Did you exercise today? If so, how much time? When did you last exercise? How about in the last month? We hear a lot about the positive effects of exercise on our physical health such as increased stamina and general physical and emotional well being. All this is true. However, physical fitness is evolving as a significant factor related to cognitive health in middle to older age. Most of us have had the experience of difficulty in recalling names or remembering where we left things as we get older. This in part is because your brain shrinks as you age, and the atrophy is related to cognitive decline and increased risk for dementia. Exercise appears to reduce that deterioration and cognitive decline.
In CNN Health News, author Morgan Manella noted recent studies showing that higher levels of physical fitness in middle-aged adults were associated with larger brain volumes five years later, particularly in brain areas having to do with memory such as the hippocampus (Kilgore, Olsen and Weber, 2013, Scientific Reports). In a study published this year in the online journal Neurology (Wiley et al), the authors found that older people who exercised regularly experienced a slower rate of mental decline.
In the Scientific Reports study, more than 1,500 people at an average age of 40 and without dementia or heart disease took a treadmill test. Twenty years later, they took another test, along with MRI brain scans. The study found that those who didn't perform as well on the treadmill test -- a sign of poor fitness -- had smaller brains 20 years later.
In the Neurology study, older adults averaging 71 years with low activity patterns (light exercise, such as walking and gardening) or high activity patterns (moderate to high-intensity exercise such as running and aerobics) were followed for up to 12 years. On neuroimaging and a battery of tests examining memory and cognitive skills, people with no signs of cognitive impairment at the start of the research who reported low activity levels showed a greater decline in processing speed and episodic memory over five years than the high activity group. Their brains aged about 10 years more than the group that exercised.
These studies suggest that promotion of physical fitness during middle age is an important step toward ensuring healthy brain aging. Researchers also have found that people with higher blood pressure and heart rate during exercise were more likely to have smaller brain sizes 20 years later. People with poor physical fitness usually have higher blood pressure and heart rate responses to low levels of exercise compared to people who exercise more. Given so many older adults have hypertension and reduced blood flow secondary to elevated levels of cholesterol, the potential effects on brain aging and decline are serious. However, exercise training programs that improve fitness may increase blood flow and oxygen to the brain over the short term. Over time, improved blood flow may have an impact on brain aging and lessen cognitive decline in older age.
Exercise is also a great stress reliever, which can protect the brain from damage caused by stress. Stress also serves to impair memory and slow down your thinking. What these studies show is that you need to keep active even into older age if you want to keep your brains intact as well as reduce stress and its negative effects on your brain.
So how much exercise should you do to receive cognitive benefits? Clearly this differs for each person and you should consult your primary care physician if you have not been doing a regular exercise program. However, in the Kilgore Scientific Reports study of middle aged adults, the average number of sessions per week was three and the average number of minutes per week was 189 (about 3 hours). This level of activity was associated with an increase in gray matter volume in the hippocampus, a region associated with memory.
So let's get active to maintain our cognitive health. The choices you make now, whatever your age, influence your fitness in all areas to include cognitive. It's never too late to take action. Good luck and best wishes on your journey.
Dr. Paul Longobardi
For information on these and related topics, please see my website at www.successandmindset.com.