Around the World Governments are encouraging us to exercise more. Studies using movement monitors in the USA have shown that we spend up to 55% of our waking time sedentary. We sit around too much. COVID seems to have made it worse.
A typical governmental activity guideline includes:
1. Sit less and move more. Any activity is better.
2. A minimum of between 150 and 300 Minutes per week of medium intensity aerobic exercise OR 75-150 minutes of vigorous activity. To assess the level of intensity try singing or speaking. If you can talk but not sing, then it is medium intensity. If you cannot talk without stopping for a breath, then it is vigorous.
3. Muscle strengthening exercise of moderate or greater intensity for all major muscle groups. This should be done at least twice a week.
4. For the over 60’s include exercise to strengthen balance.
This is the US version, but the NHS in the UK has an almost identical list. A survey in the US showed that only 28% of people met the guidelines. In country areas this was even lower. UK data is better with nearly twice that percentage meeting the guidelines.
A Cure for “Senior Moments”.
The benefits of exercise have been proven in many different studies. It is good for cardiovascular health and helps with hypertension and cholesterol. It reduces the incidence of Type 2 Diabetes and dementia.
Adults between the ages of 60 and 80, can increase the size of their brains by regular aerobic exercise. The fitter we are the more oxygenated blood our bodies can provide to the brain. Our frontal cortex grows as does our hippocampus. These are key areas for high level thinking and memory. Exercise has been linked to improved attention and processing speed. It improves the ability to retrieve facts and information. It should reduce those “senior moments”.
Measuring the Impact of Aerobic Exercise on the Brain
To understand the impact of exercise we need “randomized control experiments”. We assign participants randomly to two groups. One, “the control”, does not engage in the exercise in which we are interested. To be safe we might have a regular stretching program at the same times as the exercise classes. This would ensure there are no other factors are at work.( For Example: Is it attending a group session regularly that matters not the exercise.) The other group is put through the exercise program. It must go on long enough to have an impact. There is a minimum of three months and some studies have run for a year. Exercise must happen frequently enough to have any effect. Most studies have used the US Guidelines described above. Before and after the experiment we measure the cognitive ability in which we are interested. We do this for the control group as well and compare the difference.
We need to separate the impact of aerobic exercise from muscle building exercise. A recent review found nine different studies from around the world. They had all looked only at aerobic capacity and cognitive ability. These nine were all randomized control experiments using people over 50. Some measured our ability to recall facts. (Our “Senior Moments” when we fail). Others measured the “Executive Function” of the brain. This is the capacity to plan. The ability to have self-control and to avoid being distracted. Some measured both memory and executive function.
The results were clear. Building up an individual’s aerobic capacity significantly increases their scores on the memory tests. This happened across all studies. The results were not as big for “executive function”. However there was still a significant improvement.
Activity versus Exercise
The exercises used in these experiments were a typical “gym” routine. People went through artificial exercises like walking on a treadmill or cycling on a machine. One group were “trained” in water aerobics. In a previous Newsletter I have pointed out that the impact can be multiplied if the exercise engages the brain more (Newsletter #023 “Do Not Go Gentle Into That Goodnight”). Walking through a wood is different than walking on a treadmill. Avoiding tripping and finding your way engages far more of the body and brain.
Humans were not made to sit around. The brain and body evolved to move us around. To take us away from danger. To take us to sources of food and to help us find mates. The brain’s job is to organize that movement. It needs oxygenated blood. But it also needs to be stimulated with the tasks for which it was created. It needs new and different environments to explore. A country walk engages all the senses and all the problem-solving capabilities of the brain. The walk can even be in a complex department store or mall. Such explorations have two beneficial effects. The exercise improves our ability to send oxygen to the brain. It also stimulates the brain in a way that going to the gym will not.
In one study two groups took a country walk. They both took a test of creativity. One group then walked on a path around a woodland. The second group explored the wood. Both groups carried pedometers and returned after the same distance/exercise. They then took a second test of creativity. The “wandering in the woods” group showed a bigger before and after improvement. Perhaps the guidelines need broadening? Of course that assumes that we do what the doctors recommend. Something we do not do well. (Newsletter #123 “People Do Not Take Their Pills Anyway”).