High-intensity Interval Training Cycling Research Articles

Effects of Omega-3 Supplementation on the Delayed Onset Muscle Soreness after Cycling High Intensity Interval Training in Overweight or Obese Males

People with overweight or obesity preferred high-intensity interval training (HIIT) due to the time-efficiency and pleasure. However, HIIT leads to delayed onset muscle soreness (DOMS). The present study aimed to investigate the effects of omega-3 supplementation on DOMS, muscle damage, and acute inflammatory markers induced by cycling HIIT in untrained males with overweight or obesity. A randomized, double-blinded study was used in the present study. Twenty-four males with a sedentary lifestyle were randomly assigned to either receive omega-3 (O3) (4 g fish oil) or placebo (Con). Subjects consumed the capsules for 4 weeks and performed cycling HIIT at the 4th week. After 4 weeks-intervention, the omega-3 index of O3 group increased by 52.51% compared to the baseline. All subjects performed HIIT at 4th week. The plasma creatine kinase (CK) level of Con group increased throughout 48h after HIIT. While the CK level of O3 group increased only immediately and 24h after HIIT and decreased at 48h after HIIT. The white blood cell count (WBC) of Con group increased immediately after the HIIT, while O3 group did not show such increase. There was no change of CRP in both groups. O3 group had a higher reduction of calf pain score compared to Con group. O3 group also showed a recovery of leg strength faster than Con group. Omega-3 supplementation for 4 weeks lower increased CK level, reduced calf pain score, and recovery leg strength, DOMS markers after cycling HIIT.

Effects of a Cycling versus Running HIIT Program on Fat Mass Loss and Gut Microbiota Composition in Men with Overweight/Obesity.

High-intensity interval training (HIIT) can efficiently decrease total and (intra-)abdominal fat mass (FM); however, the effects of running versus cycling HIIT programs on FM reduction have not been compared yet. In addition, the link between HIIT-induced FM reduction and gut microbiota must be better investigated. The aim of this study was to compare the effects of two 12-wk HIIT isoenergetic programs (cycling vs running) on body composition and fecal microbiota composition in nondieting men with overweight or obesity. Sixteen men (age, 54.2 ± 9.6 yr; body mass index, 29.9 ± 2.3 kg·m -2 ) were randomly assigned to the HIIT-BIKE (10 × 45 s at 80%-85% of maximal heart rate, 90-s active recovery) or HIIT-RUN (9 × 45 s at 80%-85% of maximal heart rate, 90-s active recovery) group (3 times per week). Dual-energy x-ray absorptiometry was used to determine body composition. Preintervention and postintervention fecal microbiota composition was analyzed by 16S rRNA gene sequencing, and diet was controlled. Overall, body weight, and abdominal and visceral FM decreased over time ( P < 0.05). No difference was observed for weight, total body FM, and visceral FM between groups (% change). Conversely, abdominal FM loss was greater in the HIIT-RUN group (-16.1% vs -8.3%; P = 0.050). The α-diversity of gut microbiota did not vary between baseline and intervention end and between groups, but was associated with abdominal FM change ( r = -0.6; P = 0.02). The baseline microbiota profile and composition changes were correlated with total and abdominal/visceral FM losses. Both cycling and running isoenergetic HIIT programs improved body composition in men with overweight/obesity. Baseline intestinal microbiota composition and its postintervention variations were correlated with FM reduction, strengthening the possible link between these parameters. The mechanisms underlying the greater abdominal FM loss in the HIIT-RUN group require additional investigations.

High-protein diet with immediate post-exercise protein drink: Impact on appetite in middle-aged obesity

Successful management of obesity can be challenging if individuals constantly experience cravings. The present study investigated the effects of a high-protein diet, including a high-protein drink consumed immediately after high-intensity interval training (HIIT), on appetite and weight loss in obese middle-aged individuals. A total of 52 obese middle-aged individuals (58.2 ± 4.11 years old) were randomly assigned to one of three groups: the exercise group (E, n=19), exercise and high-protein diet group (ED, n=21), and a control group (n=12). The E and ED groups engaged in cycling HIIT (comprising 90 % of peak heart rate (HRpeak) for 3 min, followed by 70 % of HRpeak for 3 min, for a total of 5 cycles) three times a week for 3 months. The ED group consumed a high-protein drink immediately after HIIT and had a daily protein intake of 1.6g/kg. Body composition and eating behavior were assessed before and after the intervention. Additionally, appetite levels were measured before and after each exercise session, before dinner, and before bedtime during three phases of the intervention: the first phase (weeks 3-4), the second phase (weeks 5-8), and the third phase (weeks 9-12). Results showed that only the ED group experienced a decrease in body mass index (from 27.4 ± 4.28 to 26.8 ± 4.09 kg/m2, p=0.04). Appetite significantly increased after exercise in both E and ED groups (p values for the three phases ranged from 0.04 to 0.001 for the E group and from 0.042 to 0.003 for the ED group). The desire to eat significantly increased after exercise in the E group (phase 1: p = 0.026; phase 2: p = 0.011; phase 3: p = 0.003), but not in the ED group. Furthermore, the frequency of late-night snacking decreased in the ED group (the score changed from 2.4 ± 0.86 to 2.7 ± 0.80, p = 0.034). Notably, the E group tended to have a higher pre-dinner appetite score than the ED group in the third phase (p = 0.063). In summary, a high daily protein intake, combined with the consumption of high-protein drinks after exercise, resulted in reduced post-exercise appetite and a decrease in the frequency of late-night snacking.

Effect of High-intensity Interval Training Session Timing on Inflammatory Biomarkers in Overweight and Obese Individuals with Different Chronotypes

Background: Global attention on obesity prevention emphasizes cost-effective strategies, particularly physical activity. Evaluating chronobiological influences is crucial for effective treatment plans. Noncommunicable disease management requires a nuanced approach to address this pervasive health concern. Objective: This study aims to determine the effect of chronotype-based high-intensity interval training (HIIT) on inflammatory biomarkers among overweight and obese individuals. Methods: This experimental study, involving 58 obese adults, utilized pretest and post-test evaluations. Participants, aged 31.65 ± 9.1 years with a mean BMI of 29.04 ± 4.04, underwent 12 weeks of cycling HIIT (10 sec on/10 sec off) thrice weekly. Pre- and post-training venous blood samples were collected, centrifuged, and stored at -80°C. Outcome measures included metabolic, inflammatory biomarkers, and anthropometric data. Result: The findings of this study demonstrate that there is a significant difference in metabolic variables such as fasting sugar, fasting insulin, 3.7%, 27% (p=0.00), and IL6 5.7% (p=0.00) levels between the chronotype-based exercise session group (CBES) and non chronotype based exercise session group (NCBES). Anthropometric and other inflammatory variables, such as Tumor necrosis factor alpha (TNF -alpha) and high sensitive C-reactive protein (hs CRP), showed no significant differences between groups. Conclusion: The study concluded that chronotype-based HIIT is effective on metabolic markers but not on inflammatory markers in obese individuals.

Should I Rest or Should I Go Now? A Randomized Cross-Over Trial Comparing Fixed and Self-Selected Rest Durations in High-Intensity Interval Training Cycling Sessions

BackgroundIn high-intensity interval training (HIIT), the rest durations between intervals are commonly prescribed using a fixed approach (e.g., 30 s between intervals). An alternative is the self-selected (SS) approach, in which trainees select their resting durations. Studies comparing the two approaches report mixed results. However, in these studies, trainees in the SS condition rested for as little or as long as they wished, leading to dissimilar total rest durations between conditions. Here, for the first time, we compare the two approaches while controlling for total rest duration.MethodsTwenty-four amateur adult male cyclists completed a familiarization session, followed by two counterbalanced cycling HIIT sessions. Each session was composed of nine, 30-s intervals, in which the goal was to accumulate as many watts as possible on an SRM ergometer. In the fixed condition, cyclists rested for 90 s between intervals. In the SS condition, cyclists had 720 s (i.e., 8 × 90 s) of rest to allocate in any way they wished. We measured and compared watts, heart rate, electromyography of the knee flexors and extensors, rating of perceived effort and fatigue, perception of autonomy and enjoyment. Additionally, a subsample of ten cyclists completed a retest of the SS condition.ResultsWith the exception of perception of autonomy, which was higher in the SS condition, outcomes were highly similar in both conditions. For example, the average aggregated differences were: 0.57 (95% CI − 8.94, 10.09) for watts; − 0.85 (95% CI − 2.89, 1.18) for heart rate; and 0.01 (95% CI − 0.29, 0.30) for rating of perceived effort (on a 0–10 scale). Additionally, the retest of the SS condition resulted in a similar rest allocation pattern across the intervals and in similar outcomes.ConclusionGiven the similarities in performance, physiological and psychological outcomes between the fixed and SS conditions, both can be equally utilized based on coaches’ and cyclists’ preferences and training goals.

Adding High-Intensity Interval Training to Classical Resistance Training Does Not Impede the Recovery from Inactivity-Induced Leg Muscle Weakness.

Inactivity is known to induce muscle weakness, and chronically increased levels of reactive oxygen species (ROS) are proposed to have a central causative role in this process. Intriguingly, high-intensity interval training (HIIT), which involves bursts of high ROS production, can have positive effects in pathological conditions with chronically increased ROS. Here, young male volunteers were exposed to 3 weeks of unloading of the dominant leg followed by 3 weeks of resistance training without (Ctrl group) or with the addition of all-out cycling HIIT. Changes in muscle thickness were assessed by ultrasonography, and contractile function was studied by measuring the torque during maximal voluntary contractions (MVC). The results show an ~6% decrease in vastus lateralis thickness after the unloading period, which was fully restored after the subsequent training period in both the Ctrl and HIIT groups. MVC torque was decreased by ~11% after the unloading period and recovered fully during the subsequent training period in both groups. All-out cycling performance was improved by the 3 weeks of HIIT. In conclusion, the decline in muscle size and function after 3 weeks of unloading was restored by 3 weeks of resistance training regardless of whether it was combined with HIIT.

Adding Vibration During Varied-Intensity Work Intervals Increases Time Spent Near Maximal Oxygen Uptake in Well-Trained Cyclists.

Previous research suggests that the percentage of maximal oxygen uptake attained and the time it is sustained close to maximal oxygen uptake (eg,>90%) can serve as a good criterion to judge the effectiveness of a training stimulus. The aim of this study was to investigate the acute effects of adding vibration during varied high-intensity interval training (HIIT) sessions on physiological and neuromuscular responses. Twelve well-trained cyclists completed a counterbalanced crossover protocol, wherein 2 identical varied HIIT cycling sessions were performed with and without intermittent vibration to the lower-intensity workloads of the work intervals (6 × 5-min work intervals and 2.5-min active recovery). Each 5-minute work interval consisted of 3 blocks of 40seconds performed at 100% of maximal aerobic power interspersed with 60-second workload performed at a lower power output, equal to the lactate threshold plus 20% of the difference between lactate threshold and maximal aerobic power. Oxygen uptake and electromyographic activity of lower and upper limbs were recorded during all 5-minute work intervals. Adding vibration induced a longer time ≥90% maximal oxygen uptake (11.14 [7.63] vs 8.82 [6.90] min, d = 0.64, P = .048) and an increase in electromyographic activity of lower and upper limbs during the lower-intensity workloads by 20% (16%) and 34% (43%) (d = 1.09 and 0.83; P = .03 and .015), respectively. Adding vibration during a varied HIIT session increases the physiological demand of the cardiovascular and neuromuscular systems, indicating that this approach can be used to optimize the training stimulus of well-trained cyclists.

The physiological, perceptual and neuromuscular responses of team sport athletes to a running and cycling high intensity interval training session

PurposeThe acute physiological, perceptual and neuromuscular responses to volume-matched running and cycling high intensity interval training (HIIT) were studied in team sport athletes.MethodsIn a randomized cross-over design, 11 male team sport players completed 3 × 6 min (with 5 min between sets) repeated efforts of 15 s exercising at 120% speed (sdot{text{V}}O2max) or power (pdot{text{V}}O2max) at dot{text{V}}O2max followed by 15 s passive recovery on a treadmill or cycle ergometer, respectively.ResultsAbsolute mean dot{text{V}}O2 (ES [95% CI] = 1.46 [0.47–2.34], p < 0.001) and heart rate (ES [95% CI] = 1.53 [0.53–2.41], p = 0.001) were higher in running than cycling HIIT. Total time at > 90% dot{text{V}}O2max during the HIIT was higher for running compared to cycling (ES [95% CI] = 1.21 [0.26–2.07], p = 0.015). Overall differential RPE (dRPE) (ES [95% CI] = 0.55 [− 0.32–1.38], p = 0.094) and legs dRPE (ES [95% CI] = − 0.65 [− 1.48–0.23], p = 0.111) were similar, whereas breathing dRPE (ES [95% CI] = 1.01 [0.08–1.85], p = 0.012) was higher for running. Maximal isometric knee extension force was unchanged after running (ES [95% CI] = − 0.04 [− 0.80–0.8], p = 0.726) compared to a moderate reduction after cycling (ES [95% CI] = − 1.17 [− 2.02–0.22], p = 0.001).ConclusionCycling HIIT in team sport athletes is unlikely to meet the requirements for improving run-specific metabolic adaptation but might offer a greater lower limb neuromuscular load.

Comparison of the acute physiological and perceptual responses between resistance-type and cycling high-intensity interval training.

Purpose: The purpose of the present study was to compare the acute physiological and perceptual responses between resistance-type high-intensity interval training (R-HIIT)and cycling high-intensity interval training (C-HIIT). Methods: Twelve healthy and active men randomly performed C-HIIT and R-HIIT. The C-HIIT protocol was performed on a cycle ergometer and consisted of ten 60 s working intervals at 90% PPO separated by a 60 s active recovery at 25% PPO. The R-HIIT protocol consisted of ten 60 s working intervals (barbell back squat with a load of 20% bodyweight, maximum 30 reps) separated by 60 s passive recovery period in an unloaded standing position. Oxygen consumption (O2), heart rate (HR), energy expenditure (EE) and rating of perceived exertion (RPE) were measured during exercise. Blood lactate concentration (Blac), serum testosterone and cortisol, and heart rate variability (HRV) were measured before and after exercise. Results: Peak (p < 0.05) and average O2 (p < 0.001), aerobic (p < 0.001) and total EE (p < 0.05) were higher during C-HIIT compared to R-HIIT. Blac after exercise (p < 0.05) and anaerobic glycolytic EE (p < 0.05) during exercise were higher in R-HIIT compared to C-HIIT. No differences (p > 0.05) in peak and average HR, serum testosterone and cortisol, HRV, and RPE responses were observed between C-HIIT and R-HIIT. Conclusion: The R-HIIT protocol can elicit similar cardiovascular, hormones, and perceptual responses as C-HIIT but with a higher contribution to the anaerobic glycolysis energy system. In contrast, C-HIIT is superior to R-HIIT for increasing oxygen consumption during exercise. Therefore, the two types of HIIT may lead to different metabolic and neuromuscular adaptations.

High-Intensity Interval Training with Cycling and Calisthenics: Effects on Aerobic Endurance, Critical Power, Sprint and Maximal Strength Performance in Sedentary Males

TABATA protocol is considered to be one of the most effective strategies among high-intensity interval training (HIIT) methods. A limited number of studies have compared the chronic effects of cycling-based and calistenic HIIT in TABATA-type. The aim of this study was to compare the chronic effects of a 8-week TABATA-type calisthenic high-intensity interval and high-intensity interval in cycling on aerobic endurance, sprint and maximal strength performance in sedentary men. 17 sedentary males participated in our study. Participants were randomly divided into calisthenic HIIT (n=9) and cycling HIIT (n=8) groups. Training groups were given 3-sessions of exercise per week on non-consecutive days for 8 weeks. Before and after the 8-week training, the body mass, body mass index, fat percentage, 30-m sprint, 1-repetition maximal strength, aerobic power and critical power levels of the participants were determined. No statistically significant different was observed in body mass (p=0.917), body mass index (p=0.928), and body fat ratio (p=0.980) in both training groups. However, both training groups achieved statistically significant improvements in peak power output (p=0.017), maximal oxygen consumption (p=0.040) and critical power (p=0.048), and there was no significant difference in the level of improvement between the groups (p&gt;0.05). There was no statistically significant difference in 1 repetition maximal strength and sprint values of both training groups (p&lt;0.05). TABATA type HIIT performed calistenic provides chronic effects similar to that of interval cycling form.

534-P: Sustained Improvement of Whole-Body Oxidative Capacity but Not Insulin Sensitivity after Detraining of People with Type 2 Diabetes

High-intensity interval training (HIIT) improves skeletal muscle mitochondrial oxidative capacity in humans with different degrees of insulin sensitivity, whereas it increases insulin sensitivity along with number of circulating small extracellular vesicle (SEV) mainly in insulin resistant individuals with or without T2D (T2D, IR) . In order to examine the sustainability of metabolic effects induced by HIIT, this study tested whether the observed effects on insulin sensitivity, oxidative capacity and SEV number remain and/or differ between insulin sensitive (IS) , IR and T2D humans. Twenty T2D and age- and BMI-matched IR and 12 IS individuals (HbA1c in %: 7.2±0.2, 5.4±0.1, 5.4±0.1; M-value in mg*kg-1*min-1: 3.0±0.4, 4.2±0.4, 7.4±0.4) performed a 12-week HIIT cycling protocol for 3 d/week. Whole-body insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps, physical fitness (VO2max) by spiroergometry and myocellular pathways of insulin sensitivity by immunoblotting of muscle biopsies at baseline, 72 h after the last HIIT bout and 4 weeks (detraining) later. SEV were isolated from serum by size exclusion chromatography. Compared to HIIT, insulin sensitivity decreased in T2D after detraining (p&amp;lt;0.01) , instead VO2max decreased in T2D and IR (p&amp;lt;0. and p&amp;lt;0.05) , although it remained higher than baseline (p&amp;lt;0.0 and p=0.05) . Of note, HIIT-induced reduction of the nuclear factor-κB protein (p&amp;lt;0.vs. baseline) disappeared in IR after detraining, whereas decreased protein kinase Cε activity was sustained in T2D (p&amp;lt;0.vs. HIIT and p&amp;lt;0.vs. baseline) , who also showed higher circulating SEV number (p&amp;lt;0.vs. baseline) . In conclusion, HIIT-induced increases in physical fitness and SEV number, but not insulin sensitivity are maintained at least after short-term detraining in T2D. Characterization of SEV cargo might help to better understand the differences in metabolic responses to detraining in individuals with and without T2D Disclosure L.Mastrototaro: None. J.Szendroedi: Advisory Panel; Boehringer Ingelheim International GmbH. M.Roden: Advisory Panel; Eli Lilly and Company, Research Support; Boehringer Ingelheim International GmbH, Nutricia, Speaker's Bureau; Novo Nordisk. M.Apostolopoulou: n/a. N.Saatmann: None. C.Granata: None. S.Hartwig: None. Y.Karusheva: None. S.Gancheva: None. S.Lehr: None. H.Al-hasani: Consultant; Bayer AG.

Acute High-Intensity Interval Exercise Modulates Corticospinal Excitability in Older Adults.

Acute exercise can modulate the excitability of the nonexercised upper limb representation in the primary motor cortex (M1). Measures of M1 excitability using transcranial magnetic stimulation (TMS) are modulated after various forms of acute exercise in young adults, including high-intensity interval training (HIIT). However, the impact of HIIT on M1 excitability in older adults is currently unknown. Therefore, the purpose of the current study was to investigate the effects of lower limb cycling HIIT on bilateral upper limb M1 excitability in older adults. We assessed the impact of acute lower limb HIIT or rest on bilateral corticospinal excitability, intracortical inhibition and facilitation, and interhemispheric inhibition of the nonexercised upper limb muscle in healthy older adults (mean age 66 ± 8 yr). We used single and paired-pulse TMS to assess motor evoked potentials, short-interval intracortical inhibition, intracortical facilitation, and the ipsilateral silent period. Two groups of healthy older adults completed either HIIT exercise or seated rest for 23 min, with TMS measures performed before (T0), immediately after (T1), and 30 min after (T2) HIIT/rest. Motor evoked potentials were significantly increased after HIIT exercise at T2 compared with T0 in the dominant upper limb. Contrary to our hypothesis, we did not find any significant change in short-interval intracortical inhibition, intracortical facilitation, or ipsilateral silent period after HIIT. Our findings demonstrate that corticospinal excitability of the nonexercised upper limb is increased after HIIT in healthy older adults. Our results indicate that acute HIIT exercise impacts corticospinal excitability in older adults, without affecting intracortical or interhemispheric circuitry. These findings have implications for the development of exercise strategies to potentiate neuroplasticity in healthy older and clinical populations.

226-OR: ADA Presidents’ Select Abstract: Exercise Training Promotes Mitochondrial Remodeling in Skeletal Muscle of Type 2 Diabetes Humans

Altered mitochondrial dynamics may contribute to impaired mitochondrial function and insulin sensitivity in type 2 diabetes (T2D). High intensity interval training (HIIT) can induce mitochondrial biogenesis in healthy humans, but its impact on mitochondrial remodeling in insulin resistant states is still unclear. To this end, this study examined the effect of HIIT on mitochondrial function and dynamics in T2D as well as in insulin resistant (IR) and sensitive (IS) glucose tolerant humans to elucidate the interplay between mitochondrial turnover and muscle insulin sensitivity. Twenty T2D, 11 IR and 12 IS humans age- and BMI-matched (HbA1c in %: 7.2 ± 0.2, 5.4 ± 0.1, 5.5 ± 0.1; M-value in mg*kg-1*min-1: 3.0 ± 0.4, 4.1 ± 0.3, 7.4 ± 0.4) performed a 12-week HIIT cycling protocol for 3 days/week. Before the intervention (baseline) and 72 h after the last exercise bout, whole-body insulin sensitivity was measured by hyperinsulinemic-euglycemic clamps, whereas mitochondrial respiration and dynamics were assessed by high resolution respirometry and immunoblotting of skeletal muscle biopsies. After HIIT, all participants showed improved cardiorespiratory fitness and increased muscle maximal oxygen uptake (p&amp;lt;0.001 vs. baseline), whereas insulin sensitivity increased only in T2D and IR (M-value; 4.3 ± 0.5 and 5.7 ± 0.6; p&amp;lt;0.01 vs. baseline). Moreover, HIIT doubled muscle citrate synthase activity in all groups, while biomarkers of mitochondrial fission (p&amp;lt;0.01), fusion (p&amp;lt;0.001) and mitophagy (p&amp;lt;0.001 for phospho-Parkin(Ser65) and p&amp;lt;0.05 for phospho-Pink(Thr257)) increased only in T2D. In conclusion, this study suggests that mitochondrial fusion and fission synergically respond to chronic exercise training and likely contribute to the exercise training response of insulin sensitivity at least in overt T2D. Targeting these mechanisms might help to better understand muscle insulin resistance and to identify novel therapeutic strategies for tailored prevention and treatment of T2D. Disclosure L. Mastrototaro: None. M. Apostolopoulou: None. D. Pesta: None. K. Strassburger: None. Y. Karusheva: None. S. Gancheva: None. J. Szendroedi: None. M. Roden: Advisory Panel; Self; Allergan plc, Bristol-Myers Squibb Company, Novo Nordisk A/S, Research Support; Self; Boehringer Ingelheim International GmbH, Danone Nutricia, Sanofi-Aventis Deutschland GmbH.

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.

Four weeks of high-intensity interval training (HIIT) improve the cardiometabolic risk profile of overweight patients with type 1 diabetes mellitus (T1DM)

ABSTRACT This study investigated the effects of a four-week HIIT intervention on the cardiometabolic risk profile, liver fat content, insulin requirement, hypoglycaemia, physical fitness, and health-related quality of life in patients with T1DM. A supervised exercise intervention with baseline to follow-up comparison between overweight (BMI = 28.6 ± 2.1 kg/m2) and normal weight (BMI = 23.2 ± 1.40 kg/m2) T1DM patients was performed. Eleven overweight (age = 40.7 ± 14.3 years) and 11 normal weight (age = 42.2 ± 15.5 years) T1DM patients performed a four-week, low-volume, all-out cycling HIIT (4–6 bouts, work/relief ratio 1:1) twice weekly. HIIT lowered low-density lipoprotein and uric acid levels in overweight patients by up to 10.5% (vs. normal weight, p≤0.0312). HbA1c, high-density lipoprotein, and triglyceride levels did not change in any of the groups. Participants’ maximal exercise capacity and power output at individual anaerobic lactate threshold increased to an equal extend of up to 10% (p≤0.0002) in both groups. During the intervention, participants used fewer daily bolus insulin (−5.22 ± 12.80%) and less total units of insulin (−4.42 ± 10.20%, p≤0.023) compared to the pre-intervention period with no between-group difference. Overall, the average daily number of hypoglycaemias increased from 0.90 ± 0.56–1.08 ± 0.63 during the intervention (p = 0.033). SF-36 subscales showed higher scores after the intervention, with a significant improvement of “role limitations due to physical problems” (p<0.05) for both groups. We conclude that in T1DM, HIIT may exert beneficial effects on physical fitness, insulin requirement and health-related quality of life. Of note, beneficial HIIT effects on the cardiometabolic risk profile in T1DM may be larger in overweight T1DM patients.

High-Intensity Interval Training in Middle-Distance NCAA Division I 800/1500m Collegiate Athletes

Background: High-intensity interval training (HIIT) has grown in popularity, with studies demonstrating improvements in aerobic and anaerobic performances within Sedentary and Recreationally active adults. Little research has been comprised on collegiate, middle-distance runners (800m/1500m). Objective: This research study aimed to investigate the impact of four-weeks HIIT cycling training on collegiate 800/1500m runners performance, and determine whether HIIT can be used as an alternative training method for student athletes. Methods: Twelve middle-distance runners were recruited, with six athletes completing the intervention. Athletes completed pre-testing, which included a 1500m time trial, a GXT, stride length and frequency measurements, and MVIC, using Biopac electromyography (EMG). After pre-testing, athletes completed four weeks of HIIT twice per week. The HIIT consisted of four 20-second bouts with 4 minutes recovery. Following the completion of the training intervention, post-testing was performed for all measures. A paired t-test was used to determine differences between pre- and post-performance tests. An ANOVA was used to determine changes in heart rate and RPE during the GXT. Results: Significant changes were demonstrated between the pre- and post-muscle activation tests of the quadriceps (p=0.05). Significant changes were seen with both HR (p&lt;0.05) and RPE (p&lt;0.05) throughout the GXT. No other significant differences were demonstrated between pre- and post-performance tests, concluding four-weeks HIIT does not alter 800/1500m performance. Conclusion: From the results of this study, HIIT could be used as an alternate method for training for 800/1500m runners. Further reasearch should be conducted toto further understand the impacts of HIIT on middle distance athletes.

Effect of high intensity interval training on body composition in women before and after menopause: a meta-analysis.

What is the topic of this review? A meta-analysis of the efficacy of high intensity interval training (HIIT) in reducing weight, total fat mass (FM) and (intra)-abdominal FM in normal-weight and overweight/obese women before and after menopause. What advances does it highlight? HIIT programmes in women significantly decrease body weight and total and abdominal FM. Their effects are more evident in pre- than in postmenopausal women. Cycling HIIT seems more effective than running, especially in postmenopausal women, and training interventions longer than 8weeks comprising three sessions a week should be promoted. High-intensity interval training (HIIT) is a stimulating modality for reducing body weight and adipose tissue. The purpose of this meta-analysis was to assess the efficacy of HIIT in reducing weight, total fat mass (FM) and (intra)-abdominal FM in normal-weight and overweight/obese women before and after menopause. A structured electronic search was performed to find all publications relevant to our review. Stratified analyses were made of hormonal status (pre- vs. postmenopausal state), weight, HIIT modalities (cycling vs. running), programme duration (<or≥8weeks) and the methods used to measure body composition (dual-energy X-ray absorptiometry vs. computed tomography, Magnetic Resonance Imaging and others). A total of 38 studies involving 959 subjects were included. Our meta-analysis showed that overall HIIT programmes significantly decrease weight, total and abdominal FM in women. Both normal weight and overweight/obese women lost total FM after HIIT protocols whereas HIIT was only effective in decreasing abdominal FM in women with excess adiposity. When pre- and postmenopausal women were considered separately, the effect of HIIT on weight, total and abdominal FM were only significant before menopause. Cycling HIIT seemed more effective than running, especially in postmenopausal women, and training interventions longer than 8weeks comprising three sessions were more efficient. HIIT is a successful strategy to lose weight and FM in normal weight and overweight/obese women. However, further studies are still needed to draw meaningful conclusions about the real effectiveness of HIIT protocols in postmenopausal women.

Effects Of Exercise Modality And Structure On Physiological And Perceptual Responses To Exercise

Moderate intensity continuous training (MICT) and high intensity interval training (HIIT) in the form of cycling and running, are effective types of exercise for improving fitness and health. However, cycling may cause higher levels of local muscle fatigue due to the greater contribution of anaerobic metabolism, while more muscle mass is active during running, resulting in higher oxygen uptake (VO2) and energy expenditure. PURPOSE: To examine the effects of exercise modality (cycling vs. running) and structure (continuous vs. interval exercise) at an individualized exercise intensity, on physiological and perceptual responses. METHODS: Seven healthy young individuals (3 M and 4 F, age = 21 ± 1 years) performed four 20 min trials in random order: continuous cycling and running (MICT) at an intensity corresponding to 80% of the individual ventilatory threshold (VT) and intermittent cycling and running (HIIT) including 10 x 1 min bouts at 120% VT, with 1 min active recovery at 60% VT. Blood lactate concentration was measured at rest, midway during exercise and 3 min after exercise, while VO2, heart rate (HR) and rating of perceived exertion (RPE) were measured continuously. Data were analyzed using 3-way repeated measures ANOVA. RESULTS: VO2max (40.0 ± 5.8 vs. 36.0 ± 5.3 ml/kg/min, p<0.001) and VT (70.8 ± 7.6 vs. 51.4 ± 4.2 %VO2max, p<0.001), were higher in running than cycling. This resulted in energy expenditure that was highest in HIIT and MICT during running (217 ± 47 and 199 ± 61 kcal, respectively, p<0.001) and lowest in HIIT and MICT during cycling (142 ± 19 and 142 ± 17 kcal, respectively). Average HR was higher in running versus cycling (159 ± 15 and 138 ± 9 bpm, p=0.008) and in HIIT versus MICT (155 ± 10 and 142 ± 11 bpm, p=0.03), but there was no 3-way interaction (p=0.79). In contrast, blood lactate concentration was not different between cycling and running (p=0.44), while RPE was slightly higher during running than cycling (2.75 ± 1.15 and 2.10 ± 1.0 units, p=0.03) CONCLUSIONS: Running, especially in the form of HIIT at an individualized intensity close to VT, results in greater energy expenditure, while blood lactate and RPE are similar to cycling HIIT or MICT. Thus, HIIT running at this intensity may be used as an effective and tolerable exercise modality for healthy individuals when available time is limiting.

Metabolic and physiological effects of high intensity interval training in patients with knee osteoarthritis: A pilot and feasibility study

To examine the feasibility of a 6-week high intensity interval training (HIIT) program in patients with symptomatic knee osteoarthritis (OA). A secondary aim was to evaluate the change in whole-body metabolism. In a single-arm intervention, 16 adults (mean age 59.9yrs; BMI: 29.0±4.3kg/m2; 77% female) with radiographically diagnosed knee OA (Kellgren-Lawrence [KLG]: 2-4) and moderate to severe pain score (≥6) from the Western Ontario and McMasters Universities Index (WOMAC) enrolled in a 6-week, twice weekly, supervised HIIT cycle ergometry intervention. The primary outcome was feasibility; secondary outcomes included change in peak oxygen consumption (VO2peak), WOMAC, and circulating biomarkers of metabolism. Feasibility was moderate; of the 21 participants screened by phone, 16 were enrolled; 13 completed pre- and post-testing. The average adherence rate (sessions completed/available) was >96%. VO2peak was significantly improved (mean±SD: 2.6±3.0mL/min/kg; 95% CI [0.70-4.56]). Significant improvements in WOMAC (mean±SD: -8.7±12.5; CI: [18.9 to -2.80]), pain [-5.15 to -1.01], and function [-12.9 to -0.98] resulted. There was a significant reduction in concentrations of amino acids: methionine, phenylalanine, and tyrosine (p<0.02 for all), with trends towards lower concentrations of serine (p=0.08; [-20.66-1.18]) and greater aspartate/asparagine (p=0.06; [-1.99-65.73].). Post-training acylcarnitine concentrations were reduced with training. In this cohort of overweight adults with symptomatic knee OA, 6-weeks of HIIT cycling showed excellent rates of retention and adherence with no adverse events, improved cardiorespiratory fitness and OA symptoms, in concert with metabolic alterations indicative of improved skeletal muscle energetics. clinicaltrials.gov: NCT03039452.

164-OR: Role of Small Extracellular Vesicles for the Metabolic Response to Exercising in Insulin Resistant Humans

Small extracellular vesicles (SEV) are secreted into circulation after acute exercise suggesting a new mode of tissue crosstalk. High intensity interval training (HIIT) leads to improved insulin sensitivity and oxidative capacity in patients with type 2 diabetes. As the impact of HIIT on SEV release is unknown, this study examined its effects on number and proteome of SEV in insulin sensitive (IS) and insulin resistant (IR) humans to identify biomarkers for the early prediction of individual responses of insulin sensitivity to exercising. Eight T2D, 8 glucose tolerant IR and 6 IS humans with similar age and BMI (HbA1c in %: 7.4 ± 0.4, 5.3 ± 0.1, 5.5 ± 0.1; M-value in mg*kg-1*min-1: 1.8 ± 0.4, 4.1 ± 0.4, 7.2 ± 0.5) performed a 12-weeks HIIT cycling protocol for 3 days/week. Before the intervention (baseline) and 72 h after the last exercise bout, whole-body insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamps and serum samples were collected to isolate SEV by size exclusion chromatography. SEV size and number were measured by Nanoparticle Tracking Analysis and proteomic profiling was done by mass spectrometry using data independent acquisition. After 12 weeks of HIIT, T2D and IR improved their insulin sensitivity (M-value: T2D 3.5 ± 0.8, IR 6.2 ± 0.7; p&amp;lt;0.01 vs. baseline) and increased the number of circulating SEV by 52 ± 19% and 58 ± 21% (p&amp;lt;0.05 vs. baseline). Quantitative proteomic analysis of SEV revealed that HIIT regulated 258 proteins (118 in T2D, 125 in IR, 89 in IS) with an enrichment of proteins related to glycolysis in T2D, to antioxidative metabolism in IR and to lipid metabolism in IS. In conclusion, HIIT increases SEV number, but differently affects SEV mass and proteome in IS and IR humans, suggesting that SEV cargo could contribute to the individual response of insulin sensitivity to HIIT. Detailed characterization of SEV cargo can help to better understand the mechanisms of tissue crosstalk in the adaptation to exercise training and to develop novel exercise mimetics. Disclosure L. Mastrototaro: None. M. Apostolopoulou: None. S. Hartwig: None. D. Pesta: None. K. Strassburger: None. E. DeFilippo: None. Y. Karusheva: None. S. Gancheva: None. D.F. Markgraf: None. S. Lehr: None. K. Mussig: None. H. Al-Hasani: Consultant; Self; Bayer AG. J. Szendroedi: None. M. Roden: Advisory Panel; Self; Servier. Board Member; Self; Poxel SA. Consultant; Self; Eli Lilly and Company, Gilead Sciences, Inc., ProSciento, TARGET PharmaSolutions. Research Support; Self; Boehringer Ingelheim International GmbH, Novartis Pharma K.K., Sanofi US. Speaker’s Bureau; Self; Novo Nordisk A/S.