By Stephen Knight
We’ve all seen a paddler quickly glide by seemingly with little effort and know it’s because of the hours of hard training. Your second thought is “my interests are touring and enjoying the water, not going fast”. However, that thought quickly fades when you lag further behind your group of friends or can’t cover the distance they can. “I paddle a lot but I’m still slow. How come?” The answer is not the amount you paddle, but the how.
Let’s start with the “how”. Without using a heart rate monitor, we can get a good estimate on your level of exertion by how you’re breathing or the Rate of Perceived Effort (RPE). Using a 1 to 10 scale with 1 being the easiest, we can see that most recreational paddlers stay within an RPE of 1, 2 or 3. Beyond that, the ability to continue at a higher RPE is very limited. What’s more, it’s going to take a few minutes or longer to recover from a higher effort.
Now that we’ve established a way to gauge our effort while paddling, what does that tell us about what is going on within our bodies?
Taking a cue from our breathing, we can divide our response to exertion into five distinct levels and call them Heart Rate Zones. Each Zone is the body’s response to a diminishing availability of oxygen to the working muscles. At this point a heart rate monitor would be useful as a means to precisely measure our response to working harder. However, we’d need to know several other pieces of information and that’s beyond the scope of this article. For our purposes, the RPE scale is perfect.
Looking at the Zone and RPE table, we see two distinct divisions. Aerobic (with oxygen) in green, and Anaerobic (without oxygen) in red. These divisions represent the predominant type of energy generating metabolism going on in the working muscles. The tipping point or Lactate Threshold (RPE 8) is where the body is losing the ability to deliver sufficient oxygen to sustain the effort. Although glucose can still be utilized anaerobically to produce energy through an alternative pathway, it is short term and produces lactic acid as a by-product. The body does not let very much go to waste and lactic acid is no exception. It’s transported from inside the muscle cells through the blood to the liver as lactate for processing into glucose. Wait, isn’t that why I get sore after working hard? No. Lactic acid has an undeserved reputation for producing residual “muscle burn” or soreness when in fact it’s trauma to muscle cells that is the real culprit. Another name for this discomfort is Delayed Onset Muscle Soreness or “DOMS”. Fortunately, it goes away on its own and becomes less frequent with regular exercise.
Now that we’ve learned how our bodies respond to exertion let’s go back to the original question, “how” are you paddling? If you spend all of your time at an RPE of 1 or 2 there are definite benefits but your fitness level will still be quite low. Increasing the intensity to an RPE of 3-4 will provide substantial improvements in your ability to paddle longer with less effort, but it still falls short. It isn’t until you spend time at an RPE of 5 to 7 that you see significant improvements in your fitness. Training at higher levels of intensity will increase
your lung capacity, stimulate the heart to pump blood more efficiently, deliver more oxygen to the muscles through an expanded capillary bed, develop more efficient energy metabolism, and increase the number of mitochondria in muscle cells. That’s a pretty enticing return for an investment of effort. But, is it that easy, just paddle harder? Well, sort of. There’s a smart way and then there’s a hard way to improve your fitness. We’ll go with a smart way to get good results in my next entry.
Thanks for reading my blog entry for the Carolina Kayak Club. I’ve been engaged in a number of outdoor activities for most all of my life as a participant and instructor. When not competing in running, bicycle and kayak races, I’m a US Canoe and Kayak Team Paracanoe Coach and work with the Bridge-II-Sports Foundation for Adaptive Sports as the Parakayak Racing Club coach.