best form of working out?

January 19, 2006 3:53 AM

I have been told recently that a short (say 20 minutes) series of sprints, hard workouts, is more efficient and better all around for fitness than slow long distance walking or running (jogging)...true or not?
posted by Postroad to health & fitness (8 comments total)

It's called High Intensity Interval Training (HIIT). Yes, it works better. Lots of reading material on Google.
posted by madman at 4:02 AM on January 19, 2006

Only if you are already fit or not trying to lose weight.

Depends on where you are on your fitness continuum. If you have not already built "base" you won't be doing yourself a lot of good.

I try to incorporate both into my fitness goals, fwiw.
posted by konolia at 4:22 AM on January 19, 2006

On the downside, running is hard on joints. Long distance walking seems like a more sustainable kind of exercise over the years.
posted by Amizu at 5:02 AM on January 19, 2006

Different training. Intervals, in particular, increases your ability to perform at high output, by increasing your lactate threshold, among other things. For competitive sports, it's mandatory.

Medical Caveat:

Is is *IMPORTANT* to check with your doctor before starting interval training. If you are doing intervals correctly, you will be pushing your heart rate very close to maximum.

If you have an issue that will crop up at, say, 90% of max heart rate, then you can suddenly find yourself in a world of pain in the middle of a run or ride. This can well, kill you.

The point of intervals is to push yourself as hard as you possibly can go for a short distance, in order to increase the ability to perform there. You need to know if you can safely do this. If you're young, there probably isn't a problem. If you are over 35, a cardiac stress test before you start interval training is a really good idea. If you're over 50, and you've never done intervals before, you should only do so after a stress test, and maybe do your first ones in front of a hospital.

Training note:

There's a simple test to knowing if you're doing intervals correctly. If if doesn't hurt afterward, you aren't. When you are starting, you do 30 second or 1 minute intervals, and if you are doing them right, you are pushing as hard as you physcially can, and after that time, you will hurt. If you think "that was easy!", you were nowhere near max output.

Even atheletes at thier peak hurt after intervals -- of course, thier intervals are longer, and the get vastly more power output (a top tier cyclist will output 400 watts for 3 minutes, and peak close to 500 watts.) But they'll hurt afterwards, until the lactic acid flushes out and the heartrate recovers. (Competive athelets will also recover far more quickly.)

Which leads to the last bit: The recovery. For intervals to work, you need to recover afterwards. This means letting your heartrate drop to warm-up levels. Not waiting is a waste -- you won't be able to reach max output long enough to do you any good if your heart is still pumping hard and your muscles are still full of waste products.

So, a heart rate monitor is pretty much mandatory for proper interval work.
posted by eriko at 5:33 AM on January 19, 2006

Also remember that just because intervals rock for being in shape, don't go them every day. It'd be like working out the same set of muscles every day. Also, their usefuless isn't necessarily useful to every kind of runner. For example, I used to run cross country where in a 5K (3.1 miles) race, interval training is key to getting that extra push. However, before I get that far, I needed to be able to run about 5-6 miles at a decent pace in the first place.
Also, for road racers, hill workouts are wicked awesome. It's like intervals where you push yourself to limits, but use a hill to run up instead and then take it easy on the way back down.
Lastly, if your goal is just to be in shape and not to compete, there isn't much point in intervals. As others have said, save yourself the knee/whatever problems.
posted by jmd82 at 7:14 AM on January 19, 2006

I found Smart Exercise to be an excellent primer on exercise theory.
posted by jbradley at 8:25 AM on January 19, 2006

It really depends. Intervals burn more fat (than a similar length of steady state exercise), and they may push up your VO2Max, but they don't improve your endurance or necessarily accustom your joints to the exercise that you're doing.

It's worth noting that runners or bikers who are training to race do not do intervals all that often. The general rx is that no more than 10-15% of weekly mileage be done as speed work (intervals qualify as speed work). The reason is that intervals help speed etc most when performed on a very wide endurance base. Speed work also leads to frequent injury, so it's best used with care.
posted by OmieWise at 8:31 AM on January 19, 2006

Oh, there is a myth about fat burning zones and carb burning zones, which is tangentially related to your question:

While training at a slower speed may burn more fat as a percentage of calories burned than training at a higher speed, the overall increase in number of calories burned during the higher speed workout ends up bringing more fat calories than a slower workout. This obviates the notion of a fat burning zone if your only goal is to burn calories. You should work out at the highest speed which you can maintain without injuring or exhausting yourself.

On the other hand, if your goal is to build endurance, working out at a slower speed is a crucial part of training your endocrine system to facilitate continued exercise. Workouts should be long and slow.
posted by OmieWise at 8:35 AM on January 19, 2006