ABSTRACT Objectives Walking pace is a strong marker of functional and health status. We investigated whether walking pace is also associated with leucocyte telomere length (LTL), which is causally associated with several diseases and has been proposed as a marker of biological age. Methods We used baseline data from UK Biobank participants recruited from March-2006 to July-2010. Walking pace was self-reported as slow, steady/average, or brisk. Accelerometer-assessed measures of total physical activity and intensity were included to support interpretation of walking pace data. LTL was measured by qPCR assay. Bi-directional Mendelian randomization (MR) analyses were undertaken to inform likely causal directions. Results The analysed cohort comprised 405,981 adults (54% women) with mean age of 56.5 years (SD, 8.1) and body mass index 27.2 kg/m 2 (SD, 4.7). Steady/average and brisk walkers had significantly longer LTL compared with slow walkers, with a Z-standardised LTL difference of 0.066 (0.053-0.078) and 0.101 (0.088-0.113), respectively. Associations remained but were attenuated following full covariate adjustment: 0.038 (0.025-0.051) and 0.058 (0.045-0.072), respectively. Accelerometer data (n=86,002) demonstrated a non-linear association between LTL and habitual movement intensity, but not total activity. MR analysis supported a causal association of walking pace on LTL, with an increase in Z-standardised LTL of 0.192 (0.077, 0.306) for each difference in walking pace category. No evidence of a causal association was observed for LTL on walking pace. Conclusion Faster walking pace may be causally associated with longer LTL, which could explain some of the beneficial effects of brisk walking on health status.
ABSTRACT Background Although the cardiovascular disease (CVD) benefits of both overall volume and intensity of physical activity (PA) are known, the role of PA intensity, over and above volume, is poorly understood. We aimed to investigate the interplay between PA volume and intensity in relation to incident CVD. Methods Data were from 88,412 UK Biobank participants without prevalent CVD (58% women) who wore an accelerometer on their dominant wrist for 7 days, from which we estimated total physical activity energy expenditure (PAEE) using population-specific validation. Cox proportional hazards regressions modelled associations between PAEE (kJ/kg/day)] and PA intensity [%MVPA; the fraction of PAEE accumulated from moderate-to-vigorous-intensity PA] with incident CVD, adjusted for potential confounders. Results There were 4,068 CVD events during 584,568 person-years of follow-up (median 6.8 years). Higher PAEE and higher %MVPA (adjusted for PAEE) were associated with lower rates of incident CVD. In interaction analyses, CVD rates were 17% (95%CI: 8-26%) lower when MVPA accounted for 20% rather than 10% of 15 kJ/kg/d PAEE; equivalent to the difference between a 12-min stroll into a brisk 7-min walk. CVD rates did not differ significantly between values of PAEE when the %MVPA was fixed at 10%. However, the combination of higher PAEE and %MVPA was associated with lower CVD rates. Rates were 24% (10-35%) lower for 20 kJ/kg/d PAEE with 20% from MVPA, and 49% (23-66%) lower for 30 kJ/kg/d with 40% from MVPA (compared to 15 kJ/kg/d PAEE with 10% MVPA). Conclusions Reductions in CVD risk may be achievable through higher levels of PA volume and intensity, with the role of moderately intense PA appearing particularly important for future CVD risk. Our findings support multiple approaches or strategies to PA participation, some of which may be more practical or appealing to different individuals.
Abstract Background A step cadence of 100 steps/minute is widely used to define moderate-intensity walking. However, the generalizability of this threshold to different populations needs further research. We investigate moderate-intensity step cadence values during treadmill walking and daily living in older adults. Methods Older adults (≥ 60 years) were recruited from urban community venues. Data collection included 7 days of physical activity measured by an activPAL3™ thigh worn device, followed by a laboratory visit involving a 60-min assessment of resting metabolic rate, then a treadmill assessment with expired gas measured using a breath-by-breath analyser and steps measured by an activPAL3™. Treadmill stages were undertaken in a random order and lasted 5 min each at speeds of 1, 2, 3, 4 and 5 km/h. Metabolic equivalent values were determined for each stage as standardised values (METS standard ) and as multiples of resting metabolic rate (METS relative ). A value of 3 METS standard defined moderate-intensity stepping. Segmented generalised estimating equations modelled the association between step cadence and MET values. Results The study included 53 participants (median age = 75, years, BMI = 28.0 kg/m 2 , 45.3% women). At 2 km/h, the median METS standard and METS relative values were above 3 with a median cadence of 81.00 (IQR 72.00, 88.67) steps/minute. The predicted cadence at 3 METS standard was 70.3 (95% CI 61.4, 75.8) steps/minute. During free-living, participants undertook median (IQR) of 6988 (5933, 9211) steps/day, of which 2554 (1297, 4456) steps/day were undertaken in continuous stepping bouts lasting ≥ 1 min. For bouted daily steps, 96.4% (90.7%, 98.9%) were undertaken at ≥ 70 steps/minute. Conclusion A threshold as low as 70 steps/minute may be reflective of moderate-intensity stepping in older adults, with the vast majority of all bouted free-living stepping occurring above this threshold.
Abstract There are well-established chronic disease prevention and broader public health benefits associated with being physically active. However, large proportions of the adult populations of developed countries and rapidly urbanizing developing countries are inactive. Additionally, many people’s lives are now characterized by large amounts of time spent sitting—at work, at home, and in automobiles. Widespread urbanization, particularly in low- and middle-income countries, has resulted in large segments of traditionally active rural populations moving into cities. Many previously manual tasks in the occupational and household sectors have become automated, making life easier and safer in many respects. However, a pervasive consequence of these developments is that large numbers of people globally are now going about their daily lives in environments that place them at risk of overweight and obesity, type 2 diabetes, cardiovascular disease, and other health problems. This represents a formidable set of public health challenges. In this context, the present chapter describes: key definitions and distinctions relating to physical activity, exercise, and sedentary behaviour; current evidence on relationships physical inactivity and sitting time with health outcomes, and associated public health recommendations; prevalence and trends in physical activity and sedentary behaviours, and some of the key issues for surveillance and measurement; and, how physical activity and sedentary behaviour may be understood in ways that will inform broad-based public health approaches. An interdisciplinary and intersectoral strategy is emphasized. This requires working with constituencies beyond the public health field, such as urban planning, architecture, occupational health and safety, and social policy.
We investigated the effect of added load and intense exercise on jump and landing performance and ground reaction force (GRF) during landings where attentional demand was varied. Fifty-two males (37 ± 9.2 years, 180.7 ± 6.1 cm, 90.2 ± 11.6 kg, maximal aerobic fitness (V˙O2max) 50 ± 8.5 ml . kg−1 . min−1, BMI 27.6 ± 3.1, mean ± s) completed a V˙O2max test. Experimental sessions were completed (≥4 days in between) in a randomised counterbalanced order, one while wearing body armour and appointments (loaded) and one without load (unloaded). A vertical jump, a drop landing concentrating on safe touchdown, a drop jump and a drop landing with an attentional distraction were performed. These were repeated 1 min after a 5-min treadmill run. Mean jump height decreased by 12% (P < 0.001) with loading and a further by 6% following the running task. Peak GRFs were increased by 13–19% with loading (P < 0.001) depending on the landing task demands and a further by 4–9% following intense exercise. The distracted drop landing had significantly higher GRFs compared to all other landings. Results demonstrate that added load impacts on jumping and landing performance, an effect that is amplified by prior intense exercise, and distraction during landing. Such increases in GRF apply to police officer performance in their duties and may increase the risk of injury.
OBJECTIVE To investigate the association between accelerometer-derived physical activity energy expenditure (PAEE) and incident type 2 diabetes (T2D) in a cohort of middle-aged adults and within subgroups. RESEARCH DESIGN AND METHODS Data were from 90,096 UK Biobank participants without prevalent diabetes (mean 62 years of age; 57% women) who wore a wrist accelerometer for 7 days. PAEE was derived from wrist acceleration using a population-specific method validated against doubly labeled water. Logistic regressions were used to assess associations between PAEE, its underlying intensity, and incident T2D, ascertained using hospital episode and mortality data up to November 2020. Models were progressively adjusted for demographic, lifestyle factors, and BMI. RESULTS The association between PAEE and T2D was approximately linear (n = 2,018 events). We observed 19% (95% CI 17–21) lower odds of T2D per 5 kJ · kg−1 · day−1 in PAEE without adjustment for BMI and 11% (9–13) with BMI adjustment. The association was stronger in men than women and weaker in those with obesity and higher genetic susceptibility to obesity. There was no evidence of effect modification by genetic susceptibility to T2D or insulin resistance. For a given level of PAEE, odds of T2D were lower among those engaging in more moderate-to-vigorous activity. CONCLUSIONS There was a strong linear relationship between PAEE and incident T2D. A difference in PAEE equivalent to an additional daily 20-min brisk walk was associated with 19% lower odds of T2D. The association was broadly similar across population subgroups, supporting physical activity for diabetes prevention in the whole population.
<b>Purpose:</b> To determine whether interrupting sitting with brief bouts of simple resistance activities (SRAs) at different frequencies improves postprandial glucose, insulin and triglycerides in adults with medication-controlled type 2 diabetes (T2D). <p><b>Methods:</b> Participants [n=23, 10 females, Age: 62±8 y (mean±SD), BMI: 32.7 ± 3.5 kg<sup>.</sup>m<sup>-2</sup>] completed a three-armed randomized crossover trial (6-14 day washout): sitting uninterrupted for 7 h (SIT); sitting with 3-minute SRAs (half-squats, calf raises, gluteal contractions, and knee raises) every 30 minutes (SRA3); and, sitting with 6-minute SRAs every 60 minutes (SRA6). Net incremental areas under the curve (iAUC<sub>net</sub>) for glucose, insulin, and triglycerides were compared between conditions.</p> <p><b>Results:</b> <a>Glucose and insulin 7 h iAUC<sub>net </sub>were attenuated significantly during SRA6 (glucose 17.0 mmol<sup>.</sup>h<sup>.</sup>L<sup>-1</sup>, 95% CI 12.5, 21.4; insulin 1229 pmol<sup>.</sup>h<sup>.</sup>L<sup>-1</sup>, 95% CI 982, 1538) when compared to SIT (glucose 21.4 mmol<sup>.</sup>h<sup>.</sup>L<sup>-1</sup>, 95% CI 16.9, 25.8; insulin 1411 pmol<sup>.</sup>h<sup>.</sup>L<sup>-1</sup>, 95% CI 1128, 1767; <i>P</i> < 0.05), and compared to SRA3 ( for glucose only; 22.1 mmol<sup>.</sup>h<sup>.</sup>L<sup>-1</sup>, 95% CI 17.7, 26.6; <i>P </i>= 0.01) No significant differences in glucose or insulin iAUC<sub>net</sub> were observed comparing SRA3 and SIT. There was no statistically significant effect of condition on triglyceride iAUC<sub>net</sub>. </a></p> <p><b>Conclusion:</b> In adults with medication-controlled T2D, interrupting prolonged sitting with 6-minute SRAs every 60 minutes reduced postprandial glucose and insulin responses. Other frequencies of interruptions and potential longer-term benefits require examination to clarify clinical relevance. </p>
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