heart rate variability, actigraphy measures taken during sleep, and self-reported mood after awakening. To perform manipulations and measurements, this study uses wearable devices, 2 smartphone apps, web-based questionnaires, and a programmed scent device. We completed data collection as of December 24, 2021. This study can provide new insights into learning effects on cortisol and the diurnal rhythm. If the procedure does affect the CAR and associated measures, it also has potential clinical implications in the treatment of sleep and stress disorders. Netherlands Trial Register NL58792.058.16; https://trialsearch.who.int/Trial2.aspx?TrialID=NL7791. DERR1-10.2196/38087.

The acute effects of meals rich in saturated or unsaturated fatty acids on postprandial lipaemia and satiety responses in healthy men (CocoHeart Study)

The acute effects of meals rich in saturated or unsaturated fatty acids on postprandial lipaemia and satiety responses in healthy men (CocoHeart Study)

Is muscle and protein loss relevant in long‐term fasting in healthy men? A prospective trial on physiological adaptations

BackgroundFasting is attracting an increasing interest as a potential strategy for managing diseases, including metabolic disorders and complementary cancer therapy. Despite concerns of clinicians regarding protein catabolism and muscle loss, evidence‐based clinical data in response to long‐term fasting in healthy humans are scarce. The objective of this study was to measure clinical constants, metabolic, and muscular response in healthy men during and after a 10 day fast combined with a physical activity programme.MethodsSixteen men (44 ± 14 years; 26.2 ± 0.9 kg/m2) fasted with a supplement of 200–250 kcal/day and up to 3 h daily low‐intensity physical activity according to the peer‐reviewed Buchinger Wilhelmi protocol. Changes in body weight (BW) and composition, basal metabolic rate (BMR), physical activity, muscle strength and function, protein utilization, inflammatory, and metabolic status were assessed during the 10 day fast, the 4 days of food reintroduction, and at 3 month follow‐up.ResultsThe 10 day fast decreased BW by 7% (−5.9 ± 0.2 kg, P < 0.001) and BMR by 12% (P < 0.01). Fat mass and lean soft tissues (LST) accounted for about 40% and 60% of weight loss, respectively, −2.3 ± 0.18 kg and −3.53 ± 0.13 kg, P < 0.001. LST loss was explained by the reduction in extracellular water (44%), muscle and liver glycogen and associated water (14%), and metabolic active lean tissue (42%). Plasma 3‐methyl‐histidine increased until Day 5 of fasting and then decreased, suggesting that protein sparing might follow early proteolysis. Daily steps count increased by 60% (P < 0.001) during the fasting period. Strength was maintained in non‐weight‐bearing muscles and increased in weight‐bearing muscles (+33%, P < 0.001). Glycaemia, insulinemia, blood lipids, and blood pressure dropped during the fast (P < 0.05 for all), while non‐esterified fatty acids and urinary beta‐hydroxybutyrate increased (P < 0.01 for both). After a transient reduction, inflammatory cytokines returned to baseline at Day 10 of fasting, and LST were still lower than baseline values (−2.3% and −3.2%, respectively; P < 0.05 for both).ConclusionsA 10 day fast appears safe in healthy humans. Protein loss occurs in early fast but decreases as ketogenesis increases. Fasting combined with physical activity does not negatively impact muscle function. Future studies will need to confirm these first findings.

Hibiscus sabdariffa tea affects diet-induced thermogenesis and subjective satiety responses in healthy men but not in women: a randomized crossover trial.

The aim of this study was to investigate the effect of Hibiscus sabdariffa tea on energy expenditure, satiety response and food intake. This is an open-label, crossover, randomized clinical trial that comprised 21 subjects (11 women, 10 men). The individuals were evaluated at acute moments (fasting and after eating standardized breakfast accompanied by water or H. sabdariffa tea). Resting energy expenditure was measured by indirect calorimetry, subjective satiety responses were evaluated with a visual analogue scale and food intake was assessed by using food records. The volunteers who drank the H. sabdariffa tea had lower perception of hunger (p= 0.002) and greater feeling of satiety (p= 0.01) and fullness (p= 0.009) compared to control. Men who ingested the H. sabdariffa tea had an increase in nitrogen energy expenditure (water: 1501± 290.7kcal, H. sabdariffa tea: 1619± 288.9kcal; p= 0.029). In comparison to control, men presented less perception of hunger (p= 0.003) and desire to eat (p= 0.016), increased satiety (p= 0.021) and fullness (p= 0.01), and women oxidized more fat (p= 0.034) when they drank H. sabdariffa tea. There was no difference between treatments regarding the energy and macronutrient intake from the first meal and throughout the day (p> 0.05) for all participants. The H. sabdariffa tea only affected energy expenditure and satiety responses in men. Clinical trial registry: ReBEC Platform of the Brazilian Clinical Trials Registry (https://ensaiosclinicos.gov.br/) - RBR-5HZ86T. Novelty: H. sabdariffa tea promoted an increase in energy expenditure and caused less perception of hunger/desire to eat in men. H. sabdariffa tea intake increased postprandial fat oxidation in women.

Proteomic Analysis of Peripheral Blood Mononuclear Cells Following a Single High Fat High Carbohydrate Meal Challenge

ObjectivesAn individual’s ability to adapt to a dynamic environment is termed ‘phenotypic flexibility’ and can be weakened by chronic stress, leading to dysregulation of normal homeostatic processes. A long-term high energy and high fat high carbohydrate (HFHC) diet increases risk of metabolic diseases, however, the acute effect of a single HFHC meal on disturbances in metabolic homeostasis is less understood. In this study, we aimed to characterise the effect of a single HFHC meal on the postprandial proteome of peripheral blood mononuclear cells (PBMCs). MethodsTwelve healthy men (22.7 ± 3.4 years, BMI of 22.2 ± 1.5 kg/m2) were recruited. Participants consumed a HFHC milkshake after fasting overnight. The meal contained 16 g of carbohydrate and 15 g of fat per 100 g and had a total energy content of 64 kJ/kg body weight. PBMCs were collected at fasting, 3 and 6 hours following the meal. The proteome was measured via LC-MS/MS using untargeted label-free quantification. Differentially expressed proteins were identified with a modified paired t test (limma, R v.4.0.3). Gene ontology analysis was performed with ClueGO v2.5.7 in Cytoscape v3.8.2. ResultsAfter filtering to include only high confident proteins consistently detected in each condition, 6007 proteins were identified and included in analysis. Changes in protein expression relative to fasting were observed at 3 hours (143 proteins) and 6 hours (210 proteins) post meal (fold change > ±1.2, p < 0.05). The most highly altered biological processes observed at each timepoint were ‘zymogen activation’ (GO:0,031,638, 31.25% of groups at 3 hours) and ‘ribosome biogenesis’ (GO:0,042,254, 19.15% of groups at 6 hours). ConclusionsThese results reveal adaptations that occur in the PBMC proteome in response to a single HFHC meal. Changes to proenzyme activation shows a general response in PBMCs to meal-induced changes in the cellular environment, whilst regulation of ribosome synthesis pathways may reflect changes in energy regulation pathways caused by increased nutrient availability. This study characterises the PBMC response in healthy men, and provides a useful reference for future studies that investigate how PBMCs lose the ability to maintain homeostasis following a HFHC meal. Funding SourcesMonash University, Melbourne, Australia

Effects of soybean co-ingestion with carbohydrate on postprandial glycemic, insulinemic and reactive oxygen species in healthy men: A pilot study

Postprandial hyperglycemia induced by excessive intake of high carbohydrate (CHO) foods and beverages promotes oxidative stress which can cause many health risks such as cardio-metabolic diseases and diabetes. Protein when co-ingested with CHO beverages, has been shown to lower the postprandial glycaemic and insulinemic, which may help to attenuate postprandial reactive oxygen species (ROS) and oxidative stress. Soybean contains isoflavone which may provide potential benefits in regulating postprandial glucose and insulin levels as well as providing protection against ROS production. The aim of this study was to investigate the effects of soybean added CHO beverage on postprandial glycemic, insulinemic and reactive oxygen species responses in healthy men. Eight male [age 20.0 (1.2) years, body weight 59.2 (6.2) kg] consumed 500 ml of CHO added with soybean (SOY + CHO), CHO added with whey protein (WHEY + CHO) and CHO alone (Control) after an overnight fast, in a randomized counterbalanced order crossover design, separated by a one week period. Venous blood samples were collected after overnight fast (baseline) and at 30, 60, 90 and 120 min after consumption of the beverage. The mean area under the insulin curve was lower in SOY + CHO trial compared to CHO + WHEY trial. Similarly, SOY + CHO tended to have a lower postprandial ROS response than CHO + WHEY. However, no significant difference was observed between all beverages in all parameters. Soybean-based beverage may yield lower effect on postprandial ROS suggesting lower oxidative stress due to lower insulinemic responses, compared to whey protein when co-ingested with CHO

Physical fitness status modulates the inflammatory proteins in peripheral blood and circulating monocytes: role of PPAR-gamma

The aim of this study was to analyze the metabolic and molecular profile according to physical fitness status (Low or High VO2max) and its impacts on peripheral and cellular inflammatory responses in healthy men. First (Phase I), inflammatory profile (TNF-α, IL-6, IL-10) was analyzed at baseline and post-acute exercise sessions performed at low (< 60% VO2max) and high (> 90% VO2max) intensities considering the individual endotoxin concentrations. Next (Phase II), monocyte cell cultures were treated with LPS alone or associated with Rosiglitazone (PPAR-γ agonist drug) to analyze cytokine production and gene expression. Monocyte subsets were also evaluated by flow cytometry. A positive relationship was observed between LPS concentrations and oxygen uptake (VO2max) (r = 0.368; p = 0.007); however, in the post-exercise an inverse correlation was found between LPS variation (Δ%) and VO2max (r = -0.385; p = 0.004). With the low-intensity exercise session, there was inverse correlation between LPS and IL-6 concentrations post-exercise (r = -0.505; p = 0.046) and a positive correlation with IL-10 in the recovery (1 h post) (r = 0.567; p = 0.011), whereas with the high-intensity exercise an inverse correlation was observed with IL-6 at pre-exercise (r = -0.621; p = 0.013) and recovery (r = -0.574; p = 0.016). When monocyte cells were treated with LPS, High VO2max individuals showed higher PPAR-γ gene expression whereas Low VO2max individuals displayed higher IL-10 production. Additionally, higher TLR-4, IKK1, and PGC-1α gene expression were observed in the High VO2max group than Low VO2max individuals. In conclusion, even with elevated endotoxemia, individuals with High VO2max exhibited higher IL-6 concentration in peripheral blood post-acute aerobic exercise and lower IL-10 concentration during recovery (1 h post-exercise). The anti-inflammatory effects linked with exercise training and physical fitness status may be explained by a greater gene expression of IKK1, TLR-4, and PGC-1α, displaying an extremely efficient cellular framework for the PPAR-γ responses.

A Comparison of Intermittent and Continuous Exercise Bouts at Different Intensities on Appetite and Postprandial Metabolic Responses in Healthy Men.

Exercise intensity affects many potential postprandial responses, but there is limited information on the influence of exercise modality. Therefore, the aim of this study was to investigate if the nature of exercise at two different intensities would affect gastric emptying rate (GER), appetite and metabolic responses following ingestion of a semi-solid meal. Twelve healthy men completed, in a random order, four 60-min cycles at 60% VO2peak (MOD), 40% VO2peak (LOW) and in a continuous (CON) or intermittent (INT) manner. INT consisted of 20 × 1-min exercise bouts with 2-min rest breaks. INT and CON were matched for total work output at each intensity. GER of the post-exercise meal was measured for 2 h using the 13C-breath method. Blood glucose, substrate utilisation and appetite ratings were measured at regular intervals throughout all trials and 24-h energy intake (EI) post-trials was assessed. GER-Delta over Baseline (DOB) was lower (p < 0.05) on MOD-INT vs. MOD-CON from 30–120 min post-meal. Blood glucose was higher mid-exercise (p < 0.05) on MOD-INT vs. MOD-CON. Although post-exercise LOW-CON was significantly higher than LOW-INT (p < 0.05), blood glucose was also higher 30-min post-meal ingestion on both CON trials compared to INT (p < 0.001). No interaction effect was observed for perceived appetite responses 2 h after meal ingestion (all p > 0.05). 24-h post-trial EI was similar between LOW-CON vs. LOW-INT (p > 0.05), although MOD-INT vs. MOD-CON 3500 ± 1419 vs. 2556 ± 989 kCal: p < 0.001 was elevated. In summary, MOD-INT exercise delays GER without stimulating perceived appetite in the 2 h period after meal ingestion, although EI was greater in the 24-h post-trial.

Effect of Choline Forms and Gut Microbiota Composition on Trimethylamine-N-Oxide Response in Healthy Men.

Background: Trimethylamine-N-oxide (TMAO), a choline-derived gut microbiota-dependent metabolite, is a newly recognized risk marker for cardiovascular disease. We sought to determine: (1) TMAO response to meals containing free versus lipid-soluble choline and (2) effects of gut microbiome on TMAO response. Methods: In a randomized, controlled, double-blinded, crossover study, healthy men (n = 37) were provided meals containing 600 mg choline either as choline bitartrate or phosphatidylcholine, or no choline control. Results: Choline bitartrate yielded three-times greater plasma TMAO AUC (p = 0.01) and 2.5-times greater urinary TMAO change from baseline (p = 0.01) compared to no choline and phosphatidylcholine. Gut microbiota composition differed (permutational multivariate analysis of variance, PERMANOVA; p = 0.01) between high-TMAO producers (with ≥40% increase in urinary TMAO response to choline bitartrate) and low-TMAO producers (with <40% increase in TMAO response). High-TMAO producers had more abundant lineages of Clostridium from Ruminococcaceae and Lachnospiraceae compared to low-TMAO producers (analysis of composition of microbiomes, ANCOM; p < 0.05). Conclusion: Given that phosphatidylcholine is the major form of choline in food, the absence of TMAO elevation with phosphatidylcholine counters arguments that phosphatidylcholine should be avoided due to TMAO-producing characteristics. Further, development of individualized dietary recommendations based on the gut microbiome may be effective in reducing disease risk

True Interindividual Variability Exists in Postprandial Appetite Responses in Healthy Men But Is Not Moderated by the FTO Genotype

ABSTRACTBackgroundAfter meal ingestion, a series of coordinated hormone responses occur concomitantly with changes in perceived appetite. It is not known whether interindividual variability in appetite exists in response to a meal.ObjectivesThe aim of this study was to 1) assess the reproducibility of appetite responses to a meal; 2) quantify individual differences in responses; and 3) explore any moderating influence of the fat mass and obesity associated (FTO) gene.MethodsUsing a replicated crossover design, 18 healthy men (mean ± SD age: 28.5 ± 9.8 y; BMI: 27.0 ± 5.0 kg/m2) recruited according to FTO genotype (9 AA, 9 TT) completed 2 identical control and 2 identical standardized meal conditions (5025 kJ) in randomized sequences. Perceived appetite and plasma acylated ghrelin, total peptide YY (PYY), insulin, and glucose concentrations were measured before and after interventions as primary outcomes. Interindividual differences were explored using Pearson's product-moment correlations between the first and second replicates of the control-adjusted meal response. Within-participant covariate-adjusted linear mixed models were used to quantify participant-by-condition and genotype-by-condition interactions.ResultsThe meal suppressed acylated ghrelin and appetite perceptions [standardized effect size (ES): 0.18–4.26] and elevated total PYY, insulin, and glucose (ES: 1.96–21.60). For all variables, SD of change scores was greater in the meal than in the control conditions. Moderate-to-large positive correlations were observed between the 2 replicates of control-adjusted meal responses for all variables (r = 0.44–0.86, P ≤ 0.070). Participant-by-condition interactions were present for all variables (P ≤ 0.056). FTO genotype-by-condition interactions were nonsignificant (P ≥ 0.19) and treatment effect differences between genotype groups were small (ES ≤ 0.27) for all appetite parameters.ConclusionsReproducibility of postprandial appetite responses is generally good. True interindividual variability is present beyond any random within-subject variation in healthy men but we detected no moderation by the FTO genotype. These findings highlight the importance of exploring individual differences in appetite for the prevention and treatment of obesity. This trial was registered at clinicaltrials.gov as NCT03771690.

The effect of a transient immune activation on subjective health perception in two placebo controlled randomised experiments.

BackgroundPatient-reported outcomes predict mortality and play increasingly important roles in care, but factors that modify central measures such as health ratings have been little investigated. Building on designated immune-to-brain pathways, we aimed to determine how a short-term induced inflammation response impacts self-reported health status.MethodsLipopolysaccharide injections were used to provoke acute systemic inflammatory responses in healthy men and women and were compared to placebo in two double-blind randomized experiments. In Experiment 1, 8 individuals (mean 24 years; SD = 3.7) received lipopolysaccharide 0.8 ng/kg once and placebo once in a cross-over design, and in Experiment 2, 52 individuals received either lipopolysaccharide 0.6 ng/kg or placebo once (28.6 years; SD = 7.1). Main outcomes were perceived health (general and current), sickness behaviour (like fatigue, pain and negative affect), and plasma interleukin-6, interleukin-8 and tumour necrosis factor-α, before and after injection.ResultsCompared to placebo, lipopolysaccharide lead to a deterioration in both self-rated general (Experiment 1, b = 1.88 for 0.8 ng/kg) and current health (Experiment 1 b = -3.00; and Experiment 2 b = -1.79) 1.5h after injection (p’s<0.01), effects that remained after 4.5 to 5 hours (p’s<0.05). The effect on current health in Experiment 2 was mediated by increased inflammation and sickness behaviour in response to lipopolysaccharide injection (β = -0.28, p = 0.01).ConclusionHealth is drastically re-evaluated during inflammatory activation. The findings are consistent with notions that inflammation forms part of health-relevant interoceptive computations of bodily state, and hint at one mechanism as to why subjective health predicts longevity.

Associations between digit ratio (2D4D), mood, and autonomic stress response in healthy men.

The ratio between the length of the second (index) and the fourth (ring) finger (2D4D) is a putative biomarker of prenatal testosterone (T) exposure, with higher exposure leading to a smaller ratio. 2D4D has further been linked to mental and somatic disorders. Healthy male Swiss recruits (N=245; Mage = 20.30years) underwent a psychosocial stress test. Mood and salivary alpha-amylase (sAA) were assessed before and after the stress test, while heart rate (HR) and heart rate variability (HRV) were measured continuously. Additionally, 2D4D (right: R2D4D; left: L2D4D) was determined and divided into quartile groups. Correlation analysis showed no associations between R/L2D4D and outcome measures. Comparing calculated quartiles for R2D4D, subjects in the lowest R2D4D quartile expressed trendwise (p<0.10) lower positive and higher negative affect, significantly elevated sAA activity (p<0.05), but no HR and HRV differences at baseline as compared to subjects in the upper three quartiles. With regard to acute stress, subjects in the lowest as compared to subjects in the upper three R2D4D quartiles showed a higher increase of negative affect and a stronger cardiac response (p<0.05), but no alterations in positive affect and sAA activity. Young healthy men in the lowest R2D4D quartile revealed a more negative affect and increased physiological activity at baseline and in response to acute stress. An exposure to high levels of prenatal T might constitute a risk factor potentially increasing vulnerability to stress-related disorders in men.

Influence Of Short, Disrupted Sleep And High-intensity Interval Exercise On Fasting And Post-prandial Blood Lipid And Lipid-related Antioxidant Responses In Healthy Men

Exercise is known to impart transient blood lipid responses that appear consistent with reduced cardiovascular disease risk; yet, it is unclear how short, disrupted sleep (SDS) modifies post-exercise fasting and postprandial blood lipid and lipid-related antioxidant responses to a single episode of exercise. PURPOSE: To determine the influence of a single night of SDS on fasting and postprandial blood lipid and lipid-related antioxidant responses after HIIE. METHODS: Fifteen male participants (age 31.1 ± 5.3 yr; weight 83.5 ± 11.4 kg; BMI 25.8 ± 2.7 kg/m2; VO max 49.1 ± 8.5 ml/kg/min) completed a non-exercise control trial after 9 to 9.5 hrs of reference sleep (REF), HIIE by treadmill running (90% and 40% of VO2reserve in 3:2 min ratio) to expend 500 kcals after reference sleep (REF+EX) and HIIE after 3 to 3.5 hrs of short and disrupted sleep (SDS+EX) in a randomized crossover design. Blood samples were obtained by the same technician under standardized conditions just before, immediately after (IPE), 1 hr after exercise (1 HR) and just before a high-fat meal - 1240 kcals (56 g fat; 145 g carbohydrate; 38 g protein) and again 2, 4 and 6hrs after meal ingestion and at equal intervals during REF. Total, high-density and low-density lipoprotein cholesterol (HDLC and LDLC) and paraoxonase-1 concentration were measured up to 1 hr post-exercise. Post-prandial triglyceride was measured and area under the curves - total (AUCt) and incremental (AUCi) were calculated. Lipid and lipid-related antioxidant responses were analyzed using 3 (condition) by 3 (sample point) repeated measures ANOVAs. AUCt and AUCi were measured using one-way, 3 (condition) repeated measures ANOVAs. RESULTS: HDLC (+6.3%, p = 0.0023) and paraoxonase-1 (+10.8%, p <0.0001) increased and triglyceride (-18.5%, p <0.0001) decreased after REF+EX and SDS+EX; TAUCt and AUCi remained refractory to exercise and short, disrupted sleep. SUMMARY: Exercise transiently increased fasting HDL cholesterol and related antioxidant concentrations and reduced triglyceride levels, but did not modify total or incremental triglyceride AUC in response to a post-exercise high-fat meal. Short, disrupted sleep did not influence these responses.

The Acute Effect of Moderate Intensity Stair-Climbing on Postprandial Blood Glucose

PURPOSE: To investigate the effects of moderate intensity stair-climbing of various durations on postprandial glucose response in healthy men and women. The postprandial glucose response is strongly associated with cardiometabolic disease risk. METHODS: Twenty males (26.8±6.0y) and fourteen females (24.8±4.5y) completed a 75g oral glucose tolerance test (OGTT). On three subsequent visits, participants completed an OGTT combined with either 1min, 3min, or 10min of stair-climbing, all ending 28 min after subjects finished the drink. Fingerstick blood glucose measurements were taken at baseline and every fifteen minutes thereafter for one hour. RESULTS: All stair-climbing trials reduced peak (30 min) postprandial blood glucose levels compared to the control (12±31 to 35±30mg/dL, p≤.001-.038). At the 45min time point, there were significant reductions compared to the control for the 3 and 10min trials (11±29 and 23±30mg/dL, p=.037 and p≤.001), but not between 1min and control (2±33mg/dL, p=.701). No significant differences exist in BG between any trials at baseline, 15, or 60min time point (Δ=-0.3- 5.1mg/dL, p=.391-.882). There were significant differences in AUC compared to the control for the 3min and 10min trials (436±1126and 896±1108mg/ dL*min, p=.036 and p≤.001) but not for the 1min (272±1112mg/dL*min, p=.177). For iAUC, there were significant differences compared to the control for the 3 min and 10 min trials (424±1124 and 901±903mg/dL*min, p=.038 and ≤.001) but not for the 1 min (107±918mg/dL*min, p=.509). CONCLUSIONS: Moderate intensity stair-climbing bouts as short as one minute in duration are effective at attenuating peak postprandial blood glucose with longer bouts producing more substantial benefits.

Changes in brachial artery endothelial function and resting diameter with moderate-intensity continuous but not sprint interval training in sedentary men.

Moderate-intensity continuous training (MICT) improves peripheral artery function in healthy adults, a phenomenon that reverses as continued training induces structural remodeling. Sprint interval training (SIT) elicits physiological adaptations similar to MICT, despite a lower exercise volume and time commitment; however, its effect on peripheral artery function and structure is largely unexplored. We compared peripheral artery responses to 12 wk of MICT and SIT in sedentary, healthy men (age = 27 ± 8 yr). Participants performed MICT (45 min of cycling at 70% peak heart rate; n = 10) or SIT (3 × 20-s "all out" cycling sprints with 2 min of recovery; n = 9), and responses were compared with a nontraining control group (CTL, n = 6). Allometrically scaled brachial flow-mediated dilation (FMD) increased 2.2% after 6 wk of MICT and returned to baseline levels by 12 wk, but did not change in SIT or CTL (group × time interaction, P = 0.04). Brachial artery diameter increased after 6 and 12 wk (main effect, P = 0.03), with the largest increases observed in MICT. Neither training protocol affected popliteal relative FMD and diameter, or central and lower limb arterial stiffness (carotid distensibility, central and leg pulse wave velocity) (P > 0.05 for all). Whereas earlier and more frequent measurements are needed to establish the potential presence and time course of arterial responses to low-volume SIT, our findings suggest that MICT was superior to the intense, but brief and intermittent SIT stimulus at inducing brachial artery responses in healthy men.NEW & NOTEWORTHY We compared the effects of 12 wk of moderate-intensity continuous training (MICT) and sprint interval training (SIT) on peripheral artery endothelial function and diameter, and central and lower limb stiffness in sedentary, healthy men. Whereas neither training program affected the popliteal artery or stiffness indexes, we observed changes in brachial artery function and diameter with MICT but not SIT. Brachial artery responses to SIT may follow a different time course or may not occur at all.

Effect of Mid‐morning Snacks on Subjective Appetite, Food intake, and Glucose and Insulin Responses in Healthy Men and Women

Snacking contributes a significant proportion of daily energy intake. Altering the macronutrient composition of snacks may increase satiety and promote lower food intake throughout the day, which could play an important role in weight management. The objective of this study was to compare the effects of mid‐morning gel‐based snacks fortified with different macronutrients on subjective appetite, short‐term food intake, and glycaemia in healthy young adults. In a repeated measures design, 23 healthy weight adults (BMI: 23.7 ± 0.8 kg/m2) received in random order five gel snacks (238 g) containing whey‐protein (202 kcal), steel cut oats (276 kcal), coconut oil (276 kcal), maltodextrin (272 kcal), or a control snack (186 kcal) 2 h after a standardized breakfast and 2 h prior to an ad libitum pizza meal at which food intake was measured. Glucose and insulin in capillary blood samples and subjective appetite were measured at baseline and at 15, 30, 45, 60, 90 and 120 min. Compared to snack skipping, all test treatments similarly reduced subjective appetite (p=0.0026), but only the snacks containing steel cut oats (p=0.0322) and coconut oil (p=0.0307) significantly decreased test meal food intake. Blood glucose was higher after maltodextrin (p&lt;0.0001) compared with the other gel snacks. Cumulative insulin was higher after maltodextrin (p&lt;0.01) snack consumption compared to the coconut oil snack and snack skipping. Blood glucose and insulin responses had a strong positive linear correlation (R2 = 0.7897). In conclusion, gel snacks differed in their effects on food intake, blood glucose and insulin responses. Both macronutrient composition and calorie content were primary determinants of food intake but macronutrient composition was the main factor in glycaemic and insulin responses.Support or Funding InformationThis work was funded by the Hershey Company.

The Effect of Short-Term Dietary Fructose Supplementation on Gastric Emptying Rate and Gastrointestinal Hormone Responses in Healthy Men.

This study aimed to examine gastric emptying rate and gastrointestinal hormone responses to fructose and glucose ingestion following 3 days of dietary fructose supplementation. Using the 13C-breath test method, gastric emptying rates of equicaloric fructose and glucose solutions were measured in 10 healthy men with prior fructose supplementation (fructose supplement, FS; glucose supplement, GS) and without prior fructose supplementation (fructose control, FC; glucose control, GC). In addition, circulating concentrations of acylated ghrelin (GHR), glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), and insulin were determined, as well as leptin, lactate, and triglycerides. Increased dietary fructose ingestion resulted in accelerated gastric emptying rate of a fructose solution but not a glucose solution. No differences in GIP, GLP-1, or insulin incremental area under curve (iAUC) were found between control and supplement trials for either fructose or glucose ingestion. However, a trend for lower ghrelin iAUC was observed for FS compared to FC. In addition, a trend of lower GHR concentration was observed at 45 min for FS compared to FC and GHR concentration for GS was greater than GC at 10 min. The accelerated gastric emptying rate of fructose following short-term supplementation with fructose may be partially explained by subtle changes in delayed postprandial ghrelin suppression.