Swimming Anaerobic Lactate Training: How to Do High-Intensity Intervals in the Pool

Introduction

Many swimmers equate “high-intensity intervals” with “sprinting until you’re gasping for air,” but truly effective anaerobic lactate training has a precise intensity range and recovery design. Training too easy fails to provide the lactate stimulus, while training too hard shifts into the phosphocreatine system rather than the lactate system—neither effectively improves lactate tolerance in competition. Understanding the logic behind lactate training is the only way to design workouts that genuinely improve 100–400m performance.

The Physiological Basis of the Lactate System

During high-intensity exercise, the rate at which glycolysis produces ATP exceeds the aerobic oxidation system’s processing capacity, and lactate begins to accumulate in the blood. Swimming’s energy metabolism can be roughly summarized as follows:

Lactate training has two main objectives:

1. Lactate Production Training: Getting muscles accustomed to maintaining output in a high-lactate environment, suitable for 100–200m swimmers
2. Lactate Clearance Training: Improving the aerobic system’s ability to clear lactate, suitable for 400m and above swimmers

Setting Intensity for Lactate Training

How to Determine It

For swimmers without blood lactate testing, the following references can be used:

• Lactate Threshold (T1): A pace that can be maintained for 20–30 minutes, feeling “somewhat breathless,” roughly equivalent to CSS pace
• Maximal Lactate Steady State (T2): A pace that can be maintained for 10–15 minutes, feeling “very breathless but under control,” roughly equivalent to 400m race pace
• High Lactate Training Zone: A pace that can only be maintained for 2–5 minutes, roughly equivalent to 100–200m race pace

Common Intensity Markers

• %CSS: Intensity expressed as a percentage of CSS; 100% CSS = CSS pace, 110% CSS = 10% faster than CSS (faster seconds)
• Rating of Perceived Exertion (RPE): The lactate training zone typically falls at RPE 8–9, with T2 around 7–8

Sample Workout Designs

A. Lactate Production Workout (100–200m Swimmers)

Goal: Getting muscles accustomed to high lactate output

• Warm-up: 400m easy swim + 4 × 50m gradual build-up
• Main set: 6 × 75m at 100m race pace (near-maximal effort), 2 minutes rest per repeat
• Main set 2: 4 × 100m at 85–90% maximal effort, 3 minutes rest per repeat
• Cool-down: 400m easy swim

Note: Rest intervals between repeats in lactate production training should be sufficient (2–3 minutes), with the goal of maintaining high-quality speed on every repeat, rather than accumulating fatigue to build endurance.

B. Lactate Endurance Workout (200–400m Swimmers)

Goal: Improving sustained output under lactate accumulation

• Warm-up: 500m
• Main set: 3 × 200m at 400m race pace (RPE 8–8.5), 90 seconds rest per repeat
• Main set 2: 2 × 300m at slightly slower than 400m race pace, 2 minutes rest per repeat
• Cool-down: 300m easy swim

C. Lactate Clearance Workout (400m and Above Swimmers)

Goal: Maintaining moderate intensity while improving aerobic lactate clearance

• Warm-up: 500m
• Main set: 10 × 100m, first 5 repeats at CSS+5 seconds, last 5 repeats at CSS pace, 20 seconds rest throughout
• Cool-down: 300m easy swim

Warning Signs of Overtraining

• More than 2 lactate workouts per week without scheduling sufficient easy swim recovery
• Extreme fatigue lasting more than 24 hours after each high-intensity workout
• Performance plateauing or regressing while training volume continues to increase

Lactate training is recommended at most 2 times per week, with at least 1 day of easy swimming or rest scheduled between sessions.

Practical Recommendations

1. Record resting heart rate before lactate workouts; if it is more than 5 bpm above your average, consider reducing training intensity or switching to easy swimming
2. Record split times immediately after each workout to observe the fatigue curve and confirm whether training intensity is within the target zone
3. Swimmers new to lactate workouts should start with the “lactate endurance workout” rather than jumping straight into all-out sprints for “lactate production”
4. Lactate training should not make up too large a proportion during the base period; it is typically increased progressively only 8–12 weeks before the competition phase

Conclusion

Anaerobic lactate training is the final piece of the puzzle for competitive swimming performance, but it must be built on a sufficient aerobic foundation. Designing lactate workouts with the correct intensity, appropriate repeat counts, and adequate recovery is what truly improves a swimmer’s sprinting ability at critical moments in competition—rather than merely accumulating fatigue.

Related Reading

• Swimming Anaerobic Threshold Training: Workout Design for Lactate Threshold Swimming Speed
• 4-Week Swimming Anaerobic Interval Intensification: Breaking Through the Speed Ceiling
• Designing the Aerobic Base Period in Swimming Training: The Structure of Low-Intensity, High-Volume Workouts
• Building the Aerobic Base in Swimming: Setting Weekly Training Volume for Low-Intensity Long-Distance Work