The decrease in VO₂ max with aging and inactivity is largely explained by decrease in

(A) Total lung capacity

(B) Maximum heart rate

(C) Arterial mixed venous oxygen difference

(D) Lactate threshold

(E) Maximal stroke volume

Choose the correct answer from the given below:

The correct answer is (B), (C), (E) only.

Key Points

VO2 max:

• The maximum rate at which the heart, lungs, and working muscles can use oxygen during exercise.
• It measures person’s aerobic capacity.
• VO2 max decreases with aging and inactivity.
• VO2 max is largely dependent upon:
  • Gender
  • Age
  • Genetics
  • Altitude
  • Temperature

Causes of decrease in the VO2 max with aging are:

• Maximum heart rate:
  • Maximum heart rate = 220 – Age.
  • Maximum heart rate decreases when age increases.
  • Older people cannot exercise near their heart rate which is why they aren’t able to use more oxygen.
• Arterial mixed venous oxygen difference:
  • It is the difference in the oxygen content of the blood between arterial and venous blood.
  • The A-VO2 difference is the main factor in the variation in total oxygen consumption.

Additional Information

• Total lung capacity:
  • Total lung capacity is the air volume in the lungs after maximum inspiration.
• Lactate threshold: It is the level at which the intensity of exercise causes lactate to accumulate in the blood at a faster rate than it can be removed.