To calculate the intensity of a workout you need tools that carefully control cardiovascular and metabolic stress. The anaerobic threshold is defined as the highest workload at which the body maintains a stable condition , so that the accumulation and elimination of lactic acid are in balance. Therefore, this threshold is important in determining long-term performance capacity, as it represents the highest exercise intensity that can be tolerated for relatively long periods . When this threshold is exceeded, the accumulation of lactic acid in the muscles can cause fatigue in a short time.
How to calculate the anaerobic threshold?
Currently available methods for estimating the exact anaerobic threshold cannot easily be used on a daily basis, as they require specific exercise intensity measurement protocols and / or invasive blood lactate (lactic acid) samples. However, here is a simple method for you to calculate this threshold easily.
Steps to calculate your anaerobic threshold
- Warm up for 3 minutes with your favorite cardiovascular equipment: bicycle, treadmill or elliptical. Stop and get off the machine for 30 seconds to recover before continuing with step 2.
- Gradually increase your intensity over a 10 minute period , paying close attention to how you feel. Keep going until you can’t control your breathing well and can’t carry on a conversation.
- Take a break from your training and take your pulse for 10 seconds. By multiplying this number by 6, you will have an estimate of your anaerobic threshold. For example, if you count 25 beats in 10 seconds, your anaerobic threshold is approximately 150 beats per minute (25 x 6).
How to improve your anaerobic threshold?
The only way to maintain and improve your anaerobic threshold is to do your workouts consistently without lowering your guard too much. Follow these steps to achieve it:
- Try to stay below your aerobic threshold for 80% of each workout to burn fat, and just above it for 20% of the time to improve your fitness.
- Retest every 6-8 weeks to maintain an accurate measurement.
The anaerobic threshold is a highly individualized number: It will decrease as you age and will change based on your overall fitness level at any given time.
How does lactic acid accumulate?
Physiologically, when the intensity of exercise gradually increases from rest, to a certain level, the anaerobic energy pathways begin to activate and remarkably support the aerobic energy system to produce cellular energy (ATP). When anaerobic energy pathways are activated, ATP can be formed faster through glycolysis . Glycolysis is a lactic acid fermentation process in which glycogen / glucose is rapidly converted to ATP. However, this results in increased lactic acid formation in the muscles.
Until a person reaches the anaerobic threshold, lactic acid can be metabolized by the body without continued accumulation . If the intensity of exercise increases above the threshold, the aerobic energy production capabilities of the working muscles may have difficulty meeting the energy requirements of the exercise, and anaerobic energy production increases rapidly. Consequently, lactic acid begins to accumulate in the muscles and the bloodstream. This happens due to the inability of the body to eliminate lactic acid fast enough through oxidation and the formation of glucose.
Up to the anaerobic intensity threshold, bicarbonate in the blood and muscles dampens the increased acidity in the body . At intensities above the anaerobic threshold, the depletion of the body’s bicarbonate stores leads to a sharp increase in respiratory rate and ventilation, causing an increase in lactic acid.
