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Few studies have compared the relative benefits of moderate- vs. higher intensity exercise training on improving insulin sensitivity in older people while holding exercise volume constant. Healthy older (73 +/- 10 yr) women (N = 25) who were inactive, but not obese, were randomized into one of three training programs (9-mo duration): 1) high-intensity [80% peak aerobic capacity (V(O2)peak); T(H)] aerobic training; 2) moderate-intensity (65% V(O2)peak; T(M)) aerobic training; or 3) low-intensity (stretching) placebo control (50% V(O2)peak); C(TB)). Importantly, exercise volume (300 kcal/session) was held constant for subjects in both the T(H) and the T(M) groups. V(O2)peak was determined by using a graded exercise challenge on a treadmill. Total body fat and lean mass were determined with dual-energy X-ray absorptiometry. The rate of insulin-stimulated glucose utilization as well as the suppression of lipolysis were determined approximately 72 h after the final exercise bout by using a two-step euglycemic-hyperinsulinemic clamp. We observed improved glucose utilization at the higher insulin dose with training, but these improvements were statistically significant only in the T(H) (21%; P = 0.02) compared with the T(M) (16%; P = 0.17) and C(TB) (8%; P = 0.37) groups and were observed without changes in either body composition or V(O2)peak. Likewise in the T(H) group, we detected a significant improvement in insulin-stimulated suppression (%) of adipose tissue lipolysis at the low-insulin dose (38-55%, P < 0.05). Our findings suggest that long-term higher intensity exercise training provides more enduring benefits to insulin action compared with moderate- or low-intensity exercise, likely due to greater transient effects.

Background: The school setting could be a primary venue for promoting physical activity among inner-city children due to the structured natured of the school day. We examined differences in step counts between structured school days (SSD) and weekend days (WED) among a sample of public school children in Washington, DC. Methods: Subjects (N = 29) were third- to sixth-grade students enrolled in government-funded, extended-day enrichment programs. Step counts were measured using a pedometer (Bodytronics) over 2 SSD and 2 WED. Differences in mean step counts between SSD and WED were determined using multivariable linear regression, with adjustments for age, sex, and reported distance between house and school (miles). Results: Recorded step counts were low on both SSD and WED (7735 ± 3540 and 8339 ± 5314 steps/day). Boys tended to record more steps on SSD compared with girls (8080 ± 3141 vs. 7491 ± 3872 steps/day, respectively), whereas girls recorded more steps on the WED compared with boys (9292 ± 6381 vs. 7194 ± 3669 steps/day). Parameter estimates from the regression modeling suggest distance from school (P < .01) to be the strongest predictor of daily step counts, independent of day (SSD/WED), sex, and age. Conclusion: Among inner-city school children, a safe walking route to and from school may provide an important opportunity for daily physical activity. [ABSTRACT FROM AUTHOR]

Background: Little attention has been paid to the study of transient growth hormone (GH) responses to exercise in older women. We determined the effect of a single bout of exercise on GH in fit and unfit older (age 55 to 81 y; n = 19) and younger (age 18 to 25 y; n = 19) women. Methods: Exercise consisted of five 15-min intervals of treadmill exercise at 75% VO2peak. Blood samples were taken before, during, and following exercise for determination of plasma GH and insulin concentrations.   Results: GH responses to exercise were attenuated in older compared with younger women (P < 0.01); however, these age differences were minimized in older age by fitness level. Adjusted area under the curve for GH was 5.50 and 1.76 mg/L · 102 for fit and unfit older women (P < 0.01), and 8.46 and 8.46 mg/L · 102 for fit and unfit younger women. Conclusions: Low levels of cardiorespiratory fitness in older women may require a greater relative exercise stimulus to augment meaningful GH responses. [ABSTRACT FROM AUTHOR]

Physical activity offers one of the greatest opportunities for people to extend years of active independent life and reduce functional limitations. The article identifies key practices for promoting physical activity in older adults, with a focus on those with chronic disease or low fitness and those with low levels of physical activity. Key practices identified: (a) A multidimensional activity program that includes endurance, strength, balance, and flexibility training is optimal for health and functional benefits; (b) principles of behavior change including social support, self-efficacy, active choices, health contracts, assurances of safety, and positive reinforcement enhance adherence; (c) manage risk by beginning at low intensity but gradually increasing to moderate physical activity, which has a better risk:benefit ratio and should be the goal for older adults; (d) an emergency procedure plan is prudent for community-based programs; and (e) monitoring aerobic intensity is important for progression and motivation. Selected content review of physical activity programming from major organizations and institutions is provided. [ABSTRACT FROM AUTHOR]

Background: Given observational findings that physical activity reduces breast cancer risk, improves survival, and improves quality of life in breast cancer survivors, a need has been identified for randomized controlled trials that test the efficacy of exercise on biological mechanisms associated with breast cancer survival. The primary aims of the Yale Exercise and Survivorship Study were to 1) determine the feasibility of recruiting breast cancer survivors into a randomized controlled trial of the effects of exercise on biological markers and/or mechanisms associated with survival, 2) compare the effectiveness of various recruitment strategies on accrual rates and baseline characteristics, and 3) report adherence to the exercise trial.Methods: Seventy-five postmenopausal breast cancer survivors self-referred into the trial or were recruited through the New Haven Tumor [corrected] Registry and randomly assigned to an exercise (n = 37) or usual-care (n = 38) group. The exercise group participated in 150 min/wk of supervised gym-based and home-based aerobic exercise for 6 months. The usual-care group was instructed to maintain current physical activity level.Results: A total of 75 women (an accrual rate of 9.5%) were randomized to the trial. Rates of accrual were higher for women who self-referred into the study (19.8%) compared with women recruited via the cancer registry (7.6%); however, demographic, physiologic, and prognostic characteristics did not differ between the 2 recruitment strategies. On average, exercisers increased moderate- intensity to vigorous-intensity aerobic exercise by 129 minutes per week compared with 44 minutes per week among usual-care participants (P < .001). Women in the exercise-intervention group increased their average pedometer steps by 1621 steps per day compared with a decrease of 60 steps per day among women in the usual-care group (P < .01).Conclusions: Findings from this study will provide useful information for investigators who are conducting exercise trials in cancer populations, clinicians who are treating women diagnosed with breast cancer, and exercise professionals who are developing community-based exercise programs for cancer survivors. [ABSTRACT FROM AUTHOR]

The article discusses a study on adult obesity and the six-year trajectory of weight change in men. A total of 761 healthy, affluent men between the ages of 20 and 78 participated in this study. Results revealed that men with a history of adult obesity were significantly heavier than those with no history. However, rate of weight gain is slower among men with a history of adult obesity than those without a history. The author adds that diet and fitness are both important factors for weight loss.

The article presents two different views concerning the significance of maintaining enough energy availability by women athletes. One view defines energy availability as a dietary energy intake minus exercise energy expenditure. Moreover, it has been pointed out that low energy availability impairs reproductive function in women as discovered in a study. However, another view emphasizes that low energy availability does not affect the reproductive health of female athletes. All athletes who are considering to lose body weight or body fat should monitor energy availability.

The purpose of this analysis was to determine the longitudinal relation between physical activity and the trajectory of weight change in an older cohort (≥65 years) living in New Haven, Connecticut, who participated in the Established Populations for the Epidemiologic Study of the Elderly between 1982 and 1994 (n = 2,812). The authors hypothesized that body weight would decline over the follow-up and that physical activity would play an important role in minimizing weight loss over time. Physical activity and other covariables were self-reported at baseline, while body weight was self-reported annually over 12 years. Multivariable random effects regression demonstrated a curvilinear trajectory of weight loss per year with an accelerated loss at older ages. Baseline body weight was 155 (standard deviation, 30) pounds (70 (standard deviation, 14) kg) for those who survived the entire follow-up and was 153 (standard deviation, 32) pounds (70 (standard deviation, 15) kg) for those who did not. Each 1-unit increase in baseline total activity score minimized this aging-related weight loss, but this relation was most pronounced among those with chronic disease who did not survive the entire follow-up period (n = 973; 0.15 pounds (0.07 kg) per year). These data suggest that, among frail older people, even modest levels of physical activity can attenuate the rate of aging- and disease-related weight loss. [ABSTRACT FROM AUTHOR]

The article discusses the global challenges regarding public health and physical activities. It is noted that before science decides what a contagious disease is or how it works, strategies to prevent the spread of contagion must be initiated well. It is mentioned that a primary element of public health practice and healthy public policy should be the promotion of an active lifestyle across the lifespan.

While the benefits of physical activity and exercise among older persons are becoming increasingly clear, the role of exercise stress testing and safety monitoring for older persons who want to start an exercise program is unclear. Current guidelines regarding exercise stress testing likely are not applicable to the majority of persons aged 75 years or older who are interested in restoring or enhancing their physical function through a program of physical activity and exercise. In addition to being expensive and of unproven benefit, the current policy of routine exercise stress testing potentially could deter many older persons from participating in an exercise program. Research is needed to investigate current physician practices, evaluate the risk of adverse cardiac events, determine the role of pharmacological stress testing, and measure and compare absolute and relative exercise intensities. To assist clinicians, we offer a set of recommendations regarding precautions that can be taken to minimize the risk of adverse cardiac events among previously sedentary older persons who do not have symptomatic cardiovascular disease and are interested in starting an exercise program. JAMA. 2000;284:342-349 [ABSTRACT FROM AUTHOR]

Objectives. This study examined cross sectionally the physical activity patterns associated with low, moderate, and high levels . of cardiorespiratory fitness. Methods. Physical activity was assessed by questionnaire in a clinic population of 13 444 men and 3972 women 20 to 87 years of age. Estimated energy expenditure (kcal · wk-1) and volume (min · wk-1) of reported activities were calculated among individuals at low, moderate, and high fitness levels (assessed by maximal exercise tests). Results. Average leisure time energy expenditures of 525 to 1650 kcal · wk-1 for men and 420 to 1260 kcal · wk-1 for women were associated with moderate to high levels of fitness. These levels of energy expenditure can be achieved with a brisk walk of approximately 30 minutes on most days of the week. In fact, men in the moderate and high fitness categories walked between 130 and 138 min · wk-1, and women in these categories walked between 148 and 167 min · wk-1. Conclusions. Most individuals should be able to achieve these physical activity goals and thus attain a cardiorespiratory fitness level sufficient to result in substantial health benefits. [ABSTRACT FROM AUTHOR]

A letter to the editor about the effect of physical activity on the health of older adults, is presented.

Few studies have adequately assessed the simultaneous effects of changes in cardiorespiratory fitness (fitness) and body mass on cardiometabolic risk. Hence, the current study's aims were twofold: (1) To determine whether increases in body mass result in higher cardiometabolic risk after controlling for fitness changes; and (2) To assess whether increases in fitness result in lower cardiometabolic risk after controlling for weight changes. The study consisted of 3534 patients who came for preventive medicine visits ≥4 times over any 10-year period (1979-2019). The primary independent variables were body mass and fitness, and the dependent variable was metabolic syndrome (MetS) and its components. Mixed-effects regression was used to model the relationship between changes in body mass, fitness, and MetS. Results indicate that increasing body mass up to a 10-year period was significantly related to increasing risk of MetS while controlling for changes in fitness. Specifically, a 1-kg increase in body mass was associated with a 17% (OR = 1.17; 95% CI 1.15-1.19) increased odds for MetS, while adjusting for fitness changes. A 1-MET increase in fitness was related to a 23% (OR = 0.77; 95% CI 0.70-0.84) decrease in odds for MetS, while adjusting for body mass changes up to 10 years. Moreover, body mass change was significantly related to changes in all cardiometabolic components of MetS. Fitness change was significantly associated with changes in MetS components. Future interventions should focus concurrently on increasing fitness and on body mass loss (or maintenance) to improve cardiometabolic health. [ABSTRACT FROM AUTHOR]