ObjectiveTo evaluate the effect of five years of supervised exercise training compared with recommendations for physical activity on mortality in older adults (70-77 years).DesignRandomised controlled trial.SettingGeneral population of older adults in Trondheim, Norway.Participants1567 of 6966 individuals born between 1936 and 1942.InterventionParticipants were randomised to two sessions weekly of high intensity interval training at about 90% of peak heart rate (HIIT, n=400), moderate intensity continuous training at about 70% of peak heart rate (MICT, n=387), or to follow the national guidelines for physical activity (n=780; control group); all for five years.Main outcome measureAll cause mortality. An exploratory hypothesis was that HIIT lowers mortality more than MICT.ResultsMean age of the 1567 participants (790 women) was 72.8 (SD 2.1) years. Overall, 87.5% of participants reported to have overall good health, with 80% reporting medium or high physical activity levels at baseline. All cause mortality did not differ between the control group and combined MICT and HIIT group. When MICT and HIIT were analysed separately, with the control group as reference (observed mortality of 4.7%), an absolute risk reduction of 1.7 percentage points was observed after HIIT (hazard ratio 0.63, 95% confidence interval 0.33 to 1.20) and an absolute increased risk of 1.2 percentage points after MICT (1.24, 0.73 to 2.10). When HIIT was compared with MICT as reference group an absolute risk reduction of 2.9 percentage points was observed (0.51, 0.25 to 1.02) for all cause mortality. Control participants chose to perform more of their physical activity as HIIT than the physical activity undertaken by participants in the MICT group. This meant that the controls achieved an exercise dose at an intensity between the MICT and HIIT groups.ConclusionThis study suggests that combined MICT and HIIT has no effect on all cause mortality compared with recommended physical activity levels. However, we observed a lower all cause mortality trend after HIIT compared with controls and MICT.Trial registrationClinicalTrials.gov NCT01666340.
-Exercise guidelines highlight maximizing bone mass early in life as a strategy to prevent osteoporosis. Which intervention is most effective for this purpose remains unclear. This study investigated the musculoskeletal effects of high acceleration, maximal strength training (MST), in young adult women. Thirty healthy women (22 ± 2 years) were randomly assigned to a training group (TG) and a control group (CG). The TG completed 12 weeks of squat MST, executed at 85-90% of maximal strength 1 repetition maximum (1RM), emphasizing progressive loading and high acceleration in the concentric phase. The CG was encouraged to follow the American College of Sports Medicine's exercise guidelines for skeletal health. Measurements included bone mineral density (BMD) and body composition by dual-energy X-ray absorptiometry, dynamic and isometric rate of force development (RFD), and squat 1RM. Serum levels of type 1 collagen amino-terminal propeptide (P1NP), type 1 collagen C breakdown products (CTX), and sclerostin were analyzed by immunoassays. In the TG, lumbar spine and total hip BMD increased by 2.2 and 1.0%, whereas serum P1NP increased by 26.2%. Dynamic RFD and 1RM improved by 81.7 and 97.7%, and isometric RFD improved by 38% at 100 milliseconds. These improvements were significantly greater than those observed in the CG. Within the CG, dynamic RFD and 1RM increased by 27.2 and 12.9% while no other significant changes occurred. These findings suggest that squat MST may serve as a simple, time-efficient strategy to optimize peak bone mass in early adulthood.
BackgroundPublic health initiatives world-wide recommend increasing physical activity (PA) to improve health. However, the dose and the intensity of PA producing the most benefit are still debated. Accurate assessment of PA is necessary in order to 1) investigate the dose–response relationship between PA and health, 2) shape the most beneficial public health initiatives and 3) test the effectiveness of such initiatives. Actigraph accelerometer is widely used to objectively assess PA, and the raw data is given in counts per unit time. Count-thresholds for low, moderate and vigorous PA are mostly based on absolute intensity. This leads to largely inadequate PA intensity assessment in a large proportion of the elderly, who due to their declining maximal oxygen uptake (VO2max) cannot reach the moderate/vigorous intensity as defined in absolute terms. To resolve this issue, here we report relative Actigraph intensity-thresholds for the elderly.MethodsSubmaximal-oxygen-uptake, VO2max and maximal heart rate (HRmax) were measured in 111 70–77 year olds, while wearing an Actigraph-GT3X+. Relationship between VO2max percentage (%), counts-per-minute (CPM) and gender (for both the vertical-axis (VA) and vector-magnitude (VM)) and VO2max% and HRmax% was established using a mixed-regression-model. VM-and VA-models were tested against each other to see which model predicts intensity of PA better.ResultsVO2max and gender significantly affected number of CPM at different PA intensities (p < 0.05). Therefore, intensity-thresholds were created for both men and women of ranging VO2max values (low, medium, high). VM-model was found to be a better predictor of PA-intensity than VA-model (p < 0.05). Established thresholds for moderate intensity (46−63 % of VO2max) ranged from 669–3367 and 834–4048 CPM and vigorous intensity (64−90 % of VO2max) from 1625–4868 and 2012-5423CPM, for women and men, respectively. Lastly, we used this evidence to derive a formula that predicts customized relative intensity of PA (either VO2max% or HRmax%) using counts-per-minute values as input.ConclusionIntensity-thresholds depend on VO2max, gender and Actigraph-axis. PA intensity-thresholds that take all these factors into account allow for more accurate relative intensity PA assessment in the elderly and will be useful in future PA research.Trial registration(ClinicalTrials.gov Identifier: NCT02017847, registered 17. December 2013)
Aims The aim of this study was to compare the effects of 5 years of supervised exercise training (ExComb), and the differential effects of subgroups of high-intensity interval training (HIIT) and moderate-intensity continuous training (MICT), with control on the cardiovascular risk profile in older adults. Methods and results Older adults aged 70–77 years from Trondheim, Norway (n = 1567, 50% women), able to safely perform exercise training were randomized to 5 years of two weekly sessions of HIIT [∼90% of peak heart rate (HR), n = 400] or MICT (∼70% of peak HR, n = 387), together forming ExComb (n = 787), or control (instructed to follow physical activity recommendations, n = 780). The main outcome was a continuous cardiovascular risk score (CCR), individual cardiovascular risk factors, and peak oxygen uptake (VO2peak). CCR was not significantly lower [−0.19, 99% confidence interval (CI) −0.46 to 0.07] and VO2peak was not significantly higher (0.39 mL/kg/min, 99% CI −0.22 to 1.00) for ExComb vs. control. HIIT showed higher VO2peak (0.76 mL/kg/min, 99% CI 0.02–1.51), but not lower CCR (−0.32, 99% CI −0.64 to 0.01) vs. control. MICT did not show significant differences compared to control or HIIT. Individual risk factors mostly did not show significant between-group differences, with some exceptions for HIIT being better than control. There was no significant effect modification by sex. The number of cardiovascular events was similar across groups. The healthy and fit study sample, and contamination and cross-over between intervention groups, challenged the possibility of detecting between-group differences. Conclusions Five years of supervised exercise training in older adults had little effect on cardiovascular risk profile and did not reduce cardiovascular events. Registration ClinicalTrials.gov: NCT01666340.
Maintaining low DSs and high eCRF was independently associated with a lower risk of all-cause mortality. The lowest mortality risk was observed for persistently high eCRF combined with decreased or persistently low DSs. These results emphasize the effect of preventing DSs and maintaining high CRF on long-term mortality risk, which is potentially important for long-term population health.
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