High Intensity Interval Training (HIIT) was listed #3 on ACSM's 2016 Fitness Trends, down from the #1 spot it held the prior 2 years.
So even though it's popularity is fading, it's not going very far. It's still one of the most used and most asked about modes of exercise in today's era of fitness. In fact, an hour and a half was devoted to just this topic at a recent health & fitness conference I attended. The session was so packed with personal trainers we have to move rooms to accommodate.
If you aren't already familiar with HIIT, it alternates periods of higher intensity with periods of low intensity or recovery.
For example: if you are already walking for 20 minutes a day, you might start incorporating short bursts of jogging or faster walking into your routine. A good place to start is adding 1 minute of jogging for every 2 minutes of walking.
Adding HIIT workouts to your general exercise program offers many benefits.
Studies on the effectiveness of interval training started in the mid-90s and have proven time and time again to be an effective tool for fat loss. HIIT also helps improve aerobic capacity, keeps you engaged in exercise (i.e. not bored) and allows you to burn more calories in a shorter period of time. When compared to steady state cardio, these workouts have also been show to increase metabolism for a longer period of time after the workout ends. In every day terms: you keep burning calories!
On the reverse side, HIIT workouts also increase damage to muscle tissue and require longer periods of rest and recovery. An increase in intensity, even in short bursts, can lead to overuse and overtraining, resulting in injury or burnout. In some cases, building aerobic capacity means working at level that is uncomfortable or painful for some people.
Steady State Cardio or Steady State Training (SST) is just that. A steady, continuous effort. It's not the most popular form of exercise but it's important for a number of health reasons, including improving resting heart rate, reducing stress and increasing the capacity of your heart to pump blood.
Regardless of your feelings about SST or your goals, each fitness routine should have an element of SST. It is an established and proven method for improving cardiorespiratory fitness and enhancing aerobic capacity, it increases cardio efficiency with less muscular and cellular damage than HIIT and it enhances the body's ability to use fat as an efficient fuel source.
Like HIIT, SST also has some drawbacks. If your goal is weight loss, SST may extend the time frame in which the your desired weight can be achieved. It also will extend the exercise sessions themselves, which can be tough on an already busy lifestyle.
Participating in the same kind of SST (i.e. always running) can lead to stress injuries.
So, which is best?
Fitness is very specific and should help you meet your goals. If you have signed up for a 5K or are planning a trip to Disney , your focus should be on steady state cardio. This will help you prepare for the upcoming event and mimic the behavior you are trying to accomplish.
If your goal is to improve in a certain sport (basketball, soccer, tennis) the incorporating interval training 1-2 times a week might be better, due to the focus on aerobic power and short burst of energy.
If you are interested in general or health-related fitness do what you enjoy the most! Hint: it should still include at least one session of SST per week.
With all modes of exercise, duration is based on how intensely you train. At an intensity of 85% a person may get a sufficient workout in 20-30 minutes. At 50-60% intensity, the person should train for about an hour.