Several studies have shown including the above YouTube clip from the BBC Horizon Investigative Series “The Truth About Exercise” that the most effective form of exercise for the human body is called HIIT(High Intensity Interval Training). In this Horizon documentary about exercise, Dr. Mosley demonstrated that as little as 3 minutes of high intensity training per week can deliver more health and fitness benefits than doing hours of conventional exercise each week. HIIT engages far more of your muscle tissue than conventional aerobic cardio exercise. Dr. Mosley was able to improve his insulin sensitivity by 24 percent by putting in just 12 minutes of intense exercise per week, for four weeks So what exactly is HIIT.
HIIT(High Intensity Interval Training) Explained
High Intensity Interval Training (HIIT) is a type of cardio training which calls for repeated bouts of short duration, high-intensity exercise intervals intermingled with periods of lower intensity intervals of active recovery. On a scale of 1-10 in terms of physical exertion, high intensity can be considered anything over an exertion level of 7. If for example you use your max heart rate (MHR) as a measurement for physical activity, high intensity training could be considered as exercising at a level equal to 80% or above your MHR.
A typical HIIT workout should last about 20-30 minutes and should have a 2:1 ratio. By that I mean that the recovery intervals should be twice as long as the work intervals. An example of a typical sprint HIIT would be 8-10 high intensity sprints lasting 30-60 seconds interspersed with recovery intervals of 1-2 minutes. There are many variations on this, but, the general rule is that the recovery time during HIIT workouts should be twice as long the as the actual physical exertion time.
Unfortunately, anywhere from 90 – 98% of people who exercise do not partake in high intensity exercising. By focusing on slow endurance-type exercises, such as running on a treadmill, many people actually forgo many of the most profound benefits of exercise. With HIT, you are not only using your leg muscles, but also your upper body including your arms and shoulders, so that 80% of the body’s muscles are activated as compared to 20-40% for walking or moderately intense jogging or cycling.
The natural evolution of our body/skeletal structures means that we are designed to perform this type of training anyhow. HIIT trigger your body’s fight or flight hormone mechanism, which results in the release of adrenaline and epinephrine. These hormones trigger chemicals releases in the body that empties your muscles of glucose in order for it to be used for fuel. If as scientists believe we evolved as hunter/gatherers through the ages, then, high-intensity interval training is like being on the hunt and intermittently sprinting for your life for a short period of time.
The Benefits of HIIT
HIIT training can improve:
1. Aerobic and anaerobic fitness – HIIT both taxes and maximises both aerobic and anaerobic fitness leading to improved athletic speed and performance.
2. Blood pressure – HIIT can help to significantly lower resting and ambulatory blood pressure.
3. Cardiovascular health – HIIT is the most effective form of exercising for improving cardiorespiratory fitness & for reducing risk of cardiovascular morbidity and mortality even in older people.
4. Insulin sensitivity – HIIT helps the exercising muscles to more readily use glucose for fuel to
make energy. It improves your glycogen storage and utilization capabilities, which improves your insulin sensitivity.
5. Abdominal fat and body weight while maintaining muscle mass – HIIT can increase liberation of fat from adipose cells and the burning of the fat within the skeletal muscle. This stimulates chemical messengers in the body that inhibit the release and the effect of the inflammatory cytokines that are produced by body fat. They also significantly, via inhibitory effect, reduce body fat irrespective of calorie intake. It actually has a fat-reducing effect that exists outside of energy balance. They have very profound effects.
Examples of HIIT Workouts
Here are 3 potential HIIT workouts developed by 3 International fitness gurus, but really each individual must tailor their own HIIT workout to their individuals preferences and physical capabilities but without losing the INTENSITY that HIIT provides.
1. Tabata Method: The Tabata Method was developed in 1996 by Dr. Izumi Tabata of Japan. It involves high-intensity spurts at 170% of one’s VO2 max( VO2 is the measure of the volume of oxygen that is used by the body to convert the energy from the food we eat into energy molecules. VO2 max is simply the maximum possible VO2 that a given person can achieve). The workouts total four minutes and involve 20 seconds of high intensity followed by 10 seconds of rest for eight cycles. The recommended frequency of Tabata workouts is between two and four times per week. Tabata is best for those who are already fit and are looking for a workout that requires very little time. The Tabata Method can also be performed with strength training movements. To implement the Tabata Method, try the following. Start with a three-minute warm-up, then sprint for 20 seconds. Rest (walk) for 10 seconds, then repeat the sprint/walk cycle for a total of eight cycles.
2. The Little Method: The Little Method was developed by Drs. Johnathan Little and Martin Gibala in 2009. It involves high-intensity workouts at 95% of one’s VO2 max. The protocol calls for 60 seconds of high intensity followed by 75 seconds of low intensity. You repeat this for a total of 12 cycles (totaling 27 minutes) up to three times per week.
To follow the Little Method, you could start with a three-minute warm-up. Cycle for 60 seconds quickly and with max resistance. Follow that with 75 seconds of slow cycling at low resistance, and repeat the fast/slow cycle for a total of 27 minutes. This method is very effective for people who would consider themselves at an intermediate fitness level & who have about 30 minutes to exercise.
3. Turbulence training: Turbulence training was developed by exercise physiology researcher Craig Ballantyne. It involves eight-rep weight training sets alternated with one to two-minute cardio sets. This type of HIIT alternates high-weight/low-rep strength training with high-intensity cardio. The maximum 45-minute workouts combine strength training with cardio, and the recommended frequency is three times per week.
To follow the Turbulence Training method, start with a five-minute warm-up. Perform an eight-rep set of a weightlifting movement (i.e. squat press, bench press) followed by one minute of mountain climbers. Repeat through a full-body routine for 45 minutes. Turbulence Training is generally best for those who have longer to train and are looking to incorporate strength training into their routines.
I don’t have TIME: no more excuses
There are very compelling reasons for trading your hour-long walk on the treadmill for a 20-minute high intensity routine, and as HIIT proves, less time can indeed lead to a greater payout, if done correctly. As Dr. Mosley writes in his book, Fast Exercise: “I believe that we have now produced sufficient data to be able to recommend short bursts of high-intensity exercise as a safe and effective alternative to conventional workouts, removing the ‘time barrier’ as an excuse for not exercising.
This will hopefully boost compliance and help people take up an approach that will lead to a healthier way of life.”
The great thing about HIIT is that it can be done in the workplace or at home without having to go the gym, so, START EXERCISING TODAY and realise the acute benefits of HIIT.