Exercising heart rate over max rate

[RunnerBoy]

I am a 32yr old male, fit, run ultra-marathons etc.  No history of family heart disease although i do have an ectopic heart beat.

When i start out on a run, after about 400m my heart rate soars up to 240bmp.  It stays there for about 400m and then for the rest of my run, no matter how far, it is at a "normal rate" -- ie. between 140 and 160 depending on pace and elevation.

My doc hasnt heard of such a case and i cant find anything about this on the web.  

Any ideas out there?  Thanks in advance for feedback.

[erijon]

I have seen this in my workouts as well when I start out at too high a level. I am not at the same level as you, but I work out daily and bike on good days and if I start out at too high a speed, like in a sprint, I'll see a a spike in my HR. My cardiologist explained that it was most likely due to an immediate need for oxygen by the large muscle groups which cause the heart to beat at a higher than usual rate in order to compensate. Once the immediate need went away, the HR drops back down to it's exercise appropriate rate which for me is 140 - 150 BPM.

Anywho, that's what I was told. Hope this helps.

Jon

[ed34]

Well, as your Doctor cannot think of any ideas, I will have a stab in the dark because it won't do any harm and can certainly be experimented with to see if there are improvements. I'm thinking perhaps it's to do with your fuel. As you know, you burn carbs for a period of time and once low in supply your body switches to using body fat. If you are slim, which many athletes are, then your body will not have that fat to draw on, well not much anyway. So the body takes the next best available thing, protein, and uses this. Not good, because it's needed for important tasks in the body such as maintenance. Perhaps your diet needs adjusting for the specific type of exercise you do. Maybe eat a high carb diet and try again?
Like I said it's just a stab in the dark but the whole metabolism of your body is affected by your diet.