Different Intensities Of Physical Activity Research Articles

Movement behaviours are associated with lung function in middle-aged and older adults: a cross-sectional analysis of the Canadian longitudinal study on aging

BackgroundPhysical activity has been shown to attenuate the age-associated decline in lung function; however, there is little research evaluating different movement behaviours as potential correlates of lung function. Modifiable determinants need to be identified, as the prevalence of chronic respiratory disease is on the rise. The purpose of this study was to investigate associations of self-reported movement behaviours (i.e., sitting time, walking, different intensities of physical activity, and strengthening activities), with lung function in middle-aged and older adults without a respiratory disease, according to their smoking history.MethodsData from participants of the Canadian Longitudinal Study on Aging were used for analysis (n = 16,839). Lung function was assessed using spirometry. A modified version of the Physical Activity Scale for the Elderly was used to assess sitting time and physical activity levels. Smoking status was classified as non-smoking, < 10 pack years smoking, and 10 or more pack years of smoking. The association between movement behaviours and lung function was assessed using hierarchical linear regression models with all covariates (age, sex, smoking status, body mass index, education, retirement status, and sleep duration) entered into block 1, and all movement behaviours entered into block 2.ResultsAll movement behaviours were associated with Forced Expiratory Volume in 1 s (FEV1) and Forced Vital Capacity (FVC) % predicted in crude and adjusted models, regardless of smoking status. Sitting time was negatively associated with both FEV1%pred (β: -0.094, CI: -0.140, − 0.047) and FVC%pred (β: -0.087, CI: -0.128, -0.045) among those who never smoked, and strength activity was positively associated with both FEV1%pred (β: 0.272, CI: 0.048, 0.496) and FVC%pred (β: 0.253, CI: 0.063,0.442) among those who smoked < 10 pack years, as well as with FVC%pred among those who smoked 10 or more pack years (β: 0.309, CI: 0.064, 0.554).ConclusionsThis is the first study to assess the association of different movement behaviours with lung function among middle-aged and older adults without a respiratory disease. These findings indicate that movement behaviours are correlates of lung function, and that they may be modifiable determinants of the age-associated decline in lung function.

Physical activity moderates the deleterious relationship between cardiovascular disease, or its risk factors, and quality of life: Findings from two population-based cohort studies in Southern Brazil and South Australia

BackgroundFew studies have investigated the relationship between physical activity (PA) of low intensity and duration with quality of life (QoL) among individuals at risk or with cardiovascular disease (CVD).ObjectivesTo investigate whether PA of different intensity and duration moderates the relationship between CVD and its risk factors (obesity, hypertension, diabetes, dyslipidaemia) and QoL in adults.MethodsPopulation-based cross-sectional studies using data from the EpiFloripa Cohort Study (Southern Brazil; n = 1,220, 38.8±12.0 years, 48.2% males) and the North West Adelaide Health Study (NWAHS, South Australia; n = 1,661, 43.7±11.1 years, 49.7% males). The physical and psychological domains of QoL were assessed using the WHOQOL-Bref (EpiFloripa) or the SF-36 (NWAHS) questionnaires. The diagnosis of CVD and its risk factors were self-reported. PA was self-reported and quantified by its intensity [“walking” or moderate/vigorous (MVPA)] and duration (none, 1–150, ≥150 min/week). Both studies were analysed separately, and results were adjusted for sociodemographic variables.ResultsParticipants at risk or with CVD from both studies showed a lower QoL than ‘healthy’ individuals with a stronger relationship for the physical domain. PA duration showed a direct-trend relationship with QoL, but the associations were stronger for MVPA in both studies. However, when stratified by health status, the magnitude of the association between “walking” duration and a higher physical QoL was greater among those at risk or with CVD compared to ‘healthy’ individuals. Conversely, among Australians with CVD, MVPA was associated with a better physical QoL only when its duration was ≥150 min/week. All associations were stronger in the NWAHS than in the Brazilian study.Conclusions“Walking” was more prevalent than MVPA and was consistently associated with a better physical QoL among those at risk or with CVD. These findings should be considered in the design of public health interventions designed to increase PA and improve QoL.

Daily Step Count as a Simple Marker of Disease Severity in Hypertrophic Cardiomyopathy

Individuals with hypertrophic cardiomyopathy (HCM) may be asymptomatic or display activity-limiting symptoms. A common cause of symptoms is left ventricular outflow tract obstruction (LVOTO), which may impact the individuals' ability to undertake physical activity. This study sought to examine daily step count as a potential marker of exercise capacity, which may represent a proxy marker of disease severity in HCM. A cross-sectional study of 63 HCM patients was conducted from March to November 2015. Participants wore an ActiGraph GT3X+ (Pensacola, Florida, USA) accelerometer for 7 days. Minutes per day of light, moderate and vigorous physical activity and step count were calculated, and those with LVOTO were compared to those without. Similarly, those with good functional capacity (New York Heart Association; NYHA class I) were compared to those with NYHA class II-IV. The majority of HCM patients were male (n=45, 71%) with mean age of 48.8±14.9years. Hypertrophic cardiomyopathy patients with history of LVOTO and those NYHA class II-IV took significantly fewer steps per day (LV obstruction: 5527±2370 versus 7027±2095, p=0.01 and NYHA: 5346±1898 versus 6801±2339, p=0.03). No differences were observed across the different intensities of physical activity. Measurement of daily step count may be a useful and simple tool to determine exercise capacity and provide an indicator of disease severity in individuals with HCM.

Patterns of physical activity in Chilean adults across the lifespan

Background: international physical activity (PA) guidelines recommend 150 minutes of moderate to vigorous PA or 75 minutes of vigorous PA weekly; however, the proportion of the Chilean population who meet this recommendation across the lifespan remains unknown. Objective: to characterize PA patterns by age categories and sex in the Chilean population. Methods: participants from the Chilean Health Survey 2009-2010 (5,293 individuals) were included in this study. PA types (transport, moderate and vigorous) and sedentary behavior were measured using the global physical activity questionnaire (GPAQ). Time spent on different intensities of physical activity by age and sex was investigated using regression analyses. Results: compared to participants aged < 20 years (reference group), commuting-related PA decreased for both men and women from the age of 60 years onwards. Moderate intensity PA increases for both sexes reaching the highest level between the ages of 40-49 years, and then it shows a decline with increasing age. Vigorous PA reaches the highest levels between ages 30-39 and 40-49 years for women and men, respectively. Time spent sitting increased markedly on participants aged 60 years and above, reaching the highest levels at the age of 80 years. Conclusion: in the Chilean population, there are clear patterns of change in PA levels and sitting time across age groups. These findings may help informing stakeholders on tailoring interventions to increase PA levels, especially at ages when the population is more likely to reach their lowest levels of activity.

Relationships between sleep duration, physical activity and body mass index in young New Zealanders: An isotemporal substitution analysis.

BackgroundThe evidence regarding the unique effect of sedentary behaviour on obesity among children is unclear. Moreover, the effect of substituting sedentary behaviour with physical activity of different intensities on the body composition of children has received limited empirical study.ObjectiveTo examine the mathematical effects on Body Mass Index (BMI) of substituting sedentary behaviours with physical activities of different intensities on children and youth aged 5–14 years old in New Zealand.MethodsSecondary analysis of accelerometer data from the National Survey of Children and Young People’s Physical Activity and Dietary Behaviours in New Zealand (2008/09) was conducted. A total of 1812 children and youth aged 5–24 years provided accelerometer-derived data on daily sedentary time (SB), light intensity physical activity (LPA) and moderate to vigorous physical activity (MVPA). Sleep time was assessed with a validated computerised use-of-time tool. BMI was assessed using anthropometric measurements. Multiple linear regression models were used to examine the independent associations of SB, Sleep time, LPA, and MVPA on BMI. The isotemporal substitution approach was used to ascertain the mathematical effect of substituting each of the other behaviours on BMI. Analyses were stratified by age groups.ResultsSB showed a unique (inverse) association with BMI across all age groups (p<0.05) but 20–24 years (p>0.05). Similarly, MVPA was positively associated (p<0.001) across all age groups. Among age groups 5–9 years, 10–14 years and 15–19 years, the estimated impact of replacing 60 min/day of SB with the same amount of MVPA time resulted in decreased BMI for all age groups (p<0.001), ranging from -1.26 (5–9 years) to -1.43 units (15–19 years). Similar results were achieved when SB was replaced with LPA or sleeping time for children (5–19 years). In young people (age group 20–24), the impact of replacing 30 min/day of SB with MVPA resulted in an estimated -1 BMI units decrease (p<0.001).ConclusionMVPA and SB have a unique effect on BMI. Further, substituting SB with LPA or MVPA was associated with a favourable effect on BMI across all age groups; with MVPA having the strongest association.

Youth Oriented Activity Trackers: Comprehensive Laboratory- and Field-Based Validation.

BackgroundCommercial activity trackers are growing in popularity among adults and some are beginning to be marketed to children. There is, however, a paucity of independent research examining the validity of these devices to detect physical activity of different intensity levels.ObjectivesThe purpose of this study was to determine the validity of the output from 3 commercial youth-oriented activity trackers in 3 phases: (1) orbital shaker, (2) structured indoor activities, and (3) 4 days of free-living activity.MethodsFour units of each activity tracker (Movband [MB], Sqord [SQ], and Zamzee [ZZ]) were tested in an orbital shaker for 5-minutes at three frequencies (1.3, 1.9, and 2.5 Hz). Participants for Phase 2 (N=14) and Phase 3 (N=16) were 6-12 year old children (50% male). For Phase 2, participants completed 9 structured activities while wearing each tracker, the ActiGraph GT3X+ (AG) research accelerometer, and a portable indirect calorimetry system to assess energy expenditure (EE). For Phase 3, participants wore all 4 devices for 4 consecutive days. Correlation coefficients, linear models, and non-parametric statistics evaluated the criterion and construct validity of the activity tracker output.ResultsOutput from all devices was significantly associated with oscillation frequency (r=.92-.99). During Phase 2, MB and ZZ only differentiated sedentary from light intensity (P<.01), whereas the SQ significantly differentiated among all intensity categories (all comparisons P<.01), similar to AG and EE. During Phase 3, AG counts were significantly associated with activity tracker output (r=.76, .86, and .59 for the MB, SQ, and ZZ, respectively).ConclusionsAcross study phases, the SQ demonstrated stronger validity than the MB and ZZ. The validity of youth-oriented activity trackers may directly impact their effectiveness as behavior modification tools, demonstrating a need for more research on such devices.

Cross-sectional and prospective associations between physical activity, body mass index and waist circumference in children and adolescents.

SummaryObjectiveTo study the cross‐sectional and prospective associations between physical activity (PA) of different intensities, body mass index (BMI) and waist circumference (WC) in children and adolescents using isotemporal substitution modelling.MethodsPhysical activity (accelerometry), BMI and WC were assessed in 6‐ (n = 970), 9‐ (n = 2,423) and 15‐year‐olds (n = 1,544) in 2005/2006 and 2011/2012. Participants aged 9 years in 2005/2006 were followed prospectively to 2011/12 (age 15). Associations between PA of different intensities (light, moderate and vigorous), BMI and WC were examined using isotemporal substitution models.ResultsSubstituting 10 min per day of sedentary time with light PA was associated with higher WC (0.17 to 0.29 cm, p ≤ 0.003)) in all age groups. Substituting 10 min per day of sedentary time with moderate PA was associated with lower WC in 6‐ and 9‐year‐olds (−0.32 to −0.47 cm, p ≤ 0.013)). Substituting 10 min per day of sedentary time with vigorous PA was associated with lower WC in 9‐ and 15‐year‐olds (−1.08 to −1.79 cm, p ≤ 0.015)). Associations were similar with BMI as the outcome. In prospective analyses, substituting sedentary time with light, moderate or vigorous PA at age 9 was not associated with BMI or WC at age 15.ConclusionSubstituting sedentary time with moderate PA appears favourably associated with adiposity in children, whereas vigorous PA may be required in adolescents. Cross‐sectional associations were not replicated in prospective analyses.

Influence of mature men way of life on highly intensive physical activity

Highly intensive physical activity is the most effective for men’s health protection. In modern life conditions its level is insufficient. It requires organism’s appropriate physical activity, which is determined by way of life. Especially important it is before trainings. Purpose: to study special aspects of different intensity’s physical activity; of eating special food and sleeping regime of mature men before their highly intensive physical trainings. Material: in experiment men (n=26, age - 35-53years), who practice healthy life style and independent physical activity of high intensity, participated. We used bio-register Basis B1. Every day we registered: Peak - physical activity of different intensity; duration and quality of sleep; relative weight of consumed food. Besides, we calculated body mass index and physical condition. The study was conducted during 30 days in winter period. The following results were compared: indicators before not planned physical activity and average-monthly indicators. Results: Before arbitrary physical functioning we found in men: confident weakening of average intensity (by 9-11%) and low intensity (by 10%) physical activity; confident increase of consumed food’s relative weight (by 6.82%), vegetarian food (by 10.64%) and raw food (by 7.61%); confident reduction of animal origin food (by 8.7%). No changes were found in duration and quality of sleep before highly intensive physical functioning. Conclusions: specific features of mature men’s way of life before their not planned highly intensive physical functioning are as follows: reduction of general physical activity; increase of consumed food. These factors facilitate energy accumulation in organism for its realization in highly intensive physical functioning the next day.

Associations between accelerometer-measured physical activity and body fatness in school-aged children

BackgroundThe main aim of the study was to examine the cross-sectional associations between objectively measured physical activity (PA) and body fatness in 7–12-year-old children.MethodsWe performed an analysis of 365 children (209 girls). Participant recruitment was performed in eight randomly selected elementary schools in cities and towns with various numbers of inhabitants. The body composition analysis was performed according to a multi-frequency bioelectrical impedance analysis; PA was monitored using an accelerometer.ResultsIn terms of the overall PA, boys were more active than girls. No significant associations (unadjusted and adjusted models) were found between light PA and all body fatness indicators in either sex. Moderate-to-vigorous PA was significantly negatively associated with all body fatness indicators only in girls. These associations strengthened after adjustment for age, height and sedentary time (β ranging from –0.49 to –0.36, P ≤ 0.01). In contrast, vigorous PA was strongly negatively associated with body fatness indicators only in boys. In the fully adjusted model the significant negative associations were found for fat mass percentage (β = –0.15, P = 0.048) and fat mass index (β = –0.15, P = 0.040).ConclusionsThe present study suggests that increasing sex-specific PA of different intensities may be an appropriate approach for decreasing body fatness in children. Longitudinal studies are needed to verify these associations.

Determining activity count cut-points for measurement of physical activity using the Actiwatch2 accelerometer

Study objectivesSleep and physical activity are important contributors to many aspects of health. Obtaining accurate, objective measures of both behaviours is critical to health research. The Actiwatch2 is a wrist-worn sleep-monitoring device that has the potential to measure physical activity. Currently, interpretation of the Actiwatch2 physical activity data is limited by a lack of published thresholds for interpreting exercise intensity. This limits the ability to collect information on both behaviours simultaneously using one monitor. This study aims to develop thresholds to differentiate between light, moderate and vigorous-intensity physical activity and sedentary time for the Actiwatch2. MethodsThirty females, 40±14.9years, completed eight exercise tasks while wearing a Cosmed portable metabolic cart, the Actiwatch2 and the Actigraph GT3X+. Correlations between 1) activity counts from both the Actiwatch2 and Actigraph and metabolic equivalent (MET) values, and 2) activity counts from the two monitors were calculated. Area Under the Curve (AUC) was calculated, and cut points that maximized sensitivity and specificity were determined. ResultsThe correlations between MET values and Actiwatch2 counts (r=0.69) and Actigraph (r=0.69) were strong. Correlation between the two activity monitors was very strong (r=0.84). The discrimination of sedentary behaviour was almost perfect (AUC=0.96) using a threshold of 145cpm. Discrimination of moderate (AUC=0.92) and vigorous (AUC=0.77) activity was acceptable using a threshold of 274 and 597cpm respectively. ConclusionsThe Actiwatch2 demonstrated the ability to discriminate different intensities of physical activity among adult females. With these reported cut points, the Actiwatch2 can be used to simultaneously measure sleep and physical activity – two key outcomes in health research.

Penicillin-Induced Epileptiform ECoG Activity in Gerbils: Effects of Physical Exercise and a Diospyros kaki Extract

Mongolian gerbils (28 males) were divided into four groups, control (C), treadmill-exercised (Ex), treated with the extract of Diospyros kaki (Dk), and exercised plus treated with the Dk extract (Ex+Dk). Animals of the respective groups were running-exercised for 30 min per day during 8 weeks, and the Dk extract (dose 20 mg/kg) was given by gavage during five days per week within the same period. After the treatment and exercise period, an epilepsy model was produced by penicillin G injection (500 IU) into the left somatomotor cortex, and the electrocorticogram (ECoG) was recorded during 120 min. The mean frequency of spike/wave complexes was significantly smaller in the Ex and Ex+Dk groups from the 65th min of the observation period and, in the Dk group, from the 75th min than the respective value in the C group (P 0.05). Thus, both the running exercise and Dk extract applications inhibit penicillin-induced epileptiform activity by altering the spike/wave frequency or severity of seizures observed in ECoG recordings. Further studies are needed to determine the effects of physical activity of different intensities and forms and to analyze the active compounds in the Dk extract.

Physical activity throughout adolescence and body composition at 18years: 1993 Pelotas (Brazil) birth cohort study.

BackgroundAdolescence is a period of accelerated development and increases in body composition. Physical activity (PA) practice has been associated with the development of major components of body composition (bone, muscle and fat). However, the longitudinal effects of PA of different intensities during adolescence are still not well understood. Thus, the main goal this study has investigate the association between practice of moderate- and vigorous-intensity physical activity throughout adolescence and body composition, specifically lean mass (LM) and fat mass (FM), at age 18.MethodsIn this cohort study, physical activity was measured at 11, 15 and 18 years, using questionnaires. Thresholds of 300, 150 and 75 min per week, were used for MVPA, moderate- and vigorous-intensity physical activity, respectively. Consistent physical activity was defined as reaching the thresholds at the three follow-ups. FM and LM at age 18 were assessed by DXA and expressed as fat mass (FMI) and lean mass (LMI) indexes. To verify the association between the trajectories of MVPA, moderate- and vigorous-intensity physical activity in adolescence and FM and LM at 18, multivariate analyses were performed through multiple linear regressions adjusted for co-variables.ResultsA total of 3,176 adolescents were evaluated. The consistent practice of moderate- and vigorous-intensity physical activity according to thresholds during adolescence were directly related to the LMI in boys (moderate-intensity - β = 0.40 and CI95 % 0.13; 0.68 and vigorous-intensity - β = 0.95 and CI95 % 0.69; 1.21) and girls (Moderate-intensity - β = 0.23 and CI95 % 0.02; 0.45 and vigorous-intensity - β = 0.80 and CI95 % 0.29; 1.32). Practice of vigorous-intensity physical activity alone showed to be inversely associated with the FMI in boys (β = -0.53 and CI95 % -0.96;–0.10).ConclusionConsistent physical activity practice during adolescence was associated with greater lean mass in both sexes. In boys, vigorous-intensity physical activity was associated with less fat mass.

Validity of wrist worn accelerometers and comparability between hip and wrist placement sites in estimating physical activity behaviour in preschool children

Wrist-worn accelerometers can increase compliance with wearing accelerometers, however, several large scale studies continue to use hip-worn accelerometers and it is unclear how comparable data is from the two sites. The study aims were: to investigate agreement between wrist- and hip- worn accelerometers and to determine the validity of Johansson et al cut-points for wrist worn accelerometers in preschool children.A sample of 32 preschool children (21 boys, 4.2 (0.5) years, BMI 16.6 (1.1)) were videoed wearing GT3X+ accelerometers on their wrist and hip while they engaged in 1 h of free-play in their nursery. Children’s activity were coded using, the children’s activity rating scale (CARS): with CARS, level 1 ‘sedentary’ and levels 2–5 were classified as time spent in total physical activity (TPA). Accelerometry data were processed using Johansson et al cut-points for the wrist data and Evenson et al cut-points for the hip data, into time spent in different intensities of physical activity (PA). The mean counts per minute (cpm) from the hip and wrist were compared.There was a strong correlation between the hip and wrist cpm (r = 0.81, p < 0.01) and total count data (r = 0.83 p < 0.01), however there was a large systematic bias with wide limits of agreement. Good agreement (mean difference (LOA) 1.1 (−9.9, 12.1) was found between the CARS estimate of TPA (29.5 (10.4) mins) and the wrist estimate, using the Johansson et al cut points (28.4 (9.8) mins). There was also a reasonable agreement between the hip estimates with the Evenson et al cut-points and Johansson et al estimate (mean difference (LOA):6.3 (−8.8, 21.4) mins.In conclusion, the findings suggest that the Johansson et al ( Pediatr. Obes. 10 1–6) cut-points applied to wrist worn accelerometers provides a valid estimate of TPA in preschool children and have reasonable agreement with Evenson et al cut-points applied to hip accelerometers.

Effect of different intensities of physical activity on cardiometabolic markers and vascular and cardiac function in adult rats fed with a high-fat high-carbohydrate diet

BackgroundPhysical activity (PA) and diet are 2 lifestyle factors that affect cardiometabolic risk. However, data on how a high-fat high-carbohydrate (HFHC) diet influences the effect of different intensities of PA on cardiometabolic health and cardiovascular function in a controlled setting are yet to be fully established. This study investigated the effect of sedentary behavior, light-intensity training (LIT), and high-intensity interval training (HIIT) on cardiometabolic markers and vascular and cardiac function in HFHC-fed adult rats. MethodsTwelve-week-old Wistar rats were randomly allocated to 4 groups (12 rats/group): control (CTL), sedentary (SED), LIT, and HIIT. Biometric indices, glucose and lipid control, inflammatory and oxidative stress markers, vascular reactivity, and cardiac electrophysiology of the experimental groups were examined after 12 weeks of HFHC-diet feeding and PA interventions. ResultsThe SED group had slower cardiac conduction (p = 0.0426) and greater thoracic aortic contractile responses (p < 0.05) compared with the CTL group. The LIT group showed improved cardiac conduction compared with the SED group (p = 0.0003), and the HIIT group showed decreased mesenteric artery contractile responses compared with all other groups and improved endothelium-dependent mesenteric artery relaxation compared with the LIT group (both p < 0.05). The LIT and HIIT groups had lower visceral (p = 0.0057 for LIT, p = 0.0120 for HIIT) and epididymal fat (p < 0.0001 for LIT, p = 0.0002 for HIIT) compared with the CTL group. ConclusionLIT induced positive adaptations on fat accumulation and cardiac conduction, and HIIT induced a positive effect on fat accumulation, mesenteric artery contraction, and endothelium-dependent relaxation. No other differences were observed between groups. These findings suggest that few positive health effects can be achieved through LIT and HIIT when consuming a chronic and sustained HFHC diet.

Effect of Different Intensities of Physical Activity on Cardiometabolic Markers, Vascular and Cardiac Function in Adult Rats Fed with a High-Fat high-Carbohydrate Diet

Effect of Different Intensities of Physical Activity on Cardiometabolic Markers, Vascular and Cardiac Function in Adult Rats Fed with a High-Fat high-Carbohydrate Diet

Replacing Sedentary Time with Physical Activity in Relation to Mortality.

Data evaluating mortality benefit from replacing sedentary time with physical activity are sparse. We explored reallocating time spent in sedentary behavior to physical activity of different intensities in relation to mortality risk. Women and men age 50-85 yr from the National Health and Nutrition Examination Survey 2003-2004 and 2005-2006 cycles with follow-up through December 31, 2011, were included. Sedentary time and physical activity were assessed using an ActiGraph accelerometer. Isotemporal substitution models were used to estimate the effect of replacing one activity behavior with another activity behavior for the same amount of time while holding total accelerometer wear time constant. During a mean follow-up of 6.35 yr, 697 deaths from any cause occurred. Replacing 30 min of sedentary time with an equal amount of light activity was associated with 14% reduced risk of mortality (multivariable-adjusted hazard ratio (HR), 0.86; 95% confidence interval (CI), 0.83-0.90). Replacement of sedentary time with moderate to vigorous activity was related to 50% mortality risk reduction (HR, 0.50; 95% CI, 0.31-0.80). We also noted a 42% reduced risk of mortality when light physical activity was replaced by moderate to vigorous activity (HR, 0.58; 95% CI, 0.36-0.93). Replacing sedentary time with an equal amount of physical activity may protect against preterm mortality. Replacement of light physical activity with moderate to vigorous activity is also associated with protection from premature mortality.

Light-intensity and high-intensity interval training improve cardiometabolic health in rats

Physical activity has the potential to reduce cardiometabolic risk factors but evaluation of different intensities of physical activity and the mechanisms behind their health effects still need to be fully established. This study examined the effects of sedentary behaviour, light-intensity training, and high-intensity interval training on biometric indices, glucose and lipid metabolism, inflammatory and oxidative stress markers, and vascular and cardiac function in adult rats. Rats (12 weeks old) were randomly assigned to 1 of 4 groups: control (CTL; no exercise), sedentary (SED; no exercise and housed in small cages to reduce activity), light-intensity trained (LIT; four 30-min exercise bouts/day at 8 m/min separated by 2-h rest period, 5 days/week), and high-intensity interval trained (HIIT, four 2.5-min work bouts/day at 50 m/min separated by 3-min rest periods, 5 days/week). After 12 weeks of intervention, SED had greater visceral fat accumulation (p < 0.01) and slower cardiac conduction (p = 0.04) compared with the CTL group. LIT and HIIT demonstrated beneficial changes in body weight, visceral and epididymal fat weight, glucose regulation, low-density lipoprotein cholesterol, total cholesterol, and mesenteric vessel contractile response compared with the CTL group (p < 0.05). LIT had significant improvements in insulin sensitivity and cardiac conduction compared with the CTL and SED groups whilst HIIT had significant improvements in systolic blood pressure and endothelium-independent vasodilation to aorta and mesenteric artery compared with the CTL group (p < 0.05). LIT and HIIT induce health benefits by improving traditional cardiometabolic risk factors. LIT improves cardiac health while HIIT promotes improvements in vascular health.

Association between objectively measured physical activity, chronic stress and leukocyte telomere length.

Physical activity (PA) attenuates chronic stress and age-related and cardiovascular disease risks, whereby potentially slowing telomere shortening. We aimed to study the association between seven-day objectively measured habitual PA, chronic stress and leukocyte telomere length. Study participants were African (N.=96) and Caucasian (N.=107) school teachers of the Sympathetic activity and Ambulatory Blood Pressure in Africans study. All lifestyle characteristics (including PA) were objectively measured. The general health questionnaire and serum cortisol were assessed as psychological and physical measures of chronic stress. Leukocyte telomere length was measured using the quantitative real-time polymerase chain reaction. Africans had significantly shorter telomeres (P<.0001) and greater psychological distress (P=0.001) than Caucasians, whereas no group difference was seen for cortisol levels. Higher age (ß=-0.28 [-0.40, -0.16, P≤0.000), higher alcohol consumption (ß=-0.21 [-0.36, -0.08], P=0.003) and increased central obesity (ß=-0.17 [-0.30, -0.03], P=0.017) were all significantly associated with shorter telomeres. Habitual PA of different intensity was not significantly associated with markers of chronic stress or telomere length. However, more time spent with light intensity PA time was significantly and independently correlated with lower waist circumference (r=-0.21, P=0.004); in turn, greater waist circumference was significantly associated shorter telomeres (β=-0.17 [-0.30, -0.03], P=0.017). Habitual PA of different intensity was not directly associated with markers of chronic stress and leukocyte telomere length in this biethnic cohort. However, our findings suggest that light intensity PA could contribute to lowered age-related disease risk and healthy ageing by facilitating maintenance of a normal waist circumference.

Light physical activity is positively associated with cognitive performance in older community dwelling adults.

To evaluate the associations between an objective measure of different intensities of physical activity, upper- and lower-limb muscle strength and psychomotor performance and set-shifting domains of cognitive executive function in older adults. A cross-sectional study. From the Tasmanian Older Adult Cohort Study, 188 community-dwelling older adults (53.7% female; mean age±SD 63.98±7.3 years) undertook 7-day physical activity behaviour monitoring using an accelerometer. Dynamometers were used to assess leg extension strength. The Trail Maker Tests were used to measure psychomotor processing speed and set-shifting performance. When controlling for age, smoking history, alcohol intake, educational achievement and neuropsychological functioning, higher levels of light physical activity, but not sedentary behaviour or moderate or vigorous physical activity, was found to be associated with better set-shifting performance. Neither physical activity behaviour or muscle strength were found to be associated with psychomotor performance. In addition, older age, greater alcohol intake, and lower levels of educational attainment, verbal learning and memory performance were significantly associated with lower scores on the set-shifting task; whereas older age and reduced neuropsychological functioning were associated with lower psychomotor processing speed scores. Light physical activity is associated with higher executive functioning in community-dwelling older adults and this strengthens the evidence supporting exercise as a neuroprotective agent. Further studies are needed to understand why light physical activity behaviour positively influences executive functioning, and how such physical activity can be implemented into the daily routine of older adults.

Sedentary Behavior and Light Physical Activity Are Associated with Brachial and Central Blood Pressure in Hypertensive Patients.

BackgroundPhysical activity is recommended as a part of a comprehensive lifestyle approach in the treatment of hypertension, but there is a lack of data about the relationship between different intensities of physical activity and cardiovascular parameters in hypertensive patients. The purpose of this study was to investigate the association between the time spent in physical activities of different intensities and blood pressure levels, arterial stiffness and autonomic modulation in hypertensive patients.MethodsIn this cross-sectional study, 87 hypertensive patients (57.5 ± 9.9 years of age) had their physical activity assessed over a 7 day period using an accelerometer and the time spent in sedentary activities, light physical activities, moderate physical activities and moderate-to-vigorous physical activities was obtained. The primary outcomes were brachial and central blood pressure. Arterial stiffness parameters (augmentation index and pulse wave velocity) and cardiac autonomic modulation (sympathetic and parasympathetic modulation in the heart) were also obtained as secondary outcomes.ResultsSedentary activities and light physical activities were positively and inversely associated, respectively, with brachial systolic (r = 0.56; P < 0.01), central systolic (r = 0.51; P < 0.05), brachial diastolic (r = 0.45; P < 0.01) and central diastolic (r = 0.42; P < 0.05) blood pressures, after adjustment for sex, age, trunk fat, number of antihypertensive drugs, accelerometer wear time and moderate-to-vigorous physical activities. Arterial stiffness parameters and cardiac autonomic modulation were not associated with the time spent in sedentary activities and in light physical activities (P > 0.05).ConclusionLower time spent in sedentary activities and higher time spent in light physical activities are associated with lower blood pressure, without affecting arterial stiffness and cardiac autonomic modulation in hypertensive patients.