What pace should I row for UT2?

The split on the monitor tells you how much external work you are doing. It does not, by itself, tell you which physiological intensity domain you are in. Research on exercise-intensity prescription has repeatedly shown that fixed percentages and one-size-fits-all prescriptions can place different people on different sides of their physiological thresholds.

That is why a useful UT2 pace should be treated as a practical instruction for producing the intended internal load, not as a universal number that can be copied from another athlete. Heart rate is one accessible way to observe that internal response, although it is still an estimate rather than a direct measurement of lactate or ventilatory thresholds.

Heart rate and pace answer different questions. Pace tells you what to do on the machine. Heart rate helps indicate how your body is responding to that work. For steady-state rowing, the useful relationship is between the two rather than choosing one and ignoring the other.

Heart-rate reserve is one practical way to create an individual starting range because it uses both resting and maximum heart rate. Research found percentage HRR to correspond more closely with percentage oxygen-uptake reserve than a simple percentage of maximum heart rate. That still does not make an HRR band a laboratory measurement of your threshold.

Rowing Zones therefore uses heart rate as the physiological guardrail and pace as the starting execution instruction. The pace can change as the model learns how you respond; your active zone boundaries do not change from ordinary training data alone.

When exercise starts, heart rate and oxygen uptake rise towards the level required by the workload. That response has its own kinetics; it is not instantaneous. Studies of trained athletes, including rowers, describe a rapid early heart-rate response followed by slower adjustment, while oxygen uptake can take several minutes to approach a steady response.

Practically, a low heart rate in the opening minutes is not a reason to attack the first part of an otherwise steady row. Begin at the planned pace and rate, allow the response to develop, then judge whether the workload is appropriate once the session has started to settle.

Two athletes can row the same split and experience materially different internal loads. Fitness, rowing economy, body size, training history and individual thresholds all contribute. Exercise mode matters too: studies have found heart-rate responses during rowing can differ from treadmill running at comparable physiological points, which is another reason to be cautious about importing a running number directly onto the erg.

If your calculated range produces a slower split than you expected, first check the inputs and the quality of the heart-rate signal. Then judge the session against its intended physiological purpose. A slower aerobic pace is not automatically evidence that the session is ineffective.