Beginners Guide to HIIT
High intensity interval training is all the rage now and has been for a while. A lot of its popularity stems from it being a very effective and time efficient way to get your cardiovascular training in. Despite this, many people don't understand exactly how to begin a high intensity fitness program. Here are some tips to get started.
HIIT isn't just aerobic
there are three energy systems the body uses: Anaerobic Alactic - Explosive immediate energy that lasts about 10 to twenty seconds. Anaerobic Lactic - An intermediate source of quicker energy. This is when you need your body to get energy faster but also need to keep up the pace a little longer. It lasts about 1 or 2 minutes.
Aerobic - Long distance source of energy
Can break down fats and can fuel you for hours. When you perform HIIT, you are utilizing primarily the anaerobic lactic system. This is important to understand because essentially what HIIT conditioning is doing is pushing you out of your aerobic threshold because of the accumulation of lactate becomes too great for the aerobic system to deal with. This is why HIIT can be very uncomfortable.
HIIT fatigues you like weight training
Moving as quickly as you can for 30 or 45 second whether it be on a treadmill or a stair master or an elliptical forces you to recruit fast twitch fibers. This is why sprinters are so muscular. But it's important to note that if you do a HIIT or CrossFit class on Monday, which is full of sprints and burpees till max fatigue, you can't do it the very next day. This would be like hitting high volume squats on Saturday and then doing it again on Sunday.
You need to approach HIIT moderately
I would start off a HIIT workout like this: Month 1 30 second sprint all out, rest 1 min and repeat for twenty minutes.
Month 2 45 second sprint all out, rest 1 min and repeat for twenty minutes.
Month 3 1 minute sprint all out, rest 1 minute and repeat for twenty minutes.
After that, you can start to experiment with reducing resting times a bit but I caution you on this. If you’re too quick to rest, then your sprints could get so slow they won't really be sprints anymore. They'll end up just being aerobic intervals which is a completely different thing. You want your rest times to be short enough to not allow full recovery to build lactate tolerance, but long enough to where you can actually move quicker.
HIIT Builds VO2 Max And Aerobic Conditioning
Multiple studies show that HIIT not only improves anaerobic lactate tolerance but also improves aerobic function. This has been a primary marketing concept used to promote HIIT. But I will warn you, there is a reason anaerobic lactate training increase aerobic function. It's because the aerobic system has to be pushed to its very max to get you there and then it doesn't just turn off. Your aerobic system is still revving its engine, trying to play catch up, and trying to help you recover in between sprints when you’re sucking wind like a vacuum.
HIIT Isn't For The De Conditioned
I'm telling you this, if you are not in very good shape and have a very poor aerobic base, HIIT isn't a good idea. You won't be able to recover from your sprints and you will probably get nauseas and puke. HIIT isn't for total newbies. HIIT is truly awesome but like all things, it's not the Holy Grail to fitness. It's just one of the many tools that can help you get in the best shape of your life.
References: NSCA: Essentials of strength and Conditioning: PP. 32-37 Ultimate MMA Conditioning: Joel Jamieson: PP 50-55
