Low HR Training

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Question about HR for heavier/more muscular runners (Read 17 times)

Wonu


    Hey everyone, I've been trying to figure this out for a while maybe you guys can help me.

     

    So using the MAF method my max training HR is 154. My pace is around a 13 - 14 minute/mile to hover around that target HR

     

    I'm wondering... does this formula also apply to more muscular and heavier individuals? Since muscle is metabolically active and consumes oxygen, wouldn't carrying more muscle mass cause a higher heart rate while running? That combined with having to move more weight while running.

     

    So if we were to take two athletes, lets say both at 14% body fat, one weighing 150lbs and the other weighing 190lbs... surely the heavier athletes heart would be working harder right?

     

    Would the heavier athletes target HR ever be able to match the lighter athletes target HR while going at the same pace?

     

     

    Let me know what you guys think.

    SD_BlackHills


      I would guess that the heavier runner could be faster than the lighter runner at the same heart rate if he/she is fitter.  However, if they are both of equal fitness or capability of converting oxygen to energy to forward power, then the lighter runner will always win at equal effort.

       

      I had heard somewhere (perhaps a myth) that for equal forward power applied, that you lose 2 seconds per mile per pound.  So in your example, the 150 lb person would be about 1min20sec per mile faster than the 190 lb person applying the same forward power.

       

      Having said that, it's not impossible for the 190 lb person to be capable of producing much more forward power at equal effort than the 150 lb person, in which case he may completely smoke the 150 lb person at the same effort.

      BeeRunB


        MAF is based on % Fat vs. Sugar burning, a deflection point on a graph measuring this ratio. As you start out at your easiest effort, you're burning 100% fat at a particular HR. As you run more intensely, you start to burn some sugar (the Type 1 slow twitch fibers use some sugar). On the graph you'll see a rise in sugar burning, with maybe a few small plateaus, then you'll reach a more extended plateau. If the HR is being measured at the same time (usually is), this plateau in sugar-burning will cover a range of about 10 beats or so. When the Type 2 fast twitch, sugar-burning fibers begin to kick in, there will be a steep rise in sugar-burning. That point at the end of the plateau and the beginning of the steep rise is the MAF metabolically, and the corresponding HR is the MAF HR.  Here's a graph from my last RQ gas test done on a treadmill:

        If you add more weight to your body suddenly ("Suddenly" is important), the muscles will work harder in order to keep the same pace, and your HR will be higher at that same pace. 1 pound= 1-2 seconds of drag per mile (or stress).

         

        Does this mean the MAF heart rate should change with the added weight? Depends what's happening. As you probably know, Maffetone has adjustments built into calculating the formula. This is because the MAF can improve or get worse within a range of about plus or minus 10 beats from the 180-age calculation. This depends on the state of your aerobic system and metabolism. There are gas tests for resting RQ (respiratory quotient--measures  fat/sugar burning) --how much sugar you're burning at rest. In one of Maffetone's earliest books he talks about measuring some injured, overtrained athletes and that they were burning near 100% sugar at rest. Almost all of his athletes that were injured or overttrained were burning a majority of sugar at rest. Athletes who were healthy, and who had a very developed aerobic system, were burning more fat than sugar at rest. Some a very, very high amount of fat.

         

        Thus, his adjustments for the formula. He noticed that injured and overtrained athletes would have a lower MAF HR relative to 180-age, and those who were heathy and who had improved their speed at the same HR had higher MAF relative to 180-age. People who had a high % body fat and with high sugar-burning resting RQ had lower MAF.

         

        If, today, someone with a developed aerobic system, and heathy, put on a backpack with 50 pounds in it, and ran. If yesterday they could run at MAF HR at 10:00 pace per mile, then they would probably run aprox 11:00 per mile at the same HR. Their MAF HR wouldn't change, as the sugar burning would be the same at the same HR, due to the added stress on the muscles. The fast twitch kick in when they are needed.

         

        If you put on 50 pounds of fat over the next year or two, then your MAF might change for the worse 5-10 beats, as normally weight gain like that does not help the resting RQ in the direction of burning more fat at rest. Your fast twitch fibers will kick in a little sooner in relation to heart rate. This might also happen if you go from being skinny-lean to skinny-fat as they call it. You're weight didn't change, but your body fat% did. Your resting RQ shifted from majority fat-burning to majority sugar-burning. Your MAF HR can shift lower in this case as well.

         

        If you put on 50 pounds of muscle, and stay healthy, and keep your aerobic system developed, you most certainly can be faster at the same MAF HR than you were when 50 pounds less. If your resting RQ doesn't shift to majority sugar-burning, but goes in the other direction and you're burning more fat at rest than you were when you were 50 pounds lighter, then your MAF HR will probably be higher.

         

        A simple way to see it: the more developed your type 1 slow twitch muscle fibers (which burn mostly fat), the higher intensity you can go before your body begins to recruit the type 2 sugar-burning fibers. Thus, your MAF HR gets higher.

         

        Again, that's what the adjustments are for. Of course, its much easier if you can get an RQ test every year, and keep tabs on where your deflection point is, but that can get expensive, and sometimes it's not so easy to get depending on where you live. Dr. Maffetone's formula and adjustments will keep most runners in the vicinity of where their true MAF HR is. For some, it might be a little lower by 5-10 beats lower or higher depending on age. But most of the time, that's not a problem. Depending on the state of the runner's health and aerobic system. Running at a lower intensity below MAF is always okay. If you're running a little higher than what it truly is, someone who is not healthy, overtrained, and has an awful resting RQ, this might be a problem and will show up as regression in speed at MAF (aerobic speed). Lowering MAF will often help.

         

        There are always anomalies, and even though Dr. Maffetone's is fairly accurate in most cases, sometimes a person just has a higher MAF HR than the formula (even with the +5 beat adjustment), especially when you get into your 50's and above. Maffetone and Mark Allen have both said the formula gets a bit wonky in the upper age regions. Most likely because the MAF region is probably fixed within a certain range relative to MHR for an individual, give or take for the fluctuations (mentioned above) in aerobic fitness. I'm really not sure. But I do know that my MHR has not changed since I've began measuring 12 years ago. I's fluctuated a few beats up or down, but hasn't dropped a beat a year like some people said it's supposed to. I can still hit 199-200 at age 55.

         

         

        I hope this helps. Questions?

         

        End book. Please donate this to your local library for their book drive. 

        SD_BlackHills


          Wowza.  Solid info there.

           

          I have a question about RQ.  I had no idea that was even an issue at rest.  As you said, RQ is probably expensive to measure, especially if you want to track whether or not it's improving or not.  Is Resting heart rate somehow related to RQ?  Is it possible that people with high Resting HR also burn a much higher percentage of sugar at rest?

          BeeRunB


            Wowza.  Solid info there.

             

            I have a question about RQ.  I had no idea that was even an issue at rest.  As you said, RQ is probably expensive to measure, especially if you want to track whether or not it's improving or not.  Is Resting heart rate somehow related to RQ?  Is it possible that people with high Resting HR also burn a much higher percentage of sugar at rest?

             

            It cost me about 140.00 for a V02max test that included the RQ and %fat/sugar. They also can do a resting metabolism one as well. I think I had mine done at the time. I have to go back and check. The guy came to my house here in Atlanta. I don't think he does it anymore.

             

            Resting heart rate is important to keep track of if you're training heavily. Often, if you're not overtraining, it will get lower gradually (I've seen mine go down to 44-45 when really fit, and goes back to 50 when not so much. If suddenly you're resting heart rate jumps up 5 beats or more from your average, then it's usually an indicator that you should cut back on that day or rest. If it doesn't come back down, then a longer rest or cutback might be necessary. Also, if it suddenly jumps 5 beats or more lower, it also indicates something overstressed in the body. I've seen this on days after long runs (20+ miles). I've read more than a few times runners saying they were faster at the same HR the day after a long run. But that isn't an indicator of increased fitness, but of stress.  If one's resting heart rate suddenly goes 5 beats or more lower and doesn't come back up, then it's highly possible one of the three state's of overtraining. Resting heart rate does come down during training, but it is gradual.

             

            I don't think there is a connection between fat-burning and the BPM of RHR. Some people have higher RHR than other's. There are athletes who can run much faster than me, who burn a lot of fat, that have higher RHR. Mine has always been about 50 when out of shape, and in the 40's when in shape. In high school, the nurse was amazed how low it was. Just born that way.

            SD_BlackHills


              Interesting feedback on RHR.  My RHR is typically in the mid 40's.  If I drink too much alcohol it will jump into the 50's and then go back down after it's out of my system.  Apparently drinking causes extreme stress on my body.  Who knew?  

               

              It's too bad that you can't get all the stats of interest during a standard yearly physical that my company pays for.  It would be really interesting to know %fat/sugar, VO2Max and what the actual MAF (measured but not calculated) is.  Although I'm reasonably sure Maffetone's equation is close enough that there is no harm in treating the equation as gospel.

               

              And I think the answer to one of the questions in the original post is to use the equation regardless of size, weight, shape, gender or age unless you want to go pay for a measurement.