5/15/2015

Add Horsepower to Your Cardio: Increase Your Cardiac Ouput

QUESTION: True or false:  to improve your cardiovascular conditioning,  get your heart rate as high as possible in aerobic exercise?


ANSWER: False.  You improve your cardio condition by increasing cardiac output at lower heart rates.   Here's the mathematical equation used by doctors and exercise physiologists:


Q = HR x SV

Your cardiac output, Q,  is the product of your heart rate times your stroke volume - that's the amount of blood exiting the heart from the left ventricle every time it beats.   A strong heart pumps more blood with every beat.  At rest, Q is typically about 5-6 liters per minute.  During exercise it can be 3-6 times as much.  

Extra Horsepower

To improve your cardiovascular conditioning, we focus on improving your Stroke Volume, conditioning the muscle fibers in the heart to pump more blood each time it beats.  Think of it as adding horsepower to a pump.

We do this with a training program designed to increase your heart rate reserve --- the difference between your Resting Heart Rate and your Maximum Heart Rate.  Your Maximum Heart Rate is most widely accepted at 220-age, it is a theoretical number that is the same for everyone.  

We can’t change your Maximum Heart Rate, but we can lower your Resting Heart Rate. Typical Resting Heart Rate for adults is 60-80 beats per minute, if you’re already well conditioned it is probably lower.

The Frank-Starling Law

For over 100 years, doctors have relied upon the Frank-Starling law or mechanism for patients with heart arrhythmias and cardiac failure.  It explains how the heart adapts to changes in heart rate and stroke volume, and applies equally to exercise.

If you train your heart to pump more blood what’s it going to do?  Pump more blood.  You will also see a lower resting heart rate and - as your heart rate reserve increases - an increase in potential cardiac output (Q in the formula discussed above).

If you train your heart to beat faster, what’s it going to do?  Beat faster.  You may not see improvement in cardiac output, in fact it may even decline.  Frank-Starling explains that  if the heart is literally beating so fast that the chambers don’t have time to fully fill with blood, the muscle contraction is not as strong. The muscle can actually weaken slightly over time.  You burn more calories at a higher heart rate, but there's a good chance that you're burning muscle and not just fat.  More about this in an upcoming article on Metabolic Training.

Your Cardio Training Heart Rate

We use the Karvonen Formula to calculate your training zone, also called the Heart Rate reserve formula.  (More elaborate athletic training facilities may use VO2 max as a measurement, but it is difficult to consistently monitor).
  • 60-80% of your Maximum Heart Rate, using the Karvonen formula, is targeted to increase stroke volume, therefore increasing cardiac output and lowering your resting heart rate. Gradually increase intensity of exercise that you are able to do while keeping your heart rate in this range.
  • Above 80% of MHR not indicated for improving cardiac output.  It provides other benefits such as improving lactic acid removal and strengthening fast twitch muscle fibers. So it is part of your program, but not the part that improves cardiac output.
To calculate your Target Heart Rate Zone, take your Resting Heart Rate early in the morning,. preferably when you wake up without alarm or kids or noise and use the following equation:


THR = (220-Age-RHR) * Desired Intensity % + RHR

Do I need a Heart Rate Monitor?

Ideally yes, but you can also use rate of perceived exertion.   The Borg Scale is widely used, easy and scientifically validated,  you rate your perceived level of exertion on a scale of 6-20, where 6 is no exertion and 20 is extremely difficult  A rule of thumb is that you can then multiply by 10 to get an approximate heart rate.   

Proceed with caution

Talk to a doctor and a fitness professional before beginning a new exercise program or substantially increasing the intensity.  I'd be happy to meet with you to discuss your questions, goals and program options.

9/02/2014

BUSTED: Haagen-Dazs Corn Syrup Ingredient Alert

If you think that paying the price for super-premium products is a way to avoid ingredients you don't want - like corn syrup - think again.  After reading the fine print ingredients when I got it home, I recently discovered that the pint of Haagen-Dazs gelato that I paid about $5 for was made with corn syrup.  I wrote to complain and was a bit taken aback by their response shown below.  Let's forget that he called me Ms Raffle instead of Mr Raffle, and misspelled Karo syrup.  Can we talk about arrogance? 

According to Haagen-Dazs, corn syrup is a "kitchen friendly" ingredient.  Is Lard also kitchen friendly?  I think they really mean "bottom-line friendly."  The thing that concerns me is that I like Haagen-Dazs Ice Cream, and I don't think it contains corn syrup ... yet.  But I don't want to have to read the fine print to make sure I am not getting ingredients I don't want.  

No apology for my dissatisfaction. No refund.  No suggestion that if I prefer to avoid corn syrup as an ingredient (as many people do), I try their other products.  Shame on Haagen-Dazs!

Dear Ms. Raffle,

Thank you for your email regarding Häagen-Dazs®. We appreciate the time you have taken to pass your comments on to us.

The use of corn syrup goes along with the Häagen-Dazs® philosophy of using only "kitchen-friendly" ingredients. Corn syrup can be found in the kitchen and has many uses such as, pecan pie, apple butter, glazed pork, Asian b.b.q. sauce, balsamic vinaigrette, chocolate chunk cookies and many other desserts and food products.
 
At this time there is no intention to remove corn syrup from our ingredients. Corn Syrup is a common house hold ingredient like Kayro Syrup. I will be happy to report your comments and concerns to the appropriate department for review.

We hope that your questions and concerns have now been sufficiently answered. Should you require additional information, please feel free to contact us.


Thank you again for contacting us.
Sincerely,
Angel Osorio
Consumer Response Representative