Ideal heart rate

Khannie

Hi All,

I'm unfit. I have seen ideal heart rate for fat burn and cardio workouts for my age on the internet, but I would like to know if I should lower this because I'm unfit?

If so, by how much? (or is there a way to work that out)

Thanks in advance!

Stark

Stop me if I'm wrong, but shouldn't they be accurate no matter your fitness? If you're unfit then your heart is going to beat faster for the same workload, so you're going to be automatically lightening the workload to achieve the recommended heartrate.

Khannie

Originally posted by Stark
Stop me if I'm wrong, but shouldn't they be accurate no matter your fitness? If you're unfit then your heart is going to beat faster for the same workload, so you're going to be automatically lightening the workload to achieve the recommended heartrate.

Impeccible logic. I'm sold.

Thanks!

rs

I don't think you should need to lower it because you are unfit.

Target heart rates for fat loss are fairly low anyway. They are a good deal lower than your maximum heart rate.

If you can keep up that target heart rate while training then should.

If you find that that level of exercise tires you out too quickly, then perhaps set your target a little lower and work up to the "ideal".

Khannie

Originally posted by rs
I don't think you should need to lower it because you are unfit.

Target heart rates for fat loss are fairly low anyway.

Yeah, they are low. I'm more interested in a cardio workout. I'm slim enough (I think ). I just want cardio fitness for the healthiness of it.

Trojan

http://www.pponline.co.uk/encyc/0424.htm

Recent research (edit: this was 1993) at the University of Texas addressed both questions. At a Texas laboratory, five experienced cyclists worked out for at least 30 minutes at three different intensities - 25% V02max, 65% V02max, and 85% V02max. These three intensities correspond with about 40-50 per cent, 76 per cent, and 92 per cent of maximal heart rate, respectively. At each exercise level, scientists carefully studied the cyclists' rates of fat metabolism.

The trends in fat breakdown were clear. As exercise intensity increased from 25% V02max to 85% V02max, the amount of fat pouring out of the athletes' fat cells into their bloodstreams steadily declined. As a result, fat originating in fat cells made a huge contribution to the energy required for exercise at 25% V02max, providing about 80 per cent of the needed energy! By contrast, fat coming from fat cells contributed only 30-40 per cent of the total energy at 65% V02max and just 10-15 per cent of the total energy at 85% V02max.

Why did fat cells pay so little regard to the muscles' need for energy at 85% V02max? Actually, the chubby little cells were quite busy breaking down their internal fat molecules at that intensity; the real problem was in the blood. During high-intensity exercise, blood pours toward the muscles in flood-stage quantities but avoids the fat cells as much as possible. As a result, there's little blood available to 'pick up' fat from the fat cells, and the fat has to wait until after a workout is over to move into the bloodstream.

However, some additional fat is always locked away inside muscle cells. This second supply of fat doesn't have to move through the blood to get to the muscles, and it can provide a decent share of the fuel required for exercise. When the inside-muscle fat was factored in, fat contributed a steady 90 per cent of the required energy at 25% V02max, versus 50-60 per cent at 65% V02max.

So which intensity is best?
That may make it seem that 25% V02max is by far the best intensity for breaking down fat, but bear in mind that little energy is really needed to exercise at that paltry intensity, so the actual amount of fat burned was roughly 33-per cent greater at 65% V02max than at 25% V02max! At 25% V02max, the cyclists were burning energy at a rate of only about seven calories per minute; at 65%, the rate was roughly 14 calories per minute. Since fat supplied 90 per cent of the calories at the lower intensity, 90% X 7 = 6.3 calories of fat per minute. At 65% V02max, 60% X 14 = 8.4 calories per minute, a 33-per cent upswing in fat combustion.

In fact, total fat degradation was actually as high at 85% V02max as it was at 25% V02max, even though the former intensity is noted for its reliance on carbohydrate and the latter intensity is often referred to as a special 'fat-burning' zone of exercise. At 85% V02max, the cyclists used up energy at such a high rate that fat's contribution, even though it amounted to a small percentage, added up to a sizable number of calories. To put it another way, a small piece of a huge pie (the 85% 'pie') can be just as big as a large piece of a small pie (the 25% 'pie').

'Regulation of Endogenous Fat and Carbohydrate Metabolism in Relation to Exercise Intensity and Duration,' American Journal of Physiology, vol. 265, pp. E380-391, 1993

daveirl

This post has been deleted.

Khannie

ok folks, sorry to drag this one back up. I've been going to the gym for a few weeks now and decided to buy a heart rate monitor. I got the "go" from cardiosport. I'll be trying it out today, but, here's a quote from the HRM manual:

If you have not exercised for some time, begin your exercise programme in the Healthy Heart Zone. Start slowly for the first few weeks and gradually progress up to the zone that meets your personal fitness goal.

The "healthy heart zone" is 50-59% of max according to the manual.

I must say that I've been doing 75-85% since I started back because I'm looking for cardio fitness and I feel fine. I am young and have a healthy heart though (I know this because we get free bi-annual ECG's in work).

Like I said above, Stark's logic seemed perfect to me, I have been progressively running faster to reach an equivalent heart rate. I just thought I should share the above in case anyone out there isn't quite as young / healthy.

Trojan

Don't be sorry - interesting topic. I've just started training with a HRM too - well, I've kept doing the same training but started watching heart rate. I'll start using it more actively as I learn more. I've been playing about using the 10% zones that Sally Edwards mentions somewhere online (google). E.g. [z1] is 0-50% MHR, [z2] is 50-60% warmup, [z3] 60-70% "fat burn" for want of a better term, [z4] 70-80% intense aerobic/cardio and [z5] 80-90% anaerobic (HI). I find that I spend roughly 75% of my time in aerobic, 15% anaerobic.

One thing that annoys me is the ambiguity whereby Max Heart Rate is said on the one hand to be an absolute value, yet on the other that it differs dependent on the sport (I've seen this particularly in reference to running, cycling and swimming). I've used Karvonen method, but plan to try the treadmill to exhaustion to see if I can get a more accurate result.