The concept that participation in exercise/physical activity reduces the risk for a host of chronic diseases is undisputed. Along with adaptations to habitual activity, each bout of exercise induces beneficial changes that last for a finite period of time, requiring subsequent exercise bouts to sustain the benefits. In this respect, exercise/physical activity is similar to other “medications” and the idea of “Exercise as Medicine” is becoming embedded in the popular lexicon. Like other medications, exercise has an optimal dose and frequency of application specific to each health outcome, as well as interactions with food and other medications. Using the prevention of type-2 diabetes as an exemplar, the application of exercise/physical activity as a medication for metabolic “rehabilitation” is considered in these terms. Some recommendations that are specific to diabetes prevention emerge, showing the process by which exercise can be prescribed to achieve health goals tailored to individual disease prevention outcomes.
Geeske Peeters, Richard Hockey and Wendy Brown
This study was designed to compare theoretical strategies for changing physical activity (PA) in terms of their potential to reduce the incidence of chronic conditions in midage women: (1) whole population: +30 minutes/week in all, (2) high-risk: +60 minutes/week in the lowest 25% of the PA distribution, and (3) middle road: shift all those not meeting guidelines to a level commensurate with meeting guidelines.
10,854 participants (50–55 years in 2001) in the Australian Longitudinal Study of Women’s Health completed mail surveys in 2001, 2004, 2007, and 2010. PA was calculated as MET·minutes/week spent in walking, moderate and vigorous PA in the previous week. Incidence rates per 1000 person-years for diabetes, heart disease, hypertension, cancer, and depression were calculated for the actual distribution and after modeled shifts in PA.
The incidence rates were 10.6 for diabetes, 7.0 for heart disease, 30.7 for hypertension, 8.0 for cancer, and 28.4 for depression. Greater reductions in incidence were found for the middle road strategy than for the whole population and high-risk strategies, with reductions ranging from –6.3% for cancer to –12.3% for diabetes.
This theoretical modeling showed that a middle road strategy to increasing PA was superior to the whole population and high-risk strategies, in terms of reducing incidence rates of chronic conditions in middle-aged women.
Hermann Zbinden-Foncea, Luc J. C. van Loon, Jean-Marc Raymackers, Marc Francaux and Louise Deldicque
Mitogen-activated protein kinase (MAPK) pathways are activated in skeletal muscle during endurance exercise, but the upstream molecular events are incompletely resolved. As an increase in plasma nonesterified fatty acids (NEFA) is a common feature of long-lasting exercise, the authors tested the hypothesis that NEFA contribute to the activation of MAPK during endurance exercise. Acipimox was used before and during endurance exercise to prevent the elevation of plasma NEFA levels in healthy subjects and patients with diabetes. In 2 separate studies, healthy subjects cycled for 2 hr and patients with diabetes for 1 hr at 50% Wmax. In control conditions, plasma NEFA concentrations increased from 0.35 to 0.90 mM during exercise in healthy subjects and from 0.55 to 0.70 mM in patients with diabetes (p < .05). Phosphorylation states of extracellularly regulated kinase 1 and 2 (ERK1/2), p38, and c-Jun NH2-terminal kinases (JNK) were significantly increased after exercise in the vastus lateralis in both groups. Acipimox blocked the increase in plasma NEFA concentrations and almost completely repressed any rise in ERK1/2 and p38 but not in JNK. In conclusion, the data support a role for plasma NEFA in the activation of p38 and ERK1/2 in skeletal-muscle tissue of healthy and diabetic subjects during endurance exercise. Further investigation will be required to determine the molecular link between NEFA and MAPK activation during exercise in human skeletal muscle.
Chiao-Nan Chen, Lee-Ming Chuang, Mallikarjuna Korivi and Ying-Tai Wu
This study investigated the differences in exercise self-efficacy, compliance, and effectiveness of home-based exercise in individuals with and without metabolic syndrome (MetS).
One hundred and ten individuals at risk for diabetes participated in this study. Subjects were categorized into individuals with MetS and individuals without MetS. Metabolic risk factors and exercise self-efficacy were evaluated for all subjects before and after 3 months of home-based exercise. Univariate analysis of variance was used to compare the effectiveness of a home-based exercise program between individuals with and without MetS.
The home-based exercise program improved body mass index and lipid profile in individuals at risk for diabetes, regardless of MetS status at baseline. Individuals without MetS had higher exercise self-efficacy at baseline and performed greater exercise volume compared with individuals with MetS during the intervention. The increased exercise volume in individuals without MetS may contribute to their better control of insulin resistance than individuals with MetS. Furthermore, baseline exercise self-efficacy was correlated with exercise volume executed by subjects at home.
We conclude that home-based exercise programs are beneficial for individuals at risk for diabetes. However, more intensive and/or supervised exercise intervention may be needed for those with MetS.
Catrine Tudor-Locke, Nicola Lauzon, Anita M. Myers, Rhonda C. Bell, Catherine B. Chan, Linda McCargar, Mark Speechley and N. Wilson Rodger
To compare the effectiveness of a theory-based lifestyle physical activity (PA) program delivered to individuals with type 2 diabetes in diabetes education centers by professionals and peers.
Changes over 16 weeks in PA (steps/day) and related variables (weight, waist girth, resting heart rate, systolic and diastolic blood pressures) were compared (RMANOVA) for two groups: 157 participants led by 13 different professionals versus 63 participants led by 5 peer leaders.
Overall, the 81 male and 139 female participants (age = 55.7 ± 7.3 years, BMI = 35.2 ± 6.6) showed an incremental change of 4,059 ± 3,563 steps/day, which translates into an extra 37 minutes of daily walking (P < .001). Statistically significant improvements were also seen in weight, waist girth, and blood pressure (all P < .001) and resting heart rate (P < .05). There were no significant differences in outcomes between professional and peer-led groups.
A theory-based behavior modification program featuring simple feedback and monitoring tools, and with a proven element of flexibility in delivery, can be effective under real-world conditions while addressing inevitable concerns about resource allocation. Program delivery by peer leaders, in particular, could address a potential obstacle to dissemination by helping to alleviate existing high caseload demands on diabetes educators.
Shirley N. Bryan and Peter T. Katzmarzyk
Physical activity is associated with a reduced risk of chronic disease. This study describes the relationship between meeting the guidelines for physical activity described in Canada’s Physical Activity Guide and heart disease, type 2 diabetes, hypertension, obesity, and low levels of general health.
Leisure-time energy expenditure (LTEE) was calculated from leisure-time physical activities reported by adults who participated in the 2007 Canadian Community Health Survey. Respondents were classified as meeting the guidelines for physical activity or not, and were stratified by sex into quartiles of LTEE. Logistic regression was used to determine the odds for all conditions associated with not meeting the guidelines and by quartile of LTEE, adjusting for covariates.
The odds of type 2 diabetes, obesity, and fair/poor health were significantly higher among those not meeting the guidelines for both sexes and for high blood pressure among women. Significantly higher odds were seen between the lowest and highest quartiles of LTEE for type 2 diabetes and high blood pressure and across all quartiles for obesity and fair/poor health for both sexes.
Canadian adults meeting the physical activity guidelines have lower odds of chronic diseases and fair/poor health than those not meeting the guidelines.
This review is intended to critically examine the notion that physical training, in addition to its nonspecific effects on fitness, can induce disease-specific benefits in the child with a chronic disease. Conditions included in this analysis are asthma, cerebral palsy, coronary risk, cystic fibrosis, diabetes mellitus, hypertension, myopathies, and obesity. Most of the published intervention studies are deficient in design by not including randomly assigned (or matched) controls. Other constraints stem from the need to simultaneously maintain other therapeutic modalities, the progressive nature of some of the diseases, and the small pool of suitable subjects.
Leandro Martin Totaro Garcia, Kelly Samara da Silva, Giovâni F. Del Duca, Filipe Ferreira da Costa and Markus Vinicius Nahas
Our purpose was to examine the association of television viewing (hours/day), sedentary work (predominantly sitting at work), passive transportation to work (car or motorcycle), and the clustering of these behaviors (“sedentary lifestyle”), as well as leisure-time physical inactivity (LTPI), with chronic diseases (hypertension, hypercholesterolemia, type 2 diabetes, obesity, and clustering of chronic diseases) in Brazilian workers.
Cross-sectional study conducted from 2006 to 2008 in 24 Brazilian federal units (n = 47,477). A questionnaire was applied. Descriptive statistics, binary and multinomial logistic regressions were used.
Magnitude of association with chronic diseases varied greatly across domains and gender. Sedentariness at work was the most consistent behavior associated with chronic diseases, especially in men (ORhypertension = 1.10, 95% CI: 1.01–1.20; ORhypercholesterolemia = 1.34, 95% CI: 1.21–1.48; ORobesity = 1.27, 95% CI: 1.15–1.41; OR1chronic disease = 1.17, 95% CI: 1.09–1.26; OR≥2chronic diseases = 1.61, 95% CI: 1.46–1.78) compared with women (ORhypercholesterolemia = 1.15, 95% CI: 1.01–1.31; ORobesity = 1.24, 95% CI: 1.04–1.48). LTPI was associated with all diseases in men (except type 2 diabetes), but only with obesity in women.
Adverse health consequences may be differently associated according to behavior domain and gender. Sedentary work and LTPI were consistently associated with chronic disease in Brazilian workers, especially in men.
Judy Kruger, Sandra A. Ham and Serena Sanker
Physical inactivity is associated with increased morbidity and mortality. This study provides prevalence estimates of inactivity by select characteristics among older adults.
Respondents ≥50 years of age were selected from the 2005 Behavioral Risk Factor Surveillance System (N = 185,702).
Overall, 30.0% of older adults did not engage in leisure-time physical activity. Within each racial/ethnic group, the prevalence of inactivity was highest among Hispanic men (41.9%) and women (42.4%). Among men with and without disabilities, chronic disease conditions associated with inactivity were angina or coronary artery disease. Among women with disabilities, chronic disease conditions associated with inactivity were stroke and diabetes; among women without disabilities only diabetes was significantly associated with inactivity.
Regular physical activity is an important means to maintaining independence, because it substantially reduces the risk for developing many diseases; contributes to healthy bones, muscles, and joints; and can reduce the risk for falling. Health care providers are encouraged to discuss concerns regarding physical activity with their patients.
Geoff D.C. Ball, J. Dru Marshall and Linda J. McCargar
We investigated whether body composition, physical activity, physical inactivity, and cardiorespiratory fitness explained the presence of risk factors for cardiovascular disease (CVD) and type 2 diabetes in youth. Eighty-three obese children (6–12 years old) were classified as either low health risk (LHR; n = 30) or high health risk (HHR; n = 53) based on the absence/presence of metabolic risk factors that included measures of dyslipidemia, insulin resistance, and elevated blood pressure. Along with demographic and anthropometric data, body composition, physical activity, physical inactivity, and cardiorespiratory fitness variables were assessed. Risk factor clustering was evident in this sample with 24/83 (29%) possessing at least 2 risk factors. Percent body fat did not differ between the LHR (38.5%) and HHR (39.8%) groups, but total fat mass, total fat-free mass, and central body fat mass were greater in the high health risk group. The strongest predictor for the presence of risk factors was central body fat accumulation. Physical activity, physical inactivity, and cardiorespiratory fitness were unable to predict metabolic risk. Overall, we found that risk factors for CVD and type 2 diabetes were common and that body fat mass and central body fat distribution, in particular, were more important than physical activity, physical inactivity, and cardiorespiratory fitness in predicting metabolic risk in obese children.