Sedentary Middle-aged Adults Research Articles

Progressive, High Intensity Endurance Exercise Training Significantly Increases Submaximal and Maximal Stroke Volume In Middle Aged, Previously Sedentary Adults

High intensity, endurance exercise increases maximal stroke volume (SV) in young, healthy adults. It is less clear whether such gains are realized among sedentary adults who begin such a program during middle-age. PURPOSE: To determine whether a progressive, high-intensity endurance exercise program will increase SV in healthy, middle-aged adults. METHODS: We studied 42 middle-aged adults (18 males; 52.1 ± 5.0yrs). 21 were randomized to a non-aerobic exercise group (Control). The remaining 21 (10 males) were assigned to an endurance training group (Exercise), all whom completed the 9-month progression phase of a 24 month exercise prescription. This progressive regimen was gradually expanded from 3*30min moderate intensity sess./wk to 1-2*30 min and 1*60 min moderate intensity (55-70% of VO2max) sess./wk + 2 high intensity interval (≥95%peakHR) sess./wk; and 1 low intensity recovery sess./wk. Endurance training sessions were recorded by each participant via both Polar heart rate monitoring and manual data logs. VO2max was measured using the Douglas Bag method via an incremental treadmill protocol. Cardiac output (Qc) was measured by a non-invasive acetylene rebreathing method. VO2 and Qc were measured at rest, two submaximal (SS1 and SS2, 30 and 60% of peak VO2, respectively) and maximal workloads. SV was calculated from the Qc and HR measured via ECG. RESULTS: Exercise participants increased their SV at the submaximal (10.2 and 11.6%, respectively; both p<0.01) and maximal (9.7%, p=0.02) workloads (reference Table 1). SV of the Control group decreased slightly at all workloads. CONCLUSION: Healthy, previously sedentary middle-aged adults who completed a progressive endurance exercise program realized a significant increase in SV during both submaximal and maximal exercise.Table 1: Stroke Volume Increases with Progressive Endurance Training

Habitual and Maximal Dual-Task Gait Speeds Among Sedentary, Recreationally Active, and Masters Athlete Late Middle-Aged Adults.

Gait speed predicts survival in older adults; however, gait has not been evaluated in late middle-aged (LMA) populations. Evaluate single- and dual-task gait speeds among sedentary (SED), recreationally active (RA), and masters athlete (MA) LMA adults. Participants were SED (n = 20, age = 61.0 ± 5.8), RA (n = 57, age = 63.5 ± 8.4), and MA (n = 25, age = 57.5 ± 7.9). Two trials of each task (10 m) were completed: habitual speed (HS), maximal speed (MS), dual-task (counting backward from a number by 3) habitual speed (DTHS), and dual-task maximal speed (DT-MS). MA (2.08 ± 0.63 m/s) had significantly (p < .05) greater MS compared with SED (1.94 ± 0.30 m/s) and RA (1.99 ± 0.53 m/s). Similar differences existed for DT-MS (SED = 1.77 ± 0.32 m/s, RA = 1.80 ± 0.51 m/s, MA = 1.89 ± 0.63 m/s). MA had smaller MS and DT-MS changes (difference between MS and DT-MS speeds) compared with RA (12%) and SED (13%). Maintaining a competitively active lifestyle increases MS in LMA adults and may support healthy aging.

Distinguishing Perceived Competence and Self-Efficacy: An Example From Exercise

This article examined the conceptual and statistical distinction between perceived competence and self-efficacy. Although they are frequently used interchangeably, it is possible that distinguishing them might assist researchers in better understanding their roles in developing enduring adaptive behavior patterns. Perceived competence is conceived in the theoretical framework of self-determination theory and self-efficacy is conceived in the theoretical framework of social-cognitive theory. Purpose: The purpose of this study was to empirically distinguish perceived competence from self-efficacy for exercise. Method: Two studies evaluated the independence of perceived competence and self-efficacy in the context of exercise. Using 2 extant instruments with validity and reliability evidence in exercise contexts, the distinctiveness of the 2 constructs was assessed in 2 separate samples (n = 357 middle-aged sedentary adults; n = 247 undergraduate students). Results: Confirmatory factor analysis supported the conceptual and empirical distinction of the 2 constructs. Conclusions: This study supports the conceptual and statistical distinction of perceived competence from perceived self-efficacy. Applications of these results provide a rationale for more precise future theorizing regarding their respective roles in supporting initiation and maintenance of health behaviors.

Influence of Dietary Saturated Fat Intake on Endothelial Fibrinolytic Capacity in Adults

Approximately 50% of middle-aged and older adults in the United States regularly consume a diet high in saturated fat. High dietary saturated fat intake has been linked to promote atherothrombotic vascular disease. We tested the hypothesis that endothelial fibrinolytic function is diminished in middle-aged and older adults who habitually consume a diet high in saturated fat. Twenty-four healthy, sedentary middle-aged, and older adults (54 to 71years) were studied: 10 (8 men and 2 women) with a dietary saturated fat intake <10% (lower saturated fat) of total calories and 14 (9 men and 5 women) with a dietary saturated fat intake ≥10% of total calories (high saturated fat). Net endothelial release of tissue-type plasminogen activator (t-PA), the primary activator of fibrinolysis, was determined, invivo, in response to intrabrachial infusions of bradykinin (12.5 to 50.0ng/100ml tissue/min) and sodium nitroprusside (1.0 to 4.0μg/100ml tissue/min). Capacity of the endothelium to release t-PA in response to bradykinin was ∼30% less (p <0.05) in the high (from-0.7 ± 0.6 to 36.9 ± 3.3ng/100ml tissue/min) compared with the lower (from-0.3 ± 0.3 to 53.4 ± 7.8ng/100ml tissue/min) dietary saturated fat group. Moreover, total amount of t-PA released was significantly less (∼30%) (201 ± 22 vs 274 ± 29ng/100ml tissue) in the adults who reported consuming a diet high in saturated fat. These results indicate that the capacity of the endothelium to release t-PA is lower in middle-aged and older adults who habitually consume a diet high in saturated fat. In conclusion, endothelial fibrinolytic dysfunction may underlie the increased atherothrombotic disease risk with a diet high in saturated fat.

Validating two self-report physical activity measures in middle-aged adults completing a group exercise or home-based physical activity program

To compare self-reported physical activity recorded in physical activity diaries or the Active Australia Survey with objectively measured physical activity using accelerometry in sedentary middle-aged adults completing two physical activity interventions. Cross-sectional study. Sedentary 50-65 year olds were recruited to a non-randomized 6-month community group exercise program (G) or a physiotherapist-led home-based physical activity program (HB). Over 7-days, 76 participants (HB 39, G 37) wore an ActiGraph GT1M accelerometer (5s epochs), completed the Active Australia Survey (AAS) and a daily physical activity diary. Data were analysed using descriptive statistics and Spearman rank-order correlations. The two interventions had similar demographic and physical activity characteristics except that home-based participants were younger (p < 0.01), more likely to be employed full time (p ≤ 0.001) and reported less moderate-to-vigorous physical activity in the physical activity diaries compared to group exercise participants (HB 29 ± 21 min d(-1) vs. G 57 ± 35 min d(-1), p ≤ 0.001). Home-based participants had fair-to-good agreement between the physical activity diaries and AAS or ActiGraph data (r = 0.39-0.68, p < 0.05). Group exercise physical activity diary data did not correlate significantly with either the AAS or ActiGraph data. In contrast, group exercise AAS data had good correlations with ActiGraph data (r = 0.49-0.64, p ≤ 0.001). Physical activity diaries should be interpreted cautiously unless intervention participants have an adequate understanding of physical activity intensity. The AAS is the preferred self-report measure in middle-aged adults independent of intervention.

Benefits of a worksite or home‐based bench stepping intervention for sedentary middle‐aged adults – a pilot study

The aim of this study was to investigate the benefits of a low-volume, vigorous intensity bench stepping programme in sedentary middle-aged adults. Thirty-one healthy but sedentary adults (12 men; 55-64years) took part in the study. Participants accumulated up to 9min per day of stepping exercise on three days per week over the 4-week experimental period. Parameters of cardiorespiratory fitness, body composition and lower limb muscle strength were measured on three occasions: TS1 (baseline test), TS2 (following a 4-week control period) and TS3 (following the 4-week intervention). Data were analysed using a repeated-measures ANOVA. Adherence to the programme was excellent (96%). Relative to the insignificant changes following the control period, parameters of cardiorespiratory fitness were significantly improved following training. No alterations in body composition or lower limb muscle strength were detected. These results show that less than 30min per week of bench step exercise, accumulated in short bouts throughout the day, can improve parameters of cardiorespiratory fitness after only 4weeks in previously sedentary middle-aged adults. Due to its low-cost, time-efficient and discrete aspects, stepping exercise may have important implications for public health initiatives that promote physical activity in a population who commonly report 'lack of time' as a barrier to physical activity.

Effects of a Low-Volume, Vigorous Intensity Step Exercise Program on Functional Mobility in Middle-Aged Adults

Aging-related decline in functional mobility is associated with loss of independence. This decline may be mitigated through programs of physical activity. Despite reports of aging-related mobility impairment in middle-aged adults, this age group has been largely overlooked in terms of exercise programs that target functional mobility and the preservation of independence in older age. A method to quantitatively assess changes in functional mobility could direct rehabilitation in a proactive rather than reactive manner. Thirty-three healthy but sedentary middle-aged adults participated in a four week low-volume, vigorous intensity stepping exercise program. Two baseline testing sessions and one post-training testing session were conducted. Functional mobility was assessed using the timed up and go (TUG) test, with its constituent sit-to-walk and walk-to-sit phases examined using a novel inertial sensor-based method. Additionally, semi-tandem balance and knee extensor muscle isometric torque were assessed. Trunk acceleration during walk-to-sit reduced significantly post-training, suggesting altered movement control due to the exercise program. No significant training-induced changes in sit-to-walk acceleration, TUG time, balance or torque were observed. The novel method of functional mobility assessment presented provides a reliable means to quantify subtle changes in mobility during postural transitions. Over time, this exercise program may improve functional mobility.

Physiotherapist-led home-based physical activity program versus community group exercise for middle-aged adults: Quasi-experimental comparison

Objectives: Program method, program deliverer and participant preference may be important factors in increasing physical activity adherence and program effectiveness. To investigate this, we compared two physical activity interventions in middle-aged adults. Methods: Using a pragmatic quasi-experimental design, sedentary community dwelling 50 - 65 year olds (n = 2105) were recruited to a non-randomized 6-month community group exercise program (n = 93) or a physiotherapist-led home-based physical activity program (n = 65). The primary outcome was physical activity adherence derived from exercise diaries. Secondary outcomes included the Active Australia Survey, aerobic capacity (step- test), quality of life (SF-12v2), blood pressure, waist circumference, waist-to-hip ratio (WHR) and body mass index. Results: Home-based participants were more likely to be younger, working full-time and not in a relationship (p Thirty-three percent of the group participants attended ≥ 70% of group exercise sessions. Ninety percent of home-based participants received ≥ 4 of the planned 6 telephone support calls. Intention-to-treat analysis found adherence to the physical activity sessions prescribed was the same for both interventions (26% ± 28% vs. 28% ± 35%). Both interventions significantly increased the number of participants achieving self-reported “sufficient” physical activity (p ≤ 0.001) and significantly decreased waist circumference (p WHR (p 0.05). Conclusion: The physiotherapist- led home-based physical activity program, requiring few resources, appears to have increased the adoption of physical activity and adherence to physical activity program requirements for sedentary middle-aged adults. The home-based program, providing equivalent health benefits to the group exercise program, may be particularly suitable for those not interested in or unable to attend a group exercise program. Clinical Trial Registration number Australian New Zealand Clinical Trials Registry (ANZCTR), ACTRN126 1000890932.

Hatha yoga and vascular function: Results from cross-sectional and interventional studies

The aim of this study was to determine the effect of hatha yoga on arterial elasticity and endothelial function. First, a cross-sectional study was performed to determine whether yoga practitioners would demonstrate greater arterial compliance and endothelium-dependent vasodilation than their sedentary peers. Second, an intervention study involving 13 sedentary middle-aged and older adults (51±7 years) was performed to determine whether 12 weeks of hatha yoga would elicit increases in arterial compliance and endothelial function. In the cross-sectional study involving a total of 34 subjects, there were no group differences in body fatness, blood lipid and lipoprotein concentrations, carotid artery compliance or brachial artery flow-mediated dilation (FMD). Hemoglobin A1c was lower in yoga practitioners than in sedentary adults (P<0.05). Total cholesterol and hemoglobin A1c decreased after the intervention (P<0.05) while carotid artery compliance and brachial artery FMD did not change. The results of both cross-sectional and interventional studies indicate that regular practice of hatha yoga is not associated with improvements in vascular functions.

Metabolic Response of Different High-Intensity Aerobic Interval Exercise Protocols

Although high-intensity sprint interval training (SIT) employing the Wingate protocol results in significant physiological adaptations, it is conducted at supramaximal intensity and is potentially unsafe for sedentary middle-aged adults. We therefore evaluated the metabolic and cardiovascular response in healthy young individuals performing 4 high-intensity (~90% VO2max) aerobic interval training (HIT) protocols with similar total work output but different work-to-rest ratio. Eight young physically active subjects participated in 5 different bouts of exercise over a 3-week period. Protocol 1 consisted of 20-minute continuous exercise at approximately 70% of VO2max, whereas protocols 2-5 were interval based with a work-active rest duration (in seconds) of 30/30, 60/30, 90/30, and 60/60, respectively. Each interval protocol resulted in approximately 10 minutes of exercise at a workload corresponding to approximately 90% VO2max, but differed in the total rest duration. The 90/30 HIT protocol resulted in the highest VO2, HR, rating of perceived exertion, and blood lactate, whereas the 30/30 protocol resulted in the lowest of these parameters. The total caloric energy expenditure was lowest in the 90/30 and 60/30 protocols (~150 kcal), whereas the other 3 protocols did not differ (~195 kcal) from one another. The immediate postexercise blood pressure response was similar across all the protocols. These finding indicate that HIT performed at approximately 90% of VO2max is no more physiologically taxing than is steady-state exercise conducted at 70% VO2max, but the response during HIT is influenced by the work-to-rest ratio. This interval protocol may be used as an alternative approach to steady-state exercise training but with less time commitment.

Aerobic Fitness and the Brain: Increased N-Acetyl-Aspartate and Choline Concentrations in Endurance-Trained Middle-Aged Adults

Engagement in regular aerobic exercise is associated with cognitive benefits, but information on the mechanisms governing these changes in humans is limited. The goal of the current study was to compare neurometabolite concentrations relating to cellular metabolism, structure, and viability in endurance-trained and sedentary middle-aged adults. Twenty-eight endurance-trained and 27 sedentary adults, aged 40-65years, underwent general health assessment, cardiorespiratory fitness measurement, neuropsychological testing, and proton magnetic resonance spectroscopy ((1)H MRS). (1)H MRS was used to examine N-acetyl-aspartate (NAA), creatine (Cr), myo-inositol (mI), choline (Cho), and glutamate (Glu) concentrations in frontal and occipitoparietal grey matter. Group differences in concentrations of NAA, Cho, mI, and Glu, calculated as ratios over Cr, were explored using ANOVA. There were no significant differences in global cognitive function, memory, and executive function performance between the groups. In comparison to sedentary adults, the endurance-trained group displayed significantly higher NAA/Cr in the frontal grey matter (F(1, 53)=5.367, p=0.024) and higher Cho/Cr in the occipitoparietal grey matter (F(1, 53)=5.138, p=0.028). Within our middle-aged sample, endurance-trained adults demonstrated higher levels of NAA/Cr in the frontal grey matter and higher Cho/Cr in the occipitoparietal grey matter. Higher levels of NAA may indicate greater neuronal integrity and higher cerebral metabolic efficiency in association with cardiorespiratory fitness, whereas increased Cho may represent increased phospholipid levels secondary to neural plasticity.

Omega-3 supplementation lowers inflammation in healthy middle-aged and older adults: a randomized controlled trial.

Observational studies have linked lower levels of omega-3 (n-3) polyunsaturated fatty acids (PUFAs) with inflammation and depression. This study was designed to determine whether n-3 supplementation would decrease serum cytokine production and depressive symptoms in 138 healthy middle-aged and older adults (average age=51.04, SD=7.76) who were sedentary and overweight (average BMI=30.59, SD=4.50). This three-arm randomized, placebo-controlled, double-blind 4-month trial compared responses to (1) 2.5 g/d n-3 PUFAs, or (2) 1.25 g/d n-3 PUFAs, or (3) placebo capsules that mirrored the proportions of fatty acids in the typical American diet. Serum interleukin-6 decreased by 10% and 12% in our low and high dose n-3 groups, respectively, compared to a 36% increase in the placebo group. Similarly, low and high dose n-3 groups showed modest 0.2% and -2.3% changes in serum tumor necrosis factor alpha, compared to a 12% increase in the control group. Depressive symptoms were quite low at baseline and did not change significantly in response to supplementation. Our data suggest that n-3 PUFAs can reduce inflammation in overweight, sedentary middle-aged and older adults, and thus could have broad health benefits. These data provide a window into the ways in which the n-3 PUFAs may impact disease initiation, progression, and resolution. ClinicalTrials.gov identifier: NCT00385723.

Low-Volume Interval Training Improves Muscle Oxidative Capacity in Sedentary Adults

High-intensity interval training (HIT) increases skeletal muscle oxidative capacity similar to traditional endurance training, despite a low total exercise volume. Much of this work has focused on young active individuals, and it is unclear whether the results are applicable to older less active populations. In addition, many studies have used "all-out" variable-load exercise interventions (e.g., repeated Wingate tests) that may not be practical for all individuals. We therefore examined the effect of a more practical low-volume submaximal constant-load HIT protocol on skeletal muscle oxidative capacity and insulin sensitivity in middle-aged adults, who may be at a higher risk for inactivity-related disorders. Seven sedentary but otherwise healthy individuals (three women) with a mean ± SD age, body mass index, and peak oxygen uptake (VO(2peak)) of 45 ± 5 yr, 27 ± 5 kg·m(-2), and 30 ± 3 mL·kg(-1)·min(-1) performed six training sessions during 2 wk. Each session involved 10 × 1-min cycling at ∼60% of peak power achieved during a ramp VO(2peak) test (eliciting ∼80%-95% of HR reserve) with 1 min of recovery between intervals. Needle biopsy samples (vastus lateralis) were obtained before training and ∼72 h after the final training session. Muscle oxidative capacity, as reflected by the protein content of citrate synthase and cytochrome c oxidase subunit IV, increased by ∼35% after training. The transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator 1α was increased by ∼56% after training, but the transcriptional corepressor receptor-interacting protein 140 remained unchanged. Glucose transporter protein content increased ∼260%, and insulin sensitivity, on the basis of the insulin sensitivity index homeostasis model assessment, improved by ∼35% after training. Constant-load low-volume HIT may be a practical time-efficient strategy to induce metabolic adaptations that reduce the risk for inactivity-related disorders in previously sedentary middle-aged adults.

Endothelial ischemia-reperfusion injury in humans: association with age and habitual exercise

Advancing age is a major risk factor for coronary artery disease. Endothelial dysfunction accompanied by increased oxidative stress and inflammation with aging may predispose older arteries to greater ischemia-reperfusion (I/R) injury. Because coronary artery ischemia cannot be induced safely, the effects of age and habitual endurance exercise on endothelial I/R injury have not been determined in humans. Using the brachial artery as a surrogate model of the coronary arteries, endothelial function, assessed by brachial artery flow-mediated dilation (FMD), was measured before and after 20 min of continuous forearm occlusion in young sedentary (n = 10, 24 ± 2 yr) and middle-aged (n = 9, 48 ± 2 yr) sedentary adults to gain insight into the effects of primary aging on endothelial I/R injury. Young (n = 9, 25 ± 1 yr) and middle-aged endurance-trained (n = 9, 50 ± 2 yr) adults were also studied to determine whether habitual exercise provides protection from I/R injury. Fifteen minutes after ischemic injury, FMD decreased significantly by 37% in young sedentary, 35% in young endurance-trained, 68% in middle-aged sedentary, and 50% in middle-aged endurance-trained subjects. FMD returned to baseline levels within 30 min in young sedentary and endurance-trained subjects but remained depressed in middle-aged sedentary and endurance-trained subjects. Circulating markers of antioxidant capacity and inflammation were not related to FMD. In conclusion, advancing age is associated with a greater magnitude and delayed recovery from endothelial I/R injury in humans. Habitual endurance exercise may provide partial protection to the endothelium against this form of I/R injury with advancing age.

Exploring the Role of Body Mass Index on Balance Reactions and Gait in Overweight Sedentary Middle-aged Adults

Being overweight is defined as having a body mass index greater than 25. Reduced postural control has been implicated in the presence of increased body mass index. The purpose of this study was to assess the effects of body mass index on postural stability in healthy sedentary middle-aged adults. Based on body mass index, subjects were divided into 2 groups (25.00-27.49 and 27.50-29.99) to assess for differences in postural control. Twenty healthy sedentary subjects between 40 and 64 years (13 women and 7 men) with a mean age of 52.45 years were recruited by convenience. After determination of body mass index, postural control was assessed on all subjects using the Activities Specific Balance Confidence Scale, Berg Balance Scale, Timed Up and Go Test, gait speed measurement, and Biodex Stability Index testing. The Timed Up and Go Test duration was increased in these subjects when compared with normative data. Gait speed was also reduced in those subjects in the fifth and sixth decades when compared with established norms. Biodex SD balance system scores demonstrated reduced postural stability. A 2-tailed t test revealed no significant difference between body mass index ranges of 25.0 to 27.5 and 27.6 to 29.99. There may be increased risk for falls with increases in body mass short of obesity thresholds of body mass index 30% for this sedentary middle-aged adult population. Future studies, with larger groups of subjects, that address postural stability and body mass index are necessary. Although these subjects are younger, falls screening measures may prove beneficial as a prevention strategy for sedentary overweight middle-aged adults.

High Intensity Interval Training Rapidly Increases Skeletal Muscle Oxidative Capacity In Previously Sedentary Middle-aged Adults

There is growing appreciation of the potential for high intensity interval training (HIT) to rapidly stimulate metabolic adaptations that resemble traditional endurance training, despite a low total exercise volume (Exerc Sports Sci Rev 36:58-63, 2008). However, much of this work has been conducted on young active individuals (≤30 yr) and the results may not be generalized to older, less active populations. In addition, many studies have employed "all out“, variable-load exercise interventions (e.g., repeated Wingate Tests) that may not be safe, practical or well tolerated by certain individuals. PURPOSE: To determine the effect of a short program of low-volume, submaximal, constant-load HIT on skeletal muscle metabolic adaptations in sedentary middle-aged individuals who may be at higher risk for inactivity-related disorders. METHODS: Inactive but otherwise healthy men (n = 3) and women (n = 4) with a mean (±SE) age, body mass index and peak oxygen uptake (VO2peak) of 45±2 yr, 27±2 kg·m2 and 30±1 ml·kg-1·min-1 took part in the study. Subjects performed 6 training sessions over 2 wk. Each session consisted of 10 × 1 min cycling at 60% of peak power elicited during a ramp VO2peak test (∼90% of maximal heart rate) with 1 min recovery between intervals. Needle muscle biopsy samples (v. lateralis) were obtained before training and ∼72 h after the final training session. RESULTS: Muscle oxidative capacity, as reflected by the maximal activity of citrate synthase, increased by 22% after training (12.9 ± 0.7 vs. 10.6 ± 0.6 mmol·kg protein-1·h-1), which is comparable to changes previously reported after 2 wk of Wingate-based HIT in young active subjects. CONCLUSIONS: A short program of low-volume, constant-load HIT is a time-efficient strategy to rapidly increase skeletal muscle oxidative capacity in previously sedentary middle-aged men and women. Supported by CIHR.

Absence of Inhibitor of Nuclear Factor κ B Kinase‐Mediated Suppression of Vascular Endothelial Function in Middle‐Aged/Older Adults Who Exercise

We determined if reduced bioactivity of the inhibitor of nuclear factor κ B kinase (IKKB) contributes to enhanced vascular endothelial function in habitually exercising (EX) vs. sedentary (SED) middle‐aged and older adults. BMI was lower (P &lt; 0.05) in EX (n = 5 [5 m], 63 ± 3 y) than in SED (n = 7 [5 m], 61 ± 2 y), but other coronary risk factors did not differ. EX and SED were studied after 4 d of oral treatment with placebo or salsalate (3000‐4500 mg/d), an inhibitor of IKKB (randomized double‐blind crossover). During placebo, brachial artery flow‐mediated dilation (FMD), a measure of endothelium‐dependent dilation, was ~150% greater in EX vs. SED (%Δ: 6.16 ± 0.59 vs. 2.46 ± 0.62; mmΔ: 0.24 ± 0.02 vs. 0.10 ± 0.02; both P = 0.001). Salsalate increased FMD in SED (5.76 ± 0.49 %Δ and 0.23 ± 0.01 mmΔ, P &lt; 0.001 vs. SED placebo) to levels not different from EX placebo (P &gt; 0.30), but had no effect on EX (6.55 ± 1.21 %Δ and 0.24 ± 0.03 mmΔ). Infusion of the antioxidant vitamin C increased FMD by ~80% (P &lt; 0.05) in SED during placebo, but had no effect in SED during salsalate or in EX during either conditions (all P &gt; 0.10). Endothelium‐independent dilation (sublingual nitroglycerin) did not differ between groups or conditions (all p &gt; 0.05). An absence of IKKB bioactivity and reduced oxidative stress contribute to enhanced vascular endothelial function in middle‐aged/older adults who exercise.NIH AG031617, AG006537, AG013038, AG022241, RR00051; AHA 0715735Z

Habitual exercise and arterial aging

Aging affects the function and structure of arteries and increases the risk of cardiovascular diseases (CVD). In healthy sedentary adults, aging is associated with increased stiffness (reduced compliance) of large elastic arteries; impaired vascular endothelial function, including reductions in endothelium-dependent dilation (EDD), release of tissue-type plasminogen activator (fibrinolytic capacity) and endothelial progenitor cell number and function; increased intima-media wall thickness (IMT); and peripheral vasoconstriction (decreased basal leg blood flow). Habitual physical activity/increased aerobic exercise capacity is associated with reduced risk of CVD. Compared with their sedentary peers, adults who regularly perform aerobic exercise demonstrate smaller or no age-associated increases in large elastic artery stiffness, reductions in vascular endothelial function, and increases in femoral artery IMT. A short-term, moderate-intensity aerobic exercise intervention (brisk daily walking for 12 wk) improves carotid artery compliance and can restore vascular endothelial function in previously sedentary middle-aged and older adults. Reduced oxidative stress may be an important mechanism contributing to these effects. Habitual resistance exercise increases (high-intensity) or does not affect (moderate-intensity) large elastic artery stiffness, and prevents/restores the age-associated reduction in basal leg blood flow independent of changes in leg fat-free mass. Habitual exercise favorably modulates several expressions of arterial aging, thus preserving vascular function and possibly reducing the risk of CVD.

Impaired Endothelium-Dependent Vasodilation in Normotensive and Normoglycemic Obese Adult Humans

Acetylcholine (ACh)-mediated endothelium-dependent vasodilation has been shown to be impaired in obese adults. However, the mechanisms responsible for this impairment are not clear. We determined whether the blunted forearm vasodilator response to acetylcholine with obesity is due, at least in part, to reduced muscarinic receptor responsiveness. Twenty-eight sedentary middle-aged adults were studied: 14 normal weight (BMI, 23.6 +/- 0.5 kg/m) and 14 obese (32.2 +/- 0.9 kg/m). Forearm blood flow (FBF) was determined in response to intraarterial infusion of acetylcholine (8-128 microg/min) and sodium nitroprusside (SNP: 2.0-8.0 microg/min). Regardless of the dose, forearm blood flow responses to acetylcholine were 25% (P < 0.01) lower in the obese (from 4.2 +/- 0.3 to 12.0 +/- 0.8 mL/100 mL tissue/min) compared with normal weight (4.4 +/- 0.3 to 16.9 +/- 1.0 mL/100 mL tissue/min) adults. Of note, forearm blood flow responses to acetylcholine plateaued at doses higher than 32 microg/min in both groups, no further increase in forearm blood flow was observed at either 64 or 128 microg/min. EC50 for acetylcholine-stimulated vasodilation was not different between the obese (7.8 +/- 0.8 microg/min) and normal weight (7.8 +/- 0.6 microg/min) adults. There were no group differences in the vasodilator response to sodium nitroprusside. These results indicate that the obesity-related impairment in acetylcholine-mediated vasodilation in the human forearm is not due to reduced muscarinic receptor responsiveness or sensitivity.

AGING AND CARDIOVASCULAR REGULATION WITH ACUTE AND HABITUAL EXERCISE

This presentation will review our current state of knowledge regarding the effects of aging on the cardiovascular adjustments to acute exercise and adaptations to habitual exercise. The main focus will be on primary (physiological) human aging in the absence of overt chronic disease. Cardiovascular adjustments to acute exercise will be discussed in the context of both maximal and submaximal efforts. Circulatory control during submaximal exercise will be examined under conditions of both brief incremental and prolonged constant work loads. Emphasis will be placed on cardiovascular regulation during large-muscle dynamic modes of exercise, but the adjustments to isometric contractions also will be described. Systemic and regional circulatory control will be considered in an integrative manner. Cardiovascular responses to habitual exercise will focus on adaptations expressed under resting conditions as well as during acute submaximal and maximal exercise. Experimental evidence will be based on the results of both cross-sectional investigations of masters athletes and exercise intervention studies of previously sedentary middle-aged and older adults. Primary emphasis will be on the adaptations to regular aerobic-endurance exercise, but changes in response to resistance exercise training also will be considered. The contributions of neural, humoral and local mechanisms in mediating age-associated differences in the responses to acute and habitual exercise will be discussed.