Barts-MS rose-tinted-odometer ★★★
I am at the NMSS’ Pathways to Cures think tank where exercise is a major theme in terms of restoring lost function. A lot of discussions have been about how we motivate and get pwMS to exercise. Some suggested using motivational interviewing techniques and behavioural psychology to motivate and nudge pwMS to exercise. The elephant in the room is that some people simply don’t like exercise. Are you one of them?
Not many people know that your participation in exercise is largely driven by genetics. It is clear from the twin study below that genetic variation is important in relation to individual behaviour when it comes to exercise. Heritability of exercise participation in males and females was similar and ranged from 48% to 71%; this may explain why you love or hate exercise. At the moment we don’t know what this heritability in relation to exercise is due to. As the investigators’ point out in their conclusion that it may ‘involve genes influencing the acute mood effects of exercise, high exercise ability, high weight loss ability, and personality’.
One of the other aspects of exercise that was discussed was its biology, in other words how does exercise work. If we can work this out we could potentially explore drugs to mimic exercise. The problem with this reductionist approach is that exercise is very complex and hence likely to be very dirty. For example, exercise can be aerobic (oxygen) or anaerobic (lack of oxygen) and can involve resistance. Then there is intensity and duration. Is HIIT (high-intensity interval training) better than aerobic exercise? What about movement? Does exercise require you to move; is a treadmill run equivalent to an outdoor run? How important is exercise frequency; is daily better than 3-4 times a week versus the weekend warrior’s activity on Saturday and Sunday?
The bottom line is that we know exercise works for some pwMS. However, as always we have many unanswered questions. One that Robert Motl, the doyen of exercise research in MS, raised with me in one of the coffee breaks is that we don’t know if exercise may have negative effects in certain groups of pwMS. For example, during a relapse or in more advanced MS. Is flogging a dying horse, i.e. making people with walking impairment exercise their lower limbs, potentially bad for them in that overuse of the pathway through exercise is speeding up its degeneration? We need to be careful in not making pwMS feel guilty about not exercising when we don’t have a mature evidence-base to recommend it or not.
Stubbe et al. Genetic Influences on Exercise Participation in 37,051 Twin Pairs From Seven Countries. PLoS One , 1 (1), e22 2006 Dec 20.
Background: A sedentary lifestyle remains a major threat to health in contemporary societies. To get more insight in the relative contribution of genetic and environmental influences on individual differences in exercise participation, twin samples from seven countries participating in the GenomEUtwin project were used.
Methodology: Self-reported data on leisure time exercise behavior from Australia, Denmark, Finland, Norway, The Netherlands, Sweden and United Kingdom were used to create a comparable index of exercise participation in each country (60 minutes weekly at a minimum intensity of four metabolic equivalents).
Principal findings: Modest geographical variation in exercise participation was revealed in 85,198 subjects, aged 19-40 years. Modeling of monozygotic and dizygotic twin resemblance showed that genetic effects play an important role in explaining individual differences in exercise participation in each country. Shared environmental effects played no role except for Norwegian males. Heritability of exercise participation in males and females was similar and ranged from 48% to 71% (excluding Norwegian males).
Conclusions: Genetic variation is important in individual exercise behavior and may involve genes influencing the acute mood effects of exercise, high exercise ability, high weight loss ability, and personality. This collaborative study suggests that attempts to find genes influencing exercise participation can pool exercise data across multiple countries and different instruments.