Lactate Threshold Testing

What is lactate and lactic acid?

Lactate and lactic acid is a by-product of normal cellular metabolism that occurs during exercise. The muscles of the body use glucose and fat as a fuel source during rest, as well as low and moderate intensity exercise. the muscles use glucose as a fuel source. The glucose molecule is coverted to pyruvate, when combined with oxygen, acts as an energy source in the muscles.

As the intensity of the exercise increases, the ability of the body to use oxygen decreases and some pyruvate is converted to lactate instead. The rest of the body (other muscles, liver and heart) usually buffers the production of lactic acid. As exercise intensity increases, the body’s ability to remove the lactic acid is overwhelmed and an increase in the blood lactate level occurs.
This event is referred to as the lactate threshold.

So why is lactate threshold important?

The lactate threshold is a good determination of the maximum exercise intensity an athlete can hold for a longer period of time (greater than 20 to 30 minutes and typically thought to be 60 minutes). Focused training to improve an athlete’s lactate threshold results in faster race times at the same perceived effort.

How do we determing lactate threshold?

Lactic acid testing is done with a relatively painless prick of the finger or earlobe. The testing is done on either a treadmill or stationary bike. The athlete warms up and a submaximal ramp test is done, where either the speed or resistance is increased over a specific time intervals. The athlete progresses through slowly increaing intensity levels as the blood lactate level is measured at the end of each level.