Cheri L. McGowan

Sex and life expectancy.

BACKGROUND A sexual dimorphism in human life expectancy has existed in almost every country for as long as records have been kept. Although human life expectancy has increased each year, females still live longer, on average, than males. Undoubtedly, the reasons for the sex gap in life expectancy are multifaceted, and it has been discussed from both sociological and biological perspectives. However, even if biological factors make up only a small percentage of the determinants of the sex difference in this phenomenon, parity in average life expectancy should not be anticipated. OBJECTIVE The aim of this review is to highlight biological mechanisms that may underlie the sexual dimorphism in life expectancy. METHODS Using PubMed, ISI Web of Knowledge, and Google Scholar, as well as cited and citing reference histories of articles through August 2012, English-language articles were identified, read, and synthesized into categories that could account for biological sex differences in human life expectancy. RESULTS The examination of biological mechanisms accounting for the female-based advantage in human life expectancy has been an active area of inquiry; however, it is still difficult to prove the relative importance of any 1 factor. Nonetheless, biological differences between the sexes do exist and include differences in genetic and physiological factors such as progressive skewing of X chromosome inactivation, telomere attrition, mitochondrial inheritance, hormonal and cellular responses to stress, immune function, and metabolic substrate handling among others. These factors may account for at least a part of the female advantage in human life expectancy. CONCLUSIONS Despite noted gaps in sex equality, higher body fat percentages and lower physical activity levels globally at all ages, a sex-based gap in life expectancy exists in nearly every country for which data exist. There are several biological mechanisms that may contribute to explaining why females live longer than men on average, but the complexity of the human life experience makes research examining the contribution of any single factor for the female advantage difficult. However, this information may still prove important to the development of strategies for healthy aging in both sexes.

Effects of isometric handgrip training among people medicated for hypertension: a multilevel analysis.

ObjectiveTo examine the longitudinal effects of isometric handgrip (IHG) exercise training on blood pressure using hierarchical linear modeling. MethodsData from 43 participants who were medicated for hypertension at the time of training were amalgamated from three previous investigations. In each study, IHG training was completed 3 days/week for 8 weeks at 30% of maximal voluntary contraction and resting blood pressure was assessed at twice-weekly intervals throughout. ResultsHierarchical linear modeling analysis revealed a linear pattern of blood pressure decline over time with estimated reductions of 5.7 and 3 mmHg reductions in systolic and diastolic pressure, respectively. Participants with higher initial systolic pressure showed greater rates of blood pressure decline (r=−0.67), inferring that individuals with higher blood pressure stand to achieve greater benefits from this method of training. ConclusionsThese results provide further evidence that IHG training lowers resting blood pressure among persons medicated for hypertension.

Effects of isometric handgrip training on blood pressure (resting and 24 h ambulatory) and heart rate variability in medicated hypertensive patients.

ObjectivesIsometric handgrip (IHG) training (four, 2-min sustained contractions at 30% of maximal voluntary contraction, three times per week for 8–10 weeks) lowers resting arterial blood pressure (BP) in hypertensive patients, including those receiving pharmacotherapy, although the mechanisms remain elusive. Ambulatory BP measurements are more efficacious in predicting cardiovascular disease-related events, yet the effects of IHG training on ambulatory BP are unknown. The objective of the current investigation was to test the hypotheses that 8 weeks of IHG training lowers resting and 24 h ambulatory BP concomitantly in medicated hypertensive patients, and may be the result of improved vagal modulation. MethodsBP was assessed using brachial artery oscillometry, and coarse-graining spectral analysis was used to determine spectral power. Resting and 24 h ambulatory BP and heart rate variability (HRV) were measured pretraining, midtraining, and post-training in 11 medicated hypertensive patients (mean±SD, resting BP: 113.9±12.7/60.7±11.6 mmHg), and in nine medicated hypertensive controls (resting BP: 117.8±14.3/67.5±4.2 mmHg). ResultsIndices of BP and HRV were not significantly altered with IHG training (all P>0.05). ConclusionIHG training does not lower resting or ambulatory BP in hypertensive patients successfully treated with pharmacotherapy to within the normal range (⩽120/80 mmHg), nor does it improve HRV. Future studies should examine alternative IHG training protocols in well-managed hypertensive patients and/or target poorly controlled medicated hypertensive patients.

Dose-related effects of red wine and alcohol on heart rate variability

In healthy subjects a standard drink of either red wine (RW) or ethanol (EtOH) has no effect on muscle sympathetic nerve activity or on heart rate (HR), whereas two drinks increase both. Using time- and frequency-domain indexes of HR variability (HRV), we now tested in 12 subjects (24-47 yr, 6 men) the hypotheses that 1) this HR increase reflects concurrent dose-related augmented sympathetic HR modulation and 2) RW with high-polyphenol content differs from EtOH in its acute HRV effects. RW, EtOH, and water were provided on 3 days, 2 wk apart according to a randomized, single-blind design. Eight-minute segments were analyzed. One alcoholic drink increased blood concentrations to 36 + or - 2 mg/dl (mean + or - SE), and 2 drinks to 72 + or - 4 (RW) and 80 + or - 2 mg/dl (EtOH). RW quadrupled plasma resveratrol (P < 0.001). HR fell after both water drinks. When compared with respective baselines, one alcoholic drink had no effect on HR or HRV, whereas two glasses of both increased HR (RW, +5.4 + or - 1.2; and EtOH, +5.7 + or - 1.2 min(-1); P < 0.001), decreased total HRV by 28-33% (P < 0.05) and high-frequency spectral power by 32-42% (vagal HR modulation), and increased low-frequency power by 28-34% and the ratio of low frequency to high frequency by 98-119% (sympathetic HR modulation) (all, P < or = 0.01). In summary, when compared with water, one standard drink lowered time- and frequency-domain markers of vagal HR modulation. When compared with respective baselines, two alcoholic drinks increased HR by diminished vagal and augmented sympathetic HR modulation. Thus alcohol exerts dose-dependent HRV responses, with RW and EtOH having a similar effect.

Cardiovascular stress reactivity tasks successfully predict the hypotensive response of isometric handgrip training in hypertensives

This study aimed to determine whether: (a) isometric handgrip (IHG) training lowers resting blood pressure (BP), (b) cardiovascular reactivity to a serial subtraction (SST), IHG (IHGT), and cold pressor (CPT) task predicts this hypotensive response, and (c) cardiovascular reactivity is attenuated posttraining. Resting BP and cardiovascular reactivity to a SST, IHGT, and CPT were measured in 24 hypertensives (51-74 years) before and after 10 weeks of IHG training (n = 12) or control (n = 12). IHG training lowered resting BP (Δ8/5 mmHg), whereby the decrease in systolic BP was correlated to pretraining systolic BP reactivity to the SST (r = -.85) and IHGT (r = -.79; all ps < .01), but not the CPT (r = .34; p > .01). Furthermore, following IHG training, systolic BP reactivity to the SST (Δ7 mmHg) and IHGT (Δ8 mmHg) was reduced (all ps < .01). The results offer promising implications for hypertensives and may provide a tool to identify IHG training responders.

Effectiveness of commercial video gaming on fine motor control in chronic stroke within community-level rehabilitation

Abstract Purpose: The purpose of this study was to investigate the effectiveness of commercial gaming as an intervention for fine motor recovery in chronic stroke. Methods: Ten chronic phase post-stroke participants (mean time since CVA = 39 mos; mean age = 72 yrs) completed a 16-session program using the Nintendo Wii for 15 min two times per week with their more affected hand (10 right handed). Functional recovery (Jebsen Hand Function Test (JHFT), Box and Block Test (BBT), Nine Hole Peg Test (NHPT)), and quality of life (QOL; Stroke Impact Scale (SIS)) were measured at baseline (pre-testing), after 8 sessions (mid-testing) and after 16 sessions (post-testing). Results: Significant improvements were found with the JHFT, BBT and NHPT from pre-testing to post-testing (p = 0.03, p = 0.03, p = 0.01, respectively). As well, there was an increase in perceived QOL from pre-testing to post-testing, as determined by the SIS (p = 0.009). Conclusion: Commercial gaming may be a viable resource for those with chronic stroke. Future research should examine the feasibility of this as a rehabilitation tool for this population. Implications for Rehabilitation Stroke survivors often live with lasting effects from their injury, however, those with chronic stroke generally receive little to no rehabilitation due to a perceived motor recovery plateau. Virtual reality in the form of commercial gaming is a novel and motivating way for clients to complete rehabilitation. The Nintendo Wii may be a feasible device to improve both functional ability and perceived quality of life in chronic stroke survivors.

When and How to Recommend ‘Alternative Approaches’ in the Management of High Blood Pressure

Several nonpharmacologic therapies, such as sodium restriction and weight loss, have been promoted by hypertension guidelines based on the trial evidence supporting their capacity to lower blood pressure. However, many patients may not respond or be able to adhere to these nonpharmacologic treatments. Despite numerous formal diet and lifestyle recommendations, the prevalence of hypertension continues to grow worldwide. As such, additional approaches are needed to help combat this public health epidemic. In this review, we outline the evidence supporting the efficacy of a number of alternative approaches for blood pressure lowering. On the basis of the recommendations by a recent American Heart Association scientific statement, we also provide guidance on when and how to implement these methods in clinical practice. The available evidence supports several approaches, including Transcendental Meditation, device-guided slow breathing, and aerobic, resistance, and isometric exercises. Nonetheless, many questions remain, and future recommendations for using alternative approaches will need to be updated as new trials are published.

Combined Dual-Task Gait Training and Aerobic Exercise to Improve Cognition, Mobility, and Vascular Health in Community-Dwelling Older Adults at Risk for Future Cognitive Decline1

This 6-month experimental case series study investigated the effects of a dual-task gait training and aerobic exercise intervention on cognition, mobility, and cardiovascular health in community-dwelling older adults without dementia. Participants exercised 40 min/day, 3 days/week for 26 weeks on a Biodex GaitTrainer2 treadmill. Participants were assessed at baseline (V0), interim (V1: 12-weeks), intervention endpoint (V2: 26-weeks), and study endpoint (V3: 52-weeks). The study outcomes included: cognition [executive function (EF), processing speed, verbal fluency, and memory]; mobility: usual & dual-task gait (speed, step length, and stride time variability); and vascular health: ambulatory blood pressure, carotid arterial compliance, and intima-media thickness (cIMT). Fifty-six participants [age: 70(6) years; 61% female] were included in this study. Significant improvements following the exercise program (V2) were observed in cognition: EF (p = 0.002), processing speed (p < 0.001), verbal fluency [digit symbol coding (p < 0.001), phonemic verbal fluency (p < 0.001)], and memory [immediate recall (p < 0.001) and delayed recall (p < 0.001)]; mobility: usual & dual-task gait speed (p = 0.002 and p < 0.001, respectively) and step length (p = 0.001 and p = 0.003, respectively); and vascular health: cIMT (p = 0.002). No changes were seen in the remaining outcomes. In conclusion, 26 weeks of dual-task gait training and aerobic exercise improved performance on a number of cognitive outcomes, while increasing usual & dual-task gait speed and step length in a sample of older adults without dementia.

Reductions in ambulatory blood pressure in young normotensive men and women after isometric resistance training and its relationship with cardiovascular reactivity.

Background There has been very little published work exploring the comparative effects of isometric resistance training (IRT) on blood pressure (BP) in men and women. Most of the previously published work has involved men and used resting BP as the primary outcome variable. Early evidence suggests that IRT is particularly effective in older women and has a positive influence on ambulatory BP, a better predictor of disease risk. Objectives With the WHO now placing global emphasis on the primary prevention of hypertension, the goals of this proof-of-concept study were to (i) examine whether sex differences exist in the ambulatory BP-lowering effects of IRT in young, normotensive men and women and (ii) determine whether these reductions can be predicted by simple laboratory stress tasks (a 2-min sustained isometric contraction and a math task involving subtracting a two-digit number from a series of numbers). Results There were no differences in the IRT-induced reductions in 24-h (men: &Dgr;4 mmHg, women: &Dgr;4 mmHg), daytime (men: &Dgr;3 mmHg, women: &Dgr;4 mmHg), or night-time (men: &Dgr;4 mmHg, women: &Dgr;3 mmHg) ambulatory BP in men (n=13) and women (n=11) (P<0.05) and these changes were not associated with systolic BP reactivity to either stress task (all P>0.05). Conclusion Our data suggest that lower ambulatory BP can be achieved, to a similar magnitude in young healthy women as well as men, with IRT; however, the BP-lowering effectiveness cannot be predicted by systolic BP reactivity. Taken together, this work heralds a potentially novel approach to the primary prevention of hypertension in both men and women and warrants further investigation in a larger clinical outcome trial.

Evidence for the emergence of leg sympathetic vasoconstrictor tone with age in healthy women.

While muscle sympathetic nerve activity (MSNA) is elevated with advancing age, correlational evidence suggests that, in contrast to men, basal MSNA is not related to resting lower limb hemodynamics in women. However, limited data exists in women that have attempted to directly assess the degree of limb sympathetic vasoconstrictor tone, and whether it is altered with age. To address this issue, we measured changes in femoral artery vascular conductance (FVC) during an acute sympatho‐inhibitory stimulus (−60 mm Hg neck suction, NS) in groups of healthy younger (n = 8, 23 ± 1 years) and older (n = 7, 66 ± 1 years) women. The percent change in FVC in response to NS was significantly augmented in the older (P = 0.006 vs. young) women. Although NS caused no significant change (3 ± 3%, P = 0.33) in FVC in the young women, there was a robust increase in FVC (21 ± 5%, P = 0.003) in the old women. Collectively, these findings provide evidence that in women, leg sympathetic vasoconstrictor tone emerges with age.