Anaerobic Threshold

By the Watta Team · Updated

Anaerobic Threshold: The anaerobic threshold (AT2 or LT2) is the exercise intensity above which lactate accumulates faster than the body can clear it, marking the upper limit of sustainable effort.

What is Anaerobic Threshold?

The anaerobic threshold — also called the second lactate threshold (LT2) or second ventilatory threshold (VT2) — is the intensity at which blood lactate begins to accumulate exponentially. Below this threshold, the body can clear lactate roughly as fast as it is produced, making the effort sustainable. Above it, lactate accumulates rapidly, breathing becomes laboured, and the effort can only be sustained for a limited time (typically 20-40 minutes for trained athletes). In rowing terms, anaerobic threshold pace is approximately your 30-minute all-out erg pace, or roughly 5-8 seconds per 500m slower than your 2K pace. Heart rate at anaerobic threshold is typically 85-92% of maximum. Training at or near this threshold is highly effective for improving race performance but is also very fatiguing, so it should represent no more than 15-20% of total training volume.

Formula

Estimated AT heart rate ≈ 85-92% of max HR. AT rowing pace ≈ 2K pace + 5-8 seconds per 500m.

How Watta Uses Anaerobic Threshold

Watta's Effort Score uses heart rate data to assess Cardiac Load (40% weight). Workouts that push heart rate above the anaerobic threshold score higher on the Cardiac Load component. Watta helps you track how much time you spend above threshold to ensure you are balancing hard and easy training appropriately.

Further Reading

Frequently Asked Questions

What is the difference between aerobic and anaerobic threshold?
The aerobic threshold (LT1/VT1) is the lower boundary where lactate first begins to rise above resting levels — sustainable for hours. The anaerobic threshold (LT2/VT2) is the upper boundary where lactate accumulates rapidly — sustainable for only 20-40 minutes. Most rowing training happens between these two thresholds.
How do I find my anaerobic threshold?
The gold standard is a lab-based lactate test. Practical estimates: your 30-minute all-out erg pace is close to AT, or use 85-90% of your maximum heart rate. A step test with increasing pace every 4 minutes, noting where breathing becomes laboured and conversation impossible, gives a good estimate.
How much training should be done at anaerobic threshold?
Most coaches recommend 15-20% of total training volume at or above anaerobic threshold. For a rower training 10 hours per week, that is 1.5-2 hours of threshold or harder work, with the remaining 8-8.5 hours at low intensity.
Can I improve my anaerobic threshold?
Yes. Threshold training (sustained 20-30 minute pieces at AT pace), tempo intervals (e.g., 4 x 8 minutes at AT), and consistent aerobic base work all raise the anaerobic threshold over time, allowing you to sustain faster paces before lactate accumulates.

Related Content

Aerobic ThresholdThe aerobic threshold is the exercise intensity where lactate begins to rise above resting levels, typically around 55-70% of VO2 max in trained rowers.Lactate ThresholdLactate threshold in rowing is the exercise intensity at which blood lactate begins to accumulate exponentially (approximately 4 mmol/L), representing the upper boundary of sustainable aerobic effort.Heart Rate Zones (Rowing)Heart rate zones in rowing are five intensity bands based on resting and max heart rate, used to target different training adaptations.Maximum Heart RateMaximum heart rate (HRmax) is the highest number of beats per minute your heart can achieve during all-out exercise, used as the ceiling for calculating training zones.HR Zone CalculatorEffort Score CalculatorHeart Rate Training for Rowing2K Rowing Test GuideFor Competitive RowersFor Rowers
Free on iPhone

Every erg counts.

Photograph your erg screen after the piece and Watta logs it for you.

Download on the App Store

iPhone, iOS 15.1 or later · no subscription · Android beta

See everything Watta does