Hello all…I have what I think will be a quick question.
I am training for IM Wisconsin 09. Consequently I am in pretty damn good shape right now. I can’t run as much as I’d like due to a couple bum feet…but I do feel like I could do the swim and bike right now with little trouble.
I have however noticed something I consider odd.
I tend to have a lower heart rate. My resting rate is in the mid 40’s. (I"m 33 years old). When I did my V02 max test on the bike my max HR was about 165. And on a trainer…I’ve never been able to get back to that number. To me that seems low, but everyone is different. My LT threshold was about a 144.
That’s not the odd part.
The odd part is this. Every now and again when I am pulling a double I’ll hop on the bike to finish off a workout. Usually this is after a run of some kind. Now based on the fact that I am just finishing a workout you’d think my HR would be higher than when I start fresh. So I’d have to go easier on the bike to stay aerobic?
BUT…the odd part is that my HR is very low. In fact, even well into the bike ride, I can’t get my HR up. When I am fresh for my bike workout I can cruise on my computrainer at about 22mph or 200-220 watts with a HR of 124 or so. So it’s a nice easy effort. But in this situation…I can’t get my HR above 115 unless I really start cranking.
Could be a carb problem. When my tank is running low my HR follows suit. Also, if I"m training hard sometimes my HR does funny things. I don’t really let it bother me much.
So it’s not because I am a finely tuned superior athletic machine? I was hoping I was having a Lance moment where I could ride at 35mph with my HR at 125.
Perhaps you could try a tempo workout on your bike before/after a run and see how you do. If you can handle the higher training load without missing your other workouts you may be able to dial up you training.
Ironically I have the exact same questions you do. My resting is like 38 and my max is about 175. My usual training paces and HR’s are about the same as yours. Also I am 31 years old. Sometimes when I run with a heart rate monitor I will feel like I am really cranking and then look down and see maybe 150. I eat about 3000 calories a day and workout around 2 hours a day so I think I am eating enough. I have always been worried about an enlarged heart issue but I have been told by a few people it’s probably more like efficient and not enlarged. Maybe your in the same boat. I dont have a powermeter and I have never had any performance tests done so I can’t compare LT.
Are you taking beta blockers for high blood pressure, this would bring your heart rate down for sure. You should think about having a graded exercise test done at a clinic. There is a chance that your SA node is not firing, causing a junctional escape rhythm which would not be the best. If you are working hard, regardless of your fitness level your heart rate should be at a certain percentage of your heart rate reserve {(max hr - resting hr) x (% of effort like .75) + resting hr)}
I would pay careful attention to your powermeter- id be willing to bet in those “last few minutes” you FEEL like you are going hard, but you are at 180 watts not 220.
At the end of long workouts, especially if i havent been watching my nutrition, i can feel like im pushing hard, but be putting out no watts, and have a low HR, bc im limited by my sugar not my cardiac output.
if you want to test this theory- try to do a 5 minute set at close to ftp after 2 horus of anyworkout- hands off of to you if you can even BEGIN to htink about pulling it off. (and if you can, the rest of your workout was too easy)
I would pay careful attention to your powermeter- id be willing to bet in those “last few minutes” you FEEL like you are going hard, but you are at 180 watts not 220.
This absolutely happens to me, especially if I am going “overdistance,” meaning I haven’t done anything over 60-70 miles and then go out for 100 miles. The last 10-15 miles are just brutal, power drops and HR drops, achy muscles, etc. Likewise on ultra runs once I get out past 25-30 miles I am severely restricted by bloodsugar (and hydration but that’s a different story). I can run fine at moderate speed but even running hard I can’t get my HR up past 165ish before I have to back off and jog or walk. Normally on a 10k I can hit 170+ for the entire race, and I could easily do that towards the beginning of a 30 mile run.
As I mentioned above, I would also consider dehydration or overheating as a possible problem. On a trainer I have a hard time getting my HR over 140 but outdoors with a 25mph wind in my face I can hit 180 for an hour straight… Depending on your sweat rate you may be dehydrated after 2 hours, I know I can drop 3-4lb if I’m not drinking constantly. Weigh yourself before and after workouts for a while and see what happens.
No I am not taking beta blockers. I am confused by your formula. Exactly when should my heart rate be at a certain percentage of reserve? Does this mean that 75% for me would be 141?
This has happened to me too and I’ve concluded that it’s heart fatigue and/or just plain ol’ bonking.
It’s happened both ways to me. My first two half-IM I had to walk the last 5-7 miles of the run because either I was dehydrated or just plain ran out of glycogen because I wasn’t fit enough to support the pace I carried up until that point. The symptom was just headache, and exhausted feeling and my heart rate would just not go out of zone 2.
This has also happened to me at the end of bike rides that are much longer than my body is used to. Even if I’ve eaten and drank a ton, my heart at some point just refuses to go above zone 2 and I feel exhausted. The best example of this was when I recently went on a 3 day 340 mile bike tour of death valley. I had never done anything like that before. On the first day, my heart rate was up into high zone 3, low zone 4 on the climbs - average heart rate was 141. I felt fine. By the last day, my heart rate would not go above 130, even on the climbs and even when I tried to push. I remember the very end of the last day was 20 miles flat to the hotel. I was very motivated to be done. I was going along at a good clip where I was pushing it and my speed was pretty good, but my heart rate just wouldn’t cooperate, couldn’t get it above 130. Normally on a road like that, my heart rate would just track effort all the way to zone 4/5 and 175bpm. I don’t think my low heart rate was a sign of fitness, I felt pretty bad, and I don’t think it was a sign of bonking, the ride was supported and I was stopping frequently to eat a lot, I think my heart was just “tired.” I was toast.
I think the difference between bonking and heart fatigue, because they make you feel the same way, if that the former is “just” depleted glycogen so you can recover from it if you eat and wait 30 minutes to a few hours. However, if you’ve really fatigued your heart after a very long day or days, you’re done, you need to rest at least overnight and maybe for more days.
The big picture is that you can train against bonking, you get in better shape and you learn to eat and drink enough, but eventually, even with all that, you just tire out. So if you’ve checked your nutrition and this still happens, I’d say you’re just tired. Just keeping training and training and you’ll eventually push out your limit.