Vigorous exercise, fitness and incident hypertension, high cholesterol, and diabetes

Exercise systolic blood pressure response during cycle ergometry is associated with future hypertension in normotensive individuals

AIMS

We aimed to investigate the association between the exercise systolic blood pressure (SBP) response and future hypertension (HTN) in normotensive individuals referred for cycle ergometry, with special regard to reference exercise SBP values and exercise capacity.

METHODS AND RESULTS

In this longitudinal cohort study, data from 14 428 exercise tests were cross-linked with Swedish national registries on diagnoses and medications. We excluded individuals with a baseline diagnosis of cardiovascular disease or HTN. The peak exercise SBP (SBPpeak) was recorded and compared with the upper limit of normal (ULN) derived from SBPpeak reference equations incorporating age, sex, resting SBP, and exercise capacity. To evaluate the impact of exercise capacity, three SBP to work rate slopes (SBP/W-slopes) were calculated, relative to either supine or seated SBP at rest or to the first exercise SBP. Adjusted hazard ratios [HRadjusted (95% confidence interval, CI)] for incident HTN during follow-up, in relation to SBP response metrics, were calculated. We included 3895 normotensive individuals (49 ± 14 years, 45% females) with maximal cycle ergometer tests. During follow-up (median 7.5 years), 22% developed HTN. Higher SBPpeak and SBPpeak > ULN were associated with incident HTN [HRadjusted 1.19 (1.14-1.23) per 10 mmHg, and 1.95 (1.54-2.47), respectively]. All three SBP/W-slopes were positively associated with incident HTN, particularly the SBP/W-slope calculated as supine-to-peak SBP [HRadjusted 1.25 (1.19-1.31) per 1 mmHg/10 W].

CONCLUSION

Both SBPpeak > ULN based on reference values and high SBP/W-slopes were associated with incident HTN in normotensive individuals and should be considered in the evaluation of the cycle ergometry SBP response.

Exploring the role of blood pressure in the black-white disparity in cardiovascular disease mortality: a causal mediation analysis

BACKGROUND

Cardiovascular diseases (CVDs) are the leading cause of death in the USA, and high blood pressure is a major risk factor for CVD. Despite the overall declining rates of CVD mortality in the USA in recent years, marked disparities between racial and ethnic groups persist, with black adults having a higher mortality rate than white adults. We investigated the extent to which blood pressure mediated the black-white disparity in CVD mortality.

METHODS

Data came from the Multi-Ethnic Study of Atherosclerosis, a diverse longitudinal cohort. We included 1325 black and 2256 white community-based adults aged 45-80 years free of clinical CVD at baseline and followed for 14 years. We used causal mediation analysis to estimate the effect of race on CVD mortality that was mediated through blood pressure.

RESULTS

Black participants had a higher hazard of dying from CVD compared with white participants (adjusted hazard ratio (HR): 1.28 (95% CI 0.88, 1.88)), though estimates were imprecise. Systolic blood pressure mediated 27% (HR: 1.02, 95% CI 1.00, 1.06) and diastolic blood pressure mediated 55% (HR: 1.07, 95% CI 1.01, 1.10) of the racial disparities in CVD mortality between white and black participants. Mediation effects were present in men but not in women.

CONCLUSIONS

We found that black-white differences in blood pressure partially explain the observed black-white disparity in CVD mortality, particularly among men. Our findings suggest that public health interventions targeting high blood pressure prevention and management could be important strategies for reducing racial disparities in CVD mortality.

Lipoproteins and Their Effects on the Cardiovascular System

Coronary heart disease is the foremost leading cause of death across the world. It mainly involves the blood vessels, which supply the heart. Plaque formation due to lipid deposition leads to the narrowing of the vessels, obstructing blood flow. Therefore, lipoproteins such as high-density lipoproteins (HDL), low-density lipoproteins (LDL), very low-density lipoproteins (VLDL), and chylomicrons play a crucial role in cardiovascular diseases. Lipoproteins are carrier molecules made up of proteins and fats. They carry cholesterol through the bloodstream and transport it to the peripheral tissues or the liver. There are several classes of lipoproteins in the blood, namely HDL, LDL, VLDL, and chylomicrons. Depending on the lipoproteins, an excess of them can either harm or benefit the body. Low-density lipoprotein, nicknamed 'the bad cholesterol,' transports fatty molecules from the liver and deposits them in peripheral tissues or central vessels. Thus, excess LDL can cause blockage of the arteries supplying major organs. High-density lipoprotein, nicknamed 'the good cholesterol,' transports the excess fatty molecules to the liver for their metabolism and removal from the body. Hence, high levels of HDL are an indication of a healthy body. Thus, lipoproteins are important molecules, and their proper regulation is essential to maintaining a healthy body. An effective way to maintain a balanced lipoprotein level is to have a properly balanced diet with high protein and low fat. Regular exercise, both indoors and outdoors, is recommended. If cholesterol levels are not maintained by diet and exercise, medication is advised after consulting medical experts. This review aims to inform people about lipoproteins, their importance, and maintaining a healthy lipoprotein level.

Prognostic value of exercise capacity in incident diabetes: a country with high prevalence of diabetes

BACKGROUND

Diabetes Mellitus (DM) is a fast-growing health problem that imposes an enormous economic burden. Several studies demonstrated the association between physical inactivity and predicting the incidence of diabetes. However, these prediction models have limited validation locally. Therefore, we aim to explore the predictive value of exercise capacity in the incidence of diabetes within a high diabetes prevalence population.

METHODOLOGY

A retrospective cohort study including consecutive patients free of diabetes who underwent clinically indicated treadmill stress testing. Diabetic patients at baseline or patients younger than 18 years of age were excluded. Incident diabetes was defined as an established clinical diagnosis post-exercise testing date. The predictive value of exercise capacity was examined using Harrell's c-index, net reclassification index (NRI), and integrated discrimination index (IDI).

RESULTS

A total of 8,722 participants (mean age 46 ± 12 years, 66.3% were men) were free of diabetes at baseline. Over a median follow-up period of 5.24 (2.17-8.78) years, there were 2,280 (≈ 26%) new cases of diabetes. In a multivariate model adjusted for conventional risk factors, we found a 12% reduction in the risk of incident diabetes for each METs achieved (HR, 0.9; 95% CI, 0.88-0.92; P < 0.001). Using Cox regression, exercise capacity improved the prediction ability beyond the conventional risk factors (AUC = 0.62 to 0.66 and c-index = 0.62 to 0.68).

CONCLUSION

Exercise capacity improved the overall predictability of diabetes. Patients with reduced exercise capacity are at high risk for developing incidence diabetes. Improvement of both physical activity and functional capacity represents a preventive measure for the general population.

Cardiorespiratory Fitness and the Risk of All-Cause, Cardiovascular and Cancer Mortality in Men with Hypercholesterolemia

Background: Whether higher cardiorespiratory fitness (CRF) confers protection against cardiovascular disease (CVD) in individuals with manifest hypercholesterolemia is poorly understood. Methods: Participants were 8920 men aged 20−82 years with hypercholesterolemia but no history of CVD and/or cancer and who received a preventive examination at the Cooper Clinic in Dallas, TX, USA, during 1974−2001. CRF was quantified as maximal treadmill test duration and was grouped for analysis as low, moderate, or high based on the traditional Aerobics Center Longitudinal Study cutpoints. Using Cox regression analyses, we computed hazard ratios and 95% confidence intervals for risk of mortality based on CRF. Results: During an average of 17 years of follow-up, 329 CVD and 290 cancer deaths occurred. After control for baseline age, examination year, body mass index, total cholesterol, smoking, alcohol intake, physical activity, hypertension, diabetes, and parental history of CVD, hazard ratios (95% confidence interval) for CVD deaths across moderate and high categories of CRF (with low fit as referent) were: 0.66 (0.50−0.87) and 0.55 (0.39−0.79), respectively. There was an inverse association between CRF and CVD death among normal-weight (trend p < 0.0001), younger (<60 y, trend p = 0.01), and inactive men (trend p = 0.002). However, no significant association was found between CRF and cancer mortality. Conclusions: Among men with hypercholesterolemia, higher CRF was associated with a lower risk of dying from CVD independent of other clinical risk factors. Our findings underscored the importance of promoting CRF in the primary prevention of CVD in patients with hypercholesterolemia.

Adherence and Health-Related Outcomes of Beginner Running Programs: A 10-Week Observational Study

Purpose: This study aimed to explore the determinants of adherence and assess changes in fitness and health outcomes in participants of group-based beginner running programs. Methods: Participants completed adherence diaries (n = 34) during the 10-week program, and underwent fitness and health testing (n = 20) at the program start and end. Diaries included weekly visual analogue scales of enjoyment, motivation, confidence, fatigue, satisfaction, and support along with a record of training sessions. Space was provided for free-text comments. Fitness was assessed by the multi-stage 20-m shuttle run test, and measurements were taken of resting heart rate, blood pressure, body composition, and free-living physical activity. Results: Overall adherence to the 10-week program was 53 ± 27% with injury the most common reason for missing sessions and for discontinuing training. Adherence to group sessions was positively correlated with enjoyment, motivation, confidence, satisfaction with progress, and social support. Qualitative analysis of diary entries indicated three distinct themes (self-awareness, social support, personal challenge) underlying progression through the program. Significant changes were observed after 10 weeks in distance run on the fitness test (+189 ± 133 m), body mass index (-0.54 ± 0.72 kg/m²), and percentage body fat (-1.5 ± 1.6%). Blood pressure, resting heart rate, and physical activity were unchanged. Conclusion: Engagement in beginner running programs was associated with improvements in cardiorespiratory fitness and body composition within 10 weeks. A larger and longer-term study is required to determine if these programs can lead to sustained engagement in running and additional health benefits.

Gender and Exercise in Relation to Obesity in Greek Elderly Population

Purpose: The prevalence of sarcopenic obesity is increasing in older adults (>65 years) and older. Sarcopenic obesity is also related to reduced muscle synthesis, due to low physical activity levels. The purpose of the present study is to investigate possible risk factors, and effects of habitual activity status on different types of obesity in an elderly population. Methods: One hundred and two (n = 102) free living participants, aged >60 years, were randomly selected from Rehabilitation Centers for the Elderly in Thessaloniki and from municipal gymnasiums of Thessaloniki, Greece with a mean age of 68.11 ± 6.40 years. The response rate of the participants was 51%. For the purpose of this study, all the participants selected were healthy and did not receive any medication. Specifically, 46 subjects (19 men and 27 women) were members of Rehabilitation Centers for the Elderly in Thessaloniki, while 56 individuals (31 men and 25 women were members of the municipal gymnasiums of Thessaloniki and exercised 2 to 3 times per week). Anthropometric measurements were taken for all subjects. Body composition was assessed with bioelectrical impedance. Body Mass Index (BMI) was categorized according to the World Health Organization (WHO) (2000) standards. Central obesity was defined as a waist circumference of >102 cm in men and >88 cm in women. All participants completed a specific questionnaire regarding their health status, physical activity and previous weight status. Risk of sarcopenic obesity was diagnosed in the participants with co-existing sarcopenia and obesity resulting in high fat mass concurrent with low lean body mass. Results: Women had more than double risk of developing abdominal obesity (OR:2.133, 95% CI: 0.963–4.725) compared to men. More specifically, 69.6% of the elders who did not exercise regularly had central obesity (men: 52.6% and women: 81.5%), while 38.2% of the exercised elders (men: 36.7% and women: 40%) had central obesity. Sedentary elders demonstrated an increased risk of obesity according to body fat (%BF) (OR: 1.259, 95% CI: 0.576–2.750), double the risk of obesity according to body mass (OR: 2.074, 95% CI: 0.765–5.622), and triple the risk of having central obesity (OR: 3.701, 95% CI: 1.612–8.494) compared to those who exercised. Conclusion Exercise appears to have a protective role against all modes of obesity and thus possibly against obesity-related co-morbidities in the elderly.

BAck iN the Game (BANG) - a smartphone application to help athletes return to sport following anterior cruciate ligament reconstruction: protocol for a multi-centre, randomised controlled trial

Background

Sustaining injury is a common consequence of playing sport. At least one in every three recreational athletes with anterior cruciate ligament (ACL) reconstruction do not return to their preinjury sport following treatment. Psychological factors including confidence and fear of new injury exert large effects on returning to sport. The primary aim of this trial is to test whether a custom smartphone application delivering cognitive-behavioural therapy is effective for improving the number of people who return to their preinjury sport and level following ACL reconstruction.

Methods

Participants scheduled for primary ACL reconstruction are recruited prior to surgery from one of six trial sites in Sweden. We aim to recruit 222 participants (111 in each group) for the BANG trial. Participants are randomly allocated to receive either usual rehabilitation care alone or usual rehabilitation care plus the Back in the Game smartphone application intervention. Back in the Game is a 24-week Internet-delivered programme, based on cognitive-behavioural therapy. The primary outcome is return to the preinjury sport and level at 12 months follow-up. The secondary outcomes assess physical activity participation, new knee injuries, psychological factors, quality of life and physical function. Physical activity participation and new injuries are self-reported every two weeks for 12 months, then every 4 weeks to 24 months follow-up. Psychological readiness to return to sport, knee self-efficacy, motivation to participate in leisure time physical activity, knee-related quality of life, and self-reported knee function are also assessed at 3, 6, 9, 12 and 24 months after surgery. A clinical assessment of strength, knee range of motion, effusion and hopping performance is completed by a blinded assessor at 12 months to assess physical function.

Discussion

This protocol outlines how we plan to assess the efficacy of a custom smartphone application, delivering cognitive-behavioural therapy to address fear, confidence and recovery expectations, for improving return to sport following serious sports-related musculoskeletal injury. The BANG trial employs a pragmatic design to best reflect the reality of, and inform, clinical practice.

Trial registration

ClinicalTrials.gov, NCT03959215. Registered 22 May 2019.

Changes in physical activity, weight and wellbeing outcomes among attendees of a weekly mass participation event: a prospective 12-month study

BACKGROUND

Mass participation events are recognized as a way of engaging low-active individuals in health-enhancing physical activity, but there is a need to investigate the sustained effects on behaviour and health. This study aimed to examine changes in self-reported physical activity, weight and wellbeing over 12 months in participants of parkrun, a weekly mass participation 5 km running event.

METHODS

New parkrun registrants (n = 354) completed self-reported measures of physical activity, weight, happiness and stress, at registration, 6 months and 12 months. Objective data on attendance and fitness (i.e. run dates and finishing times) were obtained from the parkrun database.

RESULTS

Overall physical activity levels were high at baseline, but significantly increased over the first 6 months, before declining. By 12 months, weekly physical activity was 39 min higher than baseline. Significant reductions in body mass index were observed over 12 months, with a weight loss of 1.1% in the whole sample, and 2.4% among overweight participants. Modest increases in happiness and decreases in perceived stress were recorded. Run times suggested a 12% improvement in fitness during the study.

CONCLUSION

Significant changes in weight, fitness and wellbeing outcomes indicate the public health benefits of regular participation in parkrun.

A Randomized Community-based Exercise Training Trial in African American Men: Aerobic Plus Resistance Training and Insulin Sensitivity in African American Men

PURPOSE

To examine the impact of a community-based exercise training intervention on cardiometabolic outcomes in African American men who have a family history of type 2 diabetes.

METHODS

The Aerobic Plus Resistance Training and Insulin Sensitivity in African American Men (ARTIIS) study randomized participants into either an exercise training intervention or an information only control group for 5 months. The exercise training intervention consisted of 150 min of moderate intensity aerobic activity and 2 d of resistance training per week, consistent with the current federal physical activity guidelines. Participants in the control group received monthly newsletters featuring topics focused heavily on type 2 diabetes education and prevention. Outcome data were analyzed using repeated-measures ANCOVA models and incorporating both intention-to-treat and per-protocol principles.

RESULTS

Adherence to the aerobic and resistance training prescriptions were between 77% and 79%. Despite significant within group improvements in glucose and insulin levels (fasting, 2 h, 2 h minus baseline) and Homeostatic Model 2-Insulin Resistance, there were not significant between group differences. There was a marginally significant between group difference for Homeostatic Model 2-Beta (P < 0.06), and significant between group differences in peak cardiorespiratory fitness (P < 0.001) and waist circumference (P = 0.03).

CONCLUSIONS

These findings suggest that exercise training in accordance with the current national recommendations is effective in improving some health parameters in middle-age African American men who have a family history of type 2 diabetes, but did not have a significant impact on glycemic status.

Is cardiorespiratory fitness independently associated with the biochemical profile in overweight/obese adults with primary hypertension? The EXERDIET-HTA study

Cardiorespiratory fitness (CRF) is positively associated with enhanced cardiovascular health. This cross-sectional study aimed to determine associations between CRF and the biochemical profile of overweight/obese adults diagnosed with primary hypertension (HTN). Does cardiorespiratory fitness (exposure) positively affect the biochemical profile (outcome) in overweight/obese individuals suffering from HTN? Assessment with anthropometric, ambulatory blood pressure monitoring (24 h), CRF (peak oxygen uptake, V̇O_2peak) and biochemical analysis was performed on 214 participants (138 men, 76 women). A series of linear and logistic regression analyses were conducted. Participants were divided into CRF tertiles (classified as low, moderate and high CRF). The CRF was independently and inversely associated with aspartate aminotransferase (AST; β = -0.328, p < .05) and alanine aminotransferase (ALT; β = -0.376, p < .01) concentrations. C-reactive protein, AST/ALT ratio, gamma-glutamyl transpeptidase, total cholesterol/high-density lipoprotein cholesterol ratio, glucose, insulin and insulin resistance index (HOMA-IR), were all associated, but not independently, with CRF in linear and/or unadjusted logistic regression models. However, independently, logistic regression revealed that glucose was associated with the moderate CRF group. Findings suggest that a lower CRF is associated with an unhealthy biochemical profile in non-physically active and overweight/obese individuals with HTN. As such, this population should look to increase physical activity in order to improve their CRF and biochemical profile.

An update on the relationship between statins and physical activity

PURPOSE OF REVIEW

This review examined studies published within the last 16 months that investigated the relationship between statins and physical activity.

RECENT FINDINGS

These recent studies suggest that statins do not adversely affect cardiorespiratory fitness, muscle strength, athletic performance, or physical activity adherence. One recent study comparing patients with statin-associated myalgia and nonstatin-using controls did report that statins are associated with a slowing of time to peak power output, increased abdominal adiposity, and insulin resistance. Statin users also had different muscle gene expression than controls, but conclusions are limited by the design of that study.

SUMMARY

Previous reports suggest that statin-associated muscle symptoms such as myalgia, cramps, and weakness occur more frequently in physically active individuals, but the recent studies we reviewed do not provide additional support for this possibility. Well-designed clinical trials are needed to determine whether different statins or statin doses evoke statin-associated muscle symptoms or muscle damage that may reduce cardiorespiratory fitness and adherence to physical activity.

Exercise training impacts exercise tolerance and bioenergetics in gastrocnemius muscle of non-obese type-2 diabetic Goto-Kakizaki rat in vivo

The functional and bioenergetics impact of regular physical activity upon type-2 diabetic skeletal muscle independently of confounding factors of overweight remains undocumented. Here, gastrocnemius muscle energy fluxes, mitochondrial capacity and mechanical performance were assessed noninvasively and longitudinally in non-obese diabetic Goto-Kakizaki rats using magnetic resonance (MR) imaging and dynamic 31-phosphorus MR spectroscopy (³¹P-MRS) throughout a 6-min fatiguing bout of exercise performed before, in the middle (4-week) and at the end of an 8-week training protocol consisting in 60-min daily run on a treadmill. The training protocol reduced plasmatic insulin level (-61%) whereas blood glucose and non-esterified fatty acids levels remained unaffected, thereby indicating an improvement of insulin sensitivity. It also increased muscle mitochondrial citrate synthase activity (+45%) but this increase did not enhance oxidative ATP synthesis capacity in working muscle in vivo while glycolytic ATP production was increased (+33%). On the other hand, the training protocol impaired maximal force-generating capacity (-9%), total amount of force produced (-12%) and increased ATP cost of contraction (+32%) during the fatiguing exercise. Importantly, these deleterious effects were transiently worsened in the middle of the 8-week period, in association with reduced oxidative capacity and increased basal [P_i]/[PCr] ratio (an in vivo biomarker of muscle damage). These data demonstrate that the beneficial effect of regular training on insulin sensitivity in non-obese diabetic rat occurs separately from any improvement in muscle mitochondrial function and might be linked to an increased capacity for metabolizing glucose through anaerobic process in exercising muscle.

Walking in Relation to Mortality in a Large Prospective Cohort of Older U.S. Adults

INTRODUCTION

Engaging in >150 minutes of moderate-intensity or 75 minutes of vigorous-intensity physical activity weekly is recommended for optimal health. The relationship between walking, the most common activity especially for older adults, and total mortality is not well documented.

METHODS

Data from a large U.S. prospective cohort study including 62,178 men (mean age 70.7 years) and 77,077 women (mean age 68.9 years), among whom 24,688 men and 18,933 women died during 13 years of follow-up (1999-2012), were used to compute multivariable-adjusted hazard rate ratios and 95% CIs for walking as the sole form of activity or adjusted for other moderate- or vigorous-intensity physical activity in relation to total and cause-specific mortality (data analysis 2015-2016).

RESULTS

Inactivity compared with walking only at less than recommended levels was associated with higher all-cause mortality (hazard rate ratio=1.26, 95% CI=1.21, 1.31). Meeting one to two times the recommendations through walking only was associated with lower all-cause mortality (hazard rate ratio=0.80, 95% CI=0.78, 0.83). Associations with walking adjusted for other moderate- or vigorous-intensity physical activity were similar to walking only. Walking was most strongly associated with respiratory disease mortality followed by cardiovascular disease mortality and then cancer mortality.

CONCLUSIONS

In older adults, walking below minimum recommended levels is associated with lower all-cause mortality compared with inactivity. Walking at or above physical activity recommendations is associated with even greater decreased risk. Walking is simple, free, and does not require any training, and thus is an ideal activity for most Americans, especially as they age.

Relation of Exercise Capacity to Risk of Development of Diabetes in Patients on Statin Therapy (the Henry Ford Exercise Testing Project)

High exercise capacity (EC) has been associated with a lower risk of incident diabetes, whereas statin therapy has been associated with a higher risk. We sought to investigate whether the association between EC and diabetes risk is modified by statin therapy. This retrospective cohort study included 47,337 patients without diabetes or coronary artery disease at baseline (age 53 ± 13 years, 48% women, 66% white) who underwent clinical treadmill stress testing within the Henry Ford Health System from January 1, 1991, to May 31, 2009. The patients were stratified by baseline statin use and estimated peak METs achieved during exercise testing. Hazard ratios for incident diabetes were calculated using Cox proportional hazards models adjusted for demographic characteristics, co-morbidities, pertinent medications, and stress test indication. We observed 6,921 new diabetes cases (14.6%) over a median follow-up period of 5.1 years (interquartile interval of 2.6 to 8.2 years). Compared with the statin group, the no-statin group achieved higher mean METs (8.9 ± 2.7 vs 9.6 ± 3.0, respectively; p <0.001). After adjustment for covariates, a higher EC was associated with a lower risk of incident diabetes, irrespective of statin use (p-interaction = 0.15). Each 1-MET increment was associated with an 8%, 8%, and 6% relative risk reduction in the total cohort, the no-statin, and the statin groups, respectively (95% confidence interval, 0.91 to 0.93, 0.91 to 0.93, and 0.91 to 0.96, respectively; p <0.001 for all). We conclude that a higher EC is associated with a lower risk of incident diabetes regardless of statin use.

Self-care behavior change and depression among low-income predominantly Hispanic patients in safety-net clinics

This study examined whether changes in self-care behaviors during a 12-month period predicted the likelihood of screening positive for depression concurrently and prospectively among low-income Hispanic patients with diabetes. Secondary analyses were conducted with longitudinal data collected from a randomized controlled trial that had tested effectiveness of collaborative depression care. We examined whether changes in self-care behaviors observed during the 12 months after baseline predicted the likelihood of screening positive for depression at 12-, 18-, and 24-month follow-up. Self-care behaviors included healthy diet, exercise, self-blood glucose monitoring, and foot care, which were measured by a validated self-reported instrument. Logistic regression analyses indicated that patients with more frequent healthy diet during the 12 months after baseline had significantly lower likelihood of depression. Patients with more frequent exercise had a lower likelihood of screening for depression at 18- and 24-month follow-up. No significant association was found with self-blood glucose monitoring and foot care. These findings suggest the importance of integrated care that emphasizes healthy diet and exercise, together with traditional depression treatment, when helping low-income Hispanic patients with diabetes and comorbid depression.

Predicting diabetes mellitus using SMOTE and ensemble machine learning approach: The Henry Ford ExercIse Testing (FIT) project

Machine learning is becoming a popular and important approach in the field of medical research. In this study, we investigate the relative performance of various machine learning methods such as Decision Tree, Naïve Bayes, Logistic Regression, Logistic Model Tree and Random Forests for predicting incident diabetes using medical records of cardiorespiratory fitness. In addition, we apply different techniques to uncover potential predictors of diabetes. This FIT project study used data of 32,555 patients who are free of any known coronary artery disease or heart failure who underwent clinician-referred exercise treadmill stress testing at Henry Ford Health Systems between 1991 and 2009 and had a complete 5-year follow-up. At the completion of the fifth year, 5,099 of those patients have developed diabetes. The dataset contained 62 attributes classified into four categories: demographic characteristics, disease history, medication use history, and stress test vital signs. We developed an Ensembling-based predictive model using 13 attributes that were selected based on their clinical importance, Multiple Linear Regression, and Information Gain Ranking methods. The negative effect of the imbalance class of the constructed model was handled by Synthetic Minority Oversampling Technique (SMOTE). The overall performance of the predictive model classifier was improved by the Ensemble machine learning approach using the Vote method with three Decision Trees (Naïve Bayes Tree, Random Forest, and Logistic Model Tree) and achieved high accuracy of prediction (AUC = 0.92). The study shows the potential of ensembling and SMOTE approaches for predicting incident diabetes using cardiorespiratory fitness data.

Surgical excision of perineal nodular induration: A cyclist's third testicle

Perineal nodular induration (PNI), or biker's nodule, is a rare, bothersome, pseudotumour. Herein, we describe the surgical technique used to treat a healthy cyclist who developed an enlarging PNI for five years that grew into a perineal mass. The mass prevented him from cycling due to worsening discomfort and heaviness. The PNI-associated mass was successfully removed by wide surgical excision and a local advancement flap. Subsequently, the patient resumed cycling. Histopathology report demonstrated a benign lesion with abundant ropy collagen with native smooth muscle, vessels, and rare fibroblast-like spindle cells. With the increasing popularity of cycling, PNI may become more common, and health providers should be aware of this rare entity and how it can be safely removed.

Longitudinal Patterns of Cardiorespiratory Fitness Predict the Development of Hypertension Among Men and Women

BACKGROUND

Most of the existing literature has linked a baseline cardiorespiratory fitness or change between baseline and one follow-up measurement of cardiorespiratory fitness to hypertension. The purpose of the study is to assess the association between longitudinal patterns of cardiorespiratory fitness changes with time and incident hypertension in adult men and women.

METHODS

Participants were aged 20 to 82 years, were free of hypertension during the first 3 examinations, and received at least 4 preventive medical examinations at the Cooper Clinic in Dallas, Texas, from 1971 to 2006. They were classified into 1 of 5 groups based on all of the measured cardiorespiratory fitness values (in metabolic equivalents) during maximal treadmill tests. Logistic regression was used to compute odds ratios and 95% confidence intervals.

RESULTS

Among 4932 participants (13% women), 1954 developed hypertension. After controlling for baseline potential confounders, follow-up duration, and number of follow-up visits, odds ratios (95% confidence intervals) for hypertension were 1.00 for the decreasing group (referent), 0.64 (0.52-0.80) for the increasing group, 0.89 (0.70-1.12) for the bell-shape group, 0.78 (0.62-0.98) for the U-shape group, and 0.83 (0.69-1.00) for the inconsistent group. The general pattern of the association was consistent regardless of participants' baseline cardiorespiratory fitness or body mass index levels.

CONCLUSIONS

An increasing pattern of cardiorespiratory fitness provides the lowest risk of hypertension in this middle-aged relatively healthy population. Identifying specific pattern(s) of cardiorespiratory fitness change may be important for determining associations with comorbidity, such as hypertension.

Reduced risk of incident kidney cancer from walking and running

PURPOSE

This study aimed to test whether incident kidney cancer risk is associated with exercise energy expenditure (i.e., metabolic equivalents, 1 MET) when calculated from distance walked or run.

METHODS

Hazard ratios (HR) and 95% confidence intervals (95% CI) from Cox proportional hazard analyses of self-reported physician-diagnosed incident kidney cancer versus MET-hours per week in 91,820 subjects recruited between 1991 and 1993 (7.7 yr follow-up of 42,833 subjects) and between 1998 and 1999 (6.4 yr follow-up of 33,053 subjects) as part of the National Runners' Health Study and between 1998 and 1999 as part of the National Walkers' Health Study (5.7 yr follow-up of 15,934 subjects).

RESULTS

Fifty-two incident cancers were reported. Age- and sex-adjusted risk declined 1.9% per MET-hour per week run or walked (HR = 0.981, 95% CI = 0.964-0.997, P = 0.02). Compared with walking or running below guidelines levels (<7.5 MET·h·wk(-1)), the risk for incident kidney cancer was 61% lower for meeting the guidelines (HR = 0.39, 95% CI = 0.11-1.08, P = 0.07 for 7.5-12.5 MET·h·wk(-1)), 67% lower for exercising one to two times the recommended level (HR = 0.33; 95% CI = 0.15-0.72, P = 0.005 for 12.6-25.1 MET·h·wk(-1)), and 76.3% lower for exercising two times or more the recommended level (HR = 0.24, 95% CI = 0.11-0.52, P = 0.0005 for ≥ 25.2 MET·h·wk(-1)). Incident kidney cancer risk also increased in association with baseline body mass index (P = 0.002), smoking (P = 0.02), and hypertensive (P = 0.007) and diabetes medication use (P = 0.01); however, exercise-associated reductions in kidney cancer risk persisted for 12.6-25.1 MET·h·wk(-1) (HR = 0.35, P = 0.01) and ≥ 25.2 MET·h·wk(-1) (HR = 0.29, P = 0.004) vis-à-vis <7.5 MET·h·wk(-1) when also adjusted for body mass index, hypertension, diabetes, and pack-years smoked.

CONCLUSION

Running and walking may reduce incident kidney cancer risk independent of its other known risk factors.

Association Between Physical Activity Intensity and Physical Capacity Among Individuals Awaiting Bariatric Surgery

BACKGROUND

Physical activity is a routine component of the lifestyle modification program implemented prior to bariatric surgery, and one of the goals is to improve patients' physical capacity. However, the physical activity intensity recommended to meet that goal is unknown.

OBJECTIVE

This study aimed to assess the association between time spent at different physical activity intensities and physical capacity in patients awaiting bariatric surgery.

MATERIALS AND METHODS

A total of 39 women and 13 men were recruited. The primary outcome was physical capacity measured using six objective tests: 6-min walk, chair stand, sit and reach, unipodal balance (eyes open and eyes closed), and hand grip strength tests. The primary exposure variable was physical activity intensity (i.e., sedentary, light, moderate, and vigorous) measured by accelerometers.

RESULTS

The average body mass index was 46.3 ± 5.4 kg/m². Only 6% of total time was spent at moderate to vigorous intensity, while 71% of the time was spent sedentary. When adjusted for body mass index, age, and sex, four of the six physical capacity tests were significantly associated with moderate intensity physical activity β(SE): 6-min walk 9.7 (2.7), chair stand 0.3 (0.1), balance (eyes open) 1.8 (0.7), and hand grip strength 1.2 (0.4), and only the 6-min walk was associated with sedentary activity 1.7 (0.7).

CONCLUSION

These results suggest that physical capacity is associated with time spent at moderate intensity in individuals awaiting bariatric surgery. The next step is to study if an increase in time spent at moderate intensity will translate to improvements in physical capacity.

The Impact of Cardiorespiratory Fitness Levels on the Risk of Developing Atherogenic Dyslipidemia

BACKGROUND

Low cardiorespiratory fitness has been established as a risk factor for cardiovascular-related morbidity. However, research about the impact of fitness on lipid abnormalities, including atherogenic dyslipidemia, has produced mixed results. The purpose of this investigation is to examine the influence of baseline fitness and changes in fitness on the development of atherogenic dyslipidemia.

METHODS

All participants completed at least 3 comprehensive medical examinations performed by a physician that included a maximal treadmill test between 1976 and 2006 at the Cooper Clinic in Dallas, Texas. Atherogenic dyslipidemia was defined as a triad of lipid abnormalities: low high-density-lipoprotein cholesterol ([HDL-C] <40 mg/dL), high triglycerides ([TGs] ≥200 mg/dL), and high low-density-lipoprotein cholesterol ([LDL-C] ≥160 mg/dL).

RESULTS

A total of 193 participants developed atherogenic dyslipidemia during an average of 8.85 years of follow-up. High baseline fitness was protective against the development of atherogenic dyslipidemia in comparison with those with low fitness (odds ratio [OR] 0.57; 95% confidence interval [CI], 0.37-0.89); however, this relationship became nonsignificant after controlling for baseline HDL-C, LDL-C, and TG levels. Participants who maintained fitness over time had lower odds of developing atherogenic dyslipidemia than those with a reduction in fitness (OR 0.56; 95% CI, 0.34-0.91) after adjusting for baseline confounders and changes in known risk factors.

CONCLUSIONS

High fitness at baseline and maintenance of fitness over time are protective against the development of atherogenic dyslipidemia.

Impact of Physical Activity on Glycemic Control and Insulin Resistance: A Study of Community-dwelling Diabetic Patients in Eastern China

Objective The aim of this study was to evaluate the relationship of various intensities of physical activity with glycemic control and insulin resistance in eastern China. Methods A population-based, cross-sectional study was conducted in eastern China. The subjects included 604 community-dwelling people. The participants were classified as insufficiently active (IA); sufficiently active (SA) and very active (VA) according to the International Physical Activity Questionnaire (IPAQ). Insulin sensitivity was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR). Related social, biological, lifestyle factors and clinical characteristics were recorded and used as potential confounders. Results The cohort of 604 type 2 diabetes patients were classified according to the activity level: 107 subjects who were classified as IA, 329 met the criteria for SA, and the rest were VA. The proportion of obese patients, smokers, patients with hypertension, and the body weight, body mass index (BMI), waist circumference, hemoglobin A1c protein (HbA1c), and 2-h postprandial blood glucose (2hPG) were significantly lower in the SA and VA groups than in the IA group (p<0.05 or 0.01). The SA group had lower levels of fasting blood glucose (FPG) and HOMA-IR than the IA and VA groups (p<0.05 or 0.01). HOMA-IR was positively correlated with FPG, 2hPG, HbA1c, waist circumference and BMI. HOMA-IR was negatively correlated with the total walking activity (p<0.05). After adjusting for FPG, 2hPG, HbA1c, waist circumference and BMI among the groups, a partial correlation analysis showed a correlation between HOMA-IR and the total walking activity. Conclusion Physical activity is a significant factor regarding glycemic control and insulin sensitivity, although SA and walking may be superior to VA for ameliorating insulin sensitivity.

Type 2 diabetes in migrant south Asians: mechanisms, mitigation, and management

South Asians, particularly when living in high-income countries, are at a substantially elevated risk of type 2 diabetes compared with white Europeans, and typically develop the disease 5-10 years earlier and at a lower BMI. Migrant south Asians seem to be more insulin resistant than white Europeans across the life course and potentially experience β-cell exhaustion at a younger age. Differences in adiposity (high percentage of body fat and high proportion of deep subcutaneous and visceral fat) and skeletal muscle (low percentage of lean mass and low cardiorespiratory fitness) are likely to contribute these factors. No clear evidence is available suggesting genetic factors make a major contribution to the increased risk of diabetes in south Asians, but epigenetic factors might have a role. Irrespective of future mechanistic discoveries, south Asians need to be encouraged and helped-by various culturally appropriate methods--to maintain a high physical activity level and low bodyweight across the life course to prevent diabetes. In clinical terms, cardiovascular risks have attenuated over time in migrant south Asians with diabetes but retinopathy and renal complication risks remain high because of the high levels of glycaemia and rapid glycaemic deterioration noted in this population. We review these aspects and suggest areas for future research.

Incident diabetes mellitus, hypertension, and cardiovascular disease risk in exercising hypercholesterolemic patients

Exercise may be an important treatment for hypercholesterolemic patients, particularly in statin users who are at increased diabetes risk. We therefore used Cox proportional hazard analyses to compare running and walking dose (metabolic equivalent hours/day [MET-h/d]) to diabetes, hypertension, and cardiovascular disease (CVD) risk in hypercholesterolemic patients. There were 60 diabetic- and 373 CVD-related deaths during a 10.1-year mortality surveillance of 6,688 hypercholesterolemic patients. In addition, there were 177 incident nonfatal diabetes, 815 incident nonfatal hypertensions, and 323 incident nonfatal CVD events during a 6.4-year follow-up of 6,971 hypercholesterolemic patients who supplied follow-up questionnaires. Fatal and nonfatal diabetes risk decreased 26% (p = 0.002) and 19% (p ≤0.0001) per MET-h/d, respectively, and relative to <1.07 MET-h/d decreased 35% (p = 0.19) and 55% (p ≤0.0001), respectively, for 1.8 to 3.6 MET-h/d and 73% (p = 0.02) and 71% (p ≤0.0001), respectively, for ≥3.6 MET-h/d. Fatal and nonfatal CVD risk decreased 8% (p = 0.008) and 3% (p = 0.22) per MET-h/d, respectively, and relative to <1.07 MET-h/d decreased 10% (p = 0.45) and 36% (p = 0.008) for 1.8 to 3.6 MET-h/d, respectively, and 37% (p = 0.009) and 26% (p = 0.10), respectively, for ≥3.6 MET-h/d. Incident hypertension risk decreased 4% (p = 0.01) per MET-h/d, and relative to <1.07 MET-h/d decreased 29% (p = 0.002) for 1.8 to 3.6 MET-h/d and 31% (p = 0.001) for ≥3.6 MET-h/d. In conclusion, running and walking for exercise lowers diabetes, hypertension, and CVD risk in hypercholesterolemic patients and should more than compensate for the purported 9% increase in diabetes risk from statin use. By preventing morbidity and mortality for a specific existing medical condition, some exercise expenses may qualify for flexible spending account expenditures in hypercholesterolemic patients when prescribed by a physician.

Effects of Running on Chronic Diseases and Cardiovascular and All-Cause Mortality

Considerable evidence has established the link between high levels of physical activity (PA) and all-cause and cardiovascular disease (CVD)-specific mortality. Running is a popular form of vigorous PA that has been associated with better overall survival, but there is debate about the dose-response relationship between running and CVD and all-cause survival. In this review, we specifically reviewed studies published in PubMed since 2000 that included at least 500 runners and 5-year follow-up so as to analyze the relationship between vigorous aerobic PA, specifically running, and major health consequences, especially CVD and all-cause mortality. We also made recommendations on the optimal dose of running associated with protection against CVD and premature mortality, as well as briefly discuss the potential cardiotoxicity of a high dose of aerobic exercise, including running (eg, marathons).

Physical fitness and hypertension in a population at risk for cardiovascular disease: the Henry Ford ExercIse Testing (FIT) Project

BACKGROUND

Increased physical fitness is protective against cardiovascular disease. We hypothesized that increased fitness would be inversely associated with hypertension.

METHODS AND RESULTS

We examined the association of fitness with prevalent and incident hypertension in 57 284 participants from The Henry Ford ExercIse Testing (FIT) Project (1991–2009). Fitness was measured during a clinician‐referred treadmill stress test. Incident hypertension was defined as a new diagnosis of hypertension on 3 separate consecutive encounters derived from electronic medical records or administrative claims files. Analyses were performed with logistic regression or Cox proportional hazards models and were adjusted for hypertension risk factors. The mean age overall was 53 years, with 49% women and 29% black. Mean peak metabolic equivalents (METs) achieved was 9.2 (SD, 3.0). Fitness was inversely associated with prevalent hypertension even after adjustment (≥12 METs versus <6 METs; OR: 0.73; 95% CI: 0.67, 0.80). During a median follow‐up period of 4.4 years (interquartile range: 2.2 to 7.7 years), there were 8053 new cases of hypertension (36.4% of 22 109 participants without baseline hypertension). The unadjusted 5‐year cumulative incidences across categories of METs (<6, 6 to 9, 10 to 11, and ≥12) were 49%, 41%, 30%, and 21%. After adjustment, participants achieving ≥12 METs had a 20% lower risk of incident hypertension compared to participants achieving <6 METs (HR: 0.80; 95% CI: 0.72, 0.89). This relationship was preserved across strata of age, sex, race, obesity, resting blood pressure, and diabetes.

CONCLUSIONS

Higher fitness is associated with a lower probability of prevalent and incident hypertension independent of baseline risk factors.

Effects of Statin Therapy on Exercise Levels in Participants in the National Runners' and Walkers' Health Study

OBJECTIVES

To determine whether decreases in exercise 1) were greater in individuals who were diagnosed as having hypercholesterolemia than in those without the diagnosis during follow-up and 2) were greater in incident hypercholesterolemic participants starting statins than in those not treated with cholesterol-lowering medications.

PARTICIPANTS AND METHODS

Regression analyses of changes since baseline (Δ) in exercise vs diagnosis of hypercholesterolemia and its treatment in 66,377 runners and 12,031 walkers not using cholesterol medications at baseline who were resurveyed during the National Runners' and Walkers' Health Study follow-up (January 1, 1991, through December 31, 2006).

RESULTS

A total of 3510 runners began statin treatment, 1779 began other or unspecified cholesterol-lowering drug treatment, and 2583 had untreated hypercholesterolemia; 58,505 runners remained nonhypercholesterolemic controls during the mean 7.2-year follow-up. Usual distance run decreased significantly more in hypercholesterolemic runners who began taking statins (mean ± SE: -0.47±0.06 km/d) than in runners who remained nonhypercholesterolemic during follow-up (-0.08±0.02 km/d) (P<.001). However, running distance also decreased significantly more in hypercholesterolemic runners who began unspecified/other (-0.52±0.08 km/d) or no (-0.47±0.07 km/d) cholesterol drugs than in nonhypercholesterolemic runners during follow-up. Moreover, Δrunning distance did not differ significantly between hypercholesterolemic runners who were statin treated vs those treated with other/unspecified (P=.64) or no (P=.94) cholesterol drugs. Initiating statin therapy was not associated with Δrunning pace in hypercholesterolemic runners or Δwalking distances in hypercholesterolemic walkers.

CONCLUSION

These results are consistent with the premise that a decrease in running distance is associated with hypercholesterolemia and do not suggest that statins reduce exercise level or intensity.

Neurovascular Control and Cardiac Structure in Amateur Runners with Hypertension

PURPOSE

The neurovascular mechanisms underlying hypertension are minimized by exercise training. However, it is not known whether previously trained individuals with hypertension would have deleterious repercussion of this disease. Our aim was to investigate the neurovascular control and the cardiac structure of athletes with hypertension.

METHODS

Muscle sympathetic nerve activity (MSNA) (microneurography), baroreflex sensitivity (intravenous infusion of phenylephrine and nitroprusside), arterial stiffness (pulse wave velocity and echotracking), and cardiac structure (echocardiography) were evaluated in 17 runners with hypertension (42 ± 1 yr) and 20 normotensive (43 ± 1 yr) amateur runners.

RESULTS

Runners with hypertension had higher MSNA (+24% burst frequency, P = 0.02; +24%, burst incidence, P < 0.01), left ventricular mass (+22%, P < 0.01), septum wall thickness (+9%, P = 0.04), posterior wall thickness (+11%, P = 0.04), and left atrium (+11%, P < 0.001) compared with normotensive runners. Baroreflex control of heart rate was lower in runners with hypertension during increase (P = 0.05) but not during decrease (P = 0.11) of systolic blood pressure when compared with normotensive runners. There was no difference between groups in baroreflex control of MSNA during increase (P = 0.38) and decrease (P = 0.36) of diastolic blood pressure. Pulse wave velocity (P = 0.71) and carotid variables: intima media thickness (P = 0.18), diameter (P = 0.09), and distension (P = 0.79) were similar between groups.

CONCLUSIONS

Sympathetic overactivity seems to be involved in the underlying mechanisms of hypertension in amateur runners. Alterations in cardiac structure and decreased baroreflex control of heart rate suggest limited protection from exercise training. However, baroreflex control of MSNA and elastic properties of artery are preserved in this population.

The effect of cardiorespiratory fitness on age-related lipids and lipoproteins

BACKGROUND

Evidence on the effect of cardiorespiratory fitness (CRF) on age-related longitudinal changes of lipids and lipoproteins is scarce.

OBJECTIVES

This study sought to assess the longitudinal aging trajectory of lipids and lipoproteins for the life course in adults and to determine whether CRF modifies the age-associated trajectory of lipids and lipoproteins.

METHODS

Data came from 11,418 men, 20 to 90 years of age, without known high cholesterol, high triglycerides, cardiovascular disease, and cancer at baseline and during follow-up from the Aerobics Center Longitudinal Study. There were 43,821 observations spanning 2 to 25 health examinations (mean 3.5 examinations) between 1970 and 2006. CRF was quantified by a maximal treadmill exercise test. Marginal models using generalized estimating equations were applied.

RESULTS

Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides, and non-high-density lipoprotein cholesterol (non-HDL-C) presented similar inverted U-shaped quadratic trajectories with aging: gradual increases were noted until age mid-40s to early 50s, with subsequent declines (all p < 0.0001). Compared with men with higher CRF, those with lower CRF developed abnormal values earlier in life: TC (≥200 mg/dl), LDL-C (≥130 mg/dl), non-HDL-C (≥160 mg/dl), and triglycerides/HDL-C ratio (≥3.0). Notably, abnormal values for TC and LDL-C in men with low CRF were observed around 15 years earlier than in those with high CRF. After adjusting for time-varying covariates, a significant interaction was found between age and CRF in each trajectory, indicating that CRF was more strongly associated with the aging trajectories of lipids and lipoproteins in young to middle-age men than in older men.

CONCLUSIONS

Our investigation reveals a differential trajectory of lipids and lipoproteins with aging according to CRF in healthy men and suggests that promoting increased CRF levels may help delay the development of dyslipidemia.

Functional electrical stimulation: cardiorespiratory adaptations and applications for training in paraplegia

Regular exercise can be broadly beneficial to health and quality of life in humans with spinal cord injury (SCI). However, exercises must meet certain criteria, such as the intensity and muscle mass involved, to induce significant benefits. SCI patients can have difficulty achieving these exercise requirements since the paralysed muscles cannot contribute to overall oxygen consumption. One solution is functional electrical stimulation (FES) and, more importantly, hybrid training that combines volitional arm and electrically controlled contractions of the lower limb muscles. However, it might be rather complicated for therapists to use FES because of the wide variety of protocols that can be employed, such as stimulation parameters or movements induced. Moreover, although the short-term physiological and psychological responses during different types of FES exercises have been extensively reported, there are fewer data regarding the long-term effects of FES. Therefore, the purpose of this brief review is to provide a critical appraisal and synthesis of the literature on the use of FES for exercise in paraplegic individuals. After a short introduction underlying the importance of exercise for SCI patients, the main applications and effects of FES are reviewed and discussed. Major findings reveal an increased physiological demand during FES hybrid exercises as compared with arms only exercises. In addition, when repeated within a training period, FES exercises showed beneficial effects on muscle characteristics, force output, exercise capacity, bone mineral density and cardiovascular parameters. In conclusion, there appears to be promising evidence of beneficial effects of FES training, and particularly FES hybrid training, for paraplegic individuals.

Cardiorespiratory fitness and incident diabetes: the FIT (Henry Ford ExercIse Testing) project

OBJECTIVE

Prior evidence has linked higher cardiorespiratory fitness with a lower risk of diabetes in ambulatory populations. Using a demographically diverse study sample, we examined the association of fitness with incident diabetes in 46,979 patients from The Henry Ford ExercIse Testing (FIT) Project without diabetes at baseline.

RESEARCH DESIGN AND METHODS

Fitness was measured during a clinician-referred treadmill stress test performed between 1991 and 2009. Incident diabetes was defined as a new diagnosis of diabetes on three separate consecutive encounters derived from electronic medical records or administrative claims files. Analyses were performed with Cox proportional hazards models and were adjusted for diabetes risk factors.

RESULTS

The mean age was 53 years with 48% women and 27% black patients. Mean metabolic equivalents (METs) achieved was 9.5 (SD 3.0). During a median follow-up period of 5.2 years (interquartile range 2.6-8.3 years), there were 6,851 new diabetes cases (14.6%). After adjustment, patients achieving ≥12 METs had a 54% lower risk of incident diabetes compared with patients achieving <6 METs (hazard ratio 0.46 [95% CI 0.41, 0.51]; P-trend < 0.001). This relationship was preserved across strata of age, sex, race, obesity, hypertension, and hyperlipidemia.

CONCLUSIONS

These data demonstrate that higher fitness is associated with a lower risk of incident diabetes regardless of demographic characteristics and baseline risk factors. Future studies should examine the association between change in fitness over time and incident diabetes.

Relationship of resting heart rate and physical activity with insulin sensitivity in a population-based survey

BACKGROUND

Resting heart rate (RHR) has been identified as an independent risk factor for cardiovascular disease and mortality, contributing to atherosclerosis, the progression of heart failure, and myocardial ischemia and infarction. This study examines the association RHR and physical activity has with insulin resistance and insulin secretion in a multiethnic cohort from North Kohala, Hawai'i.

METHODS

Cross-sectional data from 1,440 participants of Native Hawaiian, Japanese, Filipino, Caucasian, and mixed ethnic ancestries were analyzed for the study to include anthropometric measurements, and biochemical markers. Body fat was estimated by calculating body mass indices (BMI); body fat distribution by waist-hip ratios (WHR); and fasting plasma glucose and insulin levels were used to calculate insulin resistance using the Homeostasis Model (HOMA-IR). First phase insulin response was estimated using the insulin secretion ratio (ISR). Associations were estimated using general linear models (GLM).

RESULTS

Caucasians had lower mean RHR than all other ethnic groups; there were no statistically significant differences between other ethnic groups on mean RHR. HOMA-IR was associated with ethnic group, BMI and WHR, PA and RHR, while ISR was associated with age, ethnic group and BMI, but none of the primary risk factors. Both RHR and physical activity level remained significant for insulin resistance.

CONCLUSIONS

In a multiethnic cohort from a rural community in Hawai'i, increased RHR and a lower level of physical activity were both independently associated with increased risk for the development of insulin resistance, suggesting cardiovascular fitness may be as important as physical activity in preventing insulin resistance.

Reduced total and cause-specific mortality from walking and running in diabetes

PURPOSE

This study aimed to assess the relationships of running and walking to mortality in diabetic subjects.

METHODS

We studied the mortality surveillance between January 1, 1989 and December 31, 2008, of 2160 participants of the National Walkers' and Runners' Health Studies who reported using diabetic medications at baseline. Hazard ratios (HR) and 95% confidence intervals (95% CI) were obtained from Cox proportional hazard analyses for mortality versus exercise energy expenditure (MET-hours per day, 1 MET·h ∼1-km run or a 1.5-km brisk walk).

RESULTS

Three hundred and thirty-one diabetic individuals died during a 9.8-yr average follow-up. Merely meeting the current exercise recommendations was not associated with lower all-cause mortality (P = 0.61), whereas exceeding the recommendations was associated with lower all-cause mortality (HR = 0.64, 95% CI = 0.49-0.82, P = 0.0005). Greater MET-hours per day ran or walked was associated with 40% lower risk for all chronic kidney disease-related deaths (HR = 0.60 per MET·h·d(-1), 95% CI = 0.35-0.91, P = 0.02), 31% lower risk for all sepsis-related deaths (HR = 0.69, 0.47-0.94, P = 0.01), and 31% lower risk for all pneumonia and influenza-related deaths (HR = 0.69, 95% CI = 0.45-0.97, P = 0.03). Running or walking ≥1.8 MET·h·d(-1) was associated with 57% reduction in cardiovascular disease (CVD) as an underlying cause of death and 46% lower risk for all CVD-related deaths versus <1.07 MET·h·d. All results remained significant: 1) adjusted for baseline BMI and 2) excluding all deaths within 3 yr of baseline.

CONCLUSIONS

These results suggest that 1) exercise is associated with significantly lower all-cause, CVD, chronic kidney disease, sepsis, and pneumonia, and influenza mortality in diabetic patients and 2) higher exercise standards may be warranted for diabetic patients than currently provided to the general population.

The impact of psychological readiness to return to sport and recreational activities after anterior cruciate ligament reconstruction

BACKGROUND

This cross-sectional study aimed to examine whether appraisal of knee function, psychological and demographic factors were related to returning to the preinjury sport and recreational activity following anterior cruciate ligament (ACL) reconstruction.

METHOD

164 participants completed a questionnaire battery at 1-7 years after primary ACL reconstruction. The battery included questionnaires evaluating knee self-efficacy, health locus of control, psychological readiness to return to sport and recreational activity, and fear of reinjury; and self-reported knee function in sport-specific tasks, knee-related quality of life and satisfaction with knee function. The primary outcome was returning to the preinjury sport or recreational activity.

RESULTS

At follow-up, 40% (66/164) had returned to their preinjury activity. Those who returned had more positive psychological responses, reported better knee function in sport and recreational activities, perceived a higher knee-related quality of life and were more satisfied with their current knee function. The main reasons for not returning were not trusting the knee (28%), fear of a new injury (24%) and poor knee function (22%). Psychological readiness to return to sport and recreational activity, measured with the ACL-Return to Sport after Injury scale (was most strongly associated with returning to the preinjury activity). Age, sex and preinjury activity level were not related.

CONCLUSIONS

Less than 50% returned to their preinjury sport or recreational activity after ACL reconstruction. Psychological readiness to return to sport and recreation was the factor most strongly associated with returning to the preinjury activity. Including interventions aimed at improving this in postoperative rehabilitation programmes could be warranted to improve the rate of return to sport and recreational activities.

Lack of Association between Polymorphisms of Hepatic Lipase with Lipid Profile in Young Jordanian Adults

The human hepatic lipase (LIPC) gene encodes hepatic lipase, an enzyme involved in lipoprotein metabolism and regulation. Therefore, variants in LIPC gene may influence plasma lipoprotein levels. In this study, the association of LIPC C-514T and G-250A polymorphisms with plasma lipid profiles in 348 young Jordanians was investigated. Genotyping of C-514T and G-250A was performed by polymerase chain reaction and subsequent digestion with DraI and NiaIII restriction enzymes, respectively, while Roche analyzer was used to determine plasma total cholesterol, triglycerides, low-and high-density lipoprotein. The G-250 and C-514 alleles were most abundant in Jordanians with 79 and 80% frequencies, respectively. Additionally, no difference was found in the lipid–lipoprotein profile between the different genotype groups of C-514T or G-250A polymorphisms, even when males and females were examined separately (P > 0.05). In young Jordanian adults, the examined LIPC polymorphisms seem to play a limited role in determining the lipid profile.

Increased cardiovascular disease mortality associated with excessive exercise in heart attack survivors

OBJECTIVE

To test whether greater exercise is associated with progressively lower mortality after a cardiac event.

PATIENTS AND METHODS

We used Cox proportional hazard analyses to examine mortality vs estimated energy expended by running or walking measured as metabolic equivalents (3.5 mL O2/kg per min per day or metabolic equivalent of task-h/d [MET-h/d]) in 2377 self-identified heart attack survivors, where 1 MET-h/d is the energy equivalent of running 1 km/d. Mortality surveillance via the National Death Index included January 1991 through December 2008.

RESULTS

A total of 526 deaths occurred during an average prospective follow-up of 10.4 years, 376 (71.5%) of which were related to cardiovascular disease (CVD) (International Statistical Classification of Diseases, 10th Revision codes I00-I99). CVD-related mortality compared with the lowest exercise group decreased by 21% for 1.07 to 1.8 MET-h/d of running or walking (P=.11), 24% for 1.8 to 3.6 MET-h/d (P=.04), 50% for 3.6 to 5.4 MET-h/d (P=.001), and 63% for 5.4 to 7.2 MET-h/d (P<.001) but decreased only 12% for ≥7.2 MET-h/d (P=.68). These data represent a 15% average risk reduction per MET-h/d for CVD-related mortality through 7.2 MET-h/d (P<.001) and a 2.6-fold risk increase above 7.2 MET-h/d (P=.009). Relative to the risk reduction at 7.2 MET-h/d, the risk for ≥7.2 MET-h/d increased 3.2-fold (P=.006) for all ischemic heart disease (IHD)-related mortalities but was not significantly increased for non-IHD-CVD, arrhythmia-related CVD, or non-CVD-related mortalities.

CONCLUSION

Running or walking decreases CVD mortality risk progressively at most levels of exercise in patients after a cardiac event, but the benefit of exercise on CVD mortality and IHD deaths is attenuated at the highest levels of exercise (running: above 7.1 km/d or walking briskly: 10.7 km/d).

Leisure-time running reduces all-cause and cardiovascular mortality risk

BACKGROUND

Although running is a popular leisure-time physical activity, little is known about the long-term effects of running on mortality. The dose-response relations between running, as well as the change in running behaviors over time, and mortality remain uncertain.

OBJECTIVES

We examined the associations of running with all-cause and cardiovascular mortality risks in 55,137 adults, 18 to 100 years of age (mean age 44 years).

METHODS

Running was assessed on a medical history questionnaire by leisure-time activity.

RESULTS

During a mean follow-up of 15 years, 3,413 all-cause and 1,217 cardiovascular deaths occurred. Approximately 24% of adults participated in running in this population. Compared with nonrunners, runners had 30% and 45% lower adjusted risks of all-cause and cardiovascular mortality, respectively, with a 3-year life expectancy benefit. In dose-response analyses, the mortality benefits in runners were similar across quintiles of running time, distance, frequency, amount, and speed, compared with nonrunners. Weekly running even <51 min, <6 miles, 1 to 2 times, <506 metabolic equivalent-minutes, or <6 miles/h was sufficient to reduce risk of mortality, compared with not running. In the analyses of change in running behaviors and mortality, persistent runners had the most significant benefits, with 29% and 50% lower risks of all-cause and cardiovascular mortality, respectively, compared with never-runners.

CONCLUSIONS

Running, even 5 to 10 min/day and at slow speeds <6 miles/h, is associated with markedly reduced risks of death from all causes and cardiovascular disease. This study may motivate healthy but sedentary individuals to begin and continue running for substantial and attainable mortality benefits.

Inadequate exercise as a risk factor for sepsis mortality

Objective

Test whether inadequate exercise is related to sepsis mortality.

Research Design and Methods

Mortality surveillance of an epidemiological cohort of 155,484 National Walkers' and Runners' Health Study participants residing in the United States. Deaths were monitored for an average of 11.6-years using the National Death index through December 31, 2008. Cox proportional hazard analyses were used to compare sepsis mortality (ICD-10 A40-41) to inadequate exercise (<1.07 METh/d run or walked) as measured on their baseline questionnaires. Deaths occurring within one year of the baseline survey were excluded.

Results

Sepsis was the underlying cause in 54 deaths (sepsis_underlying) and a contributing cause in 184 deaths (sepsis_contributing), or 238 total sepsis-related deaths (sepsis_total). Inadequate exercise was associated with 2.24-fold increased risk for sepsis_underlying (95%CI: 1.21 to 4.07-fold, P = 0.01), 2.11-fold increased risk for sepsis_contributing (95%CI: 1.51- to 2.92-fold, P<10⁻⁴), and 2.13-fold increased risk for sepsis_total (95%CI: 1.59- to 2.84-fold, P<10⁻⁶) when adjusted for age, sex, race, and cohort. The risk increase did not differ significantly between runners and walkers, by sex, or by age. Sepsis_total risk was greater in diabetics (P = 10⁻⁵), cancer survivors (P = 0.0001), and heart attack survivors (P = 0.003) and increased with waist circumference (P = 0.0004). The sepsis_total risk associated with inadequate exercise persisted when further adjusted for diabetes, prior cancer, prior heart attack and waist circumference, and when excluding deaths with cancer, or cardiovascular, respiratory, or genitourinary disease as the underlying cause. Inadequate exercise also increased sepsis_total risk in 2163 baseline diabetics (4.78-fold, 95%CI: 2.1- to 13.8-fold, P = 0.0001) when adjusted, which was significantly greater (P = 0.03) than the adjusted risk increase in non-diabetics (1.80-fold, 95%CI: 1.30- to 2.46-fold, P = 0.0006).

Conclusion

Inadequate exercise is a risk factor for sepsis mortality, particular in diabetics.

Dose-response relationship of physical activity to premature and total all-cause and cardiovascular disease mortality in walkers

Purpose

To assess the dose-response relationships between cause-specific mortality and exercise energy expenditure in a prospective epidemiological cohort of walkers.

Methods

The sample consisted of the 8,436 male and 33,586 female participants of the National Walkers' Health Study. Walking energy expenditure was calculated in metabolic equivalents (METs, 1 MET = 3.5 ml O₂/kg/min), which were used to divide the cohort into four exercise categories: category 1 (≤1.07 MET-hours/d), category 2 (1.07 to 1.8 MET-hours/d), category 3 (1.8 to 3.6 MET-hours/d), and category 4 (≥3.6 MET-hours/d). Competing risk regression analyses were use to calculate the risk of mortality for categories 2, 3 and 4 relative to category 1.

Results

22.9% of the subjects were in category 1, 16.1% in category 2, 33.3% in category 3, and 27.7% in category 4. There were 2,448 deaths during the 9.6 average years of follow-up. Total mortality was 11.2% lower in category 2 (P = 0.04), 32.4% lower in category 3 (P<10⁻¹²) and 32.9% lower in category 4 (P = 10⁻¹¹) than in category 1. For underlying causes of death, the respective risk reductions for categories 2, 3 and 4 were 23.6% (P = 0.008), 35.2% (P<10⁻⁵), and 34.9% (P = 0.0001) for cardiovascular disease mortality; 27.8% (P = 0.18), 20.6% (P = 0.07), and 31.4% (P = 0.009) for ischemic heart disease mortality; and 39.4% (P = 0.18), 63.8% (P = 0.005), and 90.6% (P = 0.002) for diabetes mortality when compared to category 1. For all related mortality (i.e., underlying and contributing causes of death combined), the respective risk reductions for categories 2, 3 and 4 were 18.7% (P = 0.22), 42.5% (P = 0.001), and 57.5% (P = 0.0001) for heart failure; 9.4% (P = 0.56), 44.3% (P = 0.0004), and 33.5% (P = 0.02) for hypertensive diseases; 11.5% (P = 0.38), 41.0% (P<10⁻⁴), and 35.5% (P = 0.001) for dysrhythmias: and 23.2% (P = 0.13), 45.8% (P = 0.0002), and 41.1% (P = 0.005) for cerebrovascular diseases when compared to category 1.

Conclusions

There are substantial health benefits to exceeding the current exercise guidelines.

The relationship of walking intensity to total and cause-specific mortality. Results from the National Walkers' Health Study

PURPOSE

Test whether: 1) walking intensity predicts mortality when adjusted for walking energy expenditure, and 2) slow walking pace (≥24-minute mile) identifies subjects at substantially elevated risk for mortality.

METHODS

Hazard ratios from Cox proportional survival analyses of all-cause and cause-specific mortality vs. usual walking pace (min/mile) in 7,374 male and 31,607 female recreational walkers. Survival times were left censored for age at entry into the study. Other causes of death were treated as a competing risk for the analyses of cause-specific mortality. All analyses were adjusted for sex, education, baseline smoking, prior heart attack, aspirin use, diet, BMI, and walking energy expenditure. Deaths within one year of baseline were excluded.

RESULTS

The National Death Index identified 1968 deaths during the average 9.4-year mortality surveillance. Each additional minute per mile in walking pace was associated with an increased risk of mortality due to all causes (1.8% increase, P=10(-5)), cardiovascular diseases (2.4% increase, P=0.001, 637 deaths), ischemic heart disease (2.8% increase, P=0.003, 336 deaths), heart failure (6.5% increase, P=0.001, 36 deaths), hypertensive heart disease (6.2% increase, P=0.01, 31 deaths), diabetes (6.3% increase, P=0.004, 32 deaths), and dementia (6.6% increase, P=0.0004, 44 deaths). Those reporting a pace slower than a 24-minute mile were at increased risk for mortality due to all-causes (44.3% increased risk, P=0.0001), cardiovascular diseases (43.9% increased risk, P=0.03), and dementia (5.0-fold increased risk, P=0.0002) even though they satisfied the current exercise recommendations by walking ≥7.5 metabolic equivalent (MET)-hours per week.

CONCLUSIONS

The risk for mortality: 1) decreases in association with walking intensity, and 2) increases substantially in association for walking pace ≥24 minute mile (equivalent to <400 m during a six-minute walk test) even among subjects who exercise regularly.

Walking and running produce similar reductions in cause-specific disease mortality in hypertensives

To test prospectively in hypertensives whether moderate and vigorous exercise produces equivalent reductions in mortality, Cox-proportional hazard analyses were applied to energy expenditure (metabolic equivalents hours/d [METh/d]) in 6973 walkers and 3907 runners who used hypertensive medications at baseline. A total of 1121 died during 10.2-year follow-up: 695 cardiovascular disease (International Classification of Diseases, Tenth Revision [ICD10] I00-99; 465 underlying cause and 230 contributing cause), 124 cerebrovascular disease, 353 ischemic heart disease (ICD10 I20-25; 257 underlying and 96 contributing), 122 heart failure (ICD10 I50; 24 underlying and 98 contributing), and 260 dysrhythmias (ICD10 I46-49; 24 underlying and 236 contributing). Relative to <1.07 METh/d, running or walking 1.8 to 3.6 METh/d produced significantly lower all-cause (29% reduction; 95% confidence interval [CI], 17%-39%; P=0.0001), cardiovascular disease (34% reduction; 95% CI, 20%-46%; P=0.0001), cerebrovascular disease (55% reduction; 95% CI, 27%-73%; P=0.001), dysrhythmia (47% reduction; 95% CI, 27%-62%; P=0.0001), and heart failure mortality (51% reduction; 95% CI, 21%-70%; P=0.003), as did ≥ 3.6 METh/d with all-cause (22% reduction; 95% CI, 6%-35%; P=0.005), cardiovascular disease (36% reduction; 95% CI, 19%-50%; P=0.0002), cerebrovascular disease (47% reduction; 95% CI, 6%-71%; P=0.03), and dysrhythmia mortality (43% reduction; 95% CI, 16%-62%; P=0.004). Diabetes mellitus and chronic kidney disease mortality also decreased significantly with METh/d. All results remained significant when body mass index adjusted. Merely meeting guideline levels (1.07-1.8 METh/d) did not significantly reduced mortality. The dose-response was significantly nonlinear for all end points except diabetes mellitus, and cerebrovascular and chronic kidney disease. Results did not differ between running and walking. Thus, walking and running produce similar reductions in mortality in hypertensives.

Walking versus running for hypertension, cholesterol, and diabetes mellitus risk reduction

OBJECTIVE

To test whether equivalent energy expenditure by moderate-intensity (eg, walking) and vigorous-intensity exercise (eg, running) provides equivalent health benefits.

APPROACH AND RESULTS

We used the National Runners' (n=33 060) and Walkers' (n=15 945) Health Study cohorts to examine the effect of differences in exercise mode and thereby exercise intensity on coronary heart disease (CHD) risk factors. Baseline expenditure (metabolic equivant hours per day [METh/d]) was compared with self-reported, physician-diagnosed incident hypertension, hypercholesterolemia, diabetes mellitus, and CHD during 6.2 years follow-up. Running significantly decreased the risks for incident hypertension by 4.2% (P<10(-7)), hypercholesterolemia by 4.3% (P<10(-14)), diabetes mellitus by 12.1% (P<10(-5)), and CHD by 4.5% per METh/d (P=0.05). The corresponding reductions for walking were 7.2% (P<10(-6)), 7.0% (P<10(-8)), 12.3% (P<10(-4)), and 9.3% (P=0.01). Relative to <1.8 METh/d, the risk reductions for 1.8 to 3.6, 3.6 to 5.4, 5.4 to 7.2, and ≥7.2 METh/d were as follows: (1) 10.1%, 17.7%, 25.1%, and 34.9% from running and 14.0%, 23.8%, 21.8%, and 38.3% from walking for hypercholesterolemia; (2) 19.7%, 19.4%, 26.8%, and 39.8% from running and 14.7%, 19.1%, 23.6%, and 13.3% from walking for hypertension; and (3) 43.5%, 44.1%, 47.7%, and 68.2% from running, and 34.1%, 44.2% and 23.6% from walking for diabetes mellitus (walking >5.4 METh/d excluded for too few cases). The risk reductions were not significantly different for running than walking for diabetes mellitus (P=0.94), hypertension (P=0.06), or CHD (P=0.26), and only marginally greater for walking than running for hypercholesterolemia (P=0.04).

CONCLUSIONS

Equivalent energy expenditures by moderate (walking) and vigorous (running) exercise produced similar risk reductions for hypertension, hypercholesterolemia, diabetes mellitus, and possibly CHD.