35 mins steady @ 93% MHR? How dangerous?

[pintoca]

OK folks,

I normally stay 45mins @ a much natural 75-82% MHR and that is not a problem at all (ellyptical).

Yesterday however, I decided to go out and run a bit (nice day outside and all that, no need to stay indoor).

I haven't run in a bit, first thing I notice: pulse shoot up past 75% in the first 3 mins and then climbed all the way to 93% where it stayed constant for the whole of 35min.

It didn't feel particularly hard (I had a nice front breeze to cool me off) and I was even pushing a stroller (tee hee). My legs were burning a bit, but I basically went through that, since I thought "OK, I just need to get the knack of running again"... no splint shins, no nothing.

After 35mins, however, I started to get worried about my heart... pumping at that rate for that long, I definitely don't want to die running pushing my son stroller.

Question is: How dangerous is this? I train about 5 times/week and do cardio at least 4-5 times a week as weel, so my heart should be OK. Is pushing it this hard for that long dangerous?

Would you consider this HIIT as well? even thoug there were no intervals, but steady state at that rate?

K for advice.

 

[pintoca]

I posted this in the Cardio forum as well (lots of athletes there), however, since my diet peers are quite knowledgeable in Cardio I decided to get your opinions too.

K for advice!

 

[Lifterforlife]

Well, in my opinion, it will not hurt you, but may not be that beneficial at fat burn. As this study shows, there is a bell curve so to speak where above a threshold, you actually stop fat burn. Notice I made bold above 92 +/-....Read on...

Med Sci Sports Exerc. 2002 Jan;34(1):92-7. Related Articles, Links

Determination of the exercise intensity that elicits maximal fat oxidation.

Achten J, Gleeson M, Jeukendrup AE.

Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, United Kingdom.

PURPOSE: The aim of this study was to develop a test protocol to determine the exercise intensity at which fat oxidation rate is maximal (Fat(max)). METHOD: Eighteen moderately trained cyclists performed a graded exercise test to exhaustion, with 5-min stages and 35-W increments (GE(35/5)). In addition, four to six continuous prolonged exercise tests (CE) at constant work rates, corresponding to the work rates of the GE test, were performed on separate days. The duration of each test was chosen so that all trials would result in an equal energy expenditure. Seven other subjects performed three different GE tests to exhaustion. The test protocols differed in stage duration and in increment size. Fat oxidation was measured using indirect calorimetry. RESULTS: No significant differences were found in Fat(max) determined with the GE(35/5), the average fat oxidation of the CE tests, or fat oxidation measured during the first 5 min of the CE tests (56 +/- 3, 64 +/- 3, 58 +/- 3%VO(2max), respectively). Results of the GE(35/5) protocol were used to construct an exercise intensity versus fat oxidation curve for each individual. Fat(max) was equivalent to 64 +/- 4%VO(2max) and 74 +/- 3%HR(max). The Fat(max) zone (range of intensities with fat oxidation rates within 10% of the peak rate) was located between 55 +/- 3 and 72 +/- 4%VO(2max). The contribution of fat oxidation to energy expenditure became negligible above 89 +/- 3%VO(2max) (92 +/- 1%HR(max)). When stage duration was reduced from 5 to 3 min or when increment size was reduced from 35 to 20 W, no significant differences were found in Fat(max), Fat(min), or the Fat(max) zone. CONCLUSION: It is concluded that a protocol with 3-min stages and 35-W increments in work rate can be used to determine Fat(max). Fat oxidation rates are high over a large range of intensities; however, at exercise intensities above Fat(max), fat oxidation rates drop markedly.

 

[devcon]

1) how are you determining your MHR?

2) are you able to run @ this rate w/o any struggle?

It seems that if it was really this close to your MHR it would probably be a little bit more difficult. IME, running @ ~95% or higher is very hard for periods over a few minutes. I would maybe re-evaluate how you are calculating it. I find my RHR in the morning upon waking, then use a calculator www.brianmac.demon.co.uk/hrm1.htm#rhr w/ RHR and age or use the basic: 217 - ( age × 0.85 )

I wouldn't use the general guideline posted on cardio machines(im sure you know this already) Just some ideas...

 

[pintoca]

1) how are you determining your MHR?

2) are you able to run @ this rate w/o any struggle?

It seems that if it was really this close to your MHR it would probably be a little bit more difficult. IME, running @ ~95% or higher is very hard for periods over a few minutes. I would maybe re-evaluate how you are calculating it. I find my RHR in the morning upon waking, then use a calculator www.brianmac.demon.co.uk/hrm1.htm#rhr w/ RHR and age or use the basic: 217 - ( age × 0.85 )

I wouldn't use the general guideline posted on cardio machines(im sure you know this already) Just some ideas...

MHR for me is simply 220-age... I use a polar watch, there you only input your birthday and that is it. I set the upper limit, for my normal cardio at 85, lower limit at 75, so my normal "zone" is 75-85

I didn't really feel exhausted at all, I was probably wound-up or something but I was going and going, I could have easliy finished up to 50 min, but got concerned about my heart, even though it didn't feel like it was coming out of my mouth or something.

 

[devcon]

MHR for me is simply 220-age...Not the best way!!! I use a polar watch, there you only input your birthday and that is it. I set the upper limit, for my normal cardio at 85, lower limit at 75, so my normal "zone" is 75-85

I didn't really feel exhausted at all Because this is not as close to your MHR as you might think, I was probably wound-up or something but I was going and going, I could have easliy finished up to 50 min, but got concerned about my heart, even though it didn't feel like it was coming out of my mouth or something.

The most accurate way to determine your MHR is first by finding RHR and not factor in your age. Age is an inaccurate measurement if you are very active as the generic formula your watch uses is same as the 220-age.

re-evaluate by:

1) finding your RHR

2) using a more updated formula/calculator to measure your MHR

 

[pintoca]

The most accurate way to determine your MHR is first by finding RHR and not factor in your age. Age is an inaccurate measurement if you are very active as the generic formula your watch uses is same as the 220-age.

re-evaluate by:

1) finding your RHR

2) using a more updated formula/calculator to measure your MHR

let's do that instead.

 

[devcon]

let's do that instead.

http://www.brianmac.demon.co.uk/hrm1.htm

This site has a calculator, but don't put in your age. It will say 217 max for everyone so just use the working heart rate after finding your RHR. I came across this same problem a few years ago when tried to do some LSD. I was @ 85% and not even breaking a sweat until 30 mins into my cardio so I decided to look into it more and found out I was really @ ~55% because my RHR is 38. Made a HUGE difference!

 

[lacoste]

Heart rate aside, I find that whenever I switch from using an elliptical machine to actual running outside or even on a treadmill, it requires a big adjustment for my body. Running no matter which way you shake it is more difficult and requires more exertion. Your body is adjusting. If you dont feel dizzy or lightheaded i would say you are fine.

 

[*Bunny*]

Heart rate aside, I find that whenever I switch from using an elliptical machine to actual running outside or even on a treadmill, it requires a big adjustment for my body. Running no matter which way you shake it is more difficult and requires more exertion. Your body is adjusting. If you dont feel dizzy or lightheaded i would say you are fine.

^^^ Pinto I absolutely agree with this statement.

Wnen I do stairs & sprints the polar HAS exceeded 200 bmp .. then climbed down & back up again. Not AS high on the machines, but 180's for duration did not use to be a problem for me either ( I currently am not tracking b/c hrm screen went nutso & I dont have another $$$ to buy another one, plus the strap is WORN out pretty bad ... {side note: the 'accurate' reading were done upon 1st purchase when it was nice & fresh & I also used the Mr.'s for comparision purposes, both strap & different model, pretty equal results...) SO, I let my body be my guide ... and haven't had a cardio session yet... )

I don't have studies & I don't really use calculations ... My polor shows I am easily in the 180's and 190's and in my head I could have went harder at times. I'm not ever really in this 'fat burn zone' and you've SEEN the fat MELT off my body, the muscle not only maintain, but grow ... I wish I could be of more help ...

Re the heart issue, that my friend worries me b/c of my situation & there will be some long term & short term sides... I am prepared for that...
I've had MUGA scan (Muga (Multi Gated Acquisition) scan is a procedure that allows the doctor to evaluate the pumping ability of your heart. A special camera captures the events in the heart's pumping cycle: the contraction of the heart, followed by its relaxation.) for heart function, requirement pre chemo & soon to be after to make sure there wasn't too much damage ... but everything seems to be going smoothly, no pains, aches, heart or chest related that is

I'm very interested in seeing how the other suggestions work for you though, please keep me updated