Why HIIT should be the focus of your cardio workouts!

Like many others, to get leaner, I was literally doing 60-90 min cardio sessions 5-6x a week, I was incorporating intervals, but not an intensity that it moved me beyond "steady state," so I was effectively only burning calories while I was working out, improving my aerobic capabilities but not accruing any additional benefits such an anaerobic improvement, metabolism boost, and additional fat burning. I was getting frustrated and was frankly exhausted and burnt out. When I discovered High Intensity Interval Training (HIIT), I was shocked that in 20-30 min cardio sessions, 2-3x a week, I could accomplish more than what I was previously putting in. Here's more on HIIT and in my prior posts are the recommended HIIT exercise approaches incorporated into a full workout routine. As the below routines stress, rest is important as HIIT requires recovery (indeed, it's the fact that it requires recovery and repair that is driving a number of its benefits, but you can't accrue those benefits unless you rest (24 hours in between sessions, would complete a max of 3 HIIT sessions week).

It's not complex or anything to be intimidated by, it will save you time and improve your results dramatically. In fact, Equinox, Spin Studios (Kinetic here in LA), and other fitness outlets have caught on to HIIT and are incorporating these approaches in their classes - so you may be getting exposure to HIIT without knowing it, I would recommend gravitating to those types of classes more! 

HIIT Defined: High Intensity Interval Training (HIIT). High intensity interval training (HIIT) is a type of cardio training in which you alternate short, very high intensity intervals with longer, slower intervals to recover. This type of training has been used by athletes to improve performance, but it's also been shown to benefit the average exerciser. HIIT training not only helps performance, it also improves the ability of the muscles to burn fat. A typical HIIT workout usually lasts about 20-30 minutes and involves a 2:1 ratio, meaning your recovery intervals are twice as long as the work intervals.

Heart Rate Targets to drive "intensity:"

• Many have asked "what is intense?" Well, your personal definition of intense is going to change over time - what was once intense will seem like a breeze as your aerobic and anaerobic endurance steadily improves. Hence, I highly recommend using a heart rate (HR) monitor for your HIIT training sessions (see "Favs" for preferred equipment).
• Here's what you should be aiming for in terms of HR targets in HIIT - During "work" interval: 85%+ of your target HR max; During "light/rest" interval: 60% of your target HR max (need to focus on your breathing and you will improve over time at bringing your HR down). If you are not hitting 85%+ of your max, you need to a) Work harder; b) Pick a different exercise perhaps; or c) Increase your rest intervals so that you can exert more intensity during the "work" interval until your body adjusts.
• To calculate your HR zones, you can use this simple calculator that starts with your resting heart rate (would take it when you first wake up) and has options for Sex and level of current fitness - finding the 85% and 60% target rates (e.g. for me, with a resting HR of 48 BPM, at age 30, using the male "Fit" formula, mine are 162+ and 114 respectively).

HIIT Benefits, from enumerate studies (many listed on Wikipedia):

• Increases both your aerobic and anaerobic endurance 
• Burns adipose (fatty) tissue more effectively than low-intensity exercise—up to 50% more efficiently.  
• Speeds up metabolism, increasing your Resting Metabolic Rate (RMR), which helps you burn more calories as a baseline. Also referred to as "EPOC" (Excess Post-exercise Oxygen Consumption) or "After-burn effect" - accompanied by an elevated consumption of fuel, fat stores are broken down and free fatty acids (FFA) are released into the blood. In a 1992 Purdue study, results showed that high intensity, anaerobic type exercise resulted in a significantly greater magnitude of EPOC than aerobic exercise of equal work output.
• Results in increased HGH levels, which is a hormone that burns fat while preserving muscle.   

HIIT Approaches - Varying theories around ratios of work to rest:

• Data shows that shorter work intervals of 15-30 seconds allow you to exert more effort, which result in stronger release of HGH and elimination of more fatty acids. Longer work intervals greater than 30 seconds require more perceived effort, resulting in greater number of calories burned, glycogen depletion levels (burning stored carbs for energy), increased EPOC/RMR, allowing your body to burn more fat after the completion of a workout. Further, the amount of rest/low intensity included dictates how much intensity you will be able to put in during the work phase.
• As a result of this data, in the below workouts, I've structured HIIT sessions to vary the interval and rest lengths and continue to experiment with different combinations as well as when to introduce the steady state cardio (some studies have shown that doing the steady state cardio afterwards or in-between HIIT cycles, allows for more active recovery of your muscles as well as better processing of the fatty acids that the HIIT has released into the bloodstream).

My current cardio approach, incorporating HIIT, as outlined in earlier posts for Carpe Life:

• 30 minutes of steady-state cardio:
• Options: Stationary bike (prefer recumbent), rowing machine, swimming, running, stair master, or elliptical. Increase your resistance or intensity every 10 minutes (e.g. could use levels 4, 5, and 6 on the machine over the course of the 30 minutes or if performing outside, increase pace/effort required, such as incorporating hills). HIIT is not easy, so work up to the below interval levels and times, if at any time you experience any dizziness, chest pain, nausea, or severe shortness of breath, discontinue immediately and consult a medical professional.
• 30 minutes of High Intensity Interval Training (HIIT) cardio:
• HIIT Options: Preferred - Jump rope or Kettlebell swings; Others - Sprint/walk on treadmill or outside, Stairmaster, Stationary bike, or stadium stairs. Use the cardio machine or ideally, the GymBoss Max to track your intervals and cycles.
• 4 Interval Sets, 1 minute of rest in between each, for total of 30 minutes: 1) 20 Seconds On / 10 Seconds Off x 10 Cycles (5 min); 2) 30 Seconds On / 15 Seconds Off x 8 Cycles (6 min); 3) 30 Seconds On / 15 Seconds Off x 8 Cycles (6 min); and 4) 1 Minute On / 30 Seconds Off x 6 Cycles (10.5 min)

2 other approaches am experimenting with that you may want to try:

1. a) 15 min steady-state cardio (typically stationary bike or stair-master); b) 11 min, 2 HIIT cycles (15-30 second range) - 1) 20 Seconds On / 10 Seconds Off x 10 Cycles (5 min) and 2) 30 Seconds On / 15 Seconds Off x 8 Cycles (6 min); c) 30 min steady-state cardio (typically stationary bike); and d) 12 min, 1 HIIT cycle (1min range) - 1 Minute On / 30 Seconds Off x 8 Cycles
2. a) 5 min steady-state cardio (typically stationary bike or stair-master); b) 16 min, 2 HIIT cycles (15-30 second range) - 1) 20 Seconds On / 10 Seconds Off x 10 Cycles (5 min); 2) 30 Seconds On / 15 Seconds Off x 8 Cycles (6 min); 3) 30 Seconds On / 15 Seconds Off x 8 Cycles (6 min); c) 30 min steady-state cardio (typically stationary bike); and d) 12 min, 1 HIIT cycle (1min range) - 1 Minute On / 30 Seconds Off x 8 Cycles.