Changes in physical activity patterns in the United States, by sex and cross-sectional age

Familial aggregation of physical activity levels in the Québec Family Study

PURPOSE

Familial aggregation of physical activity phenotypes was investigated in 696 subjects from 200 families of the Quebec Family Study. The mean age of offspring and parents was 27 and 53 yr, respectively.

METHODS

The levels of physical activity were estimated using a 3-d diary and a questionnaire dealing with physical activity during the past year.

RESULTS

An ANOVA performed on the age and sex adjusted physical activity phenotypes revealed that there were 1.40-1.52 times more variation in physical activity levels between families than within families (0.001 < P < 0.0001), suggesting that physical activity levels aggregate in families. Maximal heritabilities (SEGPATH), adjusted for the degree of spouse resemblance, reached 25%, 16%, 19%, and 17% for the degree of inactivity, time spent in moderate to strenuous physical activities, total level of daily activity, and weekly time spent in the main activity during the previous year, respectively.

CONCLUSION

These results suggest that physical activity level is characterized by a significant degree of familial resemblance, and that inactivity has a slightly higher heritability level than moderate to strenuous physical activity or total physical activity phenotypes. The pattern of familial correlations suggests that shared familial environmental factors along with genetic factors are also important in accounting for the familial resemblance in physical activity level.

Physical activity patterns in recent college alumni

Within this sample of recent college alumni, a high proportion indicated that they enjoy exercise (66.1%) and felt confident in setting their own fitness programs (79.4%). Yet, only 34.3% reported engaging in recommended levels of moderate or vigorous PA. In contrast to previous reports, rates of participation in vigorous, moderate, and strengthening-type PA did not differ between men and women. Alumni who reported that they engaged in adequate levels of moderate or vigorous PA had gained significantly less weight in the years following graduation than those who reported being insufficiently active (3.0 kg vs. 6.1 kg). Last, we noted a strong positive association between PA patterns as college seniors and current PA behavior as recent alumni.

Total physical activity in relation to age, body mass, health and other factors in a cohort of Swedish men

BACKGROUND

Despite a large public health interest in physical activity and its role in obesity and other chronic diseases, only a few reports to date have addressed total levels of physical activity in relation to age, body mass, health and other lifestyle factors.

OBJECTIVE

To investigate whether levels of total physical activity among men are associated with age, body mass, self-rated health and other lifestyle factors in a cross-sectional setting.

METHODS

In a population-based cohort of 33 466 men aged 45-79 y in central Sweden, we collected information about physical activity through a self-administered questionnaire. Level of total physical activity was assessed quantitatively based on six questions on different activities: work/occupation, housework, walking/bicycling, exercise, inactive leisure time and sleeping. The physical activity levels were measured as metabolic equivalents, MET-h/day. The relation between age, body mass index, smoking, education, marital status and self-rated health, and total physical activity was studied in a cross-sectional analysis, using multivariate regression.

RESULTS

Total daily physical activity was decreasing systematically between age 45 and 79 (-4.1%, 95% CI -4.6, -3.6). Obese men reported -2.6% (95% CI -3.0, -2.1) lower physical activity than normal weight men. Those with high education had -7.0% (95%CI -7.3, -6.7) lower total physical activity than those with elementary school. Men with self-rated poor health had -11.3% (95%CI -12.1, -10.6) lower physical activity than those reporting very good health. The cross-sectionally observed decrease with age was greatest among obese men (-8.7%), current smokers (-7.9%), low-educated men (-5.6%) and those with poor health (-9.8%); the subgroups with very good health reported almost the same level of total physical activity (-0.6%) for age 74-79 as for age 45-49.

CONCLUSIONS

The observed decreasing levels of total physical activity with age to large degree depend on health status and other factors. The characterization of subjects with low total physical activity levels is of importance for understanding observed worldwide trends in increasing prevalence of obesity. The better understanding of these phenomena might also facilitate a better planning of public health interventions with messages specifically adjusted for subgroups of population with lower physical activity.

Hormonal responses to endurance and resistance exercise in females aged 19-69 years

Thirty cross-trained, female subjects (19-69 years) completed an endurance exercise session (ES), a resistance exercise session (RS), and a control session (CS) in a randomized, balanced design. The ES consisted of 40 minutes of cycling at 75% maximum heart rate, and the RS consisted of 3 sets of 10 repetitions of eight exercises. During the CS, subjects performed no exercise. Before and after exercise, and after 30 minutes of recovery, blood samples were analyzed for plasma lactate and serum growth hormone, insulin-like growth factor 1, testosterone, estradiol, dehydroepiandrosterone, and cortisol. Samples were taken during the CS at the same intervals as during the exercise sessions. There were no age-related differences in intensity measures during exercise. Absolute change from baseline in testosterone (p <.001), estradiol (p <.05), and growth hormone (p <.01) was significantly greater in the ES and RS compared with that in the CS. Absolute change in dehydroepiandrosterone was significantly greater in the RS only (p <.05). Results indicate that an acute bout of exercise can increase concentrations of anabolic hormones in females across a wide age range.

Autopercepção corporal de variáveis da aptidão física relacionada à saúde

FUNDAMENTAÇÃO: A aptidão física apresenta duas dimensões, uma relacionada à saúde e outra ao desempenho. Não é sabido se adultos não-atletas possuem autopercepção corporal (ApC) apropriada sobre a sua aptidão física relacionada à saúde. OBJETIVOS: a) testar a ApC de indivíduos não-atletas em algumas variáveis morfofuncionais constituintes da aptidão física, b) verificar se a margem de acerto ou de erro nessa ApC depende dos resultados obtidos; e c) verificar se aqueles com maior ApC são mais aptos fisicamente. MÉTODOS: Foram obtidos dados em 63 adultos (51 homens), com idade entre 22 e 85 anos, tendo sido medida e testada a ApC das seguintes variáveis: VO2 máximo, flexibilidade, força de preensão manual, potência muscular máxima absoluta e relativa, localização predominante de gordura corporal e peso de referência, habilidade de sentar e levantar do solo e relação peso/altura, além da altura e do peso corporal. A influência da magnitude das variáveis sobre o escore de ApC (soma dos acertos nas 12 variáveis testadas) foi testada pela comparação entre os resultados do primeiro e do quinto quintis da distribuição e por correlações. RESULTADOS: Os indivíduos tendem a errar mais do que a acertar, em média, a ApC: 60 vs. 40%. A ApC é mais incorreta para a variável flexibilidade 84% de erro - e mais precisa para a habilidade de levantar do solo 66% de acerto. O escore de ApC foi maior nos indivíduos mais flexíveis (p = 0,01) e nos que possuíam maior força de preensão manual (p = 0,04) e tendia a ser maior nos que alcançavam percentual mais elevado do VO2 máximo previsto (p = 0,08). O sedentarismo era quase três vezes mais prevalente nos indivíduos com pior ApC. Os 20% com maiores escores de ApC tendiam a melhores resultados nas variáveis da aptidão física (p entre 0,03 e 0,11). CONCLUSÕES: O nível global de ApC de variáveis da aptidão física é baixo, dependendo dos níveis de flexibilidade e de força de preensão manual e pelo padrão de atividade física regular no passado e no presente. Os que apresentam melhor ApC tendem a ser mais aptos. É possível que o aumento do conhecimento sobre os níveis de aptidão física influenciem positivamente para a adoção de um estilo de vida mais ativo.

Age and gender differences in objectively measured physical activity in youth

PURPOSE

The purpose of this study was to evaluate age and gender differences in objectively measured physical activity (PA) in a population-based sample of students in grades 1-12.

METHODS

Participants (185 male, 190 female) wore a CSA 7164 accelerometer for 7 consecutive days. To examine age-related trends, students were grouped as follows: grades 1-3 (N = 90), grades 4-6 (N = 91), grades 7-9 (N = 96), and grades 10-12 (N = 92). Bouts of PA and minutes spent in moderate-to-vigorous PA (MVPA) and vigorous PA (VPA) were examined.

RESULTS

Daily MVPA and VPA exhibited a significant inverse relationship with grade level, with the largest differences occurring between grades 1-3 and 4-6. Boys were more active than girls; however, for overall PA, the magnitudes of the gender differences were modest. Participation in continuous 20-min bouts of PA was low to nonexistent.

CONCLUSION

Our results support the notion that PA declines rapidly during childhood and adolescence and that accelerometers are feasible alternatives to self-report methods in moderately sized population-level surveillance studies.

Predicted maximal aerobic power in youth is related to age, gender, and ethnicity

PURPOSE

To determine the effects of age, gender, and ethnicity on the predicted aerobic power of youth as they age from 8 to 16 yr.

METHODS

The sample was a multicohort group of 2540 African Americans (N = 543) and Caucasians (N = 1997), 1279 (50.4%) girls and 1261 (49.6%) boys. Heights, weights, and sum of skin folds (triceps + subscapular) were measured. Aerobic power ((p)VO(2max)), expressed in relative (mL x kg(-1) x min(-1)) or absolute (L x min(-1)) terms, was predicted from a three-stage cycle ergometry test.

RESULTS

Quadratic mixed-model analysis indicated that boys had higher relative and absolute (p)VO(2max) than the girls (P = 0.0004). The African American subjects had a higher absolute (p)VO(2max) (L x min(-1)) than the Caucasians, but their relative (p)VO(2max) was lower than the Caucasians (P = 0.031). Finally, age had a significant effect on (p)VO(2max) (P = 0.0001). The absolute (p)VO(2max) of the girls increased 9%.yr(-1) until age 14; but their relative (p)VO(2max) declined approximately 1.2 mL x kg(-1) x min(-1) x yr(-1). The absolute (p)VO(2max) for the boys increased yearly by approximately 14% from ages 8 to 16 yr, but the relative (p)VO(2max) of the African American males was stable from ages 8 to 11, then dropped, and stabilized again between ages 12 and 16 yr. The relative (p)VO(2max) of the Caucasian boys declined from ages 8 to 10, but then increased slightly from age 12 to 16 yr. In addition, the interactions of age and gender, and age squared and gender were significant (P < 0.02).

CONCLUSION

These data indicate that although absolute (p)VO(2max) (L x min(-1)) increases from age 8 to 16 yr, relative (p)VO(2max) (mL x kg(-1) x min(-1)) declines. The decline appears to be related to increased fat mass. Similarly, the higher relative (p)VO(2max) (mL x kg(-1) x min(-1)) of the Caucasian youth compared with the African American youth was related to lower weights and skin folds of the Caucasian youth.

Parental activity as a determinant of activity level and patterns of activity in obese children

The purposes of this study were to measure the level and pattern of moderate-to-vigorous physical activity (MVPA = > 4.5 METs) and examine predictors of activity in obese children. Fifty-one 8-12-year-old children seeking obesity treatment wore accelerometers for 3 or 4 days. Children averaged 12.2 bouts of MVPA per day that lasted an average of 4.2 min, while parents engaged in 3.9 bouts of MVPA that lasted 4.2 min. Hierarchical regression models showed parent activity improved the prediction of obese children's activity levels and the number of bouts of MVPA but not the duration of MVPA. These results suggest that programs to increase physical activity in obese children should structure the activity in short bouts and attempt to increase parental physical activity.