Study finds exercise promotes prevention, especially in people predisposed to the disease 02/22/2017
Ever suffered from mild to moderate depression, or know someone who has?
Treatment can be challenging, and the effects of depression can be incredibly disruptive.
Fortunately, there’s growing evidence that simple lifestyle measures can help deflect depression.
These appear to include exercise, diets rich in seafood-source omega-3s — and a daily cup or two of coffee.
Two recent evidence reviews seem to confirm that exercise can help prevent depression from developing.
And a recent clinical study suggests that people with certain genetic profiles may get the most preventive benefit from exercise.
Earlier Canadian review detected preventive potential in exercise
Four years ago, George Mammen and Guy Faulkner of the University of Toronto reviewed the evidence on exercise and depression available at that time.
Their review was the first to look for evidence that exercise might help prevent depression later in life, as opposed to treating existing depression.
After reviewing more than 26 years of research, Mammen and Faulkner concluded that even modest levels of physical movement (including walks or gardening for just 20-30 minutes a day) can actually ward off depression in men of all age groups.
As the Canadians wrote, “We need a prevention strategy now more than ever. Our health system is taxed. We need to shift focus and look for ways to fend off depression from the start.”
And they made this key point: “This review shows promising evidence that the impact of being active goes far beyond the physical.” (Mammen G et al. 2013)
Good cardiovascular health help deter depression
An evidence review published last December delved more deeply into a key question.
We know that exercise can help alleviate depression, but can it actually help prevent depression?
This comprehensive review was conducted by researchers from around the world, including the U.S. and the UK.
The authors narrowed their search to studies that measured the participants’ cardio-respiratory fitness — as opposed to relying on volunteers’ claims about their levels of exercise and fitness (Schuch FB et al. 2016).
In addition, they selected only studies that evaluated the participants’ mental health and mood at the outset, at the end, and at least one year beyond the study period.
Even after applying these strict research-quality standards, the studies that met the authors' criteria included more than a million participants, which lent weight to evidence.
The conclusions of this evidence review were both encouraging and actionable: Among men and women alike, good cardio-respiratory fitness was linked to a much lower risk for depression.
Conversely, poor cardiorespiratory fitness was linked to a far higher risk for developing depression.
Participants in the various studies who fell into the bottom third for cardio-respiratory fitness were 75% more likely to be diagnosed with depression, compared with people who fell into the top third for cardio-respiratory fitness.
And participants whose level of cardio-respiratory fitness fell in the middle third were nearly 25% more likely to develop depression than those who were the most fit (the top third).
As the authors pointed out, their conclusions extend the findings of the Canadian team described above, in that they showed positive benefits for both women and men. (Mammen and Faulkner’s research pointed largely to benefits for men.)
Genetic markers linked to depression risk, and exercise benefits
There’s growing evidence that the depression-preventive effects of exercise partially depend on a person’s genetic makeup.
A research team from University of Florida found that exercise seems to do more to prevent depression in people who possess certain undesirable genetic traits (Dotson VM et al. 2016).
Importantly, it looks like the same genetic markers linked to higher risk for depression also predict who might benefit the most from exercise as a preventative measure.
In this pilot study, 396 inactive older adults were separated into two groups: those who received health education classes and those who were given moderate physical activity classes for 12 months.
In addition to measuring the participants' mood and its response to exercise throughout the study, the authors tested the volunteers' genes at the outset, looking for ones associated with depression.
Men in the study who carried two specific genes showed the greatest mental health benefit in response to exercise.
One of these genes controls a brain chemical that’s critical to growth of connections among brain cells (neurons), called “brain-derived neurotrophic factor”, or BDNF.
(Omega-3 fatty acids from seafood and exercise both raise brain levels of BDNF — see Miracle-Gro for Your Brain. And there’s growing evidence that the leading antidepressant drugs — so-called “serotonin reuptake inhibitors” such as Prozac — work more by promoting growth of connections among neurons than by inhibiting the reuptake of serotonin.)
The two other genes linked to risk for depression were a serotonin transporter gene, and a variant version of a gene called apolipoprotein E, which is also linked to the risk for Alzheimer’s.
(Two nutrients that abound only in fatty seafood — vitamin D and omega-3s — raise serotonin levels. See Omega-3s and Vitamin D Boost Key Mood Chemical.)
Male participants in the study who had a genetic predisposition to depression gained the greatest benefits from exercise — benefits often equal to those that someone with similar symptoms could expect to receive from conventional drug therapy.
The University of Florida team believes the next step is to determine whether exercise is best in addition to, or in lieu of, conventional therapies.
As lead author Vonetta Dotson, Ph.D., said, “I’d like to take the same approach to exercise that we take to medication, which is to have a personalized medicine approach. If … exercise has a good chance of helping a patient because of their particular characteristics, I think that might help with patients’ motivation to exercise.”
Of course, exercise brings multiple health benefits, and is already proven to help ease existing depression.
Those facts alone that should provide ample motivation, even for folks who don’t know their personal genetic profile!
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- University of Florida. Exercise genes? Study suggests certain people with depression may benefit from exercise. May 4, 2016. Accessed at http://chp.phhp.ufl.edu/2016/05/04/exercise-genes-study-suggests-certain-people-with-depression-may-benefit-from-exercise/