2 different Heart Rate max, 2 different days

[bluesbird]

I paddle a kayak, and often times I practice on the same 15 mile srtretch of river. One day I can only get my Heart Rate up to 150, my body will not allow me to go any harder (stomach cond.) With a day of rest, then the same course, and same diet as before, I can hit a Heart Rate of 165 and feel strong. I refrain from eating 3 hours before my start and use 2 endurolytes and shot of Hammer gel 15 minutes before. I will take two more servings of gel and water across the next two hours.
I dont understand what causes this difference in HR. I dont feel any different before I start. Im stumped!
What should I do to correct this?
What do I need to do to have a HR of 165 on race day???

Thanks,
Larry C.

[ssrknordic]

Hi Larry,

There could be many reasons for this (fatigue, hydration level, biochemical). The heart is a muscle hence is subject to fatigue like all of your other muscles, and is subject to normal variations in performance. If you are well rested then it will be able to hit a true max, if fatigued then there will be a decrease in performance 10% in this instance.

Also keep in mind HR training values are based upon formulas and normal distributions (unless you have this tagged to a current lactate test). Last but not least Cardiac Output(HR x stroke volume) is king. For endurance athletes as they get in better shape stroke volume increases, their heart does not need to beat as fast to pump the same amount of blood, hence a lower HR at a high level of exertion.

For race day just be well recovered and you can count on your HR being on target. Ultimately go by how you feel, if you can push a little harder in a race and feel good keep that pace (your fitness may have improved and you can go faster)

Stuart

Stuart Kremzner, MS, CSCS
Operations Director
Athletic Republic NH
603.244.6584
stuart@athleticrepublicnh.com
www.athleticrepublicnh.com