Amanda L. Zaleski

Influence of chronic exercise on carotid atherosclerosis in marathon runners

Objectives The effect of habitual, high-intensity exercise training on the progression of atherosclerosis is unclear. We assessed indices of vascular health (central systolic blood pressure (SBP) and arterial stiffness as well as carotid intima-medial thickness (cIMT)) in addition to cardiovascular risk factors of trained runners versus their untrained spouses or partners to evaluate the impact of exercise on the development of carotid atherosclerosis. Setting field study at Boston Marathon. Participants 42 qualifiers (mean age±SD: 46±13 years, 21 women) for the 2012 Boston Marathon and their sedentary domestic controls (46±12 years, n=21 women). Outcomes We measured medical and running history, vital signs, anthropometrics, blood lipids, C reactive protein (CRP), 10 years Framingham risk, central arterial stiffness and SBP and cIMT. Results Multiple cardiovascular risk factors, including CRP, non-high-density lipoprotein cholesterol, triglycerides, heart rate, body weight and body mass index (all p<0.05), were reduced in the runners. The left and right cIMT, as well as central SBP, were not different between the two groups (all p>0.31) and were associated with age (all r≥0.41; p<0.01) and Framingham risk score (all r≥0.44; p<0.01) independent of exercise group (all p>0.08 for interactions). The amplification of the central pressure waveform (augmentation pressure at heart rate 75 bpm) was also not different between the two groups (p=0.07) but was related to age (p<0.01) and group (p=0.02) in a multiple linear regression model. Conclusions Habitual endurance exercise improves the cardiovascular risk profile, but does not reduce the magnitude of carotid atherosclerosis associated with age and cardiovascular risk factors.

Is Concurrent Training Efficacious Antihypertensive Therapy? A Meta-analysis.

: Aerobic exercise training and, to a lesser degree, dynamic resistance training, are recommended to lower blood pressure (BP) among adults with hypertension. Yet the combined influence of these exercise modalities, termed concurrent exercise training (CET), on resting BP is unclear. PURPOSE This study aimed to meta-analyze the literature to determine the efficacy of CET as antihypertensive therapy. METHODS Electronic databases were searched for trials that included the following: adults (>19 yr), controlled CET interventions, and BP measured pre- and postintervention. Study quality was assessed with a modified Downs and Black Checklist. Analyses incorporated random-effects assumptions. RESULTS Sixty-eight trials yielded 76 interventions. Subjects (N = 4110) were middle- to older-age (55.8 ± 14.4 yr), were overweight (28.0 ± 3.6 kg·m), and had prehypertension (systolic BP [SBP]/diastolic BP [DBP] = 134.6 ± 10.9/80.7 ± 7.5 mm Hg). CET was performed at moderate intensity (aerobic = 55% maximal oxygen consumption, resistance = 60% one-repetition maximum), 2.9 ± 0.7 d·wk for 58.3 ± 20.1 min per session for 19.7 ± 17.8 wk. Studies were of moderate quality, satisfying 60.7% ± 9.4% of quality items. Overall, CET moderately reduced SBP (db = -0.32, 95% confidence interval [CI] = -0.44 to -0.20, -3.2 mm Hg) and DBP (db = -0.35, 95% CI = -0.47 to -0.22, -2.5 mm Hg) versus control (P < 0.01). However, greater SBP/DBP reductions were observed among samples with hypertension in trials of higher study quality that also examined BP as the primary outcome (-9.2 mm Hg [95% CI = -12.0 to -8.0]/-7.7 mm Hg [95% CI = -14.0 to -8.0]). CONCLUSIONS Among samples with hypertension in trials of higher study quality, CET rivals aerobic exercise training as antihypertensive therapy. Because of the moderate quality of this literature, additional randomized controlled CET trials that examine BP as a primary outcome among samples with hypertension are warranted to confirm our promising findings.

Can Exercise Improve Cognitive Symptoms of Alzheimer's Disease?

To examine the effects of exercise training on cognitive function in individuals at risk of or diagnosed with Alzheimers disease (AD).

Coming of Age: Considerations in the Prescription of Exercise for Older Adults.

Older adults represent the fastest-growing age demographic of the population. Physiological changes associated with primary aging and concurrent chronic disease adversely impact functional capacity, health outcomes, and quality of life. For these reasons, there is a national emphasis for healthcare providers to improve the health, function, and quality of life of older adults to preserve independent living and psychological well-being. The benefits of regular physical activity or exercise with regard to aging and disease are indisputable, yet many clinicians do not prescribe exercise to older adults. This reluctance may be attributable to a lack of knowledge regarding appropriate exercise prescription for older adults in light of the potential risks and benefits of various doses and types of exercise. In addition, clinicians and patients may have concerns about potential health considerations relevant to older adults such as comprehensive pre-exercise screening and exercise-drug interactions. In light of this, the following review presents (1) guidelines for exercise prescription in older adults and modification of these guidelines for patients with the most common age-associated comorbidities; (2) recommendations for pre-exercise screening prior to initiating an exercise program in older adults; (3) considerations for older adults on one or more medications; and (4) common barriers to adopting and maintaining exercise in an older population. Our goal is to provide a framework that clinicians can follow when prescribing exercise in older adults while considering the unique characteristics and concerns present in this population.

High-Dose versus Low-Dose Vitamin D Supplementation and Arterial Stiffness among Individuals with Prehypertension and Vitamin D Deficiency

Introduction. Vitamin D deficiency is associated with the onset and progression of hypertension and cardiovascular disease (CVD). However, mechanisms underlying vitamin D deficiency-mediated increased risk of CVD remain unknown. We sought to examine the differential effect of high-dose versus low-dose vitamin D supplementation on markers of arterial stiffness among ~40 vitamin D deficient adults with prehypertension. Methods. Participants were randomized to high-dose (4000 IU/d) versus low-dose (400 IU/d) oral vitamin D3 for 6 months. 24 hr ambulatory blood pressure (BP), carotid-femoral pulse wave velocity, and pulse wave analyses were obtained at baseline and after 6 months of vitamin D supplementation. Results. There were no changes in resting BP or pulse wave velocity over 6 mo regardless of vitamin D dose (all p > 0.202). High-dose vitamin D decreased augmentation index and pressure by 12.3 ± 5.3% (p = 0.047) and 4.0 ± 1.5 mmHg (p = 0.02), respectively. However, these decreases in arterial stiffness were not associated with increases in serum 25-hydroxyvitamin D over 6 mo (p = 0.425). Conclusion. High-dose vitamin D supplementation appears to lower surrogate measures of arterial stiffness but not indices of central pulse wave velocity. Clinical Trial Registration. This trial is registered with www.clinicaltrials.gov (Unique Identifier: NCT01240512).

The antihypertensive effects of aerobic versus isometric handgrip resistance exercise

Background: Aerobic exercise reduces blood pressure (BP) on average 5–7 mmHg among those with hypertension; limited evidence suggests similar or even greater BP benefits may result from isometric handgrip (IHG) resistance exercise. Method: We conducted a randomized controlled trial investigating the antihypertensive effects of an acute bout of aerobic compared with IHG exercise in the same individuals. Middle-aged adults (n = 27) with prehypertension and obesity randomly completed three experiments: aerobic (60% peak oxygen uptake, 30 min); IHG (30% maximum voluntary contraction, 4 × 2 min bilateral); and nonexercise control. Study participants were assessed for carotid-femoral pulse wave velocity pre and post exercise, and left the laboratory wearing an ambulatory BP monitor. Results: SBP and DBP were lower after aerobic versus IHG (4.8 ± 1.8/3.1 ± 1.3 mmHg, P = 0.01/0.04) and control (5.6 ± 1.8/3.6 ± 1.3 mmHg, P = 0.02/0.04) over the awake hours, with no difference between IHG versus control (P = 0.80/0.83). Pulse wave velocity changes following acute exercise did not differ by modality (aerobic increased 0.01 ± 0.21 ms, IHG decreased 0.06 ± 0.15 ms, control increased 0.25 ± 0.17 ms, P > 0.05). A subset of participants then completed either 8 weeks of aerobic or IHG training. Awake SBP was lower after versus before aerobic training (7.6 ± 3.1 mmHg, P = 0.02), whereas sleep DBP was higher after IHG training (7.7 ± 2.3 mmHg, P = 0.02). Conclusion: Our findings did not support IHG as antihypertensive therapy but that aerobic exercise should continue to be recommended as the primary exercise modality for its immediate and sustained BP benefits.

The impact of tetrahydrobiopterin administration on endothelial function before and after smoking cessation in chronic smokers.

Cardiovascular disease mortality is reduced following smoking cessation but the reversibility of specific atherogenic risk factors such as endothelial dysfunction is less established. We assessed brachial artery flow-mediated dilation (FMD) in 57 chronic smokers and 15 healthy controls, alone and after oral tetrahydrobiopterin (BH4) administration, to assess the extent to which reduced bioactivity of BH4, a cofactor for the endothelial nitric oxide synthase enzyme (eNOS), contributes to smoking-associated reductions in FMD. Thirty-four smokers then ceased cigarette and nicotine use for 1 week, after which FMD (±BH4 administration) was repeated. Brachial artery FMD was calculated as the peak dilatory response observed relative to baseline (%FMD). Endothelium-independent dilation was assessed by measuring the dilatory response to sublingual nitroglycerin (%NTG). Chronic smokers exhibited reduced %FMD relative to controls: (5.6±3.0% vs. 8.1±3.7%; P<0.01) and %NTG was not different between groups (P=0.22). BH4 administration improved FMD in both groups (P=0.03) independent of smoking status (P=0.78) such that FMD was still lower in smokers relative to controls (6.6±3.3% vs. 9.8±3.2%; P<0.01). With smoking cessation, FMD increased significantly (from 5.0±2.9 to 7.8±3.2%;P<0.01); %NTG was not different (P=0.57) and BH4 administration did not further improve FMD (P=0.33). These findings suggest that the blunted FMD observed in chronic smokers, likely due at least in part to reduced BH4 bioactivity and eNOS uncoupling, can be restored with smoking cessation. Post-cessation BH4 administration does not further improve endothelial function in chronic smokers, unlike the effect observed in nonsmokers, indicating a longer-term impact of chronic smoking on vascular function that is not acutely reversible.

The effect of compression socks worn during a marathon on hemostatic balance

Abstract Introduction. Marathon running evokes parallel increases in markers of coagulation and fibrinolysis (i.e. hemostatic activation) immediately following strenuous, endurance exercise such that hemostatic balance is maintained. However, other factors incident to marathon running (i.e. dehydration, travel) may disproportionately activate the coagulatory system, increasing blood clot risk after an endurance event in otherwise healthy individuals. We investigated the effect of compression socks on exercise-induced hemostatic activation and balance in endurance athletes running the 2013 Hartford Marathon. Methods. Adults (n = 20) were divided into compression sock (SOCK; n = 10) and control (CONTROL; n = 10) groups. Age, anthropometrics, vital signs, training mileage and finishing time were collected. Venous blood samples were collected 1 day before, immediately after and 1 day following the marathon for analysis of coagulatory (i.e. thrombin–antithrombin complex [TAT] and D-dimer) and fibrinolytic (i.e. tissue plasminogen activator [t-PA]) factors. Results. Plasma D-dimer, TAT and t-PA did not differ between groups at baseline (p > 0.16). There were no significant group · time interactions (all p ≥ 0.17), however, average t-PA was lower in SOCK (8.9 ± 0.7 ng/mL) than CONTROL (11.2 ± 0.7 ng/mL) (p = 0.04). Average TAT also tended to be lower in SOCK (2.8 ± 0.2 µg/L) than CONTROL (3.4 ± 0.2 µg/L) (p = 0.07). Conclusions. Our results suggest that overall hemostatic activation (both coagulation and fibrinolysis) following a marathon tended to be lower with compression socks. Thus, compression socks do not adversely influence markers of hemostasis, appear safe for overall use in runners and may reduce exercise-associated hemostatic activation in individuals at risk for deep vein thrombosis.

Protective effect of compression socks in a marathon runner with a genetic predisposition to thrombophilia due to Factor V Leiden

Abstract Introduction. The present case study is an analysis of the effect of compression socks on hemostatic activation following a marathon in a female endurance athlete found to be heterozygous for the coagulation factor V (F5 1691 G>A [Arg>Gln rs6025/560]) risk allele that predisposes one to a genetically inherited disorder of blood clotting, Factor V Leiden. Methods. Markers for coagulation and fibrinolysis were obtained 24 h prior to (PRE), immediately after (FINISH) and 24 h after (POST) completion of two marathons: the first in which the runner was not wearing compression socks, and the second in which the runner wore compression socks throughout the race. Results. Compression socks worn during a marathon appeared to lower the overall impact on hemostasis as well as clot formation in this particular athlete as evidenced by lower t-PA (–56%), TAT (–63%) and D-dimer (–30%). Conclusions. Hemostatic activation may be lower with the use of compression socks, and thus may be effective for preserving hemostasis in endurance athletes at risk.

Statins Attenuate the Increase in P-Selectin Produced by Prolonged Exercise

Strenuous endurance exercise increases inflammatory markers and acutely increases cardiovascular risk; however, statins may mitigate this response. We measured serum levels of p-selectin in 37 runners treated with statins and in 43 nonstatin treated controls running the 2011 Boston Marathon. Venous blood samples were obtained the day before (PRE) as well as within 1 hour after (FINISH) and 24 hours after (POST) the race. The increase in p-selectin immediately after exercise was lower in statin users (PRE to FINISH: 20.5 ± 19.4 ng/mL) than controls (PRE to FINISH: 30.9 ± 27.1 ng/mL; P < 0.001). The increase in p-selectin 24 hours after exercise was also lower in statin users (PRE to POST: 21.5 ± 26.6 ng/mL) than controls (PRE to POST: 29.3 ± 31.9 ng/mL; P < 0.001). Furthermore, LDL-C was positively correlated with p-selectin at FINISH and POST (P < 0.01 and P < 0.05, resp.), irrespective of drug treatment, suggesting that lower levels of LDL-C are associated with a reduced inflammatory response to exercise. We conclude that statins blunt the exercise-induced increase in p-selectin following a marathon and that the inflammatory response to a marathon varies directly with LDL-C levels.