>General Running>Running too long at High Intensity bad for heart?
wcrunner - Thanks for the speedwork rules of thumb! At my current fitness level I doubt I could maintain even a 10 minute mile pace for 12 minutes and my quickest speed I could now sustain for 45 minutes would be a lot slower than that! It will be a challenge to progress to the paces I need.
Jogger baby - I have also heard that you don't need to run a lot of miles to achieve optimal fitness and of course adding more miles adds more stress that could lead to some damage. That said, I really like doing the long runs, even doing 20 miles or more, although it takes consistent training over many months for me to increase my long run to that distance. I think varying the pace for different runs sounds like a good idea, although I've also heard that moderate paced runs are "junk miles" that don't produce benefit. I'm sure there are many opinions about that!
Slow and steady win the race
I try to monitor my heart rate and keep it in the 130 range most of the time, I have noticed if I don't monitor it that it can easily reach to 165 -175 bps without me really noticing that much.
For instance I run my miles at 4 mph pace ( I am a 70+ lb overweight newbie runner ) and in an hour of running my average heart rate is around 130 according to chest heart rate monitor.
Today I ran 10k, about 6.2 miles on treadmill at a 5mph pace and it actually felt very comfortable and a pace easy for me to maintain, but my heart rate average around 165 -175 bps for around an hour and a half. Even though my max heart rate acording to my age 43 is 177 I can maintain a heart rate close to 177 for about an hour and half of straight running without feeling out of breath at all and actually feeling very comfortable. But even though I can run comfortable in the 165-175 bps range I won't do it often since bad for heart, I will run most of miles at 4mph where my heart rate is more around 130.
littleGizmo - The formula you are using for Max heartrate just gives an estimate based on averages. Everyone is an individual and it is quite possible that your max is higher than you think! Now I'm 70 and 220 -70 = 150 as my estimated max. I'm just starting a training cycle and my HR seems to be around 130 on the runs I am doing. When I start to pick up my pace later in training typically I'll get to 145 on the run. However, I estimated 169 as my max since that is what the Garmin said when I was all out of breath and my heart pounding when I ran up a steep hill. It could even really be higher than that since it is really difficult to reach your max. I doubt if 177 is your max if you feel comfortable running an hour at 175!
"Even though my max heart rate acording to my age 43 is 177 I can maintain a heart rate close to 177 for about an hour and half of straight running without feeling out of breath at all and actually feeling very comfortable."
No. About half of all people have a maximum heart rate within about 10 BPM of the number from that formula. The rest have maximum heart rates either higher or lower. I saw my heart rate hit 175 during some intervals. I was 65 at the time, and those intervals were hard, but well below race effort.
There is only one way to find your maximum heart rate. You need to run intervals, with each successive interval harder, and the last one all out with everything you have. Uphill. This needs to be done on an empty stomach so that you only dry heave at the end.
A sign of poor aerobic fitness is that it is easy to get your heart rate high. One coach recommends that aerobic training runs be done at a maximum heart rate of 180 minus age, or 137 for a 43 year old. If you keep your heart rate mostly under that number, and run at least four times per week for a year or so, you will be amazed at your improved fitness and speed.
I found this HR calculator and the article with it states that the standard formula (220 - age) is inaccurate, particularly for seniors and can give results that are as much as 40 BPM too low! A rough calculation with this gives me a Max of 168, which is about what I've estimated by seeing how high it went on that steep uphill! Of course JRMichler's method is the actual way to really find your MAX HR number, but I just don't feel like running so hard I vomit! https://www.ntnu.edu/web/cerg/hrmax#Important