Welcome back to the second installment of swimming efficiency. Last time, we covered the basics—Stroke Rate (SR), Stroke Length (SL), Critical Swim Speed (CSS), the T30, the Ramp Test, and, of course, the quirky SWOLF. But, as fun as it is to break down the math, all these tests leave out one crucial factor: Heart Rate. It’s the invisible cost behind the numbers, the price you pay for every second shaved off your time. So, today, we’re going to focus on what your heart is trying to tell you—through the Salo Pulse Plot—and how it can transform the way you approach swimming efficiency.

The Missing Piece: Heart Rate

We’ve all been there. You hit a fantastic CSS pace, you’re gliding through the water with what feels like the perfect combination of SR and SL, your SWOLF score looks impressive... and yet, halfway through, your chest starts burning, your heart pounds like a drum, and your body is screaming, "Why are we doing this?!"

The truth is, swimming fast or efficiently on paper means little if you can’t sustain that effort. This is where heart rate comes in. While those earlier tests measure your current condition, they don’t account for the physical cost—how hard your heart is working to achieve those numbers. To swim smarter, not just harder, we need to add heart rate into the mix to truly understand efficiency.

So, how do you measure this hidden cost? Enter the Salo Pulse Plot.

The Salo Pulse Plot: Measuring the Cost of Speed (with Heart Rate)

The Salo Pulse Plot is another test set, but one that adds the critical element of heart rate into the equation. It provides a snapshot of your current fitness level, much like the other tests, but with an added focus on how well your heart is coping with the intensity. By tracking your heart rate during and after efforts, you can see how your body is handling the load—and how quickly it recovers.

The beauty of the Salo Pulse Plot is that it’s not just a one-off snapshot; it's a tool to monitor improvement over time. If you swim the Pulse Plot test once a month while training adequately, you should see a gradual shift in your results: faster times for each segment, lower heart rates, and quicker recovery. The goal is to have the plotted line on the graph move down and toward the right, showing improved efficiency and cardiovascular fitness.

How to Perform the Salo Pulse Plot Test:

1. Structure: You’ll swim 8 intervals, typically 100 meters each, with a 4-minute rest between each set.

   • The first four swims are at increasing intensities (70%, 80%, 90%, 100% of your max effort).

   • The last four swims are at decreasing intensities (100%, 90%, 80%, 70%).

2. Heart Rate Data Collection: After each swim, you’ll record your heart rate at three intervals:

   • Immediately post-swim (within 10 seconds).

   • 30 seconds after finishing.

   • 60 seconds after finishing.

3. Plot the Data: Once you’ve collected the heart rate data for each interval, you’ll plot it against your swim speed. The ideal result is a lower heart rate for faster speeds and a quicker recovery between swims. As you progress, the plotted line should shift downward and to the right, indicating better overall fitness and efficiency.

What Does the Salo Pulse Plot Tell You?

The Pulse Plot offers a physiological snapshot of your swimming efficiency. By comparing your swim speed with heart rate and recovery data, you can see not only how fast you’re swimming but also how much effort your body is putting in to maintain that speed. Over time, a fitter swimmer should see:

• Lower heart rates at the same effort levels.

• Faster recovery after intense swims.

• Quicker swim times as fitness improves.

By repeating the Pulse Plot monthly, you can track this progression. As the plotted line moves down and to the right, it shows you're getting faster and more efficient, with less strain on your heart. If that line isn’t moving, it’s a signal to reassess your training or pacing.

Interpreting the Results:

• High Heart Rate, Slow Recovery: If your heart rate remains high after the 100% effort swims and doesn’t recover quickly, it’s a sign your body is struggling to keep up with the intensity. This could mean you’re pushing too hard or need more aerobic base training.

• Low Heart Rate, Quick Recovery: If your heart rate recovers quickly, even after maximum effort, this is a good sign that your cardiovascular system is in excellent shape. You’re ready to sustain higher intensities for longer without fatigue.

• Balanced Effort: A gradual and controlled increase in heart rate across the intensities (without big spikes) suggests you’re pacing well and finding the sweet spot between effort and efficiency.

The "At What Cost?" Factor

Let’s take a look back at our old friends—the CSS, Ramp Test, T30, and SWOLF. They’re great for showing you what you can do right now, but they don’t tell you at what cost you’re achieving those numbers.

For example:

• CSS tells you how fast you can swim a certain distance without collapsing, but it doesn’t show how much effort your heart is putting in to maintain that pace.

• SWOLF gives you a score for efficiency, but what if you’re taking fewer strokes at the expense of heart rate? You could be slowing down to stretch your stroke, but your heart is working harder because of the extra effort.

• Ramp Test reveals your limits at different stroke rates, but doesn’t tell you how your heart rate reacts to those increases in stroke speed.

• T30 measures how far you can swim in 30 minutes, but if your heart is pounding through the roof by minute 10, you’ve got a problem. Endurance isn’t just about distance—it’s about how efficiently your body can sustain the effort.

All of these tests are essential for tracking performance, but none of them consider the cost of that performance. This is why incorporating heart rate—and specifically, the Salo Pulse Plot—is crucial.

Setting Your Goals: The Kicker

Here’s the kicker: all of these metrics measure where you are right now, but they don’t tell you where you need to be for your event. You might be a SWOLF master or nail your CSS pace, but is that enough to reach your race goals?

Your goal might be to improve your endurance for a long open-water swim or to sharpen your sprint for a 50m freestyle. Whatever the target, knowing your current efficiency is only the first step. Goal setting—whether it's achieving a certain heart rate recovery time, a specific SWOLF score, or a sustainable stroke rate—needs to be part of the equation.

With the Salo Pulse Plot, you can see not only how well you’re swimming now, but whether your heart can sustain that pace and recover in time for your next race. Training with these goals in mind, rather than focusing solely on the numbers in isolation, is what will make the difference when you hit the water for real.

Conclusion

So, while SR x SL = SE, CSS, T30, and SWOLF all have their merits, they leave out one key question: At what cost? The Salo Pulse Plot fills that gap, giving you the insight you need to understand whether your heart is truly in the game—literally and figuratively. And with clear goal setting, you’ll know not only where you are now, but also where you need to be to achieve your best performance yet.

The test sets are not just about measuring your current fitness—they’re tools to guide you toward your specific goals, ensuring that when the race comes, you’re not just fast but efficient, well-recovered, and ready to crush it.

Now, let’s get back to the pool.