It is common knowledge that exercise is necessary for a healthy body, but what about for a healthy brain? While we would love for our skeletal muscles, joints, and heart to stay strong and functioning well as we age, making sure our brain stays sharp is of the utmost importance, too. Can exercise help us maintain or even improve our cognitive function as we battle Father Time? And, if so, what do various studies suggest in terms of the type of exercise to do as well as the frequency, intensity, and duration?
As a personal trainer and Muscle Activation Techniques® practitioner in Schaumburg, IL, using exercise to help my clients stay physically healthy as they age is a fundamental aspect of my business. I am well-aware of the potency of appropriate exercise when it comes to battling chronic illnesses and improving physical function and quality of life. However, I was not well-versed in the impact that exercise can have on cognitive function.
It is not uncommon for clients to report that they feel mentally “sharper” after beginning to exercise on a regular basis. But what does the literature have to say about this? Is there information to validate these seemingly subjective claims?
Fortunately for all of us, the answer is yes. Exercise does appear to have both a positive impact on performance during cognitive tasks as well as on the physical structure of the brain itself, as determined by functional MRI. And there is a mounting pile of research to back it up.
What is even more interesting–at least to me–is that not only are these changes in cognitive function dependent on the types of activity that are done, but the positive brain impacts are dependent on the frequency, duration, and intensity of the exercise, as well.
Most of the exercise world categorizes exercise into two groups – resistance training (lifting weights) and aerobic training (cardio). Both of these forms of exercise have been shown to improve brain function, but in different ways and under different conditions (Liu-Ambrose et al., 2011; Cassilhas et al., 2007; Colcombe et al., 2004).
Liu-Ambrose et al., 2011, showed that subjects who participated in resistance training two times per week had greater improvements in cognitive function than subjects who participated in resistance training once per week as well as subjects who did a series of stretching, balance training, and core exercises. The latter two groups in this study showed little to no cognitive improvement over the course of 12 months.
Additionally, Cassilhas et al., 2007, showed that both medium-intensity and high-intensity resistance training three times per week led to improved cognitive function after 24 weeks when compared to subjects who did only stretching and light resistance training exercises.
Likewise, subjects who participated in medium (40%-50% heart rate reserve) to higher intensity (60%-70% heart rate reserve) aerobic training for upwards of 45 minutes three times per week showed significant cognitive improvement over the course of six months (Colcombe et al., 2004). Again, the control group in this study participated in regular stretching, balance, and core exercises.
Interestingly, aerobic and resistance training exercises appear to cause different adaptations in the brain. Aerobic exercise appears to improve the areas of the brain that help subjects filter out irrelevant information as it relates to a given task (Liu-Ambrose et al., 2011). On the other hand, resistance training appears to improve the areas of the brain that help subjects reduce “making automatic and unwanted responses” (Liu-Ambrose et al., 2011).
Looking specifically at the areas of the brain that were affected with resistance training and aerobic exercise, the potential improvements in cognitive function are widespread. Resistance training appears to stimulate the anterior insula, the orbitofrontal cortex, and the middle temporal gyrus (Liu-Ambrose et al., 2011). Functions for these areas of the brain include regulating emotional responses to aversive stimuli (Caria et al., 2010), decision making (Bechara et al., 2000), and language and memory (Onitsuka et al., 2004).
Aerobic training appears to increase the activity of the different parietal regions of the brain as well as decrease activity of the anterior cingulate cortex (Liu-Ambrose et al., 2011). The functions of the former include the ability to maintain focus (Culham et al, 2001), while decreasing activation of the latter may help to downregulate emotions (Devinsky et al., 1995) as well as autonomic nervous system responses (Critchley et al., 2003).
Brain health and cognitive function can be improved through exercise, but what you do and how you do it matter. Resistance training should be done at least two days per week at a medium to high intensity. Two sets of six to eight reps using 50% to 80% of your 1-Rep Max for a given exercise were utilized in the studies. Positive brain benefits with aerobic training appear to occur with medium (40%-50% heart rate reserve) to high-intensity (60%-70% heart rate reserve) activity three days per week for upwards of 45 minutes.
Each of the papers discussed potential mechanisms at play, such as increases in Insulin-like Growth Factor 1 (IGF-1) as well as decreases in homocysteine. The former helps to promote neural growth and modulate brain-derived neurotrophic factor (BDNF) while the latter negatively impacts cognitive function and brain structure (Liu-Ambrose et al., 2011; Colcombe et al., 2004).
As a consumer and doer of exercise, it is of the utmost importance to make sure you are incorporating both resistance training and aerobic training for your overall physical and mental health. While specific considerations need to be taken regarding exactly how much of each is appropriate for you to do right now, there are general guidelines available that appear to improve not only the health of your body but the health of your brain, as well.
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