Increasing Exercise Intensity Research Articles

Influence of running on incidental and integral vitality and fatigue: An intensive longitudinal intervention in young Women's daily life.

Exercise intensity and perceived autonomy are important factors for the affective response toward exercise and adherence. Dual-mode theory suggests an inverted-J response curve of affect with increased exercise intensity, but little is known about how different running programs affect the affective response and subsequent incidental affect in daily life. This ambulatory assessment study examines the short- to long-term effects of two 8-week running interventions (affect-based vs. polarized-prescribed) on subjective vitality and perceived fatigue in young female novices. Participants engaged in 3 × 30 minute running sessions weekly in their natural environments and completed electronic diaries three times daily. Autoregressive multilevel models indicate small effects of training intensity on immediate affective subjective vitality (ß = -2.37; p= .03; f2= 0.02) but negligible non-significant effects on fatigue (ß = 0.26; p= 0.12; f2= 0.002). Novices experienced increased vitality throughout the day when their running was evaluated positively (ß = 0.23; p= .03; f2= 0.04), with effects lasting over two days before returning to baseline (ß = -0.26; p< .001; f2= 0.004). However, no significant long-term effects were observed over 8 weeks in vitality or fatigue. Results indicate between- and within-person variations, but limited sample power does not allow differentiating between programs. This study supports the dual-mode theory and highlights the importance of distinguishing affective response from incidental affect.

Understanding optimal cadence dynamics: a systematic analysis of the power-velocity relationship in track cyclists with increasing exercise intensity.

Background: This study aimed to investigate the changes in force-velocity (F/v) and power-velocity (P/v) relationships with increasing work rate up to maximal oxygen uptake and to assess the resulting alterations in optimal cadence, particularly at characteristic metabolic states. Methods: Fourteen professional track cyclists (9 sprinters, 5 endurance athletes) performed submaximal incremental tests, high-intensity cycling trials, and maximal sprints at varied cadences (60, 90, 120rpm) on an SRM bicycle ergometer. Linear and non-linear regression analyses were used to assess the relationship between heart rate, oxygen uptake (V.O2), blood lactate concentration and power output at each pedaling rate. Work rates linked to various cardiopulmonary and metabolic states, including lactate threshold (LT1), maximal fat combustion (FATmax), maximal lactate steady-state (MLSS) and maximal oxygen uptake (V.O2max), were determined using cadence-specific inverse functions. These data were used to calculate state-specific force-velocity (F/v) and power-velocity (P/v) profiles, from which state-specific optimal cadences were derived. Additionally, fatigue-free profiles were generated from sprint data to illustrate the entire F/v and P/v continuum. Results: HR, V.O2 demonstrated linear relationships, while BLC exhibited an exponential relationship with work rate, influenced by cadence (p < 0.05, η2 ≥ 0.655). Optimal cadence increased sigmoidally across all parameters, ranging from 66.18 ± 3.00rpm at LT1, 76.01 ± 3.36rpm at FATmax, 82.24 ± 2.59rpm at MLSS, culminating at 84.49 ± 2.66rpm at V.O2max (p < 0.01, η2 = 0.936). A fatigue-free optimal cadence of 135 ± 11rpm was identified. Sprinters and endurance athletes showed no differences in optimal cadences, except for the fatigue-free optimum (p < 0.001, d = 2.215). Conclusion: Optimal cadence increases sigmoidally with exercise intensity up to maximal aerobic power, irrespective of the athlete's physical condition or discipline. Threshold-specific changes in optimal cadence suggest a shift in muscle fiber type recruitment toward faster types beyond these thresholds. Moreover, the results indicate the need to integrate movement velocity into Henneman's hierarchical size principle and the critical power curve. Consequently, intensity zones should be presented as a function of movement velocity rather than in absolute terms.

Feasibility of Mobile Health App-Based Home Aerobic Exercise for Physical Performance in Healthy Young Adults.

To investigate the feasibility and effects of a mobile app-based home cycling exercise program compared to home cycling exercise without additional monitoring system. Compared with fitness facilities or outdoor exercise, home-based exercise programs effectively improve physical performance in an indwelling community. However, a flexible, informal environment may decrease motivation and impair adherence to physical exercise. Mobile devices for aerobic exercise and mobile applications provide real-time monitoring, immediate feedback, and encouragement to increase motivation and promote physical performance. We investigated the feasibility and effects of a mobile app-based home exercise program on body composition, muscular strength, and cardiopulmonary function. Between February and May 2023, 20 participants were randomly allocated to the intervention (mobile application with a tablet) and control groups, and they performed aerobic exercise using a stationary bicycle for ≥150 minutes per week for 6 weeks (≤30-minute exercise session, with 3-minute warm-up and 3-minute cool-down). Karvonen formula-based heartrate defined the weekly increase in exercise intensity. Outcome measures included body-composition parameters, isokinetic knee flexor and extensor strength tests, cardiopulmonary exercise test results, and rate of target heart rate (HR) achievement. Participants were assessed at baseline and after the intervention. Unrelated personal events led two participants to drop out. The intervention and control groups had similar baseline characteristics. Compared with the control group, in the post-intervention isokinetic strength test, bilateral knee flexor and extensor power, and time to target HR achievement significantly increased each week in the intervention group. Home-based exercise to achieve long-term cardiovascular fitness with portable electronic/mobile devices facilitates individualized exercise using real-time feedback to improve motivation and adherence.

Increasing aerobic exercise intensity fails to consistently improve the glycemic response in people living with prediabetes or type 2 diabetes mellitus: the INTENSITY trial.

Some individuals with prediabetes or type 2 diabetes mellitus (T2DM) who engage in exercise will not experience the anticipated improvements in glycemic control, referred to as non-responders. Increasing exercise intensity may improve the proportion of individuals who become responders. The objectives were to (i) identify responders and non-responders based on changes in glycated hemoglobin (HbA1c) in individuals with prediabetes or T2DM following 16 weeks of aerobic exercise; (ii) investigate if increasing exercise intensity enhances the responders' status for individuals not previously responding favourably to the intervention. Participants (n=40; age=58.0 years (52.0-66.0); HbA1c=7.0% (6.0-7.2)) engaged in a two-phase, randomized study design. During phase one, participants performed 16 weeks of treadmill-based, supervised, aerobic exercise at 4.5 metabolic equivalents (METs) for 150 min per week. Thereafter, participants were categorized as responders, non-responders, or unclear based on the 90% confidence interval above, below, or crossing a 0.3% reduction in HbA1c. For phase two, participants were randomized to a maintained intensity (4.5 METs) or increased intensity (6.0 METs) group for 12 weeks. Following phase one, two (4.1%) participants were categorized as responders, four (8.2%) as non-responders, and 43 (87.7%) as unclear. Following phase two, two from the increased intensity group and one from the maintained intensity group experienced an improvement in response categorization. There were no significant between or within group (maintained vs. increased) differences in HbA1c. For most people with prediabetes or T2DM, increasing exercise intensity by 1.5 METs does not improve response categorization.

Cold Ambient Temperature Does Not Alter Subcutaneous Abdominal Adipose Tissue Lipolysis and Blood Flow in Endurance-Trained Cyclists

This study sought to investigate the effect of cold ambient temperature on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and blood flow during steady-state endurance exercise in endurance-trained cyclists. Ten males (age: 23 ± 3 years; peak oxygen consumption: 60.60 ± 4.84 ml·kg−1·min−1; body fat: 18.4% ± 3.5%) participated in baseline lactate threshold (LT) and peak oxygen consumption testing, two familiarization trials, and two experimental trials. Experimental trials consisted of cycling in COLD (3 °C; 42% relative humidity) and neutral (NEU; 19 °C; 39% relative humidity) temperatures. Exercise consisted of 25 min cycling at 70% LT and 25 min at 90% LT. In situ SCAAT lipolysis and blood flow were measured via microdialysis. Heart rate, core temperature, carbohydrate and fat oxidation, blood glucose, and blood lactate were also measured. Heart rate, core temperature, oxygen consumption, and blood lactate increased with exercise but were not different between COLD and NEU. SCAAT blood flow did not change from rest to exercise or between COLD and NEU. Interstitial glycerol increased during exercise (p &lt; .001) with no difference between COLD and NEU. Fat oxidation increased (p &lt; .001) at the onset of exercise and remained elevated thereafter with no difference between COLD and NEU. Carbohydrate oxidation increased with increasing exercise intensity and was greater at 70% LT in COLD compared to NEU (p = .030). No differences were observed between conditions for any other variable. Cycling exercise increased SCAAT lipolysis but not blood flow. Ambient temperature did not alter SCAAT metabolism, SCAAT blood flow, or fat oxidation in well-trained cyclists, though cold exposure increased whole-body carbohydrate oxidation at lower exercise intensities.

Optimal exercise combinations for patients with diabetes.

Exercise is a key way to control the blood glucose, which can improve blood lipids and blood pressure, reduce glycated hemoglobin levels, and increase insulin sensitivity. It is of great significance for maintaining blood glucose homeostasis. This study aims to explore the optimal exercise combinations suitable for diabetic patients, and to provide scientific and effective personalized exercise guidance for diabetic patients. The physical examination data and questionnaire results of were collected from the Third Xiangya Hospital of Central South University. The study was involved in 3 867 diabetes from January, 2020 to December, 2021. The basic information and living habits were obtained through questionnaires. The fasting blood samples were collected to measure the levels of total cholesterol (TCh), triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and fasting blood glucose. Physical measurements included height, weight, waistline, hipline, and blood pressure. Categorical variables were tested using chi-square tests, and continuous variables were tested using non-parametric Kruskal-Wallis test. Multiple linear regression model was used to analyze the relationship between exercise behaviors (frequency, duration, and intensity), years of exercise, diet habits, medicine, and fasting blood glucose. The relationship between different exercise behaviors and various indexes (BMI, blood pressure, blood lipids, blood glucose) was analyzed by multiple rising sun rose plots. The polar thermal diagram showed the relationship of exercise behaviors with the best expected effect. Non-parametric Kruskal-Wallis test showed that there were significant differences in other indexes except LDL-C (P=0.681) among groups with different exercise behaviors (all P<0.01). The multiple rising sun rose plots showed that diabetic patients who did moderate to high intensity exercise more than 5 times a week for more than 30 min each time had a healthier BMI, blood lipid levels, blood glucose levels, and blood pressure. Polar thermal diagram showed that low-intensity exercise once or twice a week requires 30 to 60 min or more of exercise to achieve the desired results. Multiple linear regression analysis showed that frequency (β=-0.208, 95% CI -0.356 to -0.059, P=0.006), duration (β=-0.227, 95% CI -0.387 to -0.066, P=0.006), intensity of exercise (β=-0.110, 95% CI -0.218 to -0.002, P=0.046), diet habits (β=0.462, 95% CI 0.295 to 0.556, P<0.001) and medicine (β=-0.520, 95% CI -0.720 to -0.312, P<0.001) were correlated with fasting blood glucose. Moderate to high intensity exercise for more than 30 min and 5 times a week is the most beneficial combination for diabetes. Low exercise intensity should be combined with higher exercise frequency and longer exercise time to achieve the desired effect. With the increase of exercise intensity, the relationship between low exercise frequency and long exercise time is weakened.

The intensity-dependent effects of exercise and superimposing environmental heat stress on autophagy in peripheral blood mononuclear cells from older men

We demonstrate that autophagic stimulation occurs in response to short-duration (30-min) vigorous-intensity exercise in peripheral blood mononuclear cells from older adults; however, no changes in autophagy occur during low- or moderate-intensity exercise. Moreover, older adults exhibit autophagic impairments when the same vigorous-intensity exercise is performed in hot ambient conditions. When paired with an attenuated heat shock response, as well as elevated apoptotic responses, older men may exhibit greater cellular vulnerability to exertional heat stress.

Effects of Visual-Motor Illusion via Image Videos Showing Increased Exercise Intensity on the Tibial Anterior during Sit-to-Stand Movement: A Study of Healthy Participants.

Visual-motor illusion (VMI) elicits kinesthetic sensation from visual stimulation. We have previously performed ankle motion VMI with resistance applied to the ankle joint on the paralyzed side (power-VMI (P-VMI)) and ankle motion VMI without resistance (standard-VMI (S-VMI)) to activate the tibialis anterior (TA) muscle in stroke-paralyzed patients and compared sit-to-stand (STS) durations, but these studies did not measure TA activity during the STS movement. The purpose of this study was to evaluate the effects of different intensities of visual stimuli presented during VMI on TA and STS movement. Healthy right-footed adults (n = 18) observed two different VMI videos of ankle dorsiflexion, including S-VMI and P-VMI, with an observation time of 2 min each. STS movement was evaluated before and after watching each video. Each participant performed both S-VMI and P-VMI interventions on the same day. Only P-VMI enhanced the integrated electromyogram of the TA, increased the angular velocities of the trunk forward inclination and the ankle dorsiflexion, and shortened the STS duration. Our results indicate that P-VMI facilitates the activation of TA during STS, and we believe that we have clarified the intervention mechanism of VMI.

Can different variations of suspension exercises provide adequate loads and muscle activations for upper body training?

The purpose of this study was to assess the differences in muscle activation (EMG) and body weight distribution (%BW) between suspension (TRX™ push-up and TRX™ inverted row) and conventional exercises (bench press and lying barbell row) using different contraction types (isometric and isotonic) and position variations (feet on the ground [FG] and feet on suspension device [FD]). It was also used to determine the intensity of the force applied to the straps of the suspension device corresponding to one repetition maximum (1-RM). Twelve male athletes (ages-24.5±4.2 years (mean±standard deviation [SD]); Height-181.0±6.8 cm; body mass-83.08±6.81 kg) participated in this study. Two suspension devices were used, one for the FD variation and one for the FG variation pectoralis major (PM) and triceps brachii (TRI) activations were assessed during the TRX™ push-up and bench press exercises. Transversus trapezius (TRA) and biceps brachii (BB) activations were assessed during the TRX™ inverted row and lying barbell row exercises. The results showed significant differences between exercises (FG and FD variations of TRX™ push-up and bench press) in PM activities (isometric and isotonic) (p≤0.05). However, these differences were only observed during isometric TRI activation (p≤0.05). In the FG and FD variations of the TRX™ inverted row and lying barbell row exercises, there were only differences in the isometric contractions of the TRA and BB (p≤0.05). In the suspension device of push-ups and inverted row for the FD variations, 70.5% and 72.64% of 1-RM intensity were obtained, respectively. Similar responses to training intensities and muscle activations can be obtained in suspension exercises and conventional exercises. FD variations of suspension exercises can be more effective in terms of muscle activations than FG variations, and isotonic suspension exercises increase exercise intensity more than isometric suspension exercises.

Improved physical performance of elite soccer players based on GPS results after 4 days of carbohydrate loading followed by 3 days of low carbohydrate diet.

Carbohydrate loading is an established sports nutrition strategy for endur- 16 ance exercise performance. We tested if carbohydrate loading could improve the performance of 17 elite soccer players under ecologically valid circumstances using Global Positioning System (GPS) data. Twenty-two adult Iran Premier league soccer players were divided into a carbohydrate-loading group (CLG) and Control group (CG). The carbohydrate loading group restricted carbohydrate intake for three days to 1.5 g/kg/d while increasing exercise intensity. From days four to seven, exercise intensity was decreased and carbohydrate intake was considerably increased up to 7.5 g/kg/d on the day of the match, during which performance was analyzed using GPS data. The control group performed the same exercise training but maintained their habitual carbohydrate intake of 5-6 g/kg/d. The data were analyzed using a univariate ANCOVA with baseline data from a pre-intervention match as the control variable. The carbohydrate loading team scored significantly higher on running distance, maximum speed and the number of top and repeated sprints; the carbohydrate loading group scored significantly lower on player load, metabolic power and running imbalance compared to the control team during their match. Our findings suggest carbohydrate loading enabled elite soccer players to achieve greater running outputs with greater metabolic efficiency and lower fatigue compared to their habitual diets.

Soluble RAGE and skeletal muscle tissue RAGE expression profiles in lean and obese young adults across differential aerobic exercise intensities.

Nearly 40% of Americans have obesity and are at increased risk for developing type 2 diabetes. Skeletal muscle is responsible for >80% of insulin-stimulated glucose uptake that is attenuated by the inflammatory milieu of obesity and augmented by aerobic exercise. The receptor for advanced glycation endproducts (RAGE) is an inflammatory receptor directly linking metabolic dysfunction with inflammation. Circulating soluble isoforms of RAGE (sRAGE) formed either by proteolytic cleavage (cRAGE) or alternative splicing (esRAGE) act as decoys for RAGE ligands, thereby counteracting RAGE-mediated inflammation. We aimed to determine if RAGE expression or alternative splicing of RAGE is altered by obesity in muscle, and whether acute aerobic exercise (AE) modifies RAGE and sRAGE. Young (20-34 yr) participants without [n = 17; body mass index (BMI): 22.6 ± 2.6 kg/m2] and with obesity (n = 7; BMI: 32.8 ± 2.9 kg/m2) performed acute aerobic exercise (AE) at 40%, 65%, or 80% of maximal aerobic capacity (V̇o2max; mL/kg/min) on separate visits. Blood was taken before and 30 min after each AE bout. Muscle biopsy samples were taken before, 30 min, and 3 h after the 80% V̇o2max AE bout. Individuals with obesity had higher total RAGE and esRAGE mRNA and RAGE protein (P < 0.0001). In addition, RAGE and esRAGE transcripts correlated to transcripts of the NF-κB subunit P65 (P < 0.05). There was no effect of AE on total RAGE or esRAGE transcripts, or RAGE protein (P > 0.05), and AE tended to decrease circulating sRAGE in particular at lower intensities of exercise. RAGE expression is exacerbated in skeletal muscle with obesity, which may contribute to muscle inflammation via NF-κB. Future work should investigate the consequences of increased skeletal muscle RAGE on the development of obesity-related metabolic dysfunction and potential mitigating strategies.NEW & NOTEWORTHY This study is the first to investigate the effects of aerobic exercise intensity on circulating sRAGE isoforms, muscle RAGE protein, and muscle RAGE splicing. sRAGE isoforms tended to diminish with exercise, although this effect was attenuated with increasing exercise intensity. Muscle RAGE protein and gene expression were unaffected by exercise. However, individuals with obesity displayed nearly twofold higher muscle RAGE protein and gene expression, which positively correlated with expression of the P65 subunit of NF-κB.

Effect of gait on, and repeatability of heart rate and heart rate variability measurements in exercising Warmblood dressage horses

Abstract Heart rate variability (HRV) is a non-invasive measurement of the balance between the sympathetic and parasympathetic innervation to the myocardium. Used as an indicator of health, welfare and fitness level, its measurement during exercise has been suggested to be helpful in sport horses. The aims of this study were to assess the within- and between-day repeatability of time-domain HRV-measurements during exercise, and to evaluate the effect of gait (as a factor of increasing exercise intensity) on HRV. Heart rate (HR), root mean square of successive differences (RMSSD) between normal heartbeats and the standard deviation of normal (R-R) intervals (SDNN) were assessed during a standardised exercise test (SET) on five consecutive days in a sample of 21 healthy Warmblood dressage horses. All variables showed good between-day repeatability (Spearman’s rank correlation coefficient), while only RMSSD showed reliable within-day repeatability (Wilcoxon signed-rank test). Increase of exercise intensity was significantly associated with increased HR and decreased RMSSD and SDNN, with a negative correlation between HR and the two HRV-measurements. HR and HRV values varied significantly with intensity of exercise (rest, walk, trot, canter and whole SET), though HRV at rest was not different to that at walk, and HRV at trot was not different to that at canter. In conclusion, the results of this study support the use and show the repeatability of time-domain HRV-measurements during exercise in Warmblood dressage horses. Further investigation for use of HRV in other equestrian disciplines, levels and health state is warranted.

Validation of Wearable Digital Devices for Heart Rate Measurement During Exercise Test in Patients With Coronary Artery Disease.

To assess the accuracy of recently commercialized wearable devices in heart rate (HR) measurement during cardiopulmonary exercise test (CPX) under gradual increase in exercise intensity, while wearable devices with HR monitors are reported to be less accurate in different exercise intensities. CPX was performed for patients with coronary artery disease (CAD). Twelve lead electrocardiograph (ECG) was the gold standard and Apple watch 7 (AW7), Galaxy watch 4 (GW4) and Bio Patch Mobicare 200 (MC200) were applied for comparison. Paired absolute difference (PAD), mean absolute percentage error (MAPE) and intraclass correlation coefficient (ICC) were evaluated for each device. Forty-four participants with CAD were included. All the devices showed MAPE under 2% and ICC above 0.9 in rest, exercise and recovery phases (MC200=0.999, GW4=0.997, AW7=0.998). When comparing exercise and recovery phase, PAD of MC200 and AW7 in recovery phase were significantly bigger than PAD of exercise phase (p<0.05). Although not significant, PAD of GW4 tended to be bigger in recovery phase, too. Also, when stratified by HR 20, ICC of all the devices were highest under HR of 100, and ICC decreased as HR increased. However, except for ICC of GW4 at HR above 160 (=0.867), all ICCs exceeded 0.9 indicating excellent accuracy. The HR measurement of the devices validated in this study shows a high concordance with the ECG device, so CAD patients may benefit from the devices during high-intensity exercise under conditions where HR is measured reliably.

Effects of a Multicomponent Exercise and Therapeutic Lifestyle (CERgAS) Intervention on Gait Function in Lower-Income Urban-Dwelling Older Adults: A Cluster Randomized Controlled Trial.

This study aims to determine the effectiveness of a multicomponent exercise and therapeutic lifestyle (CERgAS) intervention at improving gait speed among older people in an urban poor setting in Malaysia. A total of 249 participants were divided into the intervention (n = 163) and control (n = 86) groups. The mean (SD) age of participants was 67.83 (6.37) and consisted of 88 (35.3%) males and 161 (64.7%) females. A generalized estimating equation with an intention-to-treat analysis was used to measure gait speed at four time points, baseline (T0), 6weeks (T1), 3months postintervention (T2), and 6months postintervention (T3). The results showed significant changes for time between T0 and T3 (mean difference = 0.0882, p = .001), whereas no significant association were found for group (p = .650) and interaction (p = .348) effects. A 6-week intervention is inadequate to improve gait speed. Future efforts should introduce physical activity monitoring and increase exercise duration, frequency, and intensity.

Acidosis attenuates CPT-I-supported bioenergetics as a potential mechanism limiting lipid oxidation

Fuel interactions in contracting muscle represent a complex interplay between enzymes regulating carbohydrate and fatty acid catabolism, converging in the mitochondrial matrix. While increasing exercise intensity promotes carbohydrate use at the expense of fatty acid oxidation, the mechanisms underlying this effect remain poorly elucidated. As a potential explanation, we investigated whether exercise-induced reductions in intramuscular pH (acidosis) attenuate carnitine palmitoyltransferase-I (CPT-I)-supported bioenergetics, the rate-limiting step for fatty acid oxidation within mitochondria. Specifically, we assessed the effect of a physiologically relevant reduction in pH (pH 7.2 versus 6.8) on single and mixed substrate respiratory responses in murine skeletal muscle isolated mitochondria and permeabilized fibers. While pH did not influence oxidative phosphorylation stoichiometry (ADP/O ratios), coupling efficiency, oxygen affinity, or ADP respiratory responses, acidosis impaired lipid bioenergetics by attenuating respiration with L-carnitine and palmitoyl-CoA, while enhancing the inhibitory effect of malonyl-CoA on CPT-I. These acidotic effects were largely retained following a single bout of intense exercise. At rest, pyruvate and succinate-supported respiration were also impaired by acidosis. However, providing more pyruvate and ADP at pH 6.8 to model increases in glycolytic flux and ATP turnover with intense exercise overcame the acidotic attenuation of carbohydrate-linked oxidative phosphorylation. Importantly, this situation is fundamentally different from lipids where CPT-I substrate sensitivity and availability is impaired at higher power outputs suggesting lipid metabolism may be more susceptible to the effects of acidosis, possibly contributing to fuel shifts with increasing exercise intensity.

Effects of sturgeon fillet intake on top-ranked Japanese female long-distance runners.

The aim of this study is to investigate whether consumption of sturgeon fillets reduces the oxidative stress marker urinary 8-hydroxy-2'-deoxyguanosine (8OHdG) in top-ranked Japanese female long-distance runners. In a before-and-after study, nine professional long-distance female athletes ate 100 g/day of sturgeon fillets for 2 weeks. Urinalysis (8OHdG, an oxidative stress marker, and creatinine), blood tests (fatty acids and 25-hydroxyvitamin D [25OHD]), exercise intensity, subjective fatigue, muscle elasticity, muscle mass, body fat mass, and nutritional intake using image-based dietary assessment (IBDA) were compared before, immediately after, and 1 month after the intervention. Consumption of sturgeon fillets suppressed 8OHdG (p < 0.05) in the increased exercise intensity female athletes. Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and 25OHD levels in blood increased from before to immediately after and 1 month after the intervention (p < 0.05). IBDA showed that intake of n-3 fatty acid increased after and one month after the intervention, whereas DHA, imidazole dipeptide and vitamin D intake increased after the intervention (p < 0.05) and then decreased after 1 month (p < 0.05). There were no significant changes in subjective fatigue, muscle elasticity, muscle mass, and body fat. The results suggest that eating sturgeon fillets during intense training may increase blood levels of EPA, DHA, and 25OHD, which may suppress urinary oxidative stress (8OHdG) in top-ranked Japanese long-distance runners.

The talk test as a useful tool to monitor aerobic exercise intensity in healthy population.

The talk test (TT) is subjective method to measure exercise intensity in costless and feasible manner, compared to sophisticated laboratory equipment. We attempted to investigate whether the TT was a valid method for evaluation of exercise intensity, by comparing with values derived from various physiologic markers during cardiopulmonary exercise testing on treadmill in healthy population. A total of 17 healthy subjects (12 males and 5 females) participated in this study. The TT was applied, which consisted of 3-stages difficulties demanding respiratory load while they performed the cardiopulmonary exercise testing on treadmill. In each of the TT stages, ergospirometric and psychophysiologic response marker were collected such as heart rate, oxygen consumption, respiratory exchange ratio, minute ventilation, carbon dioxide output, tidal volume, respiratory rate, and rating of perceived exertion of breathing. Statistical analyses revealed a significant difference of all dependent variables in each of three TT stages, comparing with the resting phase before the TT. The TT showed strong correlation coefficient with all variables except for rating of perceived exertion during the resting phase before the TT. According to increase of exercise intensity, all dependent variables showed a linear tendency with the stages of the TT. Our findings indicated that each of the TT stages was strongly correlated with ergospirometric variables as well as psychophysiologic response during cardiopulmonary exercise testing on treadmill. We suggested that the TT can be used to evaluate and prescribe exercise intensity of aerobic activity in cardiovascular and pulmonary rehabilitation settings.

Sustained exercise load by young adult females while wearing surgical mask raises core body temperature measured with zero-heat-flux thermometer.

When a pandemic such as that caused by the novel coronavirus disease termed COVID-19 emerges, it is recommended to wear a mask when in public situations, with information regarding the impact on thermoregulation essential, especially during exercise or hard physical labor. The present study investigated changes in core body temperature (CBT) while wearing a surgical mask (SM) during exercise (TCBT) using a non-invasive zero-heat-flux (ZHF) thermometer. Nine young adult females performed ergometer exercise for 30min at 60 W with (mask group) and without (control) a SM under a non-hot condition, shown by wet bulb globe temperature (WBGT) findings. TCBT, mean skin temperature (TMST), heart rate (HR), and humidity in the perioral region of the face (%RH) were determined. Each of those markers showed increased values during exercise, with the increases in TCBT, HR, and %RH, but not TMST, during exercise found to be significantly greater in the mask group. HR reserve (%HRR), derived as load intensity during exercise, was also significantly higher in the mask group. Each subject completed all of the experimental protocols without noting pain or discomfort. These results suggest that wearing a SM while performing mild exercise contributes to increased TCBT associated with increased exercise intensity, expressed as %HRR in a non-heated condition. Furthermore, the ZHF thermometer was shown to be safe and is considered useful for conducting such studies. Additional examinations will be necessary to examine gender and age group differences, as well as the use of different exercise methods and intensity and ambient conditions.

Respiratory Rate Estimation during Walking and Running Using Breathing Sounds Recorded with a Microphone.

Emerging evidence suggests that respiratory frequency (fR) is a valid marker of physical effort. This has stimulated interest in developing devices that allow athletes and exercise practitioners to monitor this vital sign. The numerous technical challenges posed by breathing monitoring in sporting scenarios (e.g., motion artifacts) require careful consideration of the variety of sensors potentially suitable for this purpose. Despite being less prone to motion artifacts than other sensors (e.g., strain sensors), microphone sensors have received limited attention so far. This paper proposes the use of a microphone embedded in a facemask for estimating fR from breath sounds during walking and running. fR was estimated in the time domain as the time elapsed between consecutive exhalation events retrieved from breathing sounds every 30 s. Data were collected from ten healthy subjects (both males and females) at rest and during walking (at 3 km/h and 6 km/h) and running (at 9 km/h and 12 km/h) activities. The reference respiratory signal was recorded with an orifice flowmeter. The mean absolute error (MAE), the mean of differences (MOD), and the limits of agreements (LOAs) were computed separately for each condition. Relatively good agreement was found between the proposed system and the reference system, with MAE and MOD values increasing with the increase in exercise intensity and ambient noise up to a maximum of 3.8 bpm (breaths per minute) and -2.0 bpm, respectively, during running at 12 km/h. When considering all the conditions together, we found an MAE of 1.7 bpm and an MOD ± LOAs of -0.24 ± 5.07 bpm. These findings suggest that microphone sensors can be considered among the suitable options for estimating fR during exercise.

Prediction of oxygen uptake kinetics during heavy-intensity cycling exercise by machine-learning analysis.

Non-intrusive estimation of oxygen uptake (V̇O2) is possible with wearable sensor technology and artificial intelligence. V̇O2 kinetics have been accurately predicted during moderate exercise using easy-to-obtain sensor inputs. However, V̇O2 prediction algorithms for higher intensity exercise with inherent nonlinearities are still being refined. The purpose of this investigation was to test if a machine learning model can accurately predict dynamic V̇O2 across exercise intensities, including slower V̇O2 kinetics normally observed during heavy- compared to moderate-intensity exercise. Fifteen young healthy adults (7 females; peak V̇O2: 42±5 mL·min-1·kg-1) performed three different pseudorandom binary sequence (PRBS) exercise tests ranging in intensity from low-to-moderate, low-to-heavy, and ventilatory threshold-to-heavy work rates. A temporal convolutional network was trained to predict instantaneous V̇O2, with model inputs including heart rate, percent heart rate reserve, estimated minute ventilation, breathing frequency, and work rate. Frequency domain analyses between V̇O2 and work rate were used to evaluate measured and predicted V̇O2 kinetics. Predicted V̇O2 had low bias (-0.017 L·min-1, 95% limits of agreement: [-0.289, 0.254]), and was very strongly correlated (rrm=0.974, p<0.001) with the measured V̇O2. The extracted indicator of kinetics, mean normalized gain (MNG), was not different between predicted and measured V̇O2 responses (main effect: p=0.374, ηp2=0.01), and decreased with increasing exercise intensity (main effect: p<0.001, ηp2=0.64). Predicted and measured V̇O2 kinetics indicators were moderately correlated across repeated measurements (MNG: rrm=0.680, p<0.001). Therefore, the temporal convolutional network accurately predicted slower V̇O2 kinetics with increasing exercise intensity, enabling non-intrusive monitoring of cardiorespiratory dynamics across moderate- and heavy-exercise intensities.