AEROBIC EXERCISE PREVENTS BRAIN LOSS FOR ALL

Beginning in the third decade of life, the brain shows structural decline, especially in cognitive processes.  The declining effects are prominent later on in life, which is especially important as the “baby boom” generation ages.  Studies support that aerobic exercise improves cognitive function, including:  working memory, switching between tasks, and inhibiting irrelevant information, all of which are thought to be sub-served, in part, by the frontal lobes of the brain.

Research shows that chronic aerobic exercise induce new capillary growth and interconnections of neurons (via dendritic cells).  This leads to a more flexible and adaptive brain.  One study found that older adults with a history of chronic aerobic exercise had better preserved brains then the same sedentary counterparts.  The greatest difference was in the frontal and parietal regions, responsible for memory, tasking, and personality.   

VO2 max is the maximum rate of oxygen consumption during exercise.  The more oxygen you body can utilize, the greater shape you in.  The average untrained male has a VO2 max of about 35-40 ml/(kg x min), and female 27-31 ml/(kg x min).  Elite runners can consume around 80 ml/(kg x min).

A study in The Journals of Gerontology examined 59 sedentary participants in a 6 months trial of aerobic vs toning exercise.  Each group attended three 1-hour exercise training session per week.  The aerobic group began at 40-50% of heart rate reserve with increases to 60-70%.  Heart rate reserve is the difference between one’s maximum heart rate and resting rate.  Maximum heart rate is calculated by 220 - age, and the typical resting heart rate in adults is 60-80 beats per minute (bpm).  So for a 60 y/o, the maximum heart rate is 160 bpm with a heart rate reserve of 90 bpm above resting heart rate, assuming resting heart rate is about 70 bpm.  Their heart rate reserve at 45% is about 40 bpm above baseline resting heart rate (70+40 = 110 bpm goal during exercise).  The change in maximum oxygen uptake (VO2 max) after 6 months was 16.1% increase in the aerobic group compared to 5.3% non-aerobic group.  The previous sedentary aerobic group had increases in brain volume, in both grey and white matter.


Aerobic exercise is very important in preventing age-related losses in brain structure, stimulating neuron proliferation and capillary bed growth in a simple and inexpensive way, not requiring medications, special tests, and multiple doctor visits.  Also, there is supporting evidence, as above, that only 6 months of regular aerobic exercise not only spares brain volume but also increases brain volume, even in previous sedentary individuals.  So now matter what your age is, there are benefits of aerobic exercise for all. 

To began your aerobic routine, calculate heart rate reserve (HRmax - HRresting), and aim to reach 40% of heart rate reserve to start, increasing slowly until you can maintain 60-70% of heart rate reserve during activity, which can generally be done in 12 weeks.  Many people can reach 40% of heart rate reserve by simply walking.  To see the benefits of aerobic exercise, perform the activity 3 times a week for 1 hour each time, or 6 times a week for 30 minutes.  You do not need be training like an Olympic sprinter to benefit from aerobic exercise.