Sedentary Males Research Articles

Exercise Intensity and Its Relation to Sperm Count on Healthy Male Adults

Physical activity is well known for maintaining fitness and health. Recent studies also found that low semen quality and quantity are associated with the risk of many diseases and life expectancy. We conducted a literature search with key concepts of “exercise”, “sperm count”, and “adult”. The search was carried out through comprehensive literature searches on 4 databases (Pubmed, Web of Science, Scopus, and Google scholar), reference searches or citation matching, and/or other method searches. The literature search was done in November 2022. We identified 17 literatures that analyzed these correlations. Among them, 7 articles showed that there is a correlation between exercise intensity and sperm count. However, there are other studies that showed no significant correlation between the intensity of exercise and sperm count. In conclusion, physical activity in sedentary adult males has shown a positive effect on sperm count. However, athletes showed no significant decrease in sperm count.

Acute Response of Blood Lipids and Lipoproteins to Different Intensities of Exercise in Obese Males

This study aimed to examine the response of lipid and lipoprotein levels following different intensities of exercise in obese males. Fifteen obese (body mass index > 30 kg/m2), sedentary (less than 2 days per week of physical activity) males, aged 18–30 years, participated in this randomized, cross-over study. The participants performed a single bout of cycling exercise (average energy expenditure: ~300 kcal) at two different intensities [lower-intensity: 50% of maximal heart rate and higher-intensity: 80% of maximal heart rate] in a random order. Overnight fasting blood samples were collected at baseline, immediately post-exercise (IPE), 1-hr PE, and 24-hr PE for each intensity of exercise to determine the profile of blood lipids and lipoproteins [total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C)]. A 2(intensity) × 4(time) analysis of variance with repeated measures was used to examine the main and interaction differences in intensity and time on the profile of blood lipids and lipoproteins. The blood lipids and lipoproteins were not significantly altered following either lower or higher intensity exercise. There was no significant interaction between intensity and time. The results suggest that regardless of exercise intensity, an acute bout of aerobic exercise requiring 300 kcal energy expenditure may not be enough to significantly alter blood lipids and lipoproteins in physically healthy obese males. Therefore, it is recommended that future research determine whether different intensities of chronic exercise requiring the same or higher volume of energy expenditure can positively alter the blood lipid profiles in obese males.

Exercise Training Improves Mitochondrial Bioenergetics of Natural Killer Cells.

Mitochondrial bioenergetics is critical for immune function in natural killer (NK) cell. Physical exercise modulates NK cell functionality, depending on the intensity and type of exercise. This study elucidates how interval and continuous exercise regimens affect the phenotypes and mitochondrial bioenergetics of NK cells. Sixty healthy sedentary males were randomly assigned to engage in either high-intensity interval training (HIIT, 3-min intervals at 80% and 40% maximal O2, n = 20; age, 22.2 yr; body mass index [BMI], 24.3 kg·m-2) or moderate-intensity continuous training (MICT, sustained 60% maximal O2, n = 20; age, 22.3 yr; BMI, 23.3 kg·m-2) for 30 min·d-1, 5 d·wk-1 for 6 wk or were assigned to a control group that did not receive exercise intervention (n = 20; age, 22.6 yr; BMI, 24.0 kg·m-2). Natural killer cell phenotypes, granule proteins, and mitochondrial oxidative stress/oxidative phosphorylation after graded exercise test (GXT) were measured before and after the various interventions. Before the intervention, the GXT increased the mobilization of CD57+NK cells into the blood and elevated mitochondrial matrix oxidant burden (MOB) in NK cells, Following the 6 wk of interventions, both HIIT and MICT (i) diminished mobilization of CD57+NK cells into the blood and depressed mitochondrial MOB level in NK cells immediately after GXT, (ii) increased mitochondrial membrane potential and cellular perforin and granzyme B levels in NK cells, and (iii) enhanced the maximal and reserve O2 consumption rates and heightened bioenergetic health index in NK cells. In addition, HIIT increased maximal work rate than those of MICT. Either HIIT or MICT increases the expressions of cytotoxic granule proteins and depresses mitochondrial MOB elevated by GXT, along with improving mitochondrial bioenergetic functionality in NK cells. Moreover, HIIT is superior to MICT in improving aerobic capacity.

Redox balance in human skeletal muscle-derived endothelial cells - Effect of exercise training

Aerobic training can improve vascular endothelial function in-vivo. The aim of this study was to elucidate the mechanisms underlying this improvement in isolated human microvascular endothelial cells. Sedentary males, aged 57 ± 6 years completed 8 weeks of intense aerobic training. Resting muscle biopsies were obtained from the thigh muscle and used for isolation of endothelial cells (pre n = 23, post n = 16). The cells were analyzed for mitochondrial respiration, H2O2 emission, glycolysis, protein levels of antioxidants, NADPH oxidase, endothelial nitric oxide (NO) synthase and prostacyclin synthase (PGI2S). In-vivo microvascular function, assessed by acetylcholine infusion and arterial blood pressure were also determined. Endothelial mitochondrial respiration and H2O2 formation were similar before and after training whereas the expression of superoxide dismutase and the expression of glutathione peroxidase were 2.4-fold (p = 0.012) and 2.3–fold (p = 0.006) higher, respectively, after training. In-vivo microvascular function was increased by 1.4-fold (p = 0.036) in parallel with a 2.1-fold increase in endothelial PGI2S expression (p = 0.041). Endothelial cell glycolysis was reduced after training, as indicated by a 65% lower basal production of lactate (p = 0.003) and a 30% lower expression of phosphofructokinase (p = 0.011). Subdivision of the participants according to blood pressure at base-line (n = 23), revealed a 2-fold higher (p = 0.049) rate of H2O2 production in endothelial cells from hypertensive participants. Our data show that exercise training increases skeletal muscle microvascular endothelial cell metabolism, antioxidant capacity and the capacity to form prostacyclin. Moreover, elevated blood pressure is associated with increased endothelial mitochondrial ROS formation.

The root of the matter: nitrate-rich beetroot juice reduces skeletal muscle O2 uptake during exercise.

The root of the matter: nitrate-rich beetroot juice reduces skeletal muscle O2 uptake during exercise.

Central Suppression of the GH/IGF Axis and Abrogation of Exercise-Related mTORC1/2 Activation in the Muscle of Phenotype-Selected Male Marathon Mice (DUhTP).

The somatotropic axis is required for a number of biological processes, including growth, metabolism, and aging. Due to its central effects on growth and metabolism and with respect to its positive effects on muscle mass, regulation of the GH/IGF-system during endurance exercise is of particular interest. In order to study the control of gene expression and adaptation related to physical performance, we used a non-inbred mouse model, phenotype-selected for high running performance (DUhTP). Gene expression of the GH/IGF-system and related signaling cascades were studied in the pituitary gland and muscle of sedentary males of marathon and unselected control mice. In addition, the effects of three weeks of endurance exercise were assessed in both genetic groups. In pituitary glands from DUhTP mice, reduced expression of Pou1f1 (p = 0.002) was accompanied by non-significant reductions of Gh mRNA (p = 0.066). In addition, mRNA expression of Ghsr and Sstr2 were significantly reduced in the pituitary glands from DUhTP mice (p ≤ 0.05). Central downregulation of Pou1f1 expression was accompanied by reduced serum concentrations of IGF1 and coordinated downregulation of multiple GH/IGF-signaling compounds in muscle (e.g., Ghr, Igf1, Igf1r, Igf2r, Irs1, Irs2, Akt3, Gskb, Pik3ca/b/a2, Pten, Rictor, Rptor, Tsc1, Mtor; p ≤ 0.05). In response to exercise, the expression of Igfbp3, Igfbp 4, and Igfbp 6 and Stc2 mRNA was increased in the muscle of DUhTP mice (p ≤ 0.05). Training-induced specific activation of AKT, S6K, and p38 MAPK was found in muscles from control mice but not in DUhTP mice (p ≤ 0.05), indicating a lack of mTORC1 and mTORC2 activation in marathon mice in response to physical exercise. While hormone-dependent mTORC1 and mTORC2 pathways in marathon mice were repressed, robust increases of Ragulator complex compounds (p ≤ 0.001) and elevated sirtuin 2 to 6 mRNA expression were observed in the DUhTP marathon mouse model (p ≤ 0.05). Activation of AMPK was not observed under the experimental conditions of the present study. Our results describe coordinated downregulation of the somatotropic pathway in long-term selected marathon mice (DUhTP), possibly via the pituitary gland and muscle interaction. Our results, for the first time, demonstrate that GH/IGF effects are repressed in a context of superior running performance in mice.

Alteration of skeletal and cardiac muscles function in DBA/2J mdx mice background: a focus on high intensity interval training.

Duchenne muscular dystrophy (DMD) is a recessive hereditary myopathy due to deficiency of functional dystrophin. Current therapeutic interventions need more investigation to slow down the progression of skeletal and cardiac muscle weakness. In humans, there is a lack of an adapted training program. In animals, the murine Mdx model with a DBA/2J background (D2-mdx) was recently suggested to present pathological features closer to that of humans. In this study, we characterized skeletal and cardiac muscle functions in males and females D2-mdx mice compared to control groups. We also evaluated the impact of high intensity interval training (HIIT) in these muscles in females and males. HIIT was performed 5 times per week during a month on a motorized treadmill. Specific maximal isometric force production and weakness were measured in the tibialis anterior muscle (TA). Sedentary male and female D2-mdx mice produced lower absolute and specific maximal force compared to control mice. Dystrophic mice showed a decline of force generation during repetitive stimulation compared to controls. This reduction was greater for male D2-mdx mice than females. Furthermore, trained D2-mdx males showed an improvement in force generation after the fifth lengthening contraction compared to sedentary D2-mdx males. Moreover, echocardiography measures revealed a decrease in left ventricular end-diastolic volume, left ventricular ejection volume and left ventricular end-diastolic diameter in sedentary male and female D2-mdx mice. Overall, our results showed a serious muscle function alteration in female and male D2-mdx mice compared to controls. HIIT may delay force loss especially in male D2-mdx mice.

Body fat content correlates with maximum aerobic capacity in healthy sedentary Indian males

BackgroundObesity is a multifactorial public health problem with varying effects on physical fitness determined by maximum aerobic capacity or VO2max. The relationship between body fat content and VO2max has shown varying results. The present study was planned as an experimental study to evaluate the relationship between body fat content and maximum aerobic capacity. Methods104 healthy Indian males [Age: 21 (4.87)years; Height: 171.4 (6.14)cm; Weight: 64.1 (8.57)kg] were evaluated for body fat content using body mass index (BMI), bioimpedance, skinfold thickness (SFT), body girth (BG) measurements, waist circumference (WC), and waist-hip ratio (WHR). Maximum aerobic capacity or VO2max for all subjects was determined indirectly from maximum heart rate achieved using an incremental treadmill protocol using Astrand and Astrand nomogram. ResultsVO2max, when expressed in L/min, showed a statistically significant positive correlation with body fat irrespective of the method of estimation. VO2max, when expressed in ml/kg/min, showed negative correlation with five of the seven clinical parameters of fat estimation. Of these, a statistically significant negative correlation was seen with SFT. ConclusionVO2max (L/min) shows a significant positive correlation with all methods of body fat estimation. VO2max (ml/kg/min) shows a significant negative correlation with skinfold thickness. Monitoring of body fat content using skinfold thickness could be studied further for its use in the early identification of young, healthy adult Indian males with low aerobic fitness.

Moderately trained male football players, compared to sedentary male adults, exhibit anatomical but not functional cardiac remodelling, a cross-sectional study

BackgroundElite athletes have been the subject of great interest, but athletes at an intermediate level of physical activity have received less attention in respect to the presence of cardiac enlargement and/or hypertrophy. We hypothesized that playing football, often defined as demanding less endurance components than running or cycling, would still induce remodelling similar to sports with a dominating endurance component.Methods23 male football players, age 25+/− 3.9 yrs. underwent exercise testing, 2D- and 3D- echocardiography and cardiac magnetic resonance (CMR). The results were compared with a control group of engineering students of similar age. The athletes exercised 12 h/week and the control subjects 1 h/week, p < 0.001.ResultsThe football players achieved a significantly higher maximal load at the exercise test (380 W vs 300 W, p < 0.001) as well as higher calculated maximal oxygen consumption, (49.7 vs 37.4 mL x kg− 1 x min− 1, p < 0.001) compared to the sedentary group. All left ventricular (LV) volumes assessed by 3DEcho and CMR, as well as CMR left atrial (LA) volume were significantly higher in the athletes (3D-LVEDV 200 vs 154 mL, CMR-LVEDV 229 vs 185 mL, CMR-LA volume 100 vs 89 mL, p < 0.001, p = 0.002 and p = 0.009 respectively). LVEF and RVEF, LV strain by CMR or by echo did not differentiate athletes from sedentary participants. Right ventricular (RV) longitudinal strain, LA and right atrial (RA) strain by CMR all showed similar results in the two groups.ConclusionModerately trained intermediate level football players showed anatomical but not functional cardiac remodelling compared to sedentary males.

Aerobic Exercise Attenuates Frailty in Aging Male and Female C57Bl/6 Mice and Effects Systemic Cytokines Differentially by Sex

Aerobic exercise is a promising intervention to attenuate frailty, but preclinical studies have used only male animals. We investigated the impact of voluntary aerobic exercise on frailty, biological age (FRailty Inferred Geriatric Health Timeline [FRIGHT] clock), predicted life expectancy (Analysis of FRAIlty and Death [AFRAID] clock), and mortality in both sexes and determined whether exercise was associated with changes in inflammation. Older (21–23 months) male (n = 12) and female (n = 22) C57Bl/6 mice matched for baseline frailty scores were randomized into exercise (running wheel) and sedentary (no wheel) groups. Frailty index scores were measured biweekly (13 weeks), and 23 serum cytokines were measured at midpoint and end point. Exercise levels varied between mice but not between the sexes. Exercise had no effect on mortality, but it attenuated the development of frailty in both sexes (female = 0.32 ± 0.04 vs 0.21 ± 0.01; p = .005; male = 0.30 ± 0.02 vs 0.22 ± 0.02; p = .042) and reduced frailty in older females after 10 weeks. FRIGHT scores were unaffected by exercise but increased with time in sedentary males indicating increased biological age. Exercise prevented the age-associated decline in AFRAID scores in older females such that exercised females had a longer life expectancy. We investigated whether aerobic exercise was associated with changes in systemic inflammation. Cytokine levels were not affected by exercise in males, but levels of pro-inflammatory cytokines were positively correlated with the frequency of exercise in females. Despite increases in systemic inflammation, exercise reduced frailty and increased life span in older females. Thus, voluntary aerobic exercise, even late in life, has beneficial effects on health in both sexes but may be especially helpful in older females.

Gender differences in metabolic rates and thermal comfort in sedentary young males and females at various temperatures

Human metabolic rate is a fundamental and essential aspect of thermal comfort, and gender differences in metabolic rate may underlie gender differences in comfort. This study explores gender differences in physiological and subjective responses to a wide range of cold to hot temperatures. Forty healthy college students (20 females and 20 males) participated in the experiments. Subjects were sedentary, wearing 0.6 clo, staying at 26 °C for 30 min, then exposed to either at cool (14, 16, 18, 20 °C), neutral (24, 26 °C), or warm (28, 30, 32, and 34 °C) temperatures for 90 min. Both subjective questionnaires (thermal sensation, thermal comfort, thermal acceptability) and physiological measurements (metabolic rate, skin temperature, skin blood flow, and skin wettedness) were collected during the exposures. Females tend to have lower metabolic rates than males at all temperatures, although significant differences were only found at 14, 16, and 18 °C. Females tend to be cooler and less comfortable than males at cool temperatures, which could be explained by the lower metabolic rates and lower skin temperatures in females. Males tend to be warmer and less comfortable at warm temperatures, which could be explained by higher metabolic rates and higher skin wettedness in males. No significant gender differences in subjective or physiological responses were found at neutral conditions.

Fasting and postprandial trimethylamine N-oxide in sedentary and endurance-trained males following a short-term high-fat diet.

Gut bacteria release trimethylamine (TMA) from dietary substrates. TMA is absorbed and is subsequently oxidized in the liver to produce trimethylamine N‐oxide (TMAO). Plasma TMAO levels are positively correlated with risk for type 2 diabetes (T2D) and cardiovascular disease (CVD). High‐fat diet (HFD) consumption has been reported to increase fasting and postprandial TMAO in sedentary individuals. However, whether the increase in TMAO with consumption of an HFD is observed in endurance‐trained males is unknown. Healthy, sedentary (n = 17), and endurance‐trained (n = 7) males consumed a 10‐day eucaloric diet comprised of 55% carbohydrate, 30% total fat, and <10% saturated fat prior to baseline testing. Blood samples were obtained in a fasted state and for a 4‐hour high‐fat challenge (HFC) meal at baseline and then again following 5‐day HFD (30% carbohydrate, 55% total fat, and 25% saturated fat). Plasma TMAO and TMA‐moiety (choline, betaine, L‐carnitine) concentrations were measured using isocratic ultraperformance liquid chromatography‐tandem mass spectrometry. Age (23 ±3 vs. 22 ± 2 years) and body mass index (23.0 ± 3.0 vs. 23.5 ± 2.1 kg/m2) were similar (both p > 0.05) in the sedentary and endurance‐trained group, respectively. VO2max was significantly higher in the endurance‐trained compared with sedentary males (56.7 ± 8.2 vs. 39.9 ± 6.0 ml/kg/min). Neither the HFC nor the HFD evoked a detectable change in plasma TMAO (p > 0.05) in either group. Future studies are needed to identify the effects of endurance training on TMAO production.

Effect of eccentric and concentric squat exercise on quadriceps thickness and lower extremity performance in healthy young males

Background: In clinical practice, resistance training, which includes concentric and eccentric dynamic muscle movements, is widely used by physiotherapists to strengthen the quadriceps muscle. However, although eccentric training is assumed to induce greater hypertrophy compared to concentric contractions, there are also studies reporting that similar increases in muscle thickness can be seen in both eccentric and concentric training.Objective: This study aims to assess the effect of the eccentric and concentric squat exercise on quadriceps thickness, and lower extremity performance during jumping and walking in healthy young sedentary males. Methods: Participants were randomly divided into three groups: concentric exercise group (CE; n = 19), eccentric exercise group (EE; n = 13) and control group (CG; n = 16). Both exercises were performed seven days a week, for eight weeks with a gradual strength increase. The CG was not given any exercise. Ultrasound assessment of quadriceps muscle thickness, performance in Six-Minute Walk Test and vertical jump was measured. Results: Thickness of dominant side of rectus femoris (p = .008) and vastus lateralis (p = .021) differed significantly among the three groups; post hoc analysis revealed the thickness of rectus femoris in CG was significantly lower than in the CE (p = .046) and EE (p = .006) and the thickness of vastus lateralis in the EE was significantly higher than in the CG (p = .018). Six-Minute Walk Test score in the EE was significantly higher than in the CG (p = .025) and the vertical jump score in the CG significantly lower than in the EE (p = .002) and CE (p &lt; .001). Conclusions: Eccentric and concentric training both benefits muscle hypertrophy and lower extremity functional performance. However, eccentric training also appears to offer a small advantage over concentric training.

Six weeks of high intensity interval training (HIIT) facilitates a four year preservation of aerobic capacity in sedentary older males: A reunion study.

Long-term implications of acutely increased cardiorespiratory fitness following short-term exercise interventions in older adults are unknown. In this study, we examined peak oxygen uptake (VO2peak) after 4-years of 'free-living' after a high intensity interval training (HIIT) intervention. Seventeen lifelong exercisers (LEX) and 17 previously sedentary (SED) males (55-74years of age in 2012) were tested four years (phase D) after our previous experiment which included 6-weeks of aerobic moderate intensity exercise (phase B), followed by 6-weeks of HIIT (phase C). At all stages, a standard incremental exercise protocol on a cycle ergometer was completed to determine VO2peak. SED (P=1.000, Cohen's d=0.01) and LEX (P=1.000, Cohen's d=0.11) VO2peak at phase D was not different from phase A (enrolment). SED experienced a large decrease in VO2peak from phase C to phase D (32±6ml·kg·min-1 to 27±6ml·kg·min-1 [P<0.001, Cohen's d=0.81]). LEX experienced a small decrease in VO2peak from phase C to phase D (42±7ml·kg·min-1 to 39±9ml·kg·min-1 [P<0.001, Cohen's d=0.46]). At phase D, LEX had greater VO2peak than SED (P<0.001, Cohen's d=1.73). The proportion of subjects who reported discontinuing training, maintaining moderate training, and maintaining HIIT differed between groups (P=0.023), with LEX self-reporting more HIIT, and SED self-reporting more discontinuation from exercise. Those who continued exercising experienced a reduction in VO2peak over the four years from 39±7ml·kg·min-1 to 36±9ml·kg·min-1 (N=25, P<0.001, Cohen's d=0.37), and those who discontinued exercising also experienced a reduction in VO2peak from 30±7ml·kg·min-1 to 25±9ml·kg·min-1 (N=9, P=0.003, Cohen's d=0.62). Four years after completing a brief period of aerobic exercise and HIIT, older males demonstrated a preservation of VO2peak, irrespective of training status (LEX or SED). However, LEX exhibited greater VO2peak than SED after 4-years of unsupervised 'free-living'. Notably, participants who discontinued exercising experienced a greater reduction in VO2peak. These data suggest that a 6weeks of supervised HIIT can facilitate the long term.

Commentaries on Viewpoint: Fragile bones of elite cyclists: to treat or not to treat?

Commentaries on Viewpoint: Fragile bones of elite cyclists: to treat or not to treat?

Hypoxic Exercise Training Elevates Erythrocyte Aggregation

Pathological erythrocyte aggregation reduces capillary perfusion and oxygen transfer to tissue, which is determined by the negative surface charge on the erythrocyte membrane (intrinsic aggregability) and fibrinogen–erythrocyte interaction (extrinsic factor). Exercise-induced oxidative stress is important for rheological adaptation to training but may also cause erythrocyte senescence. This study clarifies the effects of hypoxic exercise training on intrinsic/extrinsic factors of aggregation. In total, 60 healthy sedentary males were randomly assigned to either hypoxic (HE; FIO2 = 0.15) or normoxic exercise training (NE; FIO2 = 0.21) groups for 30 min·d−1, 5 d·wk−1 for 6 weeks at 60 % of the maximum work rate or to a control group (CTL). A hypoxia exercise test (HET, FIO2 = 0.12) was performed before and after the intervention. Erythrocyte aggregation was assessed by ektacytometry, and fibrinogen binding affinity and senescence biomarkers were assessed by flow cytometry. An acute 12% oxygen HET significantly enhanced erythrocyte global aggregation through intrinsic aggregability. Resting aggregation is promoted by both intrinsic aggregability and fibrinogen binding probability and force after HE, whereas NE is mainly associated with ameliorated fibrinogen–erythrocyte interactions. The HET still facilitated global aggregation after HE because of the augmented fibrinogen-related factors, even though the intrinsic factor was suppressed. Additionally, HE further increased reticulocyte counts while reducing the expression of CD47 and CD147. Resting aggregability is promoted by both intrinsic and extrinsic factors after HE, whereas NE is mainly associated with an ameliorated affinity for fibrinogen. Although an accelerated turnover rate was observed, HE further led to erythrocyte senescence.

A randomized controlled trial of enhancing hypoxia-mediated right cardiac mechanics and reducing afterload after high intensity interval training in sedentary men

Hypoxic exposure increases right ventricular (RV) afterload by triggering pulmonary hypertension, with consequent effects on the structure and function of the RV. Improved myocardial contractility is a critical circulatory adaptation to exercise training. However, the types of exercise that enhance right cardiac mechanics during hypoxic stress have not yet been identified. This study investigated how high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT) influence right cardiac mechanics during hypoxic exercise A total of 54 young and healthy sedentary males were randomly selected to engage in either HIIT (3-min intervals at 40% and 80% of oxygen uptake reserve, n = 18) or MICT (sustained 60% of oxygen uptake reserve, n = 18) for 30 min/day and 5 days/week for 6 weeks or were included in a control group (CTL, n = 18) that did not engage in any exercise. The primary outcome was the change in right cardiac mechanics during semiupright bicycle exercise under hypoxic conditions (i.e., 50 watts under 12% FiO2 for 3 min) as measured by two-dimensional speckle tracking echocardiography.: After 6 weeks of training, HIIT was superior to MICT in improving maximal oxygen consumption (VO2max). Furthermore, the HIIT group showed reduced pulmonary vascular resistance (PVR, pre-HIIT:1.16 ± 0.05 WU; post-HIIT:1.05 ± 0.05 WU, p < 0.05) as well as an elevated right ventricular ejection fraction (RVEF, pre-HIIT: 59.5 ± 6.0%; post-HIIT: 69.1 ± 2.8%, p < 0.05) during hypoxic exercise, coupled with a significant enhancement of the right atrial (RA) reservoir and conduit functions. HIIT is superior to MICT in dilating RV chamber and reducing radial strain but ameliorating radial strain rate in either systole (post-HIIT: 2.78 ± 0.14 s-1; post-MICT: 2.27 ± 0.12 s-1, p < 0.05) or diastole (post-HIIT: − 2.63 ± 0.12 s-1; post-MICT: − 2.36 ± 0.18 s-1, p < 0.05). In the correlation analysis, the changes in RVEF were directly associated with improved RA reservoir (r = 0.60, p < 0.05) and conduit functions (r = 0.64, p < 0.01) but inversely associated with the change in RV radial strain (r = − 0.70, p < 0.01) and PVR (r = − 0.70, p < 0.01) caused by HIIT. HIIT is superior to MICT in improving right cardiac mechanics by simultaneously increasing RA reservoir and conduit functions and decreasing PVR during hypoxic exercise.

COVID-19 and physical activity in sedentary individuals: differences in metabolic, cardiovascular, and respiratory responses during aerobic exercise performed with and without a surgical face masks.

The Coronavirus-19 (COVID-19) impairs metabolic, cardiovascular, and pulmonary functions in human metabolism, and wearing face masks is recommended for the prevention of contracting or exposing others to cardio-respiratory infections. Since the effect of wearing a surgical face mask (SFM) on cardiopulmonary exercise capacity has not been systematically reported we aimed to determine the effects of wearing SFM during an incremental walking test on metabolic, cardiovascular, and pulmonary gas exchange responses in sedentary individuals. The evaluations were performed using a repeated measures study design. Seven sedentary males (age: 40 years, height: 178 cm, weight: 88 kg, BMI: 28 kg/m2, VO<inf>2max</inf>: 32.7±3.9 mL/kg/min) and 7 sedentary female participants (age: 34 years, height: 169 cm, weight: 62 kg, BMI: 22 kg/m2, VO<inf>2max</inf>: 32.1±6.8 mL/kg/min) volunteered to participate in the current study. Anthropometric parameters were measured using a Bioelectrical impedance analysis prior to each testing session. The measures of lung function assessed by spirometry, breathing pattern, maximal exercise capacity with-and-without mask were measured with a breath-by-breath automated exercise metabolic system during incremental Bruce protocol on a treadmill with two consecutive sessions with 48-h intervals. Blood pressure values (systolic and diastolic pressure) of the individuals were taken and recorded within 1 minute at the end of every ten minutes, without speed changes. VO<inf>2</inf>, VCO<inf>2</inf>, and VE were significantly lower during exercise performed with SFM (P<0.001). Heart rate, systolic and diastolic blood pressure were also found significantly higher during exercise performed with SFM (P<0.01). Wearing a SFM during incremental walking predispose a decrease in oxygen delivery while increasing pulmonary ventilation in sedentary individuals. Thus, it could be speculated that surgical face masks have a negative impact on oxygen delivery during exercise which results in decreased exercise performance due to the restricted ventilatory conditions.

Exercise for affect and enjoyment in overweight or obese males: a comparison of high-intensity interval training and moderate-intensity continuous training

ABSTRACT High-intensity interval training (HIIT) is effective for generating positive cardiovascular health and fitness benefits. This study compared HIIT and moderate-intensity continuous training (MICT) for affective state and enjoyment in sedentary males with overweight or obesity. Twenty-eight participants performed stationary cycling for 6 weeks × 3 sessions/week. Participants were randomly allocated to HIIT (N=16) (10 × 1-minute intervals at ~90% peak heart rate) or MICT (N=12) (30 minutes at 65-75% peak heart rate). Affective state changes were assessed after 6-weeks training. Enjoyment and acute change in affect were assessed after individual training sessions. HIIT participants reported improved positive affect following 6 weeks training (∆ 3.6 ± 4.6, p = 0.007, effect size d = 0.70), without corresponding improvement in negative affect (p = 0.48, d = -0.19). MICT did not induce any improvement in positive affect (p = 0.56, d = 0.16) or negative affect (p = 0.23, d = -0.41). Enjoyment ratings were comparable for both exercise formats (HIIT: 4.4 ± 0.4 on a 7-point scale; MICT: 4.3 ± 0.3; p = 0.70, d = 0.15). Six weeks of HIIT induced improvement in positive affect in sedentary participants with overweight or obesity. Enjoyment of training was only slightly above neutral levels for both training formats. What’s already known about this topic? Exercise training can improve general affect however the optimal exercise characteristics for improving affect are unclear. Studies assessing the relative enjoyment of HIIT in comparison to MICT have largely been equivocal to date. What does this study add? HIIT can improve affective state in males with overweight or obesity. Six weeks of stationary cycling HIIT were rated as only mildly enjoyable, comparable to ratings for MICT.

Endurance training alters motor unit activation strategies for the vastus lateralis, yet sex-related differences and relationships with muscle size remain.

To examine the effects of 10weeks of endurance cycling training on mechanomyographic amplitude (MMGRMS)-torque relationships and muscle cross-sectional area (mCSA) of the vastus lateralis (VL) for 10 sedentary males (Age ± SD; 20.2 ± 1.9years) and 14 sedentary females (21.9 ± 5.3years). Participants performed maximal voluntary contractions (MVCs) and an isometric ramp up muscle action to 70% MVC of the knee extensors before (PRE) and after training at the same absolute pre-treatment submaximal torque (POSTABS). MMG was recorded from the VL and b terms were calculated from the natural log-transformed MMGRMS-torque relationships for each subject. mCSA was determined with ultrasonography. Cycling decreased MVCs from pre- (168.10 ± 58.49 Nm) to post-training (160.78 ± 58.39 Nm; p = 0.005) without changes in mCSA. The b terms were greater for POSTABS (0.623 ± 0.204) than PRE (0.540 ± 0.226; p = 0.012) and for males (0.717 ± 0.171) than females (0.484 ± 0.168; p = 0.003). mCSA was correlated with the b terms for PRE (p < 0.001, r = 0.674) and POSTABS (p = 0.020, r = 0.471). The decrease in MVC and increase in MMGRMS (b terms) post-training suggests increased motor unit (MU) recruitment to match pre-training torques. The greater acceleration in the b terms by males may reflect sex-related differences in fiber-type area. MMGRMS-torque relationships during a high-intensity contraction provided insight on MU activation strategies following endurance training and between sexes. Furthermore, the findings suggest a relationship between MMGRMS and muscle size.