The ACSM guidelines for physical activity in the United States are 150 minutes of moderate activity or 75 minutes of vigorous activity per week. Less than 50% of the population meet these guidelines and physical inactivity is a major cause of morbidity and mortality. One of the biggest excuses people have for not meeting these guidelines is lack of time.
High intensity interval training (HIIT) could be a wonderful solution and actually emerged as researchers were looking for ways to get people to adhere to exercise guidelines.
By definition HIIT simply means alternating between intense work and recovery, similar to performing reps and sets with rest breaks in between during a strength training workout.RELATED: RECOMMENDED PLANS FOR YOU
There are two different categories of HIIT, “aerobic HIIT” and “body weight or resistance HIIT” and the difference between the two is the modality of training.
Although both types are proven to be effective, most of the research has been done on aerobic HIIT training which is based on 3 different models; the Wingate, the Scandinavian and the Practical models.
The Wingate is an anaerobic test which involves “all out” high intensity cycling at for 30 seconds preceded by a 3-5 minute warm up and followed by a 1-2 minute cool down. This is considered low volume interval training because of the short amount of time it takes.
It is primarily used to test short term power in athletes and is not recommended for a long term training program.
The Scandinavian model was developed for cardiac patients and uses several 4 minute intervals followed by an easy recovery of a similar length of time.
In this mode, the amount of time doing heavy exercise is longer than 15 minutes it is considered high volume interval training, similar to typical endurance training. Also, the intervals are not performed at an “all out” high intensity, they are below maximum effort.
The practical model lies somewhere in the middle of the Wingate and Scandinavian models and involves 10, I minute intervals at a 9 out of 10 RPE (rate of perceived exertion= 0 no effort, 10 all out) alternated with 1 minute recovery intervals.
This method can be performed by the general population, including people with type 2 diabetes. It is considered a ” medium volume” interval training program and most closely resembles HIIT in today’s health and fitness industry.
There are many benefits associated with aerobic HIIT training including improved cardiovascular health (the function of blood vessels and heart), metabolic health (hypertension, high cholesterol, diabetes) as well as increased aerobic fitness (cardiorespiratory, greater V02 max). HIIT sessions can help increase speed and endurance in athletes and increase fat loss in people with body weight concerns.
Research has also shown that HIIT exercise is often perceived as more enjoyable than longer, moderate or vigorous exercise sessions and can give you a greater sense of accomplishment afterwards. This indicates that people would be more likely to adhere to their exercise program long term.
Although HIIT is effective for a broad range of people, those with moderate risk factors should be medically cleared by a doctor and high risk factor individuals should be medically supervised while exercising.
Virtually any mode can be used to perform HIIT; cycling indoors or out, walking/ running indoors or out, elliptical and rowing machines as well as swimming. Doing sprints on a treadmill does pose more of a risk so elevating rather than increasing speed is a safer way to perform the high intensity bout.
HIIT is not a one size fits all program, here are some general guidelines to get started with your own HIIT workout:
Warm up at a low to moderate intensity for 2-5 minutes
1 minute high intensity interval at an 9 RPE (rate of perceived exertion) 1 minute low intensity interval at a 1 or 2 RPE
Repeat both intervals 10 times for 20 minutes
Cool down 2-5 minutes at a low to moderate intensity
Start slowly and gradually increase the number of HIIT sessions performed in your exercise program. Try a variety of different HIIT workouts until you find the one that you enjoy most. Try exercising indoors and outdoors, alone or with a friend, with music or without.
You can progress your individual workouts by changing all or any of the following factors; duration, intensity and number of work and rest intervals.
Fitness fads come and go but aerobic HIIT, with it’s proven health benefits and increasing scientific evidence to support it, will likely be around for a long, long time. For more HIIT workout ideas check out this link.
ACSM’s September/October 2014 Health and Fitness Journal
“High-Intensity Interval Training, A review of Physiological and Psychological responses” “Developing an Interval Training Program”
Mike Boyle’s StrengthCoach.com November 2011
“Interval Training HIIT or Miss?”