Gary's new website

Saturday, September 08, 2012

Why is my maximum heart rate declining as I get fitter?

My Brother-in-law, Ioasa, showing
good heart.
Have you had much to do with Max heart rates? 
Heaps of conflicting views online - 99% saying so long as you exercise, your Max stays the same. 
4yrs ago - on both run or bike, i could hit 183
Last year, max 178
4 months ago, 174/5 
Now, 172 

My "theory" - well, i ran basically 6 months of base work - this enlarged the heart, creating a greater a Stroke Volume, Same strength heart as 183 days, but larger = slower. It no longer has the torque to pump as fast due to being bigger. 

Would, a solid 4 months of progressive prep towards track racing (i have done about 6 wks now, and aiming for Gold Coast Pan Pacs in Nov, 800,1500m) would that increase the Strength and torque of the heart, and thereby increase the Max back towards the 180 beats minute barrier? 

I'm finding during training now - to only use the heart rate as a guide - esp now that i've left the O2 only training. 

I would like to do another Concini treadmill test, but mine only goes to 16km/hr... I need to find a faster one. 


Mark, there is no single answer to your question.  I have some thoughts which are as follows:

  • With each year from about 30 years of age, maximum heart rate declines by a factor of about 0.01.  However some people decline faster, others slower.
  • As far as I know the heart chambers of an adult do not enlarge with exercise, although they might in a child.  What does make the heart appear larger is the hypertrophy of the muscle.  Excessive hypertrophy may reduce stroke volume such as seen in steroid abusing body-builders.  This is unlikely in a scrawny runner!
  • Heart volume is determined partly by the ability of the heart to relax.  The more the heart relaxes between beats, the bigger the volume.  
  • ATP formation determines the ability of the heart to relax (same applies to all muscles).  Lack of ATP = cramp.  In the case of the heart this may be felt as a "weakness of heart" and palpitations.  Many factors affect ATP formation, including crucial nutrients such as magnesium, vitamins, Q-10, creatine and a number of other nutrients.  Athletes deplete these at extraordinary rates.
  • Toxins like mercury, lead and aluminium can interfere with the metabolic pathways for ATP formation.  Most of us have some of these in our bodies.  Some have excessive amounts.
  • Arterial elasticity affects heart rate.  With ageing the arteries tend to calcify and lose their elasticity.  Systolic blood pressure tends to rise, especially during intense exercise.  The heart must contract harder to deliver a given amount of blood.
  • Venous flow back to the heart also affects the ability of the heart to pump blood.  If flow back to the heart is poor, the heart takes longer to fill with blood before it can pump and when it pumps, the amount may be less than optimum.  Venous flow is seriously affected by muscles that are hard and full of knots.  A muscle is a sponge pump. When it contracts, the old blood is squirted out via a one way valve system back to the heart. When it relaxes, fresh arterial blood fills the muscle. This is the "muscle pump effect" and it is as important for blood flow during exercise as the pumping of the heart muscle.
  • Strong adrenal glands fire up all systems for battle, including the cardiovascular system.  When you stand on the start line and you feel your heart beating powerfully in anticipation of the gun firing - that's your adrenals at work!  Weak adrenals = weak heart.  My findings are that all athletes have a degree of adrenal fatigue.  many are severe.
  • The maximum heart rate of a conditioned athlete may be lower than a totally unfit person.  With conditioning, the heart tends not to beat beyond a point where efficiency is lost.  In your case the optimum for your age and gender may be around 180 beats per minute.  I have found that really unfit people may rev to an excess of 200 beats.  But this is done with a progressive loss of efficiency.  One can assume that the unfit heart is only partially filling and therefore expelling increasingly less blood per beat as 200+ beats are exceeded.
So, what would I do in your case?  I'd be inclined to carefully and methodically explore and address all of the above: Nutrients, toxic elements, skeletal muscle tone, adrenals and thyroid.  Get these right and you will find a steady gain in performance that will accrue over the months and even years.

You could go ahead and take some extra magnesium, pop a few Q-10 pills etc, but I am not going to recommend that because it is hit and miss stuff that often leads to disappointment.  It is better to do some accurate testing and then you can intervene with accuracy and purpose.  For that you will need to organise a consultation.
About this website
The advice in these articles is given freely without promise or obligation.  Its all about giving you and your family the tools and information to take control of your health and fitness.


Lars said...

If there has been no deterioration in performance and maybe an improvement ... who cares that your exercising heart rate has come down ? This shows adaptation ... not just of your heart but your whole body to that intensity of exercise ...

Gary Moller said...

Yes, good point Lars. However, there are other factors that bring heart rate down which are undesirable, as listed in my article. These can be masked, partially or fully by the apparent improvements in performance. As time passes, usually 1-15 years the gains in conditioning are no longer able to compensate for the loss of health (hardening of muscles, stiffening of arteries, failure of adrenals etc) and there is a steady deterioration of performance and health (usually known as "ageing").

This may help explain why a few of my running aquaintances, some of whom represented NZ to Olympic and World Champ standard, dropped dead without warning. Their extreme fitness masked disease processes.

In my case, adrenal fatigue reduced my peak pulse in the exercise lab to a spectacular low of 109 beats in 1991. Medical tests showed extremely low levels of cortisol (adrenal fatigue bordering on Addison's. Peak pulse is now back up to about 180 BPM which is well above my age adjusted theoretical peak. This has been achieved by methodically picking away at each of the factors listed in the article.