Five Reasons Why Your VO2 Max Is Decreasing
Aging
One reason for your VO2 max decrease is the physiological factor of aging. Men’s VO2 max decreases by roughly 0.43 ml/kg/min and women’s VO2 max by 0.3 ml/kg/min with each year [1].
The direct reason for this decrease in VO2 max with age is the physiological change in the muscles. It leads to a decrease in the oxygen capacity in the muscle [2].
Heart
The heart itself can cause VO2 max to decrease. The physiological age limits its rate. The older you are, the less beats per minute your heart can achieve. The maximal heart rate can be estimated in two ways.
- 220 – your age = maximal heart rate.
- 207 - 0.7 x your age = maximal heart rate
The second equation is considered more precise than the first.
For a 25-year-old man, the maximal heart rate will be between 190 and 195 beats per minute.
Furthermore, the heart needs training as any other muscle. Prolonged bed stay or break from physical activity lead to changes in the heart. The VO2 max after a long break will decrease as the heart adjusts to low blood demand in the body [3].
However, the decrease in VO2 max caused by prolonged inactivity is transient. You will regain the lost VO2 max after resuming training.
Not enough recovery
Another reason why your VO2 max is decreasing is not enough recovery. In the pursuit of progress, recovery can easily be forgotten.
During recovery, the organism rebuilds the muscles and ligaments, and the heart has time to recover. You can help the muscles during this process with good sleep, a healthy and balanced diet, and rest.
Without a proper recovery phase, not only your muscles will still be sore. You can also overtrain your body and, with it, cause a decrease in VO2 max.
Lower hemoglobin concentration
A decrease in VO2 max can be caused by low hemoglobin concentration. A small amount of hemoglobin limits the oxygen capacity of the blood, thus the VO2 max decreases. A situation like this can happen, for example, in vegetarians and women with intensive menstruation [2, 4].
Development of a disease
Lastly, VO2 max can also decrease due to the development of certain diseases.
Among the examples of diseases that can decrease the VO2 max are:
- diabetes type 2 [5],
- chronic obstructive pulmonary disease (COPD) [6],
- congenital heart failure [7].
Why is Vo2 max important for the training?
VO2 max is the measure of how much oxygen the body can consume to produce energy. This ability is crucial for athletic performance. Especially during high-intensity sports, it is a must to have enough VO2 max [8, 9].
High levels of VO2 max indicate that the organism can produce a lot of energy. It allows coping with aerobic activities like running [8].
Improvement of VO2 max leads to better performance. Someone with high VO2 max values can effectively and with less effort run or swim for a longer time.
VO2 max is also a measure of pulmonary and cardiovascular health. An increase in VO2 max can potentially improve the overall health. For example, it is associated with a lower risk of heart problems [10].