The associations of daily steps and body mass index with incident gastroesophageal reflux disease in older adults

Background

High body mass index (BMI) is a major risk factor of gastroesophageal reflux disease (GERD), a prevalent morbidity of older adulthood linked to lower quality of life and an increased risk of esophageal cancers. Daily stepping behavior, the most common physical activity of older adulthood, is associated with an array of favorable health outcomes, sometimes independent of high BMI. Whether stepping behavior is associated with the incidence of GERD independently or in combination with BMI is currently unclear.

Materials and methods

We followed 442 individuals (58.4% female) aged 65-91 years enrolled in the Physical Activity and Aging Study. Baseline steps were obtained by pedometer and categorized by tertiles (lower, middle, upper), while BMI was categorized into normal weight, overweight, and obesity. To explore joint associations, daily steps were dichotomized into "high steps" (middle/upper tertiles) and "low steps" (lower tertile), while BMI was dichotomized into normal weight and overweight/obesity. The joint exposure categories included "low steps and overweight/obesity," "low steps and normal weight," "high steps and overweight/obesity," and "high steps and normal weight."

Results

We identified 35 (7.9%) cases of GERD over a mean follow-up of 2.5 years. Compared to the lower tertile of steps, the hazard ratios (HRs) [95% confidence intervals (95% CIs)] of GERD were 0.44 (0.20-0.96) and 0.17 (0.05-0.54) for the middle and upper tertiles, respectively, after adjusting for confounders (including BMI). Compared to normal weight, the HRs (95% CIs) of GERD were 1.35 (0.54-3.37) and 3.00 (1.19-7.55) for overweight and obesity, respectively, after adjusting for confounders (including steps). In a joint analysis, compared to "low steps and overweight/obesity," the HRs (95% CIs) of GERD were 0.32 (0.10-1.00), 0.23 (0.10-0.54), and 0.20 (0.07-0.58) for "low steps and normal weight," "high steps and overweight/obesity," and "high steps and normal weight," respectively.

Conclusion

Higher daily steps were associated with a lower risk of GERD in older adults, independent of BMI. Since accumulating steps through walking is an achievable and acceptable modality of physical activity in older adulthood, future lifestyle interventions designed to achieve high daily steps counts may have favorable implications for the development of GERD in older adults of any BMI status.

Vascular Responses to Acute Induced Inflammation With Aging: Does Fitness Matter?

Acute inflammation impairs vascular function in an age-dependent manner and affects cardiovascular event risk. Regular aerobic exercise preserves vascular function with aging and potentially modifies how acute inflammation affects the vasculature. We hypothesize high cardiorespiratory fitness may accompany greater arterial responsiveness post-acute inflammation in older adults.

Physical Activity Intensity and Risk of Dementia

INTRODUCTION

Regular participation in aerobic physical activity is associated with a reduced risk of dementia. It is currently unclear whether this association is due to the total volume or intensity of physical activity.

METHODS

This prospective cohort study analyzed 386,486 adults from the UK Biobank who were free of dementia and self-reported >0 minutes of moderate-to-vigorous intensity physical activity (MVPA) at baseline (2007-2010). Participants were categorized as performing 0%, >0%-30%, or >30% of their total MVPA in vigorous activity (VPA). Cox proportional hazards regression models were used to examine the associations between categories of VPA and incident dementia while adjusting for sociodemographic and lifestyle factors including total MVPA. Analyses were performed in 2022.

RESULTS

Over an average follow-up of 12.0 (1.7) years, there were 5,177 (1.3%) cases of dementia. Compared to the group reporting 0% VPA, the hazard ratios (95% confidence intervals) of dementia for the groups reporting >0%-30% and >30% VPA were 0.73 (0.68-0.78) and 0.81 (0.75-0.87), respectively, in the fully adjusted model. In a joint analysis, reporting some VPA was associated with a reduced risk of dementia regardless of meeting the aerobic physical activity guidelines (HR=0.78 [0.72-0.85]) or not (HR=0.76 [0.60-0.98]), while meeting the aerobic physical activity guidelines alone without VPA was not associated with incident dementia (HR=0.98 [0.90-1.07]), compared to the group that did not meet the guidelines and reported no VPA.

CONCLUSIONS

These results suggest that engaging in VPA as part of MVPA is associated with a lower risk of dementia.

Older females but not males exhibit increases in cerebral blood velocity, despite similar pulsatility increases after high-intensity resistance exercise

Sex differences in resting cerebral hemodynamics decline with aging. Given that acute resistance exercise (RE) is a hypertensive challenge, it may reveal sex-dependent abnormalities in cerebral hemodynamics. Thus, we hypothesized that cerebral blood velocity and pulsatility responses to RE would be sex-dependent in older adults. Fourteen older females and 11 males (50-68 yr) completed a high-intensity unilateral isokinetic knee flexion/extension exercise. Measurements were collected at baseline, immediately, 5- and 30-min post-RE. Blood pressure was measured via finger photoplethysmography. Mean middle cerebral artery blood velocity (MCAv) and pulsatility were assessed via transcranial Doppler ultrasound. Carotid pulsatility was obtained via duplex ultrasound. MCAv increased immediately after RE in older females [mean difference (d) = 6.02, 95% CI: 1.66 to 10.39 cm/s, P < 0.001] but not in males (d = -0.72, 95% CI: -3.83 to 5.27 cm/s, P = 0.99), followed by similar reductions 5-min post-RE in older females (d = -4.40, 95% CI: -8.81 to -0.10 cm/s, P = 0.045) and males (d = -6.41, 95% CI: -11.19 to -1.62 cm/s, P = 0.003). MCAv pulsatility increased similarly in older females (d = 0.24, 95% CI: 0.11 to 0.40, P < 0.001) and males (d = 0.38, 95% CI: 0.20 to 0.53, P < 0.001), persisting 5-min post-RE. Older females showed smaller increases in carotid pulsatility immediately after RE (d = 0.18, 95% CI: 0.03 to 0.38, P = 0.01) than males (d = 0.48, 95% CI: 0.26 to 0.68, P < 0.001). An exercise-mediated hypertensive stimulus revealed differential sex responses in MCAv and carotid pulsatility but not in cerebral pulsatility. Cerebral pulsatility findings suggest a similar sex susceptibility to cerebrovascular abnormalities following exercise-mediated hypertensive stimulus in older adults.NEW & NOTEWORTHY Sex differences in resting cerebral hemodynamics decline with advancing age as females experience larger reductions in cerebral blood velocity and steeper pulsatility increases than males. However, an exercise-mediated hypertensive stimulus might reveal sex differences in cerebral hemodynamics not apparent at rest. Following high-intensity resistance exercise, older females but not males exhibit increases in cerebral blood velocity, despite similar increases in cerebral pulsatility. The susceptibility to cerebrovascular abnormalities following exercise-mediated hypertensive stimulus appears similar between sexes.

Increasing Lifestyle Walking by 3000 Steps per Day Reduces Blood Pressure in Sedentary Older Adults with Hypertension: Results from an e-Health Pilot Study

Increasing daily steps by an additional 3000 steps/day on 5 days/week equates to ~150 min/week of aerobic physical activity to meet the physical activity guidelines; however, its effectiveness for blood pressure control in older adults with hypertension is unknown. A 20-week, single-arm, pilot e-health lifestyle walking intervention was conducted in 21 sedentary older adults (73 ± 5 years old) with hypertension (13 female, 8 male) to investigate the effectiveness of increasing daily steps by an additional 3000 steps/day for blood pressure control. The intervention consisted of two phases, with behavior change assistance provided during the first active phase (weeks 1-10) to help reach step goals and minimal assistance provided during the second self-maintenance phase (weeks 11-20). Nineteen participants (91%) completed both the 10- and 20-week assessments. The participants wore the pedometer for ≥10 h on 97% of the days over 20 weeks. They significantly increased average steps/day from 3899 ± 2198 at baseline to 6512 ± 2633 at 10 weeks and 5567 ± 2587 at 20 weeks. After 20 weeks, both systolic (137 ± 10 to 130 ± 11 mm Hg, p < 0.001) and diastolic (81 ± 6 to 77 ± 6 mm Hg, p = 0.01) blood pressure improved. The response was consistent in participants with (n = 8) and without (n = 13) anti-hypertensive medication. The results of our lifestyle walking intervention are encouraging for reducing blood pressure in older adults with hypertension; however, larger randomized, controlled trials need to be performed to confirm these findings.

Comprehensive cardiopulmonary profile of individuals with Down syndrome

BACKGROUND

Individuals with Down syndrome (DS) have low levels of cardiorespiratory fitness and previous studies have shown that these low levels of fitness have a physiological cause. During exercise, the cardiovascular, ventilatory and muscular systems are simultaneously active. While individual parameters of these systems have been investigated in DS before, the interaction between these parameters and systems have not been discussed in detail. Doing so may provide important insight regarding the aetiology of low cardiorespiratory fitness and which parameters of the cardiovascular, pulmonary and muscular systems are altered in individuals with DS compared with their peers without DS.

METHODS

Cardiopulmonary exercise tests were performed in healthy adults with and without DS. Parameters related to the cardiovascular, ventilatory and muscular systems were collected until VO_2peak . In total, 51 participants were included in analysis, of which 21 had DS.

RESULTS

Individuals with DS showed lower peak values for all collected outcomes (P ≤ 0.001) compared with those without DS, except for ventilatory threshold as a percentage of maximal oxygen uptake and V_E /VCO₂ slope, which were similar.

CONCLUSIONS

Our results show that individuals with DS present impairments across the cardiovascular, ventilatory and muscular aspects of the cardiopulmonary system.

Associations between cardiorespiratory fitness and diverticulitis in older adults

Objectives

Examine the independent and joint associations of cardiorespiratory fitness (CRF) and body mass index (BMI) with the prevalence of diverticulitis in older adults.

Methods

476 older adults (61% Female; 71 ± 5 years) with no history of myocardial infarction, stroke, cancer, inflammatory bowel disease, or diabetes were included in this cross-sectional study. Diverticulitis cases were identified by self-reported physician diagnosis from the medical history questionnaire. Logistic regression was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of the prevalence of diverticulitis by tertiles of CRF and BMI category. CRF and BMI were further dichotomized into either “unfit” (the lowest one-third of CRF), “fit” (the upper two-thirds of CRF), “overweight/obese” (BMI ≥25.0 kg/m2), or “normal-weight” (BMI <25.0 kg/m2) to investigate the joint association of CRF and BMI with diverticulitis.

Results

Thirty-five (7.4%) participants were identified as having diverticulitis. Compared with the lowest CRF tertile, the ORs (95% CIs) of diverticulitis were 0.52 (0.22–1.22) and 0.33 (0.12–0.94) in the middle and upper CRF tertiles, respectively, after adjusting for potential confounders. After further adjustment for BMI, the association was no longer significant with ORs (95% CIs) of 0.55 (0.23–1.33) and 0.37 (0.12–1.10) in middle and upper CRF tertiles, respectively. Compared with the normal-weight group, the ORs (95% CIs) of diverticulitis were 2.86 (1.05–7.79) and 2.98 (0.95–9.35) in the overweight and obese groups, respectively, after adjusting for possible confounders and CRF. Compared with the “unfit and overweight/obese” group in the joint analysis, the OR (95% CI) of diverticulitis was 0.16 (0.04–0.61) in the “fit and normal-weight” group.

Conclusions

Older adults who maintain higher CRF and lower BMI may have significantly lower odds of diverticulitis, with the lowest odds found in the normal-weight and fit older adults.

Influence of sex and presence of cardiovascular risk factors on relations between cardiorespiratory fitness and cerebrovascular hemodynamics

Cerebral hemodynamics and pulsatility are important mechanisms of cerebrovascular and brain health. Cardiorespiratory fitness may improve cerebrovascular pulsatility in healthy females, but not in males. Whether cardiovascular disease (CVD) risk factors modify sex-specific associations of fitness with cerebral hemodynamics and vascular contributors to cerebral hemodynamics is unknown. We assessed V̇o_2peak and cerebrovascular hemodynamics in 157 adults without (42 ± 13 yr, BMI 24.5 ± 2.7 kg/m²), and 66 adults with modifiable CVD risk factors (54 ± 8 yr, BMI 29.9 ± 4.0 kg/m²). Intracranial [middle cerebral artery (MCA) pulsatility index (PI), mean velocity, conductance, and pulsatile damping] and extracranial hemodynamics [carotid artery wave transmission/reflection, PI, pulse wave velocity (PWV)-β, and carotid-femoral PWV] were assessed via transcranial Doppler/ultrasound and tonometry. Cardiorespiratory fitness was assessed via V̇o_2peak during an incremental exercise test. Multiple regression was used to assess contributions of V̇o_2peak to cerebrovascular outcomes after adjustment for relevant covariates. V̇o_2peak was inversely associated with MCA PI among females (β = −0.39, P = 0.01) but not males (β = −0.16, P = 0.25) without CVD risk factors. V̇o_2peak was positively associated with MCA PI among females (β = 0.44, P = 0.01) and not associated in males with CVD risk factors (β = −0.06, P = 0.079). V̇o_2peak was beneficially associated with vascular contributors to cerebral hemodynamics but had sex-specific associations with carotid stiffness and pulse pressure in females without CVD risk factors only. These results suggest that sex-specific associations between fitness and cerebral pulsatility among females without CVD risk factors may relate to the differential effects of fitness on carotid stiffness and pulse pressure. In addition, the presence of modifiable CVD risk factors may influence the protective relations of fitness on cerebrovascular hemodynamics.

NEW & NOTEWORTHY We identify beneficial associations between cardiorespiratory fitness and lower carotid stiffness and pulse pressure as potential mechanisms underlying sex-specific associations of fitness and cerebral pulsatility in females without modifiable risk factors. Greater fitness is beneficially associated with conductance, pulsatile damping, and forward wave energy among adults without risk factors; however, associations are attenuated among adults with modifiable risk factors. These data suggest sex and risk factors may alter cerebrovascular sensitivity to cardiorespiratory fitness.

The effect of aging on carotid artery wall mechanics during maximal resistance exercise

INTRODUCTION

Age-related stiffening of the large elastic arteries (e.g., common carotid artery [CCA]) may impair wall dynamics (i.e., strain) and amplify transmission of pulsatile blood flow into the brain with large increases in pressure that occur during maximal resistance exercise (RE). The purpose of this study was to compare CCA arterial wall dynamics, central hemodynamics, and cerebral blood velocity responses during maximal RE between young and older adults.

METHODS

Thirty-one young (YA; 26 ± 5 yrs; 23.8 ± 3.3 kg/m²) and 25 older adults (OA; 60 ± 6 yrs; 30.0 ± 5.5 kg/m²) performed a unilateral maximal isokinetic knee flexion/extension exercise protocol (i.e., maximal RE). All measures were recorded at baseline and during the last 10 s of maximal RE. Common carotid artery strain, CCA strain time to peak, and CCA strain rate (i.e., variables of arterial wall dynamics) were analyzed using 2D speckle tracking software from circumferential ultrasound images. Transcranial Doppler was used to measure right middle cerebral artery (MCA) blood velocity. Non-invasive arterial blood pressure measurements were obtained using finger photoplethysmography.

RESULTS

Older adults had greater reductions in CCA strain time to peak from baseline to maximal RE (345 ± 39 to 242 ± 52 ms) than YA (308 ± 35 to 247 ± 42 ms; interaction effect, p < 0.01). MCA velocity was similar between YA and OA during maximal RE (p = 0.48), despite a greater arterial pressor response in OA (p < 0.01).

CONCLUSION

These data suggest cerebral blood velocity responds similarly during maximal RE among OA compared to YA, despite subtle age-related differences in the pressor and extracranial vascular response during maximal RE.

Breast cancer survivors with preserved or rescued cardiorespiratory fitness have similar cardiac, pulmonary and muscle function compared to controls

Breast cancer survivors (BCS) have a high prevalence of cardiovascular disease and low cardiorespiratory fitness (CRF). CRF is an important predictor of survival in BCS. However, the physiological factors that contribute to low CRF in BCS have not been completely elucidated. To assess differences in physiological factors (cardiac, pulmonary, muscle function) related to CRF between BCS and controls. Twenty-three BCS and 23 age-body mass index (BMI) matched controls underwent a peak cycling exercise test to determine CRF, with physiological factors measured at resting and at peak exercise. Cardiac hemodynamics (stroke volume [SV], SVindex, heart rate [HR], cardiac output [Formula: see text], and [Formula: see text]index) were evaluated using ultrasonography. Pulmonary function was evaluated using the oxygen uptake efficiency slope (OUES), ventilation to carbon dioxide production slope [Formula: see text] and breathing reserve at peak exercise (BR). Muscle oxygenation variables (oxygenated [HbO₂] deoxygenated [HHb] and total hemoglobin [Hb], and tissue oxygenation index [TSI]) were measured with near-infrared spectroscopy (NIRS). Both groups had similar CRF and similarly increased all hemodynamic variables (HR, SV, SVindex, [Formula: see text] and [Formula: see text]index) at peak exercise compared to resting (p < 0.001). BCS had higher overall HR and lower SVindex (group effect, p < 0.05). BCS had similar OUES, [Formula: see text] and BR compared to the controls. Both groups decreased TSI, and increased Hb and HHb similarly at peak exercise compared to resting (p < 0.001). Our data suggest BCS do not exhibit differences in cardiac, pulmonary, or muscle function at peak exercise compared to controls, when both groups have similar CRF and physical activity.

Effect of the COVID-19 Pandemic on Physical Activity and Sedentary Behavior in Older Adults

Whether the COVID-19 pandemic has long-lasting effects on physical activity (PA) and sedentary behavior in the vulnerable older adult population is uncertain. A total of 387 older adults (75 ± 6 years) completed a retrospective questionnaire on time spent sitting, walking, and performing aerobic and muscle-strengthening PA before, during the first three months, and one year into the COVID-19 pandemic. Whether the participants met the aerobic and muscle-strengthening PA guidelines was then determined. Of the 387 older adults, 376 (97%) were vaccinated. The participants completed 361 ± 426, 293 ± 400, and 454 ± 501 min/week of moderate-to-vigorous aerobic PA before, during the first three months, and one year into the pandemic, respectively. During the same time periods, the participants performed muscle-strengthening PA 87 ± 157, 68 ± 163, and 90 ± 176 min/week, walked 2.4 ± 1.7, 2.3 ± 1.7, and 2.6 ± 1.9 h/day, and sat 6.2 ± 2.9, 7.4 ± 3.1, and 6.1 ± 2.9 h/day, respectively. Aerobic PA, muscle-strengthening PA, and walking time decreased, whereas sitting time increased, during the first three months of the pandemic (p < 0.05), and then returned to pre-pandemic levels after one year (p < 0.05). The percentage of participants meeting both aerobic and muscle-strengthening PA guidelines decreased during the first three months of the pandemic (48.9% to 33.5%, p < 0.001), but returned to pre-pandemic levels one year later (p < 0.001). In conclusion, the COVID-19 pandemic significantly decreased PA and increased sitting time in older adults; however, both PA and sitting time returned to pre-pandemic levels after one year.

Reactive hyperemia augments local heat-induced skin hyperemia

NEW FINDINGS

What is the central question of this study? It is valuable to be able to monitor disease or treatment related changes in the microcirculation. Laser doppler flowmetry with local heating allows noninvasive monitoring of the skin microcirculation and its ability to vasodilate. Does reactive hyperemia augment the increase in skin blood flow elicited by local heating? What is the main finding and its importance? The results of this study show that the addition of reactive hyperemia to local heating results in greater vasodilation than heating alone. Thus, reactive hyperemia can augment local heat-induced hyperemia in the skin.

ABSTRACT

The skin circulation has been proposed as a model of generalized microvascular function which could be monitored noninvasively using laser doppler flowmetry (LDF). The response to heat hyperemia (HH) is commonly used to monitor disease or treatment related changes in microvascular function. We hypothesized that reactive hyperemia would augment the increase in skin blood flow elicited by local heating. Fourteen healthy young adults were subjected to 3 different conditions: reactive hyperemia (RH; skin temperature controlled at 33°C), heat hyperemia (HH; 42°C held for 40 minutes), and HH+RH. Two Peltier-controlled thermomodules with laser LDF probes were placed on the right forearm to continuously monitor skin blood flow. A cuff was placed on the right upper arm to elicit RH by inflation to 220 mmHg for 5 minutes. This procedure was performed with skin temperature at 33°C and again after 40 min of local heating to 42°C. Beat-by-beat mean arterial pressure (MAP) obtained by a photoplethysmographic sensor on the middle finger of the left hand allowed calculation of cutaneous vascular conductance (CVC) as LDF / MAP. Both HH and RH increased LDF (p<0.0001 and p <0.0001, respectively) and CVC (p = 0.0001 and p<0.0001) above baseline values. LDF and CVC values were significantly higher during HH+RH when compared to RH or HH alone (p<0.0001). In summary, HH+RH resulted in greater vasodilation when compared to HH or RH alone. These results indicate that RH can augment local heat-induced hyperemia in the skin. This article is protected by copyright. All rights reserved.

Effect of live-fire training on ventricular-vascular coupling

INTRODUCTION

Cardiovascular events are a leading cause of firefighter duty-related death, with the greatest risk occurring during or shortly after fire suppression activity. Increased cardiovascular risk potentially manifests from detrimental changes in ventricular function, vascular load, and their interaction, described as ventricular-vascular coupling.

PURPOSE

To determine the effect of live-fire training on ventricular-vascular coupling.

METHODS

Sixty-eight male (28 [Formula: see text] 7 years, 26.9 [Formula: see text] 3.9 kg/m²) and fifteen female (36 [Formula: see text] 8 years, 24.3 [Formula: see text] 3.9 kg/m²) firefighters completed hemodynamic and cardiac measures before and after 3 h of intermittent live-fire training. Left ventricular function was assessed as ejection fraction (EF) and ventricular elastance (E_LV: end systolic pressure [ESP]/end systolic volume) via echocardiography and applanation tonometry-estimated ESP. Vascular load was assessed as arterial elastance (E_A: ESP/stroke volume [SV]). Ventricular-vascular coupling (VVC) was quantified as the ratio of E_A to E_LV and indexed to body surface area (E_AI, E_LVI).

RESULTS

Following firefighting EF decreased (p < 0.01) with no change in E_LVI (p = 0.34). SV decreased (p < 0.01) with no change in ESP (p = 0.09), driving a significant increase in E_AI (p < 0.01). These changes resulted in a significant increase in the VVC ratio (p < 0.01).

CONCLUSION

The findings suggest that firefighting does not alter ventricular elastance but increases arterial elastance in healthy firefighters, resulting in a mismatch between ventricular and vascular systems. This increase in ventricular-vascular coupling ratio and concomitant reduction in ventricular systolic function may contribute to increased cardiovascular risk following live firefighting.

Oral vitamin C restores endothelial function during acute inflammation in young and older adults

Oxidative stress has been linked to reductions in vascular function during acute inflammation in young adults; however, the effect of acute inflammation on vascular function with aging is inconclusive. The aim of this study was to determine if oral antioxidant administration eliminates vascular dysfunction during acute inflammation in young and older adults. Brachial flow-mediated dilation (FMD) and carotid-femoral pulse wave velocity (PWV) were measured in nine young (3 male, 24 ± 4 yrs, 26.2 ± 4.9 kg/m2 ) and 16 older (13 male, 64 ± 5 yrs, 25.8 ± 3.2 kg/m2 ) adults before and 2-h after oral consumption of 2 g of vitamin C. The vitamin C protocol was completed at rest and 24 h after acute inflammation was induced via the typhoid vaccine. Venous blood samples were taken to measure markers of inflammation and vitamin C. Both interleukin-6 (Δ+0.7 ± 1.8 pg/ml) and C-reactive protein (Δ+1.9 ± 3.1 mg/L) were increased at 24 h following the vaccine (p < 0.01). There was no change in FMD or PWV following vitamin C administration at rest (p > 0.05). FMD was lower in all groups during acute inflammation (Δ-1.4 ± 1.9%, p < 0.01), with no changes in PWV (Δ-0.0 ± 0.9 m/s, p > 0.05). Vitamin C restored FMD back to initial values in young and older adults during acute inflammation (Δ+1.0 ± 1.8%, p < 0.01) with no change in inflammatory markers or PWV (p > 0.05). In conclusion, oral vitamin C restored endothelial function during acute inflammation in young and older adults, with no effect on aortic stiffness. The effect of vitamin C on endothelial function did not appear to be due to reductions in inflammatory markers. The exact mechanisms should be further investigated.

Association Between Relative Quadriceps Strength and Type 2 Diabetes Mellitus in Older Adults: The Yangpyeong Cohort of the Korean Genome and Epidemiology Study

BACKGROUND

To examine the independent and combined association between relative quadriceps strength and the prevalence of type 2 diabetes mellitus (T2DM) in older adults.

METHODS

Among 1441 Korean older adults aged ≥65 years (71 [4.7] y) recruited between 2007 and 2016, 1055 older adults with no history of myocardial infarction, stroke, or cancer were included in the analysis. Cases of T2DM were identified by self-reported physician diagnosis, use antihyperglycemic medication or insulin, or fasting blood glucose ≥126 mg/dL. Logistic regression was used to calculate the odds ratios and 95% confidence intervals of T2DM by quartiles of relative quadriceps strength.

RESULTS

There were 162 T2DM cases (15%). Compared with the lowest quartile (weakest), the odds ratios (95% confidence intervals) of T2DM were 0.56 (0.34-0.90), 0.60 (0.37-0.96), and 0.47 (0.28-0.80) in the second, third, and fourth quartiles, respectively, after adjusting for possible confounders, including body mass index. In the joint analysis, compared with the "weak and overweight/obese" group, the odds (odds ratios [95% confidence intervals]) of T2DM was only lower in the "strong and normal weight" group (0.36 [0.22-0.60]) after adjusting for possible confounders.

CONCLUSIONS

Greater relative quadriceps strength is associated with reduced odds of T2DM in older adults after adjusting for potential confounders including body mass index.

Associations between relative grip strength and type 2 diabetes mellitus: The Yangpyeong cohort of the Korean genome and epidemiology study

Objective

To investigate the association between relative grip strength and the prevalence of type 2 diabetes mellitus (T2DM) independently and in combination with body mass index (BMI) in Korean adults.

Methods

The cross-sectional study includes 2,811 men and women (age 40 to 92 years old) with no history of heart disease, stroke, or cancer. Relative grip strength was measured by a handheld dynamometer and calculated by dividing absolute grip strength by body weight. Logistic regression analysis was used to calculate the odds ratios (ORs) and 95% confidence intervals (CIs) of T2DM by sex-specific quintiles of relative grip strength. In a joint analysis, participants were classified into 4 groups: “weak (lowest 20% quintile one) and normal weight (BMI <25.0 kg/m²)”, “weak and overweight/obese (BMI ≥25.0 kg/m²)”, “strong (upper 80% four quintiles) and normal weight” or “strong and overweight/obese”.

Results

Among the 2,811 participants, 371 were identified as having T2DM. Compared with the lowest quintile of relative grip strength (weakest), the ORs (95% CIs) of T2DM were 0.73 (0.53–1.02), 0.68 (0.48–0.97), 0.72 (0.50–1.03), and 0.48 (0.32–0.74) in upper quintiles two, three, four, and five, respectively, after adjusting for BMI and other potential confounders. In the joint analysis, compared with the “weak and overweight/obese” reference group, the odds of T2DM [ORs (95% CIs)] was lower in the “strong and overweight/obese” group [0.65 (0.46–0.92)] and the “strong and normal weight” group [0.49 (0.35–0.67)], after adjusting for potential confounders.

Conclusion

In this cross-sectional study, greater relative grip strength was associated with a lower prevalence of T2DM independent of BMI in Korean adults. Additional prospective studies are needed to determine whether a causal association exists between relative grip strength and T2DM prevalence considering BMI.

Resting Heart Rate and Risk of Cancer Mortality

BACKGROUND

Increased resting heart rate (RHR) is a predictor of mortality. RHR is influenced by cardiorespiratory fitness (CRF). Little is known about the combined associations of RHR and CRF on cancer mortality.

METHODS

50,108 men and women (mean age 43.8 years) were examined between 1974 and 2002 at the Cooper Clinic in Dallas, Texas. RHR was measured by electrocardiogram and categorized as <60, 60-69, 70-79, or ≥80 beats/minute. CRF was quantified by maximal treadmill test and dichotomized as unfit and fit corresponding to the lower 20% and the upper 80%, respectively, of the age- and sex-specific distribution of treadmill exercise duration. The National Death Index was used to ascertain vital status. Cox regression was used to compute HRs and 95% confidence intervals (CI) for cancer mortality across RHR categories.

RESULTS

During a mean follow-up of 15.0 ± 8.6 years, 1,090 cancer deaths occurred. Compared with RHR <60 beats/minute, individuals with RHR ≥80 beats/minute had a 35% increased risk of overall cancer mortality (HR, 1.35; 95% CI, 1.06-1.71) after adjusting for confounders, including CRF. Compared with "fit and RHR <80 beats/minute", HRs (95% CI) for cancer mortality were 1.41 (1.20-1.66), 1.51 (1.11-2.04), and 1.78 (1.30-2.43) in "unfit and RHR <80," "fit and RHR ≥80," and "unfit and RHR ≥80 beats/minute," respectively.

CONCLUSIONS

RHR ≥80 beats/minute is associated with an increased risk of overall cancer mortality. High CRF may help lower the risk of cancer mortality among those with high RHR.

IMPACT

RHR along with CRF may provide informative data about an individual's cancer mortality risk.

Firefighter hemodynamic responses to different fire training environments

Firefighting is associated with an increased risk for a cardiovascular (CV) event, likely due to increased CV strain. The increase in CV strain during firefighting can be attributed to the interaction of several factors such as the strenuous physical demand, sympathetic nervous system activation, increased thermal burden, and the environmental exposure to smoke pollutants. Characterizing the impact of varying thermal burden and pollutant exposure on hemodynamics may help understand the CV burden experienced during firefighting. The purpose of this study was to examine the hemodynamic response of firefighters to training environments created by pallets and straw; oriented strand board (OSB); or simulated fire/smoke (fog). Twenty-three firefighters had brachial blood pressure measured and central blood pressure and hemodynamics estimated from the pressure waveform at baseline, and immediately and 30 minutes after each scenario. The training environment did not influence the hemodynamic response over time (interaction, p > 0.05); however, OSB scenarios resulted in higher pulse wave velocity and blood pressure (environment, p < 0.05). In conclusion, conducting OSB training scenarios appears to create the largest arterial burden in firefighters compared to other scenarios in this study. Environmental thermal burden in combination with the strenuous exercise, and psychological and environmental stress placed on firefighters should be considered when designing fire training scenarios and evaluating CV risk.

Impact of acute changes in blood pressure and arterial stiffness on cerebral pulsatile haemodynamics in young and middle-aged adults

NEW FINDINGS

What is the central question of this study? Does cerebrovascular pulsatility respond differently to acute increases in arterial stiffness in middle-aged compared with young adults? What is the main finding and its importance? Compared with young adults, middle-aged adults exhibited similar changes in cerebral pulsatile damping despite attenuated changes in carotid diameter and cerebrovascular pulsatility during blood pressure-dependent, but not blood pressure-independent, increases in large artery stiffness.

ABSTRACT

Acute manipulation of arterial stiffness through interventions that increase sympathetic activity might provoke cerebral pulsatility and damping and reveal whether cerebrovascular haemodynamics respond differently to transient elevations in arterial stiffness in middle-aged compared with young adults. We compared cerebral pulsatility and damping in middle-aged versus young adults during two different sympathetic interventions [cold pressor test (CP) and lower-body negative pressure (LBNP)] that increase arterial stiffness acutely. Cerebrovascular haemodynamics were assessed in 15 middle-aged (54 ± 7 years old; 11 female) and 15 sex-matched young adults (25 ± 4 years old) at rest and during the CP test (4 min, 6.4 ± 0.8°C) and LBNP (6 min, -20 mmHg). Mean blood pressure was measured continuously via finger photoplethysmography. Carotid-femoral pulse wave velocity (cfPWV) and carotid stiffness were measured via tonometry and ultrasound. Blood velocity pulsatility index (PI) was measured at the middle cerebral (MCA) and common carotid artery (CCA) using Doppler, with pulsatile damping calculated as CCA PI divided by MCA PI. Increases in cfPWV were driven by changes in mean pressure during CP but not during LBNP in both groups (P < 0.05). Pulsatile damping decreased in both groups (P < 0.05) despite reductions in MCA PI and greater carotid dilatation during CP in young compared with middle-aged adults (P < 0.05). Pressure-independent increases in cfPWV during LBNP did not alter pulsatile damping but decreased MCA PI in both young and middle-aged adults (P < 0.05). These data suggest that changes in carotid diameter and cerebrovascular pulsatility differ between young and middle-aged adults despite similar changes in cerebral pulsatile damping during blood pressure-dependent, but not blood pressure-independent, increases in large artery stiffness.

Central and Peripheral Postexercise Blood Pressure and Vascular Responses in Young Adults with Obesity

INTRODUCTION

Adults with obesity are at an increased risk of incident hypertension. Regular aerobic exercise is recommended for the prevention and treatment of hypertension, but whether young adults with obesity exhibit impaired postexercise blood pressure (BP) and vascular responses remains unclear.

PURPOSE

We tested the hypothesis that young adults with obesity exhibit attenuated postexercise hypotension (PEH) and postexercise peripheral vasodilation compared with young adults without obesity.

METHODS

Thirty-six normotensive adults without and with obesity (11 men and 7 women per group) underwent measurements of brachial and central BP, and leg blood flow (Doppler ultrasound) at baseline and at 30, 60, and 90 min after acute 1-h moderate-intensity cycling. Leg vascular conductance (LVC) was calculated as flow/mean arterial pressure.

RESULTS

Both groups exhibited similar brachial and central PEH (peak change from baseline, -2 and -4 mm Hg for brachial and central systolic BPs, respectively, for both groups; time effect, P < 0.05). Both groups also exhibited postexercise peripheral vasodilation, assessed via LVC (time effect, P < 0.05), but its overall magnitude was smaller in young adults with obesity (LVC change from baseline, +47% ± 37%, +29% ± 36%, and +20% ± 29%) compared with young adults without obesity (LVC change from baseline, +88% ± 58%, +59% ± 54%, and +42% ± 51%; group effect, P < 0.05).

CONCLUSIONS

Although obesity did not impair PEH after acute moderate-intensity exercise, young adults with obesity exhibited smaller postexercise peripheral vasodilation compared with young adults without obesity. Collectively, these findings have identified evidence for obesity-induced alterations in the peripheral vasculature after exercise.

Blunted autonomic response to standing up and head-up tilt in individuals with intellectual disabilities

Previous research suggests individuals with intellectual disabilities (ID) may experience autonomic dysfunction, however, this has not been thoroughly investigated. The aim of this study was to compare the autonomic response to standing up (active orthostasis) and head-up tilt (passive orthostasis) in individuals with ID to a control group without ID. Eighteen individuals with and 18 individuals without ID were instrumented with an ECG-lead and finger-photoplethysmography for continuous heart rate and blood pressure recordings. The active and passive orthostasis protocol consisted of 10-min supine rest, 10-min standing, 10-min supine recovery, 5-min head-up tilt at 70°, followed by 10-min supine recovery. The last 5 min of each position was used to calculate hemodynamic and autonomic function (time- and frequency-domain heart rate and blood pressure variability measures and baroreflex sensitivity). Individuals with ID had higher heart rate during baseline and recovery (P < 0.05), and an attenuated hemodynamic (stroke volume, heart rate) and heart rate variability response to active and passive orthostasis (interaction effect P < 0.05) compared with individuals without ID. Mean arterial pressure (MAP) was higher in individuals with ID at all timepoints. Individuals with ID demonstrated altered hemodynamic and autonomic regulation compared with a sex- and age-matched control group, evidenced by a higher mean arterial pressure and a reduced response in parasympathetic modulation to active and passive orthostasis.NEW & NOTEWORTHY Individuals with ID demonstrated altered hemodynamic and autonomic regulation to the clinical autonomic function tasks standing up and head-up tilt (active and passive orthostasis). Higher resting heart rate and higher MAP throughout the protocol suggest a higher arousal level, and individuals with ID showed a blunted response in parasympathetic modulation. Further research should investigate the relationship of these findings with clinical outcomes.

Anthropometry does not fully explain low fitness among adults with Down syndrome

BACKGROUND

Cardiorespiratory fitness, expressed as peak oxygen uptake during exercise (VO₂ peak), is an important predictor of cardiovascular health and is related to anthropometry in the general population. Individuals with Down syndrome (DS) have reduced cardiorespiratory fitness and often exhibit different anthropometrics compared with the general population. Interestingly, the relation between anthropometry and cardiorespiratory fitness found in the general population is not apparent in individuals with DS. However, accurate measures with dual energy X-ray absorptiometry (DEXA) scan have not been used to investigate this relationship in this population. The purpose of this paper was to investigate the relationship between accurate measures of anthropometry and cardiorespiratory fitness in adults with DS compared with an age-matched and sex-matched control group.

METHODS

Anthropometrics (height, weight, waist and hip circumference, body composition via DEXA) and cardiorespiratory fitness (VO₂ peak, measured during a graded maximal exercise test) were assessed in adults with (n = 9; 25 ± 3 years; 6 male patients) and without DS (n = 10, 24 ± 4 years; 5 male patients).

RESULTS

Participants with DS were shorter (P < 0.01) than without DS and had a higher body mass index (P < 0.01), waist circumference (WC) (P = 0.026) and waist/height ratio (WHtR) (P < 0.01), but similar weight, body surface area (BSA), waist/hip ratio and body composition (P > 0.05). Participants with DS had significantly lower relative VO₂ peak and VO₂ peak corrected for total lean mass (TLM), but similar absolute VO₂ peak, compared with without DS. In participants with DS, only WC and WHtR were associated with VO₂ peak, whereas in participants without DS, height, weight, BSA, TLM, leg lean mass and body fat percentage were associated with VO₂ peak.

CONCLUSIONS

These results suggest that the relation between anthropometry and cardiorespiratory fitness found in the general population is not the same in adults with DS and that anthropometrics do not fully explain cardiorespiratory fitness in adults with DS. Further research into potential alternative explanations is required.

Associations of total and aerobic steps with the prevalence and incidence of frailty in older adults with hypertension

PURPOSE

To examine the associations of total steps/day and faster aerobic steps/day (≥60 steps/min) with the development of frailty in older adults with hypertension (HTN) using a two-phased cross-sectional and prospective approach.

METHODS

The sample consisted of 427 older adults with HTN from the Physical Activity and Aging Study (PAAS), aged ≥65 years, with valid step data from an accelerometer-based pedometer. Participants were classified into tertiles of total steps/day (low, mid, high) and three categories of aerobic steps/day (none, low, high). Frailty was defined using a modified Fried score with 5 subdomains including shrinking, weakness, slowness, low physical activity (PA), and exhaustion.

RESULTS

We observed a negative dose-response relationship across categories of total steps/day and aerobic steps/day for the prevalence of frailty and the subdomains of slowness, low PA, and exhaustion (all p for trends <0.05). Greater aerobic steps/day, but not total steps/day, was associated with lower incidence of developing frailty in the 241 participants with a follow-up examination who had no frailty at baseline.

CONCLUSION

Higher aerobic steps/day were more strongly associated with the lower prevalence and incidence of frailty compared to total steps/day, suggesting that faster aerobic walking may potentially provide greater benefits regarding frailty in older adults with HTN.