ArticlePDF Available

High-intensity interval training: A review of physiological and psychological responses

September 2014
ACSMʼs Health & Fitness Journal 18(5):11-16

DOI:10.1249/FIT.0000000000000067

Authors:

Marcus Kilpatrick

University of South Florida

Mary E Jung

University of British Columbia

Jonathan Peter Little

University of British Columbia - Okanagan

Learning Objectives Develop an understanding of the impacts of high-intensity interval training on physiological and psychological responses.• Develop a strategy for prescribing and using high-intensity interval training in varied client, member, and patient populations.

Summary of Physiological Benefits of HIIT

…

Recommendations for Practitioners

…

Figures - uploaded by Marcus Kilpatrick

Content may be subject to copyright.

Content uploaded by Marcus Kilpatrick

Content may be subject to copyright.

HIGH-INTENSITY

INTERVAL TRAINING

A Review of Physiological and

Psychological Responses

by Marcus W. Kilpatrick, Ph.D.; Mary E. Jung, Ph.D.; and Jonathan P. Little, Ph.D.

Learning Objectives

•Develop an understanding of the impacts of high-intensity interval

training on physiological and psychological responses.

•Develop a strategy for prescribing and using high-intensity

interval training in varied client, member, and patient populations.

Key words:

Intervals, Adaptations, Metabolic, Psychological, Perceptual,

Motivation

Current guidelines for physical activity

(PA) recommend the accumulation of

150 minutes of moderate or 75

minutes of vigorous activity per week (15).

Importantly, research indicates that fewer than

half of all Americans meet current activity

guidelines (16). These numbers reflect little

change during the last decade and indicate that

public health efforts related to boosting PA

have not generated desired outcomes. Physical

inactivity is now believed to be a major cause

of morbidity and mortality, making clear that

physical inactivity is problematic (11). There-

fore, researchers and practitioners must search

for PA programming options that provide

health benefits while possessing characteristics

that lead to sustained behavior. Interval train-

ing is an emerging trend that may have merits

in this regard.

INTERVAL TRAINING BASICS

Interval training involves alternating periods of

relatively intense work and recovery. Altering the

intensity and duration of the work and recovery

periods allows for the production of a nearly

infinite number of interval training workouts.

Modern fitness programming has adopted the

term ‘‘high-intensity interval training’’ or HIIT as

a way to describe this approach to fitness and

performance, and two general categories have

emerged. One category is referred to as ‘‘aerobic

HIIT’’ and the other is ‘‘body weight HIIT’’ or

‘‘resistance HIIT’’ (see Sidebar). Both involve

periods of intense effortfollowedbyrecovery

segments, with the primary difference being the

modality of exercise. Aerobic HIIT training most

often uses running and cycling to deliver the desired

intensities by way of activities such as spin classes

and track-based running workouts. In contrast,

resistance/body weight HIIT makes use of calisthe-

nics, plyometrics, and/or loaded lifts in training

VOL. 18/ NO. 5 ACSM’s HEALTH & FITNESS JOURNALA11

programs like Tabata, CrossFit, boot camp training, or other similar

classes. Although both types of HIIT programs are used widely and

research indicates the effectiveness of body weight-type HIIT

programming (13), most research has focused on HIIT that primarily

is aerobic because cycling and treadmill running enable more

accurate assessment of work to describe the training stimulus.

Therefore, this article provides an overview of common protocols

and evidence-based strategies to support designing effective pro-

gramming using aerobic HIIT.

CONTEMPORARY RESEARCH MODELS

OF INTERVAL TRAINING

Whereas modern interval training has linkages to military

preparedness and athletic competition, the recent resurgence of

interest in interval training can be attributed to potential health-

related benefits of HIIT. Although a variety of aerobic HIIT training

methods have emerged, research related to aerobic HIIT is linked

primarily to three different models that vary on intensity, duration,

and total exercise volume.

Wingate Model

Much of the current attention directed towards HIIT is linked to an

approach that incorporates several trials of the famed Wingate

Anaerobic Test. A single Wingate trial involves all-out, supramax-

imal cycling for a period of 30 seconds and remains the gold

standard for assessing anaerobic capacity. Use of Wingate-based

protocols within HIIT research requires the exerciser to complete

several sprints separated by 4 minutes of unloaded pedaling (4).

This HIIT training model typically is referred to as ‘‘low volume’’

because the total amount of work and time spent exercising is low

(see Sidebar). Importantly, this approach to HIIT primarily was

developed to demonstrate the potency of interval training in

producing rapid cardiometabolic adaptations and is not generally

the style of training recommended for a long-term program.

Scandinavian Model

Another prominent style of HIIT developed for cardiac patients

incorporates several 4-minute intervals separated by an easy

recovery of similar duration (18). As such, this training model is

considered ‘‘high-volume’’ interval training because total time

spent doing heavy exercise typically exceeds 15 minutes and total

time is similar to traditional endurance training approaches.

Importantly, intervals are performed somewhat below the maximal

heart rate and are therefore not ‘‘all-out’’ exercise. Results from

these studies generally demonstrate superior cardiovascular benefits

of HIIT compared with standard aerobic exercise training (18).

Practical Model

A more recent variation of HIIT was developed as an alternative to

the all-out intensities linked to the Wingate Model that maintains

time efficiency. This approach involves performing 10 intervals on a

cycle ergometer at intensities near peak work capacity for 60 seconds

alternated with easy recovery intervals of the same duration (10).

Given that this approach to interval training represents a midpoint of

sorts between the two models above with respect to intensity,

recovery, and total volume, this practical model can be considered a

‘‘medium-volume’’ interval training program. Whereas the acute and

chronic tolerability of any interval-based training program requires

additional research, a training approach based around a more

practical model is appropriate for much of the general population,

including type 2 diabetes mellitus (DM) patients (10).

PHYSICAL ACTIVITY GUIDELINES

AND INTERVAL TRAINING

An important issue related to HIIT is the consideration of how such

training can be incorporated within a PA program designed to meet

current public health recommendations. Interval training does not

explicitly ‘‘fit’’ within PA guidelines in a traditional sense. Although

the work interval portion exceeds the intensity threshold for

vigorous exercise, most aerobic HIIT sessions include no more than

10 to 12 minutes at this intensity. Similarly, most interval training

sessions use relatively easy recovery segments that are best

described as low intensity. As such, a typical interval training

session does contribute toward meeting PA recommendations but

primarily via vigorous intensities. Meeting the goal of 75 minutes

of vigorous activity per week may prove challenging through HIIT

alone. An important, yet presently unanswered, question is how to

best substitute HIIT for more traditional forms of exercise for

promoting health. Although the answer to this question is not yet

fully settled, it is becoming increasingly clear that aerobic HIIT

provides numerous health and fitness benefits.

PHYSIOLOGICAL BENEFITS

Research investigating aerobic HIIT-styled training indicates

improvements in markers of cardiovascular health, metabolic

capacity, and aerobic performance that are similar, and often

superior, to more traditional continuous moderate-intensity

SIDEBAR: INTERVAL TERMINOLOGY

Interval Training: exercise that involves periods of intense work

and recovery that vary on the intensity and duration of each segment.

Body Weight or Resistance HIIT: interval training that uses

bodily movements, weighted objects, bars, or devices for high-

repetition resistance activities.

Aerobic HIIT: interval training that uses traditional aerobic

exercise modalities such as running and cycling.

SIDEBAR: SPEED VS. GRADE

Each 1 mph increase in speed is roughly equal to 4% grade increase.

This means that exercisers can pick and choose whether to increase

work by way of speed or climbing a hill.

12 ACSM’s HEALTH & FITNESS JOURNALA|www.acsm-healthfitness.org VOL. 18/ NO. 5

High-Intensity Interval Training

exercise (3,5,6,9,18). The exact mechanisms promoting these

seemingly potent adaptations to HIIT are not yet fully known but

may be related to the training time spent at or near V

˙O

2max

, a high

degree of muscle fiber recruitment, and other related cardiovascu-

lar and cellular signaling pathways. Table 1 provides an overview

of the benefits of HIIT, and the next sections highlight some key

findings demonstrating that HIIT can promote physiological

adaptations that are linked to improved health.

Aerobic Fitness

Because of the well-known benefits of vigorous exercise for im-

proving cardiorespiratory fitness, it is not surprising that aerobic HIIT

leads to improvements in V

˙O

2max

and various indicators of the

oxidative capacity of skeletal muscle. However, studies in clinical

populations have shown that higher-volume HIIT programs using

longer intervals lead to greater improvements in V

˙O

2max

when com-

pared with continuous moderate-intensity training of equal volume and

time commitment (5,18). These studies also have shown superior

improvements in markers of muscle mitochondrial content after HIIT

and potent effects of HIIT for improving V

˙O

2max

after as little as

2 weeks of training. Data with lower-volume HIIT protocols are

less consistent, with 2-week programs failing to induce aerobic fitness

changes that are observed more readily in 6-week programs (3).

Together, these findings indicate that some minimum volume or

duration of training may be a key feature in the benefits related to HIIT.

Metabolic Health

Improvements in insulin sensitivity and glucose control after aerobic

exercise play a key role in the prevention and management of type 2

DM and related conditions (e.g., metabolic syndrome, prediabetes).

Because replenishment of muscle glycogen is a key factor

mediating the improvement in insulin sensitivity after acute exercise

(11), it is hypothesized that greater depletion of muscle glycogen

after aerobic HIIT may facilitate enhanced muscle glucose uptake

and improved insulin sensitivity. Importantly, research indicates that

HIIT can increase insulin sensitivity and improve glycemic

regulation, particularly in those with or at risk for type 2 DM.

Two weeks of low-volume HIIT produced significant improve-

ments in insulin sensitivity in overweight individuals (11). Less

extreme HIIT protocols, which likely are more practical for

individuals with metabolic diseases to perform, also have shown

promise for improving insulin sensitivity along with glucose

control. Research indicates that 2 weeks of HIIT training using

the practical model produce improvements in insulin sensitivity in

type 2 DM patients (3,9). Other HIIT protocols also seem to

improve glycemic control and may be superior to continuous

moderate-intensity exercise. One recent 12-week training study

indicated that high-volume interval walking was more beneficial for

glucose control than continuous moderate exercise despite no

differences in total energy expenditure (8). This study also reported

greater benefits of interval walk training for reduced abdominal

visceral fat mass, a key component of metabolic health.

Vascular Health

The benefits of aerobic exercise for improving the health and

function of blood vessels is linked to endothelial cells within the

vasculature, which release nitric oxide and have potent vasodilat-

ing effects to protect cardiovascular function and health. The

proper function of these endothelial cells ensures efficient blood

flow distribution. Research studies clearly demonstrate greater

improvements in endothelial function after HIIT when compared

with continuous exercise. These findings appear consistent across a

range of cardiovascular disease states and also have shown that

HIIT can improve the elasticity of arterial blood vessels (5,18).

PSYCHOLOGICAL RESPONSES

Although much research has examined the physical health

benefits of aerobic HIIT, very little is known about how people

TABLE 1: Summary of Physiological Benefits

of HIIT

Aerobic fitness HIIT increases V

˙O

2max

to a greater extent

and more quickly than continuous

moderate exercise.

Metabolic health HIIT improves insulin sensitivity more

effectively than continuous moderate exercise,

especially in individuals at risk for developing

diabetes mellitus.

Cardiovascular

health

HIIT improves endothelial function more

effectively than all forms of continuous exercise.

References for above: 5,8,11,19.

IPG Gutenberg UK Ltd/iStock/Think stock

VOL. 18/ NO. 5 ACSM’s HEALTH & FITNESS JOURNALA13

perceive HIIT, whether they like it or dislike it, whether they can

tolerate it, and most importantly, whether they will adhere to HIIT.

Knowing how people respond perceptually and behaviorally to

HIIT is of paramount importance if this approach to exercise is to

be encouraged for use by clients and patients. The next sections

consider what currently is known about the impact of aerobic HIIT

training on affect, enjoyment, and adherence.

Affective Responses

‘‘Affect’’ is a response that is elicited somewhat reflexively or

instinctively without significant thought and is linked to pleasure or

displeasure and tension or calmness (12). Clearly, aerobic HIIT is

not a viable approach to exercise if clients and patients perceive it as

aversive (i.e., painful, displeasurable, stress provoking), which is the

common outcome of prolonged exercise at high intensities. Although

popularized media programs give the impression that HIIT is entirely

grueling, interval exercise need not be a displeasurable experience. A

built-in benefit of HIIT with respect to affect is the recovery period,

which provides exposure to lower-intensity exercise, which is known

to produce more favorable responses. So what about affect

experienced during the work intervals, where people are exercising

at very high intensities? Research indicates that affect experienced

during these intense bursts is not different from the affect experienced

during continuous moderate-intensity exercise and is significantly

more positive than continuous vigorous-intensity exercise (7,14).

These responses tend to be consistent across a relatively wide range of

demographics including healthy young adults and middle-aged adults

with prediabetes or DM. Furthermore, this research suggests that the

‘‘most pleasurable interval’’ might be relatively short (60 seconds or

less) and near-maximal (approximately 90% of aerobic capacity).

Enjoyment Responses

Whereas affect is an instinctive mood response, enjoyment is a

psychological state that is unique in that it is elicited after appraising

or cognitively evaluating a situation. Enjoyment considers the

answers to questions like: Do I like that feeling? Do I feel

accomplished? Do I feel revived or refreshed? Or more globally, did I

enjoy my exercise experience? This focus on enjoyment is relevant

because of concerns that vigorous-intensity exercise may be less

enjoyable and, thus, less well tolerated than moderate-intensity

exercise. Although this concern related to intense exercise is true for

continuous exercise (e.g., walking for 30 minutes typically is

perceived as more enjoyable than fast running for 30 minutes),

recent data suggest that vigorous-intensity exercise performed in an

intermittent fashion is very enjoyable (2,7,14). When comparing

aerobic HIIT with continuous moderate-intensity exercise and

continuous vigorous-intensity exercise, participants report highest

enjoyment for HIIT conditions (2,7,14).

Adherence

Although research indicates positive affective responses and

perceived enjoyment of HIIT, questions related to long-term

exercise adherence remain. There is, however, a limited amount of

data demonstrating that affective responses during exercise are

better able to predict exercise adherence than the responses that

occur after the completion of exercise (17). This research makes

clear that how we feel during exercise is important. Aerobic HIIT

does appear promising in that it has been viewed as equally or

more favorable during the exercise bout than continuous

moderate-intensity or continuous vigorous-intensity exercise,

although these results are preliminary.

SAFETY CONSIDERATIONS

Although HIIT may be both potent for health and generally well

tolerated, participation in this form of exercise requires practitioners

to consider established guidelines related to risk (1). Specifically, this

form of training fits somewhat loosely within the umbrella of

vigorous exercise and therefore is only appropriate for low-risk

individuals, moderate-risk individuals who have been cleared for

vigorous intensities by a medical professional, and high-risk

individuals who are under direct medical supervision during exercise

training. A related risk consideration is linked to exercise modality.

Most of the research to date in this area has been conducted on cycle

ergometers. Importantly, exercising on a treadmill poses a greater

risk of injury via falling than cycle-based exercise. Practitioners

should, therefore, remind clients and patients to be cautious while

performing aerobic HIIT. One specific recommendation might

include inducing high intensities by adjusting treadmill grade rather

than speed, which can pose additional risk for those unaccustomed

to fast running on a treadmill (see Sidebar).

SIDEBAR: TIME EFFICIENCY

Some of the excitement surrounding HIIT exercise is that it can

deliver powerful outcomes with relatively low volumes of exercise

and a minimal time commitment. Although there is much potential

for this type of claim, it is important to consider that each form of

HIIT is different in the amount of time spent doing heavy exercise

and the total amount of time spent completing the session.

14 ACSM’s HEALTH & FITNESS JOURNALA|www.acsm-healthfitness.org VOL. 18/ NO. 5

High-Intensity Interval Training

HIIT RECOMMENDATIONS

The growing amount of research related to aerobic HIIT should

provide practitioners with increased confidence in prescribing this

form of exercise, especially versions that focus significantly on

aerobic-type activities. Furthermore, utilization of aerobic HIIT

seems both feasible and valuable for a range of individuals V

from diabetic patients to devoted fitness enthusiasts and every

group in between. The task of the health and fitness practitioner is

to recommend HIIT as an option for the individuals they serve in

their daily work. Part of this process is the recognition that HIIT

comes in many forms and that a ‘‘one size fits all’’ approach likely

is not possible. Table 2 provides several recommendations and a

sample prescription for practitioners on how they might go about

encouraging HIIT exercise for their clients and patients.

A final note on how HIIT exercise can fit into a long-term

plan for health and wellness links to motivation. As many

health and fitness practitioners know, motivation derived from

the desire to achieve a lofty outcome goal is perhaps less

facilitative for long-term adherence than goals and motivations

linked to the process of the behavior. Specifically, outcome

goals such as weight loss or improving V

˙O

2max

represent a

focus on what exercise can deliver across time. In contrast,

process goals such as having a pleasurable experience and

sensations of accomplishment from exercise sessions may

produce more desirable long-term adherence as they encourage

the exerciser to take note of their positive affective experience.

Therefore, practitioners are encouraged to focus client and

patient attention on these near-term beneficial aspects of

aerobic HIIT-based exercise.

SUMMARY

Experienced health and fitness practitioners know that fitness

fads come and go quickly. However, it is unlikely that the

current fascination with interval training will fade away given

the growing scientific evidence in support of HIIT. The many

potential positive benefits described within this article make

clear that aerobic HIIT programs provide great benefit to

health. However, more research is needed to assess body

weight/resistance versions of HIIT. Furthermore, there is work

to be done to examine the impact of HIIT on acute

psychological responses and exercise adherence. For now,

however, practitioners are encouraged to consider HIIT as a

valuable tool in the promotion of health and fitness in a wide

variety of populations.

References

1. American College of Sports Medicine. ACSM’s Guidelines for Exercise

Testing and Prescription. 9th ed. Philadelphia (PA): Lippincott Williams

and Wilkins; 2013. pp. 19Y38.

2. Bartlett JD, Close GL, MacLaren DPM, Gregson W, Durst B, Morton JP.

High-intensity interval running is perceived to be more enjoyable than

moderate-intensity continuous exercise: implications for exercise adherence.

J Sport Sci. 2011;29:547Y53.

3. Gibala MJ, Little JP, Macdonald MJ, Hawley JA. Physiological adaptations to

low-volume, high-intensity interval training in health and disease. JPhysiol.

2012;590:1077Y84.

4. Gibala MJ, McGee SL. Metabolic adaptations to short-term high-intensity interval

training: a little pain for a lot of gain? Exerc Sport Sci Rev. 2008;36:58Y63.

5. Guiraud T, Nigam A, Gremeaux V, Meyer P, Juneau M, Bosquet L.

High-intensity interval training in cardiac rehabilitation. Sports Med.

2012;42:587Y605.

6. Hegerud J, Hoydal K, Wang E, et al. Aerobic high-intensity intervals

improve V

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2max

more than moderate training. Med Sci Sports Exerc.

2007;39:665Y71.

7. Jung M, Little J. Taking a HIIT for physical activity: is interval training

viable for improving health. In: Paper presented at the American College

of Sports Medicine Annual Meeting: Indianapolis (IN). American College

of Sports Medicine; 2013.

8. Karstoft K, Winding K, Knudsen SH, et al. The effects of free-living

interval-walking training on glycemic control, body composition, and physical

fitness in type 2 diabetic patients: a randomized, controlled trial. Diabetes Care.

2012;36:228Y36.

TABLE 2: Recommendations for Practitioners

Educate Provide clients and patients with information related to the benefits of HIIT.

Base prescription Warm-up at a low to moderate intensity for 2 to 5 minutes.

First complete a 1-minute high-intensity work interval at about 90% of max effort.

Then complete a 1-minute low-intensity recovery interval at about 10% max effort.

Repeat the work and recovery intervals 10 times for a total of 20 minutes.

Cooldown at a low to moderate intensity for 2 to 5 minutes.

Start slowly Increase the number of HIIT sessions into an exercise program across time.

Trial and error Encourage clients to try a variety of HIIT workouts to find one that is enjoyed.

Consider manipulating the duration of the intervals to shorter or longer periods.

Adjust the recovery period for more or less rest between work intervals.

Change it up Try HIIT exercises indoors and outdoors, with music and without music, alone and with workout partners, etc.

Be careful Reinforce that intense exercise increases risk and to be cautious when trying new HIIT routines, especially those

that require any unorthodox movement patterns.

VOL. 18/ NO. 5 ACSM’s HEALTH & FITNESS JOURNALA15

9. Kessler HS, Sisson SB, Short KR. The potential for high-intensity interval

training to reduce cardiometabolic disease risk. Sports Med. 2012;42:489Y509.

10. Little JP, Gillen JB, Percival ME, et al. Low-volume high-intensity interval

training reduces hyperglycemia and increases muscle mitochondrial capacity

in patients with type 2 diabetes. J Appl Phys. 2011;111:1554Y60.

11. Lollgen H, Bockenhoff A, Knapp G. Physical activity and all-cause

mortality: an updated meta-analysis with different intensity categories.

Int J Sports Med. 2009;30:213Y24.

12. Lox C, Martin K, Petruzzello S. The Psychology of Exercise: Integrating

Theory and Practice. 3rd ed. Scottsdale: Holcomb Hathaway; 2010:349 p.

13. McCrae G, Payne A, Zelt JGE, et al. Extremely low volume, whole-body

aerobic resistance training improves aerobic fitness and muscular endurance

in females. J Appl Physiol Nutr Metab. 2012;37:1124Y31.

14. Martinez N. Perceptual responses to high-intensity interval training in

overweight and sedentary individuals [thesis]. Tampa (FL): University of

South Florida; 2013.

15. United States Department of Health and Human Services. Physical Activity

Guidelines for Americans. Rockville (MD): Public Health Service; 2008.

16. United States Department of Health and Human Services. Summary Health

Statistics for U.S. Adults: National Health Interview Survey, 2010. Hyattsville,

MD: Public Health Service; 2012.

17. Williams DM. Exercise, affect, and adherence: an integrated model and a

case for self-paced exercise. J Sport Exerc Psychol. 2008;30:471Y96.

18. Wisloff U, Ellingsen O, Kemi OJ. High-intensity interval training to maximize

cardiac benefits of exercise training? Exerc Sport Sci Rev. 2009;37:139Y46.

Disclosure: The authors declare no conflicts of interest and do

not have any financial disclosures.

Marcus W. Kilpatrick, Ph.D., is an associate

professor of Exercise Science in the School of

Physical Education and Exercise Science at

the University of South Florida. His education

is in the areas of nutrition, kinesiology, and

health education. His research interests in-

clude physical activity motivation, perceived

exertion, and mood.

Mary E. Jung, Ph.D., is an assistant professor

of Exercise Science in the School of Health

and Exercise Sciences at the University of

British Columbia at Okanagan. Her educa-

tion is in the areas of kinesiology and exercise

psychology. Her research interests include

self-regulation of health behaviors such as

physical activity, diet, and smoking.

Jonathan P. Little, Ph.D., is an assistant

professor of Exercise Science in the School of

Health and Exercise Sciences at the University

of British Columbia at Okanagan. His education

is in kinesiology where he specializes in exercise

physiology. His research interests focus on

the impact of obesity, insulin resistance, and

type 2 diabetes on metabolic health.

BRIDGING THE GAP

AerobicHIITisaneffectiveandprovenapproachtofitness

training that is known to benefit aerobic fitness, metabolic

health, and cardiovascular function. Such training requires

the exerciser to engage in exercise at intensities that are

known to have negative impacts on mood. However,

emerging research suggests that this form of training is

pleasurable and may provide a viable training option for

individuals desiring to improve health and fitness.

BRIDGING THE GAP

AerobicHIITisaneffectiveandprovenapproachtofitness

training that is known to benefit aerobic fitness, metabolic

health, and cardiovascular function. Such training requires

the exerciser to engage in exercise at intensities that are

known to have negative impacts on mood. However,

emerging research suggests that this form of training is

pleasurable and may provide a viable training option for

individuals desiring to improve health and fitness.

16 ACSM’s HEALTH & FITNESS JOURNALA|www.acsm-healthfitness.org VOL. 18/ NO. 5

High-Intensity Interval Training

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Full-text available

Jan 2025

Abstract Regular exercise produces a variety of physiological changes that improve exercise capacity and health, regardless of age, gender, or chronic illness status. Despite widespread physical inactivity due to time restrictions, High-Intensity Interval Training (HIIT) has evolved as a popular and time-saving strategy for strenuous exercise that improves physical fitness by increasing maximum oxygen uptake (VO2max) and muscle power. HIIT, which consists of brief bursts of intense activity at or near peak effort interspersed with intervals of rest or low-intensity exercise, causes a variety of physiological changes that improve exercise capacity and metabolic health in both clinical and healthy populations. Given the expanding scientific understanding and broad use of HIIT, this clinical commentary seeks to thoroughly investigate its definition, parameters, scientific foundations, multifarious benefits, and evidence acrossvaried groups and situations. Keywords High intensity interval training – scientific foundations – chronic health diseases – exercise – training

Effects of Two In-Season Short High-Intensity Interval Training Formats on Aerobic and Neuromuscular Performance in Young Soccer Players

Article

Full-text available

Dec 2024
J SPORT SCI MED

Supplementary high-intensity interval training (HIIT) programs, focusing on different aspects of fitness, are commonly used in soccer practice. This study examined the impact of two different HIIT formats applied during the competitive season on aerobic and neuromuscular performance. Twenty-six young players from two youth amateur soccer teams (aged 18.1 ± 0.7 and 18.7 ± 1.1 years) participated. In a randomized design, Team A served as an experimental group, performing either a 10s/10s linear running HIIT or a 15s/15s HIIT with changes of direction, both at 100% of maximum aerobic speed, twice per week for six weeks. In that period, team B acted as a control group, maintaining their usual training soccer regimen. Following two weeks of lower volume and frequency training, team B added the two HIIT formats in their training for six weeks, while team A acted as control. Before and after each 6-weeks period, aerobic fitness and neuromuscular performance was evaluated by the countermovement jump (CMJ). The 3-way ANOVA showed that both HIIT formats significantly enhanced Yo-Yo Intermittent Recovery Test Level 1 (Yo-YO IR1) performance compared to the respective control periods. However, the main finding was that the 10s/10s compared with the 15s/15s HIIT format induced 45-50% greater improvements in Yo-YO IR1 (total distance: 18.5 ± 11.7% vs. 9.0 ± 8.5%, V́O2max: 5.6 ± 3.2% vs. 3.0 ± 2.7%, and vV́O2max: (3.3 ± 1.9% vs. 1.8 ± 1.7%, all p = 0.39, d = 0.85). Countermovement jump performance remained unchanged across both groups (p > 0.68). During HIIT rating of perceived exertion was higher in the 15s/15s vs. the 10s/10s format (6.4 ± 0.5 vs. 4.7 ± 1.2 a.u., p < 0.001). These findings suggest that while both HIIT formats effectively enhance aerobic performance during the season, the 10s/10s format offers superior benefits with less perceived exer-tion, while the 15s/15s format induces higher internal load.

Acute Effects of a High-Intensity Interval Training Protocol on Pain Sensitivity and Inflammatory Markers in Persons with Chronic Nonspecific Low Back Pain: A Controlled Clinical Trial

Article

Full-text available

Mar 2025

Chronic nonspecific low back pain (CNSLBP) might be associated with increased pain sensitivity and inflammation. High-intensity interval training (HIIT) has been suggested to reduce pain outcomes and inflammatory markers, but its effects compared to moderate-intensity continuous training (MICT) remain unclear. This study aimed to evaluate the acute effects of HIIT on pain sensitivity and inflammatory markers in persons with CNSLBP compared to healthy controls (HCs) and to determine how these effects differ from MICT. Twenty persons with CNSLBP and twenty HCs were assessed before (PRE) and after (POST) a single HIIT and MICT protocol for pain sensitivity (cuff pressure pain threshold (cPPT), temporal summation of pain (TS), conditioned pain modulation (CPM)), and inflammatory markers (IL-6, TNF-α). Data were analyzed using one-way ANOVAs, paired t-tests, and correlation analyses. At PRE, persons with CNSLBP exhibited lower cPPT (28.2 ± 7.1, Δ = −5.5, p = 0.040), higher TS (1.11 ± 0.89, Δ = 0.79, p = 0.042), and lower CPM (36.2 ± 11.6, Δ = −10.0, p = 0.023) compared to HCs. HIIT resulted in PRE–POST improvements in cPPT (38.9 ± 12.6, Δ = 5.2, p = 0.019) in HCs. No PRE–POST differences were observed in pain processing in those with CLBP. No PRE or PRE–POST differences were observed in the inflammatory markers in either group. The current exploratory study suggests that a single HIIT session might have a beneficial effect on pain sensitivity in HCs but does not alter acute pain sensitivity or inflammatory markers in persons with CNSLBP. Further research is needed to clarify the involved mechanisms and explore the (relation with the) long-term effects of HIIT.

YÜKSEK YOĞUNLUKLU ARALIKLI EGZERSİZ: MİTOKONDRİYAL BİYOGENEZDE ROL ALAN POTANSİYEL MOLEKÜLER MEKANİZMALAR

Chapter

Full-text available

Nov 2024

Melih Çalışır

Son yıllarda kilo vermek ve fiziksel aktivite önerilerini karşılamak için genel sağlık ve fitnes endüstrisi temel hareket modellerine odaklanan yeni egzersiz rutinleri ve eğilimleri (trendler) üzerinde çalışmalara odaklanmıştır. Buna paralel olarak bilim insanları, egzersiz profesyonelleri ve antrenörler sporcuların performansını daha kısa sürelerde optimize ve maksimize edecek stratejiler geliştirmek ve aynı zamanda hareketsiz kişilerin sağlıkla ilgili parametrelerini iyileştirmek için araştırmalar gerçekleştirmiştir (Tekin vd., 2015; Tekin vd., 2018). Günümüze kadar olan süreçte ise farklı egzersiz metotları ortaya atılmış ve geniş bir çeşitliliğe ulaşmıştır. Bu bağlamda yüksek yoğunluklu aralıklı egzersiz (YYAE) modaliteleri haftada daha az zaman gerektirmesi ve farklı bir çalışma-dinlenme oranına sahip olması nedeniyle popülaritesini artırmış, Amerikan Spor Hekimliği Koleji tarafından gerçekleştirilen yıllık fitnes eğilimleri anketlerinde ön sıralarda yer almıştır (Thompson, 2018; Thompson, 2022; Kercher vd., 2022). Dahası YYAE modalitelerini ele alan bilimsel yayınların sayısı da önemli ölçüde artmış, YYAE'nin maksimum aerobik kapasiteyi ve egzersiz performansını iyileştirdiği, daha kısa antrenman dönemleri sayesinde daha yüksek antrenman etkileri oluşturabildiği, sürekli antrenmana benzer şekilde maksimum kardiyovasküler iyileşme sağladığı (Franchini vd., 2019; Harrison vd., 2015; Costa vd., 2018; Gibala ve Jones, 2013), sağlık ve yaşam parametrelerini iyileştirmede etkili olduğu, zaman açısından verimli ve keyifli bir yaklaşım olabileceği gösterilmiştir (Coates vd., 2023; Maillard vd., 2018; Gibala, 2007). Literatür incelendiğinde, YYAE modalitesinin muhtemel etki mekanizması, yüksek yoğunluklu yüklenmelerin mitokondriyal enzim artışları ve aerobik enerji sağlama potansiyelindeki artışlar gösterilmektedir (Gibala ve McGee, 2008; Ross ve Leveritt, 2001). Dahası, belirli bir süre (4-6 hafta) YYAE uygulamalarının iskelet kası protein içeriğinde, glikoz ve serbest yağ asidi taşınımı ile oksidasyonlarında etkileri olduğu bildirilmektedir. Bununla birlikte, YYAE'nin, insan organizması için son derece önemli olan karbonhidrat, yağ ve proteinlerin regülasyonu, transkripsiyonu ve stimulasyonu açısından etki potansiyeli olduğu düşünülmektedir (Burgomaster vd., 2008). Bu noktadan hareketle bu araştırmada YYAE modalitelerine yanıt olarak mitokondriyal biyogenezde rol oynayabilecek potansiyel moleküler mekanizmalara ilişkin kısa bir genel bakış sunulacaktır.

Guiding role of infrared thermal radiation images based on sensors in sports Training: Application of artificial intelligence

Article

Feb 2025

Visualizations on Smart Watches while Running: It Actually Helps!

Conference Paper

Oct 2024

Solving the High-Intensity Multimodal Training Prescription Puzzle: A Systematic Mapping Review

Article

Full-text available

Jul 2024

Background High-Intensity Multimodal Training (HIMT) refers to all styles of high-intensity combined aerobic, resistance and/or bodyweight exercise. Previous heterogeneity in exercise prescription and reporting in HIMT reduces the understanding of which factors should be considered when prescribing HIMT (e.g., exercise volume, intensity, duration). Previous studies have demonstrated positive effects of HIMT on health and performance outcomes. However, methodological disparities limit comparisons between findings. The objective of this systematic mapping review was to examine which prescriptive considerations and health and performance outcomes have been reported on in HIMT. This review also examined the quantity and trends of research conducted on HIMT. Methods A systematic literature search was conducted using Ovid Medline, SPORTDiscus and Cochrane Library databases and additional sources to identify studies up until February 2023. A total of 37,090 records were retrieved, of which 220 were included for review. 246 individual HIMT protocols were included for categorical analysis against the Consensus on Exercise Reporting Template (CERT) and Applied Research Model for the Sport Sciences (ARMSS). Results A total of 85 unique terms were used to describe HIMT. Included studies most commonly prescribed HIMT using a consistent exercise selection and circuit format. Exercise intensity was inconsistently reported on and a large proportion of studies prescribed ‘high-intensity’ exercise at a level lower than the American College of Sports Medicine criteria for high-intensity (i.e., < 77% heart rate maximum). Participation location, supervision and participation format were the most commonly reported non-training variables. The most frequently reported outcomes were cardiovascular health, perceptual outcomes, body composition and biochemical outcomes. A large proportion of previous HIMT research was experimental in design. Conclusions Previous HIMT research demonstrates a lack of standardisation in reporting. Future studies should seek to follow guidelines (i.e., CERT) to improve reporting rigour. Additionally, forthcoming research should attempt to actively involve practitioners in implementation studies to improve ecological validity among interventions. Finally, future outcome measures should be accessible in practice and reflect common training goals of participants. Registration This review adhered to PRISMA-ScR guidelines. Preregistration: osf.io/yknq4.

The Effects of Free-Living Interval-Walking Training on Glycemic Control, Body Composition, and Physical Fitness in Type 2 Diabetic Patients

Article

Full-text available

Jan 2012
DIABETES CARE

OBJECTIVEdTo evaluate the feasibility of free-living walking training in type 2 diabetes patients, and to investigate the effects of interval-walking training versus continuous-walking training upon physical fitness, body composition, and glycemic control. RESEARCH DESIGN AND METHOD SdSubjects with type 2 diabetes were randomized to a control (n = 8), continuous-walking (n = 12), or interval-walking group (n = 12). Training groups were prescribed five sessions per week (60 min/session) and were controlled with an accelerometer and a heart-rate monitor. Continuous walkers performed all training at moderate intensity, whereas interval walkers alternated 3-min repetitions at low and high intensity. Before and after the 4-month intervention, the following variables were measured: VO 2 max, body composition, and glycemic control (fasting glucose, HbA 1c , oral glucose tolerance test, and continuous glucose monitoring [CGM]). RESULTSdTraining adherence was high (89 6 4%), and training energy expenditure and mean intensity were comparable. VO 2 max increased 16.1 6 3.7% in the interval-walking group (P , 0.05), whereas no changes were observed in the continuous-walking or control group. Body mass and adiposity (fat mass and visceral fat) decreased in the interval-walking group only (P , 0.05). Glycemic control (elevated mean CGM glucose levels and increased fasting insulin) wors-ened in the control group (P , 0.05), whereas mean (P = 0.05) and maximum (P , 0.05) CGM glucose levels decreased in the interval-walking group. The continuous walkers showed no changes in glycemic control. CONCLUSION SdFree-living walking training is feasible in type 2 diabetes patients. Con-tinuous walking offsets the deterioration in glycemia seen in the control group, and interval walking is superior to energy expenditure–matched continuous walking for improving physical fitness, body composition, and glycemic control.

''High-Intensity Interval Training in Cardiac Rehabilitation''

Article

Full-text available

Jul 2012

High-intensity interval training (HIIT) is frequently used in sports training. The effects on cardiorespiratory and muscle systems have led scientists to consider its application in the field of cardiovascular diseases. The objective of this review is to report the effects and interest of HIIT in patients with coronary artery disease (CAD) and heart failure (HF), as well as in persons with high cardiovascular risk. A non-systematic review of the literature in the MEDLINE database using keywords ‘exercise’, ‘high-intensity interval training’, ‘interval training’, ‘coronary artery disease’, ‘coronary heart disease’, ‘chronic heart failure’ and ‘metabolic syndrome’ was performed. We selected articles concerning basic science research, physiological research, and randomized or non-randomized interventional clinical trials published in English. To summarize, HIIT appears safe and better tolerated by patients than moderate-intensity continuous exercise (MICE). HIIT gives rise to many short- and long-term central and peripheral adaptations in these populations. In stable and selected patients, it induces substantial clinical improvements, superior to those achieved by MICE, including beneficial effects on several important prognostic factors (peak oxygen uptake, ventricular function, endothelial function), as well as improving quality of life. HIIT appears to be a safe and effective alternative for the rehabilitation of patients with CAD and HF. It may also assist in improving adherence to exercise training. Larger randomized interventional studies are now necessary to improve the indications for this therapy in different populations.

The Potential for High-Intensity Interval Training to Reduce Cardiometabolic Disease Risk

Article

Full-text available

Jun 2012

In the US, 34% of adults currently meet the criteria for the metabolic syndrome defined by elevated waist circumference, plasma triglycerides (TG), fasting glucose and/or blood pressure, and decreased high-density lipoprotein cholesterol (HDL-C). While these cardiometabolic risk factors can be treated with medication, lifestyle modification is strongly recommended as a first-line approach. The purpose of this review is to focus on the effect of physical activity interventions and, specifically, on the potential benefits of incorporating higher intensity exercise. Several recent studies have suggested that compared with continuous moderate exercise (CME), high-intensity interval training (HIT) may result in a superior or equal improvement in fitness and cardiovascular health. HIT is comprised of brief periods of high-intensity exercise interposed with recovery periods at a lower intensity. The premise of using HIT in both healthy and clinical populations is that the vigorous activity segments promote greater adaptations via increased cellular stress, yet their short length, and the ensuing recovery intervals, allow even untrained individuals to work harder than would otherwise be possible at steady-state intensity. In this review, we examine the impact of HIT on cardiometabolic risk factors, anthropometric measures of obesity and cardiovascular fitness in both healthy and clinical populations with cardiovascular and metabolic disease. The effects of HIT versus CME on health outcomes were compared in 14 of the 24 studies featuring HIT. Exercise programmes ranged from 2 weeks to 6 months. All 17 studies that measured aerobic fitness and all seven studies that measured insulin sensitivity showed significant improvement in response to HIT, although these changes did not always exceed responses to CME comparison groups. A minimum duration of 12 weeks was necessary to demonstrate improvement in fasting glucose in four of seven studies (57%). A minimum duration of 8 weeks of HIT was necessary to demonstrate improvement in HDL-C in three of ten studies (30%). No studies reported that HIT resulted in improvement of total cholesterol, low-density lipoprotein cholesterol (LDL-C), or TG. At least 12 weeks of HIT was required for reduction in blood pressure to emerge in five studies of participants not already being treated for hypertension. A minimum duration of 12 weeks was necessary to see consistent improvement in the six studies that examined anthropometric measures of obesity in overweight/obese individuals. In the 13 studies with a matched-exercise-volume CME group, improvement in aerobic fitness in response to HIT was equal to (5 studies), or greater than (8 studies) in response to CME. Additionally, HIT has been shown to be safe and effective in patients with a range of cardiac and metabolic dysfunction. In conclusion, HIT appears to promote superior improvements in aerobic fitness and similar improvements in some cardiometabolic risk factors in comparison to CME, when performed by healthy subjects or clinical patients for at least 8-12 weeks. Future studies need to address compliance and efficacy of HIT in the real world with a variety of populations.

Low-volume high-intensity interval training reduces hyperglycemia and increases muscle mitochondrial capacity in patients with type 2 diabetes

Article

Full-text available

Aug 2011
J APPL PHYSIOL

Low-volume high-intensity interval training (HIT) is emerging as a time-efficient exercise strategy for improving health and fitness. This form of exercise has not been tested in type 2 diabetes and thus we examined the effects of low-volume HIT on glucose regulation and skeletal muscle metabolic capacity in patients with type 2 diabetes. Eight patients with type 2 diabetes (63 ± 8 yr, body mass index 32 ± 6 kg/m(2), Hb(A1C) 6.9 ± 0.7%) volunteered to participate in this study. Participants performed six sessions of HIT (10 × 60-s cycling bouts eliciting ∼90% maximal heart rate, interspersed with 60 s rest) over 2 wk. Before training and from ∼48 to 72 h after the last training bout, glucose regulation was assessed using 24-h continuous glucose monitoring under standardized dietary conditions. Markers of skeletal muscle metabolic capacity were measured in biopsy samples (vastus lateralis) before and after (72 h) training. Average 24-h blood glucose concentration was reduced after training (7.6 ± 1.0 vs. 6.6 ± 0.7 mmol/l) as was the sum of the 3-h postprandial areas under the glucose curve for breakfast, lunch, and dinner (both P < 0.05). Training increased muscle mitochondrial capacity as evidenced by higher citrate synthase maximal activity (∼20%) and protein content of Complex II 70 kDa subunit (∼37%), Complex III Core 2 protein (∼51%), and Complex IV subunit IV (∼68%, all P < 0.05). Mitofusin 2 (∼71%) and GLUT4 (∼369%) protein content were also higher after training (both P < 0.05). Our findings indicate that low-volume HIT can rapidly improve glucose control and induce adaptations in skeletal muscle that are linked to improved metabolic health in patients with type 2 diabetes.

High-intensity interval running is perceived to be more enjoyable than moderate-intensity continuous exercise: Implications for exercise adherence

Article

Full-text available

Feb 2011
J SPORT SCI

The aim of this study was to objectively quantify ratings of perceived enjoyment using the Physical Activity Enjoyment Scale following high-intensity interval running versus moderate-intensity continuous running. Eight recreationally active men performed two running protocols consisting of high-intensity interval running (6 × 3 min at 90% VO(2max) interspersed with 6 × 3 min active recovery at 50% VO(2max) with a 7-min warm-up and cool down at 70% VO(2max)) or 50 min moderate-intensity continuous running at 70% VO(2max). Ratings of perceived enjoyment after exercise were higher (P < 0.05) following interval running compared with continuous running (88 ± 6 vs. 61 ± 12) despite higher (P < 0.05) ratings of perceived exertion (14 ± 1 vs. 13 ± 1). There was no difference (P < 0.05) in average heart rate (88 ± 3 vs. 87 ± 3% maximum heart rate), average VO(2) (71 ± 6 vs. 73 ± 4%VO(2max)), total VO(2) (162 ± 16 vs. 166 ± 27 L) or energy expenditure (811 ± 83 vs. 832 ± 136 kcal) between protocols. The greater enjoyment associated with high-intensity interval running may be relevant for improving exercise adherence, since running is a low-cost exercise intervention requiring no exercise equipment and similar relative exercise intensities have previously induced health benefits in patient populations.

Physical Activity and All-cause Mortality: An Updated Meta-analysis with Different Intensity Categories

Article

Full-text available

Mar 2009
INT J SPORTS MED

In a meta-analysis we investigated the effect of physical activity with different intensity categories on all-cause mortality. Many studies have reported positive effects of regular physical activity on primary prevention. This recent meta-analysis analyzed all-cause mortality with special reference to intensity categories. A computerized systematic literature search was performed in EMBASE, PUBMED, and MEDLINE data bases (1990-2006) for prospective cohort studies on physical leisure activity. Thirty-eight studies were identified and evaluated. The presentation refers to studies with 3 or 4 different intensities of regular physical activity according to a standard questionnaire. There was a significant association of lower all-cause mortality for active individuals compared with sedentary persons. For studies with three activity categories (mildly, moderately, and highly active) and multivariate-adjusted models, highly active men had a 22% lower risk of all-cause mortality (RR=0.78; 95% CI: 0.72 to 0.84) compared to mildly active men. For women, the relative risk was 0.69 (95% CI: 0.53 to 0.90). We observed similar results in moderately active persons compared to mildly active individuals (RR=0.81 for men and RR=0.76 for women). This association of activity to all-cause mortality was similar and significant in older subjects. Regular physical activity over longer time is strongly associated with a reduction in all-cause mortality in active subjects compared to sedentary persons. There is a dose-response curve especially from sedentary subjects to those with mild and moderate exercise with only a minor additional reduction with further increase in activity level.

Affective And Enjoyment Responses To High-intensity Interval Training In Overweight And Sedentary Individuals: 800 Board #215 May 28, 3

Article

May 2014

The psychology of exercise: Integrating theory and practice.

Article

Jan 2003

Interweaves theory, research, application, and intervention in exercise psychology, applying theories and models to actual situations that readers are likely to encounter professionally. Each chapter includes examples, review questions, and activities to enhance learning. Part I is devoted to helping readers better understand and modify exercise behavior. Part II reviews the most commonly promoted and studied psychosocial aspects of physical activity, such as the relationship between exercise and personality and the impact of exercise on depression, stress/anxiety, emotional well-being, and self-esteem. Chapters on social influences, body image, and health-related quality of life offer the latest information on these emerging areas of study. (PsycINFO Database Record (c) 2012 APA, all rights reserved)

Physiological adaptations to low-volume, high-intensity interval training in health and disease

Article

Mar 2012
J PHYSIOL-LONDON

Exercise training is a clinically proven, cost-effective, primary intervention that delays and in many cases prevents the health burdens associated with many chronic diseases. However, the precise type and dose of exercise needed to accrue health benefits is a contentious issue with no clear consensus recommendations for the prevention of inactivity-related disorders and chronic diseases. A growing body of evidence demonstrates that high-intensity interval training (HIT) can serve as an effective alternate to traditional endurance-based training, inducing similar or even superior physiological adaptations in healthy individuals and diseased populations, at least when compared on a matched-work basis. While less well studied, low-volume HIT can also stimulate physiological remodelling comparable to moderate-intensity continuous training despite a substantially lower time commitment and reduced total exercise volume. Such findings are important given that 'lack of time' remains the most commonly cited barrier to regular exercise participation. Here we review some of the mechanisms responsible for improved skeletal muscle metabolic control and changes in cardiovascular function in response to low-volume HIT. We also consider the limited evidence regarding the potential application of HIT to people with, or at risk for, cardiometabolic disorders including type 2 diabetes. Finally, we provide insight on the utility of low-volume HIT for improving performance in athletes and highlight suggestions for future research.

High-Intensity Interval Training to Maximize Cardiac Benefits of Exercise Training?

Article

Aug 2009
EXERC SPORT SCI REV

WISLOFF, U, O. ELLINGSEN, and O.J. KEMI. High-intensity interval training to maximize cardiac benefits of exercise training? Exerc. Sport Sci. Rev., Vol. 37, No. 3, pp. 139-146, 2009. We hypothesized that high-intensity aerobic interval training results in a greater beneficial adaptation of the heart compared with that observed after low-to-moderate exercise intensity. This is supported by recent epidemiological, experimental, and clinical studies. Cellular and molecular mechanisms of myocardial adaptation to exercise training are discussed in this review.