increased heart rate at rest

[BEECHCRAFT]

My heart rate will increase by approximately 50% at rest at random, but not very often. Should this be of great concern? A stress test was conducted & found to be normal. I am 40 years old, I work out 4 times per week(with high intensity). I eat a healthy meal 5 times a day. 6'3 240 lbs. muscular build. I own my own business. Stressful most of the time.  Thank you for your response.

[chuparosa]

I'm not sure what you mean by "increases by approx. 50%".... Are you having tachycardia?

When I have an svt attack, it always starts when I am sitting around doing nothing. Like watching tv or reading a book, etc. My heart rate jumps to about 170 bpm when this happens. It usually lasts like an hour or two before stopping on it's own.

[BEECHCRAFT]

My stress level doesn't seem to be up at the time this happens. I eat relatively healthy. I could stand to lose ten pounds to bring the detail in my abs out. That may give an idea how my build is. I'm not obese. I do have a long background of bodybuilding/weight lifting. Just found out yesterday that my cholestrol is a little high. Thanks for the response.

[Jerry_NJ]

May I assume your HR goes from about 60 to 90 while in a resting state?  There isn't anything particularly troubling about either of those number for a resting HR, albeit 90 is a bit high.  But, a jump without any cause does seem strange.  Something is triggering it, can you relate the jump to anything else, what you're doing at the time, what you have/are eating/drinking at the time?  How are you feeling stress-wise when the HR jumps?  

It the HR regular, just faster, or does it have an irregular rhythm when it speeds up?  

I'm not saying answers to any or all of these question will define the cause, but they are questions I'd be asking myself if my HR jumped up in rate when resting.

As for your body statistic: 240 at 6'3" it sounds like it could be a bit overweight, but I suppose a strong muscle build does weigh more.  I go about 240 at 6'5"+ (was 6-6 until I started to shrink :(  ) and I've got some weight that would be better lost.  This isn't, I think at the root of the "problem".

If you have no other heart rhythm symptoms I'd would think it fine to just get a regular check up from you primary care doctor and discuss the situation with him the next time your see him.