The benefits of low to moderate intensity exercise for cancer survivors have been well reported and is deemed to promote improvements in aerobic fitness, functional capacity and psychological factors (Mutrie et al., 2007; McNeely et al., 2006). Continuous moderate intensity training (CMIT) is commonly prescribed in the usual care for cancer survivors but there is a growing body of evidence that high-intensity intervaltraining (HIIT) may be one of the most effective ways of improving cardiometabolic health (Kessler, Sisson & Short, 2012; Weston et al., 2014). High-intensity intervaltraining (HIIT) is not commonly prescribed in clinical practice for cancer survivors, however, its application as a modality for the treatment and management of chronic disease is gathering momentum and research studies in chronic disease populations such as; cardiac (Aamot et al., 2014) stroke (Mattlage et al., 2013), diabetes (Gillen et al., 2012), cancer (Gibala et al., 2012), and hypertension (Brito et al., 2014) have recently been published. The growing body of evidence suggests that HIIT may impart benefits that are greater than those elicited through low or moderate intensity training in healthy populations, but less has been published on cancer survivors (Adamsen et al., 2009).
> 90% maximum heart rate) and aerobic intervaltraining (4 minute intervals at 80–100% max- imum heart rate) . A growing number of small, tightly controlled laboratory-based studies demonstrate that both SIT and low-volume HIT promotes significant improvements in aerobic exercise capacity, blood pressure, vascular function and whole-body insulin sensitivity in sed- entary and obese individuals and type 2 diabetes patients (reviewed in [10, 11]). Importantly, the magnitude of improvements in aerobic exercise capacity and other key cardio-metabolic risk factors following sprint intervaltraining appear to be similar to moderate-intensity contin- uous training (MICT) [12–14], despite only requiring a fraction of the total energy expenditure and a vastly reduced total time commitment. Therefore, sprint intervaltraining and/or low- volume HIT may provide an effective and time-efficient alternative to traditional MICT-based interventions to improve metabolic health.
ible measure of cardiorespiratory fitness (CRF) , and a predictor of morbidity and mortality ,, as their primary outcome ,. Results from both studies were positive. We chose to base our AIT exercise intervention on the study by Tjonna , which used 4 minute intervals at 90% maximal HR, followed by three minutes of active recovery at 70% maximal HR. Although multiple studies on selected populations in controlled settings have shown HIIT to be an effective method of improving markers of cardiometabolic fitness ,, HIIT has yet to be applied to a real world community setting using moderately unselected participants. The purpose of the current study was to extend and translate the HIIT concept into a real world community setting, by undertaking a randomized controlled trial (RCT) feasibility study. In keeping with the real world objectives of the study, participants were selected because they were at high risk Figure 1. Flow of participants through each stage of the trial. a WALK = walking to 65–75% of heart rate max, AIT = aerobic intervaltraining
The World Health Organization has stated that physical inactivity is the fourth leading risk fac- tor for global mortality (6% of deaths worldwide), which is equivalent to approximately 3.2 million deaths per year . The American College of Sports Medicine recommends at least 20 minutes a day of vigorous exercise three times per week . High intensity intervaltraining (HIIT) is characterized by periods of high intensity exercise combined with short rest intervals, resulting in aerobic-like effects. In addition, HIIT protocols shorten the total time spent on physical activity while producing the same work load [3, 4]. This training strategy is currently applied in humans as an alternative exercise intervention in different disease conditions, such as heart failure, hypertension, type II diabetes, obesity and chronic obstructive pulmonary dis- ease [5–10].
Stepping is a convenient form of scalable high-intensity intervaltraining (HIIT) that may lead to health benefits. However, the accurate personalised prescription of stepping is hampered by a lack of evidence on optimal stepping cadences and step heights for various popula- tions. This study examined the acute physiological responses to stepping exercise at vari- ous heights and cadences in young (n = 14) and middle-aged (n = 14) females in order to develop an equation that facilitates prescription of stepping at targeted intensities. Partici- pants completed a step test protocol consisting of randomised three-minute bouts at differ- ent step cadences (80, 90, 100, 110 stepsmin -1 ) and step heights (17, 25, 30, 34 cm). Aerobic demand and heart rate values were measured throughout. Resting metabolic rate was measured in order to develop female specific metabolic equivalents (METs) for step- ping. Results revealed significant differences between age groups for METs and heart rate reserve, and within-group differences for METs, heart rate, and metabolic cost, at different step heights and cadences. At a given step height and cadence, middle-aged females were required to work at an intensity on average 1.9 ± 0.26 METs greater than the younger females. A prescriptive equation was developed to assess energy cost in METs using multi- level regression analysis with factors of step height, step cadence and age. Considering recent evidence supporting accumulated bouts of HIIT exercise for health benefits, this equation, which allows HIIT to be personally prescribed to inactive and sedentary women, has potential impact as a public health exercise prescription tool.
Coronary artery disease (CAD) is a multifactorial disease inﬂuenced by a wide range of modiﬁable risk factors (dyslipidemia, hypertension, obesity, diabetes, and physical inactivity) as well as non-modiﬁable factors (age and genetic proﬁle) (1). Exercise practice has been strongly recom- mended for the management of CAD and control of modi- ﬁable risk factors in the context of cardiac rehabilitation, given the beneﬁts on the cardiovascular system and con- trol of modiﬁable risk factors (2). Randomized controlled trials and meta-analyses have shown that aerobic intervaltraining (AIT) is recommended for this population due to its effectiveness in improving aerobic functional capacity compared to continuous and moderate physical training (3–5). However, changes in serum lipids are small and
Several studies have addressed the characteristics of High Intensity IntervalTraining - HIIT in an attempt to increase the training of individuals who normally have little time to perform their session, and predominantly present anaerobic capacity, since it uses 90% or more of the individual's cardiorespiratory capacity. Thus, among the benefits of this training is the prevention of diseases related to Metabolic Syndrome. Thus, the objective of the study is to compare glycemic responses between healthy men aged 18 to 25 years submitted to the HIIT Training carried out between the bicycle and the treadmill. The sample consisted of healthy young men, and on the day of data collection, all volunteers received a dose of Maltodextrin thirty minutes before the start of the test, which was performed randomly using the Treadmill and Stationary Bike. To control the intensity, the Borg Scale was used with the use of PSE and Heart Rate. For the analysis of the glycemic curve, four collections were used along the protocol that used the Tabata® method. Among the main results, we highlight that the protocol performed on the Treadmill and the Stationary Bike, the results were similar. We concluded in this way, that the use of the training method through HIIT is satisfactory for the glycemic control in the individual.
Objective(s): High-intensity intervaltraining (HIIT) increases energy expenditure and mechanical energy efficiency. Although both uncoupling proteins (UCPs) and endothelial nitric oxide synthase (eNOS) affect the mechanical efficiency and antioxidant capacity, their effects are inverse. The aim of this study was to determine whether the alterations of cardiac UCP2, UCP3, and eNOS mRNA expression following HIIT are in favor of increased mechanical efficiency or decreased oxidative stress. Materials and Methods: Wistar rats were divided into five groups: control group (n=12), HIIT for an acute bout (AT1), short term HIIT for 3 and 5 sessions (ST3 and ST5), long-term training for 8 weeks (LT) (6 in each group). The rats of the training groups were made to run on a treadmill for 60 min in three stages: 6 min running for warm-up, 7 intervals of 7 min running on treadmill with a slope of 5° to 20° (4 min with an intensity of 80-110% VO2max and 3 min at 50-60% VO2max), and 5-min running for cool-down. The control group did not participate in any exercise program. Rats were sacrificed and the hearts were extracted to analyze the levels of UCP2, UCP3 and eNOS mRNA by RT-PCR.
This study analyzed the inﬂuence of a 4-week high-intensity intervaltraining on the pacing strategy adopted by runners during a 5-km running trial. Sixteen male recreational long-distance runners were randomly assigned to a control group (CON, n=8) or a high-intensity intervaltraining group (HIIT, n=8). The HIIT group performed high-intensity interval-training twice per week, while the CON group maintained their regular training program. Before and after the training period, the runners performed an incremental exercise test to exhaustion to measure the onset of blood lactate accumulation, maximal oxygen uptake (VO 2 max), and peak treadmill speed (PTS). A submaximal constant-speed test to measure the running economy (RE) and
The purpose of this study was to compare the effects of Small-Sided Games (SSG) vs. IntervalTraining (IT) in soccer training on aerobic fitness and physical enjoyment in youth elite soccer players during the last 8 weeks of the season. Seventeen U-16 male soccer players (age = 15.5 ± 0.6 years, and 8.5 years of experience) of a Spanish First Division club academy were randomized to 2 different groups for 6 weeks: SSG group (n = 9) and IT group (n = 8). In addition to the usual technical and tactical sessions and competitive games, the SSG group performed 11 sessions with different SSGs, whereas the IT group performed the same number of sessions of IT. Players were tested before and after the 6- week training intervention with a continuous maximal multistage running field test and the counter movement jump test (CMJ). At the end of the study, players answered the physical activity enjoyment scale (PACES). During the study, heart rate (HR) and session perceived effort (sRPE) were assessed. SSGs were as effective as IT in maintaining the aerobic fit- ness in elite young soccer players during the last weeks of the season. Players in the SSG group declared a greater physical enjoyment than IT (P = 0.006; ES = 1.86 ± 1.07). Coaches could use SSG training during the last weeks of the season as an option without fear of los- ing aerobic fitness while promoting high physical enjoyment.
While the present study and work by others highlights the efficacy of SIT for improving indices of cardiometabolic health, the potential effectiveness of intervaltraining in its various forms and likely impact on public health remains contentious . Research in the field of exercise behavior has demonstrated a negative relationship between exercise intensity and affect, partic- ularly in less trained individuals, which suggests people are less likely to adhere to a program of vigorous exercise since it is deemed aversive [52,53]. However, in a recent study by Jung et al , subjects reported greater enjoyment of, and a preference to engage in, a high-intensity intermittent exercise protocol as compared to continuous moderate- or vigorous-intensity exercise. The interval protocol involved 20 minutes of alternating 60-second periods of exercise at 100% and 20% Wpeak, whereas the continuous protocols involved exercise at 40% Wpeak for 40 minutes or 80% Wpeak for 20 minutes. Other work by the same authors showed that adherence to a 4-week high-intensity intervaltraining program, assessed by self-report in free- living conditions, was greater than for moderate-intensity continuous exercise in people with prediabetes . These findings highlight the potential utility of intense intervaltraining as an alternative exercise strategy that could bolster exercise adherence, but longer and more com- prehensive studies are warranted in this regard.
This study indicates HIIT is feasible and well tolerated by pregnant rats. Six weeks of HIIT did not lead to significant heart remodeling in young, female rats whether they become pregnant or not. There were no adverse effects of HIIT in pregnancy on the mother and it did not alter the structure and function of maternal heart. The fetal and placental growth was not affected. The total antioxidant capacity in the placenta and fetal heart was lower than in the liver sug- gesting that suggesting that the fetal liver is well protected against reactive oxygen species. Oxi- dative stress and total antioxidant capacity in placenta, fetal heart and liver were not affected by HIIT. However, some genes related to oxidative stress were altered in the fetal heart and liver indicating that protective mechanisms are activated. Before extensive training at the anaerobic threshold can be ruled as safe in pregnant women, clinical studies with meticulous monitoring of the fetus must be performed.
test programme could have revealed even higher maximum values. More frequent testing could on the other hand elicit an unwanted training effect in the detraining period. Another aspect would have been to elucidate which mechanisms were causing the signs of fatigue during and after HF training. However, this study was not designed to examine these underlying mechanisms. The study was originally designed also to investigate retraining after the detraining period, but due to the strain of the participants, this part of the study was not implemented.
We enrolled women with PCOS from July to October 2013 through community advertise- ment (Fig 1). PCOS was defined according to the Rotterdam criteria : A minimum of two of the following criteria; (i) PCO morphology (12 or more 2–9 mm follicles or > 10 ml in volume, in at least one ovary), (ii) hyperandrogenism (either clinical signs as hirsutism or acne, or bio- chemical), and (iii) oligo/amenorrhea. Hirsutism was defined as a Ferriman Gallwey score 8 . Cut-off values for biochemical hyperandrogensim was defined as testosterone >3.0 nmol/ L, calculated free testosterone > 32 nmmol/L, SHBG <30 nmol/L, or free androgen index (FAI as 100 x testosterone concentration (nmol/L) /SHBG concentration (nmol/L) >5% . Oligo- menorrhea was defined as an intermenstrual interval > 35 days and < 8 menstrual bleedings in the past year. Amenorrhea was defined as absent menstrual bleeding or none bleeding in the past 90 days. Some of the included women were diagnosed by their own gynecologist. In women who had no prior PCOS diagnosis, we first assessed if they had oligo/amenorrhea and hyperandrogenism. If they fulfilled only one of these criteria, a vaginal ultrasound was done to confirm the diagnosis before study entry. Exclusion criteria included regular high-intensity endurance or strength training (defined as 2 sessions of vigorous exercise per week), physical ailments/injuries that limited exercise performance, on-going pregnancy, concurrent treat- ments (insulin sensitizers as metformin and pioglitazone) or drugs known to affect gonadotro- pin or ovulation, with a wash out period of one month prior to inclusion. The exception was regular use of oral contraceptives, and women were included if they did not change the type or dose > 1 month prior to the study or during the intervention period.
8. Warburton DE, McKenzie DC, Haykowsky MJ, Taylor A, Shoemaker P, Ignaszewski AP, et al. Effectiveness of high- intensity intervaltraining for the rehabilitation of patients with coronary artery disease. Am J Cardiol. 2005;95(9):1080-4. http://dx.doi.org/10.1016/j.amjcard.2004.12.063. PMid:15842976. 9. Currie KD, Dubberley JB, McKelvie RS, MacDonald MJ. Low-volume, high-intensity intervaltraining in patients with CAD. Med Sci Sports Exerc. 2013;45(8):1436-42. http:// dx.doi.org/10.1249/MSS.0b013e31828bbbd4. PMid:23470301. 10. Munk PS, Butt N, Larsen AI. High-intensity interval exercise
haematopoietic cells have been reported to migrate towards arterial injury , adhere to implanted grafts  and restore circulation to the ischemic limb of mice , providing evidence for their role in endothelial repair and angiogenesis. The present study is the first to show elevated numbers of CACs following exercise training in a healthy population and suggests an increased reparative potential if required. In contrast, no change in CACs was observed following 8 weeks of continuous endurance training in healthy older men  and in our lab following 6 weeks of moderate intensity intervaltraining in healthy young adults . Although in the latter study, some participants exhibited a sustained mobilisation of CACs following heavy intensity intervaltraining, which may have been a result of the higher exercise intensity. This evidence combined with the sustained mobilisation of CACs following both SIT and SCT in the present study, suggests that the high intensity nature and not the duration or the interval vs. continuous nature of the exercise, was the main contributor to increased CACs. This supports the theory that a greater metabolic stress during exercise leads to a sustained upregulation of CACs in healthy individuals, as both training programmes in the present study involved maximal exertion sprints that have been shown to achieve _ V VO 2max (unpublished data
Body mass was not different between groups in both moments, before and after protocol; however, body mass was signiicantly different within each group from pre to post protocol (P<0.05, Table 3). There was no difference among the groups at the beginning of the study with regard to maximal exercise capacity evaluated by test duration and maximum speed (25 m/min; data not shown). The training intensity was determined by percentage of maximum speed (ACT at 60% = 15 m/min and AIT at 60% = 15 m/min and 92%= 23 m/min). Eight weeks of aerobic exercise protocols were able to increase maximal exercise capacity when compared with pre and post measurements within each trained group. However, aerobic intervaltraining promoted a superior gain in maximal exercise capacity compared with aerobic continuous training (P <0.05) (Table 3).
Methods: 22 individuals with mean age of 40±8 years were distributed into the following groups: control (CO), endurance training (ET) and intervaltraining (IT). The protocols lasted 12 weeks, three times a week, with intensities of 10% below and 20% above the anaerobic threshold (AnT). The following measurements were taken: total body mass (TBM), body mass index (BMI), waist circumference (WC), hip circumference (HC), and body composition, in addition to plasma concentrations of glucose (GLU), total cholesterol (CHO), and triglycerides (TG). Waist-hip ratio (WHR) and conicity index (C index) were also calculated.
Methods: Forty Wistar rats were evaluated by echocardiography 21 days after the AMI. Those with LVEF = 50% (n = 29) were included in the study and randomized to control group (CG n = 10), continuous training group (CTG n = 9) or intervaltraining group (ITG, n = 10). Then, a swimming test with control of lactate production was performed. Based on its result, the lactate threshold (LT) was established to define the training intensities. After six weeks, the animals were reassessed by echocardiography and lactate production. Outcome measures were end-diastolic diameter (EDD), end-systolic diameter (ESD), left ventricular ejection fraction (LVEF, %) lactate at rest, lactate without overload, and lactate with 12g and 13.5g of additional load. Group comparisons of quantitative variables of the study were performed by one-factor analysis of variance (ANOVA). The Newman-Keuls test was used for multiple comparisons of the groups. Within-group comparisons of dependent variables between the two training protocols were performed by Student’s t-test. Normality of the variables was tested by the Shapiro-Wilks test. Values of p < 0.05 indicated statistical significance.