[runbill]

On my twenty mile runs, my heart rate was at about 120bpm for the first 10 miles and then gradually increased to 150 by mile 20 at a constant pace (average heart rate 128.) Aside from heart rate, nothing much changes - breathing stays regular, etc. (Max heart rate is 175-180)<br><br>
This is pretty consistent over 5 20 mile runs in my marathon training. My marathon is in two weeks. What does this tell me about planning race pace?

 

[Mailbox Head]

Bill. I've esperimented around with heart rate training (albeit not during a marathon training cycle) and found a similar phenomenon. From my experience, it's so difficult to determine what kind of heart rate you'll be able to maintain for a marathon. Have you done any races in preparation or have any previous marathons to go by? I would think you'd be able to get a better gague of your ability from that, and wouldn't have to be constantly checking your heart rate during the big event.<br>
Sorry, I know that doesn't really answer your question.

 

[runbill]

Yes, I have run other marathons, but have never paid much attention to heart rate. With a marathon coming in less than 2 weeks, I am getting the usual nervousness. This year, I've been using a heart rate monitor, not to control training, but just wearing it for fun. The heart rate climbing makes me nervous that my training may not be sufficient.<br><br>
I have to decide whether to start targeting a 3:45 marathon(my dream time) or backing off and going for 4:00.

 

[Jensparks]

I'd put away the heart rate monitor and go by feel. <img alt="" class="inlineimg" src="http://www.kickrunners.com/forum/images/smilies/smile.gif" style="border:0px solid;" title="Smile"> (I know nothing, it's just what I'd do!)

 

[Runninlaw]

I agree with Jen. I am also interested in the weather you are running in. This time of year there is often a 30+ temp swing from start to finish in my long runs. If the same is true for you, that is the cause of the heart rate creep.<br><br>
I'd say if you've hit 5 20 milers, you should be in good shape come race day. Don't wear the HRM during the marathon - it will only freak you out.<br><br>
Best indicator of the shape you are in is your resting HR and how quickly your HR drops down when you stop running IMO.

 

[4boysmom]

Are you drinking enough during your run?<br><br>
Also, are you considering conditions? If you are out there for 3hrs, how hot/humid/sunny is it getting? If you are doing an out and back, are you starting with a downhill, returning with an uphill?

 

[runbill]

The long runs all started at 8:00am, so it did get hotter, not 30 degree swings but still significant. As to how hilly, that didn't seem to matter much. I am drinking as much as I can, but still drop 2-3 pounds over the course of a long run.

 

[Boyerdavea]

Bill - This is actually pretty normal and your numbers don't seem off balance. Are you running based on heart rate or are you just monitoring it out of curiosity? You should be running your long runs at about 75% - 80% of your heart rate reserve. Max HR - Resting HR times 75% or 80% + Resting HR.<br><br>
If you haven't been training based on HR, I would not use it for your upcoming race.

 

[Complete Pete]

That happens to me as well.<br><br>
I had always assumed that it was dehydration or my body just needs to work harder as it gets closer to its limits.<br><br>
Never really felt it was a big deal.

 

[tigger]

I haven't run that far for a couple of years, but I used to see my HR go DOWN slightly after the first hr of steady pacing, and then hold steady for up to three hrs, or until just before glycogen depletion set in. Then it rose significantly and rapidly.<br><br>
Using HR to control pace is an inaccurate science at best. I've seen my HR vary as much as 10 beats per minute at the same pace over the same ground under similar weather. But being a data freak I used HR to learn what a particular pace felt like, and then began to note HR but to rely on how I felt during any particular run. When I was running higher mileage the most important HR level in my training was LT level, and even then I often exceeded it if I feel good.<br><br>
One final note....beware of using a HR monitor in races. Particularly short ones. Usually your HR will be much higher during a race than during a run at the same effort.

 

[runbill]

thanks to all

 

[Runninlaw]

To follow up on Tigger's note, I never wear my HRM in races (well, rarely) for the reasons stated. Amazingly (or maybe not so much) prior to races during warm up my HR is usually out of control. Unless you are a religious HRM traininer, definitely leave at home on race day. Although, as I mentioned before, I always being mine to guage resting HR before race.... GOOD LUCK BILL!

 

[Boyerdavea]

I would have to agree with tigger. There are a lot of varying factors that affect your HR, humidity, temperature, sleep, sickness, etc. I wear mine all the time, I only really use it now on my recovery runs to keep my pace slow. The rest of the time I use it to analyze my run after the fact. I rarely use it in a race, except when the HR peaks over 200. I will back off the pace at that time. Over 200 is a danger zone for me. I have run a 10 miler with an avg HR of 199 and I peaked at 206. It was hot and humid and my HR was high from the very start of the race.