Posted May 6, 2012 by LaVonne Goodman, M.D.

Why is a healthy life style important in HD?  A big part of the answer includes BDNF, the "Mircle Gro" chemical for the brain, and a complicated process called neuroplasticity, both of which are enhanced by healthy life style factors. The "plasticity" part of neuroplasticity refers to capacity to change, similar to how plastic is malleable and can be made into many shapes.  Similarly, neuroplasticity describes the ability of nerve cells to change -- based on various forces -- by making new, or stronger connections to other nerve cells in the brain. This is the brain process that makes learning and memory possible.  And vitally important in brain diseases, neuroplasticity is a process that can preserve brain function while damage occurs -- at least for a while.

Neuroplasticity in HD: The Battle: There is a constant battle regarding neuroplasticity in HD.  On one side is mutant huntingtin protein that, in ways not yet known, can weaken the forces of neuroplasticity.  The other side is a protective force that is active very early in HD. We know this because brain imaging studies show that specific types of nerve cell damage occur long before HD symptoms begin. Or said another way, neuroplastic forces are at work to compensate by forming new connections that detour around damaged areas. And while the detour may not be as good as the original path, it works effectively for a long time. The very good news is that a healthy life style will make stronger detours around the areas of brain most damaged by HD, and tip the BDNF and neuroplasticity balance to the good side.

What healthy life style factors?  Healthy life style factors include exercise, sleep, diet, social and intellectual experience, and stress reduction.  There is increasing scientific evidence that each of these factors can increase BDNF and neuroplasticity, and that combining factors increases it more.  The other good news is that working on one factor makes others easier.  For instance, good sleep gives us more energy to exercise, and in turn exercise improves sleep and reduces stress. 

• Sleep: I recommend working on this one first.  Go to bed at the same time each night and get up in the morning at the same time -- even if still tired -- while maximizing the sunlight hours. Exercise your body and your mind during the day. Have regular healthy diet meals. Don't snack all day. Decrease mental stimulation before bedtime -- no TV or computer games, email, etc.  No caffeine, and alcohol limited to no more than 1 drink. Alcohol may initially make you sleepy, but interferes with sleep later. 
• Exercise: What kind?  Aerobic (walking, swimming, etc) is probably better than strengthening (lifting weights, etc).  Combining some of both is best. Intensity will depend on your level of fitness when you start, but an easy rule is that it needs to be enough to speed your heart and increase breathing rate.  How much time?  Thirty minutes of aerobic exercise every day is probably minimum.  But if you are out of shape, you should start with shorter times, then build up.  I recommend getting up to about 45 minutes each day of aerobic exercise, and thirty minutes 2-3 times a week for strengthening.  A word of caution: there is some evidence that high intensity exercise like running marathons, can be harmful in HD.
• Diet:  What kind?  One that promotes "metabolic health", or a diet low in saturated fat, higher in omega 3 unsaturated fat (as in fish). I recommend "healthy carbohydrates", ones that are whole grain based, because these limit the rise in blood sugar and insulin after a meal. For a healthy sugar, I recommend trehalose, a disaccharide sugar that may be neuroprotective in HD for other reasons, because it promotes lower insulin and glucose blood levels.  Blueberries or other brightly colored fruits (probably between 1 or 2 cups a day) may be helpful.  And for those coffee lovers, caffeine can increase BDNF levels too.
• Intellectual and social stimulation
  
• Stress reduction:  Emotional stress causes an increase in cortisol, which in turn impairs neuroplasticity.

But does a healthy life style work in HD?  The evidence says yes. Studies show that higher degrees of exercise (physical and mental) are correlated with delay of onset of symptoms by as much as 4.6 years [Trembath 2010], and in other study that disease progression measures stabilized over a 2 year period with intensive intermittent combined therapy [Zinzi 2007].  We can probably trust these results as true,  because similar levels of benefit are seen in aging [Nemati Karimooy 2012], and in other neurodegenerative diseases like Alzheimer's [Venturelli 2011] and Parkinson's [Ahlskog 2011].

Author's comments:  Like a constant battle between good and evil, in HD there is a molecular level battle between protective neuroplasticity forces and destructive mutant protein toxicity.  Healthy life style with its extra doses of BDNF can tip the balance to protection, at least for a while.  Think of it this way, if HD had a drug that gave more years of good life, we'd all be running to get it.  Until then, let's get our daily BDNF "Miracle Gro" by working -- every day -- on a healthy life style.

References

Trembath MK, Horton ZA, Tippett L, Hogg V, Collins VR, Churchyard A, Velakoulis D, Roxburgh R, Delatycki MB. A retrospective study of the impact of lifestyle on age at onset of Huntington disease. Mov Disord 2010 Jul 30;25(10):1444-50. PubMed abstract

Zinzi P, Salmaso D, De Grandis R, Graziani G, Maceroni S, Bentivoglio A, Zappata P, Frontali M, Jacopini G. Effects of an intensive rehabilitation programme on patients with Huntington's disease: a pilot study. Clin Rehabil 2007 Jul;21(7):603-13. PubMed abstract

Nemati Karimooy H, Hosseini M, Nemati M, Esmaily HO. Lifelong physical activity affects mini mental state exam scores in individuals over 55 years of age. J Bodyw Mov Ther 2012 Apr;16(2):230-5. PubMed abstract

Venturelli M, Scarsini R, Schena F. Six-month walking program changes cognitive and ADL performance in patients with Alzheimer. Am J Alzheimers Dis Other Demen 2011 Aug;26(5):381-8. PubMed abstract

Ahlskog JE. Does vigorous exercise have a neuroprotective effect in Parkinson disease? Neurology 2011 Jul 19;77(3):288-94. PubMed abstract