Hi everyone. I am a soph. in high school, and was wondering what I should be doing my tempo runs (or cruise intervals) at in terms of heart rate. Should I be doing them at 80% or 85%? I use the Karvonen formula, and I do all my runs at >70% except the track stuff my coach make me do. Any help would be great!
I wouldn't use formulas to predict your Heart Rate for threshold workouts. I would do it more by feel, and then only use the heart rate monitor as a guide. A good way to do this is to go to a track and start to run at a pace that you know is probably around your threshold or a little faster. As you do this note what your heart rate is. If you feel fine at first but find that you suddenly start to labor you should look and see what your heart rate has climbed to. I am willing to bet it has just gone up, and that your threshold pace is just a couple of beets below this Heart Rate. You can play with it a bit, seeing what you feel like if you run above that heart rate, as well as what it feels like below it. You will mostly notice an increase in your breathing at this point. It takes about 20 seconds running past this heart rate before you physically feel it.
You should probably run at least four miles so that you can get an accurate estimation of the right heart rate. Once you know the heart rate you can do your tempo runs on the roads. Then you don't have to worry about the distance of the run. Just run for the amount of time you want (at least 15 minutes) at your predetermined heart rate.
Watch out for cardiac drift though. Your predetermined heart rate only works for like weather days. If it is a lot warmer than when you did your test your heart rate may not tell you anything. Luckily, practicing the above 4 mile test can make you become more aware of what running at threshold pace is, and then you will be able to figure out what heart rate you should be using while you are doing the tempo run.
On another note your heart rate will be very inaccurate if you are still recovering from a prior hard workout. You need to be recovered before you do another workout. You will notice this as the inability to get your heart rate up, even though it feels like you running pretty hard. This does not occur in all runners, but it is common. A lot of coaches suggest running bellow a predetermined heart rate on your easy days. This is a bad idea if your overstressed and your heart rate is not beating as high as normal. If you go by the heart rate you may over train because you will believe that you can run faster, because that is what your heart rate monitor is telling you. You really just need to run at a pace that feels easy on your easy days. By the way your resting heart rate will still be higher on these days. For some reason it only effects your heart rate during exertion.
Good luck with this.
90%
I use 80-85 for my aerobic/long tempo runs and 88-92 percent at a max for anaerobic/cruise tempo. You can find a good explanation from www.ffh.us/cn/part2.htm .