Aerobic dive limit

The measurement of Weddell seals and emperor penguins blood lactate concentration pre- and post-dive led to the definition of aerobic dive limit (ADL) as the dive duration after which there is an increase in the post-dive concentration of lactate.

For all other species, where no pre- and post-dive lactate measurement is made, the aerobic dive limit has been calculated by dividing usable oxygen stores by an estimation of the rate of oxygen consumption during diving.

In this simulation, we will use both approaches, as Weddell seals can, in fact, dive for at least 2-3 times longer than their ADL. This means that at ADL, there is still some usable oxygen remaining in the stores.

Below, you can find the equations used to calculate oxygen stores and aerobic dive limit from stores.

Calculate oxygen stored in the lungs

VO₂ in lungs (mL) = lung volume (L) x O₂ in lung(mL/L)

Calculate oxygen stored in the blood

VO₂ in blood (mL) = O₂ in hemoglobin(mL/g) x hemoglobin(g/kg) x blood mass (kg)

Calculate oxygen stored in the muscle

VO₂ in muscle (mL) = O₂ in myoglobin(mL/g) x myoglobin(g/kg) x blood mass (kg)

Total O₂ stores can then be calculated by the sum of O₂ in all compartments. Further dividing this value by the total body mass(kg)provides a relative and more comparable measure (in mL/kg).

Once we know the total oxygen and an estimation of the factorial increase in O₂ consumption during diving, we can calculate the O₂ consumption during diving:

Diving O₂ consumption = factorial increase x resting O₂ consumption (mL/min)

And then, finally, the aerobic dive limit:

ADL (min) = total O₂ in stores (mL) / rate of O₂ consumption during diving (mL/min)