Exercise standards. A statement for health professionals from the American Heart Association

Physical performance and glycemic control under SGLT-2-inhibitors in patients with type 2 diabetes and established atherosclerotic cardiovascular diseases or high cardiovascular risk (PUSH): Design of a 4-week prospective observational study

Background

Type 2 diabetes (T2D) is associated with limitation in physical performance. Results from animal studies report enhancement of physical performance in T2D rodents treated with sodium glucose cotransporter 2 inhibitors (SGLT2is). However, in human patients with T2D and established atherosclerotic cardiovascular disease (ASCVD) or high cardiovascular risk, the impact of guideline directed SGLT2i medication on physical performance has not been sufficiently examined.

Objectives

The main objectives of this study are thus firstly, to assess the changes in physical performance after 4 weeks of exercise therapy in patients with established ASCVD or high cardiovascular risk categorized into three groups according to their glycemic control at baseline. Secondly, to investigate the association of glycemic control at baseline and new guideline directed antidiabetic treatment (inadequate glycemic control and diabetes + new SGLT2i vs. adequate glycemic control and diabetes vs. no diabetes) with change in physical performance.

Methods and design

This is a 4-week prospective observational study of 450 participants with established ASCVD or high cardiovascular risk with or without T2D and without previous SGLT2i medication undergoing exercise therapy during inpatient rehabilitation in a single center in Switzerland. Upon admission, participants are categorized into 3 groups of 150 participants each according to their glycemic control. Group I consisting of participants with inadequately controlled T2D defined as mean fasting plasma glucose (FPG) of ≥7 mmol/L, who are consequently administered new treatment with an SGLT2i. Group II comprises of participants with adequately controlled T2D with mean FPG of <7 mmol/L requiring no antidiabetic medication change. Group III consists of participants with no diabetes and mean FPG of ≤ 5.5 mmol/L. Primary outcomes are 6-min walk distance and rate of perceived exertion. Secondary outcomes are echocardiographic parameters (left ventricular mass index; global longitudinal strain average; end-diastolic volume), fatigue, muscle, metabolic, and anthropometric measures.

Ethics and dissemination

This study is conducted in accordance with the Declaration of Helsinki with ethical approval from the Cantonal Ethical Commission of Bern, Switzerland. The results will be published in a peer-reviewed journal. The implementation and reporting will be according to the SPIRIT guidelines.

Study protocol registration

https://www.clinicaltrials.gov/, identifier: NCT03422263.

Perception and Performance of Physical Activity Behavior after Head and Neck Cancer Treatment: Exploration and Integration of Qualitative and Quantitative Findings

Maintaining or increasing physical activity (PA) may prevent loss of muscle mass and strength after completion of head and neck cancer (HNC) treatment. However, the exercise level of HNC patients may not meet PA guidelines. We aimed to explore HNC survivors' views on PA, their report of PA, and to compare these with objectively measured PA. Combined qualitative and quantitative data of HNC survivors were explored post-treatment. Data from semi-structured interviews, questionnaires, and objective measurements of PA were collected, analyzed, and integrated. This resulted in the identification of five themes related to prioritizing, day-to-day life, intention, positive feelings, and social support, respectively, in nine HNC survivors (male: n = 5; age: 52-67 years). Objectively measured PA levels were sedentary to low. The lack of intention to increase PA may be related to HNC survivors' perception that their current activity level is sufficient, despite low levels of measured PA. While some participants feel they need no help with PA, others are insecure about possible harms. Healthcare professionals may be able to help improve PA in HNC survivors with a tailored approach that reduces fear of harm and helps to incorporate higher intensity PA in daily activities.

Factors influencing physical activity engagement following coronary artery bypass graft surgery: A mixed methods systematic review

BACKGROUND

Engagement in physical activity during the initial months following coronary artery bypass graft (CABG) surgery is important in order to improve health, quality of life and functional outcomes. There are, however, many potential barriers to physical activity engagement during the recovery period. No review studies have focused on barriers and facilitators to engagement in physical activity during the early stages of recovery following CABG surgery.

OBJECTIVE

To explore the factors that influence engagement in physical activity during the first three months following CABG surgery.

METHODS

Four electronic databases were searched. Extracted data from selected studies were synthesised using the Joanna Briggs Institute convergent integrated approach.

RESULTS

Nineteen studies met the inclusion criteria. Four main themes that influenced engagement were identified: sociodemographic variables; physical symptoms; psychosocial factors; and environmental factors. More barriers were identified than facilitating factors. Psychosocial factors were the most commonly reported barriers in the literature.

CONCLUSIONS

The findings of this review provide insights into factors that inhibit and facilitate engagement in physical activity following CABG surgery. Further research specifically exploring factors that influence engagement, especially facilitators, is required.

Retina Vascular Perfusion Dynamics During Exercise With and Without Face Masks in Healthy Young Adults: An OCT Angiography Study

Purpose

To determine possible impacts on retinal microvasculature in healthy young adults during exercise with a face mask, using optical coherence tomography angiography (OCTA).

Methods

Twenty-three healthy participants (23 eyes, 17 women and 6 men) performed the incremental continuous running test (ICRT) with different masks. OCTA of the macula and optic nerve head were performed before and after ICRT to detect changes in retinal vessel density (VD). All participants were in groups A, B, and C (before ICRT) and groups A′, B′, and C′ (after ICRT), which comprised data from volunteers without a mask, with a surgical mask, and with an N95 mask, respectively.

Results

Before ICRT, group C showed significantly reduced VD in the superficial plexus (SP), except foveal VD, compared with group A (P < 0.05). After ICRT, groups B′ and C′ showed significantly shorter maximum running time, lower oxygen saturation, and lower perifoveal VD of SP compared with group A′ (P < 0.05).

Conclusions

Use of an N95 mask reduced VD in SP even under quiescent conditions, which might have clinical implications for protecting healthy workers and indoor manual labor workers from potential risks of retinal damage due to long-term mask use. Moreover, mask use while exercising might lead to attenuated exercise ability and lower VD in SP, which should be investigated in additional studies.

Translational Relevance

Retina vascular perfusion dynamics could be monitored in vivo by OCTA, which would be valuable to study physiologic retinal blood flow redistribution and potential impacts on retinal vascular perfusion during exercise with face masks.

By discontinuing beta-blockers before an exercise test we may precipitate a rebound phenomenon

BACKGROUND

There is a need to analyse the current approach to beta-blocker (BB) use in relation to exercise-based stress tests.

OBJECTIVE

We compared various guidelines regarding recommending abrupt vs gradual discontinuation of BB prior to exercise tests. We also analyse the shortcomings of the currently recommended approach and suggest a new approach to avoid BB rebound.

METHODS

A narrative review is used to analyse this topic due to lack of valid randomized clinical trials.

RESULTS

Omitting the BB therapy prior to exercise-based test has been recommended in guidelines for many years. Although reasonable, this approach has potential disadvantages since sudden BB withdrawal may induce a rebound phenomenon, which is, also, acknowledged in several guidelines.

CONCLUSIONS

We observed inconsistency among relevant guidelines; there is no homogenous approach regarding BB use before exercise tests. Most guidelines recommend BB withdrawal for a couple of days before the test; they do not advise BB dose tapering. This approach is not standardised and raises the risk of BB rebound phenomenon both before and during the test. Therefore, we suggest using the half the prescribed BB dose at the usual time of administration (in the morning, prior to the exercise test).

Effects of physical exercise on macular vessel density and choroidal thickness in children

We used swept-source (SS) optical coherence tomography (OCT) and OCT angiography (OCTA) to investigate the effects of moderate physical exercise on retinal and choroidal vessel densities (VDs) and thicknesses in children. One eye in each of 40 myopic children (mean age, 11.70 years) and 18 emmetropic children (mean age, 11.06 years) were included. SS-OCT 6 × 6-mm radial scans and SS-OCTA 3 × 3-mm images were centered on the macula. Heart rate (HR), systolic and diastolic blood pressure, and intraocular pressure (IOP) were recorded before and immediately after a 20-min stationary cycling exercise and after a 30-min rest. The subfoveal choroidal thickness (SFCT), choroidal thickness (CT), and VD at the superficial and deep retinal layers, choriocapillaris, and deeper choroidal vessels were determined. SFCT and CT were significantly lower at all locations immediately after exercise (p < 0.001) and did not fully recover after rest (p < 0.05). VD was lower in the deep retinal layer after exercise (p = 0.02) and higher in the superficial layer after rest (p = 0.03) in myopic eyes while it was higher in the superficial (p < 0.01) and deep layer (p < 0.01) after rest in emmetropic eyes. No significant exercise-related changes in the superficial retinal VD, choroidal VD, or IOP were observed. ΔCT% and ΔSFCT% were significantly correlated with increases in HR in myopic group (p = 0.04 and p = 0.03, respectively). Exercise increased retinal VD after rest in emmetropic eyes, and caused significant CT thinning that lasted for at least 30 min in both emmetropic and myopic eyes.

Assessment of baroreceptor reflex sensitivity in young obese Saudi males at rest and in response to physiological challenges

Autonomic imbalance in overweight/obese persons could lead to an increased risk of cardiovascular complications including hypertension and arrhythmias. Baroreceptor reflex sensitivity is a sensitive indicator to detect an altered sympathovagal balance in overweight/obese individuals. This study investigated the effects of overweight/obesity on baroreceptor sensitivity in young Saudi males at rest and in response to physiological challenges.

SUBJECTS AND METHODS

In this cross-sectional study, spontaneous baroreceptor sensitivity at rest and in response to deep breathing, isometric hand grip exercise and moderate intensity isotonic exercise were recorded in 20 normal weight and 20 overweight/obese subjects. Finger arterial blood pressure signal, recorded through Finometer, was used to calculate baroreceptor sensitivity through cross-correlation method. The baroreceptor sensitivity data were log transformed before application of parametric tests.

RESULTS

The spontaneous baroreceptor sensitivity was similar in both groups at baseline, but exhibited a significant increase during deep breathing only in normal weight (p < .001). Immediately after the isotonic exercise the baroreceptor sensitivity was significantly lower than baseline in both normal weight and overweight/obese and remained significantly lower in overweight/obese individuals compared to normal weight (p < .05) throughout the recovery period. There was a significant rise in baroreceptor sensitivity after isometric exercise in overweight/obese group only (p = .001). Pearson's correlation showed a significant negative correlation of baroreceptor sensitivity with body mass index during deep breathing (r = -.472, p = .004) and in post-isotonic exercise recovery period (r = -.414, p = .013).

CONCLUSION

A significantly reduced baroreceptor sensitivity response to deep breathing, reduced baroreceptor sensitivity recovery after isotonic exercise, and an exaggerated shoot up after isometric exercise in overweight/obese suggests an altered sympathovagal balance. Baroreceptor sensitivity measurements in response to physiological challenges, deep breathing, and isotonic exercise, may be more sensitive investigations for detection of early attenuation of cardiac autonomic function. This would enable timely intervention thereby delaying complications and improving the quality of life.

Renal Functional Reserve Is Related to the Nondipping Phenotype and to the Exercise Heart Rate Response in Patients with Essential Hypertension and Preserved Renal Function

BACKGROUND

Renal functional reserve (RFR), defined as the difference between stress and resting glomerular filtration rate (GFR), may constitute a diagnostic tool to identify patients at higher risk of developing acute kidney injury or chronic kidney disease. Blunted RFR has been demonstrated in early stages of hypertension and has been attributed to impaired vascular reactivity due to an overactive sympathetic nervous system (SNS).

OBJECTIVE

The purpose of this study was to investigate whether RFR correlates with other phenotypes expressing overactivity of the SNS in patients with essential hypertension and preserved renal function.

METHODS

Thirty-six patients with untreated essential hypertension and a GFR >60 mL/min/1.73 m2 were enrolled. The following parameters were measured: RFR, 24-h ambulatory blood pressure (BP) profile, a treadmill stress test, and an echocardiographic examination. Urine and venous samples were obtained at specific time points for the determination of clinical parameters, and both resting and stress GFR were calculated by using endogenous creatinine clearance for the measurement of RFR after an acute oral protein load (1 g/kg).

RESULTS

Twenty-one patients had a RFR <30 mL/min/1.73 m2 and 15 had a RFR above this cutoff. A nondipping pattern of 24-h BP was significantly more frequent in patients with low RFR (57.1 vs. 25.0%, p < 0.05 for systolic BP and 52.3 vs. 10.0%, p < 0.02 for diastolic BP). Moreover, patients with lower RFR values showed a blunted heart rate (HR) response to exercise during treadmill test (r = 0.439, p < 0.05). None of the echocardiographic parameters differed between the two groups of patients.

CONCLUSIONS

In hypertensive patients with preserved GFR, reduced RFR is related to nondipping BP phenotype as well as to attenuated exercise HR response. Overactivity of the SNS may be a common pathway. Since loss of RFR may represent a risk factor for acute or chronic kidney injury, hypertensive patients with blunted RFR might need a more careful renal follow-up.

Sex Differences in Cardiometabolic Traits and Determinants of Exercise Capacity in Heart Failure With Preserved Ejection Fraction

Importance

Sex differences in heart failure with preserved ejection fraction (HFpEF) have been established, but insights into the mechanistic drivers of these differences are limited.

Objective

To examine sex differences in cardiometabolic profiles and exercise hemodynamic profiles among individuals with HFpEF.

Design, Setting, and Participants

This cross-sectional study was conducted at a single-center tertiary care referral hospital from December 2006 to June 2017 and included 295 participants who met hemodynamic criteria for HFpEF based on invasive cardiopulmonary exercise testing results. We examined sex differences in distinct components of oxygen transport and utilization during exercise using linear and logistic regression models. The data were analyzed from June 2018 to May 2019.

Main Outcomes and Measures

Resting and exercise gas exchange and hemodynamic parameters obtained during cardiopulmonary exercise testing.

Results

Of 295 participants, 121 (41.0%) were men (mean [SD] age, 64 [12] years) and 174 (59.0%) were women (mean [SD] age, 61 [13] years). Compared with men, women with HFpEF in this tertiary referral cohort had fewer comorbidities, including diabetes, insulin resistance, and hypertension, and a more favorable adipokine profile. Exercise capacity was similar in men and women (percent predicted peak oxygen [O2] consumption: 66% in women vs 68% in men; P = .38), but women had distinct deficits in components of the O2 pathway, including worse biventricular systolic reserve (multivariable-adjusted analyses: ΔLVEF β = -1.70; SE, 0.86; P < .05; ΔRVEF β = -2.39, SE=0.80; P = .003), diastolic reserve (PCWP/CO: β = 0.63; SE, 0.31; P = .04), and peripheral O2 extraction (C(a-v)O2 β=-0.90, SE=0.22; P < .001)).

Conclusions and Relevance

Despite a lower burden of cardiometabolic disease and a similar percent predicted exercise capacity, women with HFpEF demonstrated greater cardiac and extracardiac deficits, including systolic reserve, diastolic reserve, and peripheral O2 extraction. These sex differences in cardiac and skeletal muscle responses to exercise may illuminate the pathophysiology underlying the development of HFpEF and should be investigated further.

Exercise testing after chronic total coronary occlusion revascularization in patients with STEMI and a concurrent CTO: A subanalysis of the EXPLORE-trial

OBJECTIVES

To assess the effect of chronic total occlusion percutaneous coronary intervention (CTO PCI) on ventricular ectopy (VE) and symptomatology during exercise testing.

BACKGROUND

During exercise, the hypoxic myocardium in the CTO-territory can act as a substrate for VE and could lead to anginal complaints.

METHODS

In the EXPLORE-trial, 302 ST-segment elevation myocardial infarction (STEMI)-patients were randomized to CTO PCI or no-CTO PCI. For this sub-study, we analyzed all available exercise electrocardiograms (X-ECGs) at 4 months follow-up on symptoms and electrocardiographic parameters.

RESULTS

A total of 155 X-ECGs were available, 80 in the CTO PCI group (51.6%) and 75 in the no-CTO PCI group (48.4%). There were no differences regarding exercised time, achieved endurance, ST-deviation nor maximum heart-rate. The percentage of patients experiencing chest-pain during exercise was lower in the CTO PCI group (0% vs. 8.5%, p = .03). Also, there was a trend towards a higher maximum systolic blood pressure (SBP, 185 mmHg vs. 175, p = .09). No difference in VE was found between randomization groups, but patients with successful CTO PCI had a higher frequency of VE, compared to failed and no-CTO PCI (26% vs. 8%, p = .02). This did not result in higher frequencies of sustained ventricular arrhythmias or mortality.

CONCLUSION

In conclusion, in STEMI-patients, CTO PCI is associated with a small reduction of chest-pain during exercise and tended to be associated with an increase of maximum SBP. The observation that successful CTO PCI was associated with more VE during exercise, compared with failed/no-CTO PCI needs further exploration.

Evaluation of the convergent validity of an estimated cardiorespiratory fitness algorithm

PURPOSE

Examine the convergent validity of a cardiorespiratory fitness (CRF) algorithm when compared to treadmill-assessed CRF.

METHODS

Data from the 1999-2004 NHANES were used (N = 3259 adults 20-49 years). Cardiorespiratory fitness was estimated from an algorithm. Participants completed a submaximal treadmill-based protocol. We (1) evaluated the pairwise association (and ICC) between estimated and measured cardiorespiratory fitness, (2) employed a paired samples t test to examine potential mean differences between estimated and measured cardiorespiratory fitness, (3) constructed a Bland-Altman plot and 95% limits of agreement (LoA) to explore systematic differences and random error between estimated and measured cardiorespiratory fitness, and (4) examined the association (via linear regression) of estimated and measured cardiorespiratory fitness with chronic disease prevalence and C-reactive protein (CRP).

RESULTS

Mean estimated CRF (10.68 METs) was lower than the mean measured CRF of 11.37 METs (p < 0.0001). The calculated pairwise correlation was of a moderate strength, r = 0.43 (p < 0.0001), with an ICC of 0.40 (p < 0.001). Calculated LoA indicated that estimated CRF may differ from measured CRF by 40% below to 48% above. Regression analyses yielded statistically significant inverse associations of estimated (unstandardized coefficient = - 0.026; p < 0.001) and measured (unstandardized coefficient = - 0.007; p = 0.002) CRF with chronic disease and estimated (unstandardized coefficient = - 0.08; p < 0.001) and measured (unstandardized coefficient = - 0.03; p < 0.001) CRF with CRP.

CONCLUSION

Measured and estimated CRF were moderately correlated. However, estimated and measured CRF were statistically significant different from one another with noteworthy scatter around the average difference. As such, when feasible, objective measurements of CRF should be taken.

Acute effects of incremental exercise on central hemodynamics in young basketball athletes

Acute effects of competitive sports on central hemodynamics are controversial. This study was aimed to evaluate acute effects of incremental exercise on central hemodynamics in young basketball athletes during 1-hour recovery. Fifteen young basketball athletes and fifteen controls underwent the acquisition of peripheral and central blood pressure before exercise and at 0, 5, 10, 15, 20, 30, 40, 50, 60 min after incremental exercise. The incremental exercise was performed by Bruce test. Aortic systolic pressure (ASP), sub-endocardial viability ratio and stroke volume were significantly higher in athletes at all time points measured before and after exercise (P<;0.05). Heart rate and ejection duration were significantly lower in athletes (P<;0.01 for all). Augmentation index (AIx) was higher in athletes than that in controls at rest. AIx significantly reduced in athletes at 0 min after exercise (P<;0.01), but not in controls. Both Cardiac output and total peripheral resistance significantly changed in athletes at 0 min after exercise (P<;0.01). Cardiac functions to incremental exercise at all time points in basketball athletes are stronger than those in controls. However, potential mechanism of vascular functions should be further explored because basketball athletes have higher ASP and AIx than those in controls.

Level of physical activity and aerobic capacity associate with quality of life in patients with temporal lobe epilepsy

Epilepsy is more than seizures and includes a high risk of comorbidities and psychological disorders, leading to poor quality of life (QOL). Earlier studies have showed a sedentary lifestyle in people with epilepsy (PWE), which could contribute to poorer health and psychological problems. The purpose of the present study was to compare habits of physical activity (PA), aerobic capacity, and QOL between PWE and healthy controls in order to identify the necessity of intervention of habits and information on physical exercise (PE) and to better understand the importance of PE for PWE. The study included 38 patients with temporal lobe epilepsy and 20 normal controls. Both groups answered the WHOQOL-Bref, which assesses the level of QOL, and IPAQ to evaluate the level of PA. In addition, they were submitted to a treadmill maximal cardiopulmonary effort test to identify physical capacity. The continuous variables were compared between groups by t-test and a general linear model, and the frequencies were compared by Chi-Square test through SPSS software. There was no difference in the level of PA between groups by questionnaire evaluation. However, there were significant differences in overall QOL, physical health, and level of PA in relation to work and physical capacity between groups; controls demonstrated better scores than PWE. Controls presented better physical capacity than PWE by cardiopulmonary effort test. According to intra-group analyses, PWE who were physically active had better QOL than inactive PWE. The study concluded that questionnaires about PE may not be the best instrument of evaluation, as demonstrated by the discrepancy of results compared to the validated objective cardiopulmonary evaluation of level of PA and physical capacity in this study.

Examining the relationship between sport and health among USA women: An analysis of the Behavioral Risk Factor Surveillance System

BACKGROUND

Research has been conducted linking sports participation and health in childhood and adolescence; however, little is known about the contribution of sport to women's health. The purpose of this study was to examine the relationship between sport and women's health in the USA by analyzing data from the Behavioral Risk Factor Surveillance System (BRFSS).

METHODS

This study was a secondary data analysis of the 2013 national BRFSS survey. Unlike the BRFSS core component from previous years, in 2013, participants were questioned extensively about their physical activity behaviors. Seventy-six different activities were identified by the participants. Two researchers categorized the 76 activities as sport, conditioning exercise, recreation, or household tasks based on previously identified categories. Logistic regression was utilized to calculate odds ratios and adjusted odds ratios for chronic diseases based on physical activity category.

RESULTS

Women who participated in sport had better health outcomes with significantly lower odds for all chronic diseases except asthma and better general health than women who participated in conditioning exercise, household tasks, or recreation, and many of the significant differences remained after controlling for demographic characteristics.

CONCLUSION

Sport participation was associated with more positive health outcomes among women in the USA compared with the other categories. As a means to improve health of women, the USA could focus on efforts to increase sport participation among women.

Midlife exercise blood pressure, heart rate, and fitness relate to brain volume 2 decades later

OBJECTIVE

To determine whether poor cardiovascular (CV) fitness and exaggerated exercise blood pressure (BP) and heart rate (HR) were associated with worse brain morphology in later life.

METHODS

Framingham Offspring participants (n = 1,094, 53.9% female) free from dementia and CV disease (CVD) underwent an exercise treadmill test at a mean age of 40 ± 9 years. A second treadmill test and MRI scans of the brain were administered 2 decades later at mean age of 58 ± 8 years.

RESULTS

Poor CV fitness and greater diastolic BP and HR response to exercise at baseline were associated with a smaller total cerebral brain volume (TCBV) almost 2 decades later (all p < 0.05) in multivariable adjusted models; the effect of 1 SD lower fitness was equivalent to approximately 1 additional year of brain aging in individuals free of CVD. In participants with prehypertension or hypertension at baseline, exercise systolic BP was also associated with smaller TCBV (p < 0.05).

CONCLUSION

Our results suggest that lower CV fitness and exaggerated exercise BP and HR responses in middle-aged adults are associated with smaller brain volume nearly 2 decades later. Promotion of midlife CV fitness may be an important step towards ensuring healthy brain aging.

A preprocessing tool for removing artifact from cardiac RR interval recordings using three-dimensional spatial distribution mapping

Artifact is common in cardiac RR interval data that is recorded for heart rate variability (HRV) analysis. A novel algorithm for artifact detection and interpolation in RR interval data is described. It is based on spatial distribution mapping of RR interval magnitude and relationships to adjacent values in three dimensions. The characteristics of normal physiological RR intervals and artifact intervals were established using 24-h recordings from 20 technician-assessed human cardiac recordings. The algorithm was incorporated into a preprocessing tool and validated using 30 artificial RR (ARR) interval data files, to which known quantities of artifact (0.5%, 1%, 2%, 3%, 5%, 7%, 10%) were added. The impact of preprocessing ARR files with 1% added artifact was also assessed using 10 time domain and frequency domain HRV metrics. The preprocessing tool was also used to preprocess 69 24-h human cardiac recordings. The tool was able to remove artifact from technician-assessed human cardiac recordings (sensitivity 0.84, SD = 0.09, specificity of 1.00, SD = 0.01) and artificial data files. The removal of artifact had a low impact on time domain and frequency domain HRV metrics (ranging from 0% to 2.5% change in values). This novel preprocessing tool can be used with human 24-h cardiac recordings to remove artifact while minimally affecting physiological data and therefore having a low impact on HRV measures of that data.

A case of fitness to work in a worker with COPD using the exercise stress test

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is a chronic respiratory disease characterized by persistent airflow limitation. Therefore, both work ability and workday length may be affected in individuals with this disease. We studied a worker with suspected COPD and assessed fitness to work using post-bronchodilator spirometry, symptom assessment scales, and the exercise stress test.

CASE REPORT

The patient was a 58-year-old man due to work as a field supervisor in the ship construction sector. He had a 40 pack-year smoking history and experienced occasional dyspnea when climbing stairs. He visited this hospital to receive cardiopulmonary function tests and to determine his ability to work. Post-bronchodilator spirometry revealed severe irreversible airway obstruction corresponding to a modified Medical Research Council grade of 2 on the dyspnea scale. His COPD Assessment Test score was 12, placing him in patient group D (high risk, more symptoms) based on the Global Initiative for Chronic Obstructive Lung Disease classification system. His maximum oxygen uptake (VO2max) was determined to be 19.16 ml/kg/min, as measured by the exercise stress test, and his acceptable workload for 8 h of physical work was calculated to be 6.51 ml/kg/min. His work tasks required an oxygen demand of 6.89 ml/kg/min, which exceeded the acceptable workload calculated. Accordingly, he was advised to adjust the work tasks that were deemed inappropriate for his exercise capacity.

CONCLUSION

As COPD incidence is expected to rise, early COPD diagnosis and determination of fitness to work is becoming increasingly important. Performing the exercise stress test, to evaluate the functional capacity of workers with COPD, is considered an acceptable solution.

QT hysteresis index improves the power of treadmill exercise test in the screening of coronary artery disease

BACKGROUND

QT hysteresis phenomenon exists in healthy subjects, and is more exaggerated in patients with coronary artery disease (CAD) and long QT syndrome. The purpose of this study was to establish an appropriate method to evaluate the magnitude of QT hysteresis, and assess the value of QT hysteresis index in the treadmill exercise test (TET) in predicting CAD. METHODS AND RESULTS: A total of 138 subjects with suspected CAD and referred for TET and selective coronary angiography (SCA) were divided into positive (n=77) and negative (n=61) SCA groups. Dynamic ECG were recorded during TET. QT/RR curves were constructed and QTp (Q-Tpeak) and QTe (Q-Tend) hysteresis indices were calculated for each subject. SYNTAX score in the positive SCA group was determined. The QTp and QTe hysteresis indices in the positive SCA group were significantly higher than in the negative SCA group. The combination of QTe hysteresis index and conventional TET criteria had the highest sensitivity and negative predictive value according to receiver operating characteristic curve, and was an independent predictor on multivariate logistic regression. QT hysteresis indices significantly correlated with SYNTAX score in the positive SCA group.

CONCLUSIONS

QTe hysteresis index enhances the specificity of predicting CAD in TET. It improves the diagnostic value of TET for CAD significantly when combined with conventional criteria and is associated with the severity of CAD.

Effects of Exercise Type on Hemodynamic Responses and Cardiac Events in ACS Patients

[Purpose] This study investigated the effects of mid, and high exercise intensities on hemodynamic responses and cardiac events during two exercise types of treadmill exercise (TM) and cycle ergometer exercises (CE) in patients with acute coronary syndrome (ACS). [Subjects] Patients who had percutaneous coronary intervention (PCI) for ACS and were participating in cardiac rehabilitation program were included. [Methods] The patients were assessed for hemodynamic responses, cardiac events, and rate of perceived exertion (RPE) with target heart rates of 60% and 85% heart rate reserve (HRR) during TM and CE. [Results] Maximum systolic blood pressure (SBP), diastolic blood pressure (DBP), RPE, and rate pressure product (RPP) measured during CE were significantly higher than their values in TM at the same exercise intensities. The highest SBP was shown at 85% HRR during CE. SBP_max to SBP_max ratios obtained during the graded exercise test (GXT) showed that all %SBP_max were significantly greater in CE than in TM at the same exercise intensities. Out of 102 patients, cardiac events occurred in 8 at 85% HRR during CE, and 1 at 85% HRR during TM. Patients with cardiac events (CE-E) had significantly higher %SBP, %RPP, and RPE at 85% HRR than those without events (CE-NE) during CE. [Conclusion] Prescribing exercise based on the intensity obtained in a treadmill GXT may expose patients to cardiovascular complications such as higher RPP, higher exercise intensity, and cardiac events during CE.

Cardiovascular responses to plyometric exercise are affected by workload in athletes

Introduction

With regard to blood pressure responses to plyometric exercise and decreasing blood pressure after exercise (post-exercise hypotension), the influence of different workloads of plyometric exercise on blood pressure is not clear.

Aim

The purpose of this investigation was to examine the effects of a low, moderate and high workload of plyometric exercise on the post-exercise systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and rate-pressure product (RPP) responses in athletes.

Material and methods

Ten male athletes (age: 22.6 ±0.5 years; height: 178.2 ±3.3 cm; and body mass: 75.2 ±2.8 kg) underwent PE protocols involving 5 × 10 reps (Low Workload – LW), 10 × 10 reps (Moderate Workload – MW), and 15 × 10 reps (High Workload – HW) depth jump exercise from a 50-cm box in 3 non-consecutive days. After each exercise session, SBP, DBP and HR were measured every 10 min for a period of 70 min.

Results

No significant differences were observed among post-exercise SBP and DBP when the protocols (LW, MW and HW) were compared. The MW and HW protocols showed greater increases in HR compared with LW. Also the HW indicated greater increases than LW in RPP at post-exercise (p < 0.05).

Conclusions

All protocols increased SBP, HR and RPP responses at the 10^th and 20^th min of post-exercise. With regard to different workloads of plyometric exercise, HW condition indicated greater increases in HR and RPP and strength and conditioning professionals and athletes must keep in their mind that HW of plyometric exercise induces greater cardiovascular responses.

Evidence-based risk recommendations for best practices in the training of qualified exercise professionals working with clinical populations

This systematic review examines critically "best practices" in the training of qualified exercise professionals. Particular attention is given to the core competencies and educational requirements needed for working with clinical populations. Relevant information was obtained by a systematic search of 6 electronic databases, cross-referencing, and through the authors' knowledge of the area. The level and grade of the available evidence was established. A total of 52 articles relating to best practices and (or) core competencies in clinical exercise physiology met our eligibility criteria. Overall, current literature supports the need for qualified exercise professionals to possess advanced certification and education in the exercise sciences, particularly when dealing with "at-risk" populations. Current literature also substantiates the safety and effectiveness of exercise physiologist supervised stress testing and training in clinical populations.

Effects and costs of home-based training with telemonitoring guidance in low to moderate risk patients entering cardiac rehabilitation: The FIT@Home study

Background

Physical training has beneficial effects on exercise capacity, quality of life and mortality in patients after a cardiac event or intervention and is therefore a core component of cardiac rehabilitation. However, cardiac rehabilitation uptake is low and effects tend to decrease after the initial rehabilitation period. Home-based training has the potential to increase cardiac rehabilitation uptake, and was shown to be safe and effective in improving short-term exercise capacity. Long-term effects on physical fitness and activity, however, are disappointing. Therefore, we propose a novel strategy using telemonitoring guidance based on objective training data acquired during exercise at home. In this way, we aim to improve self-management skills like self-efficacy and action planning for independent exercise and, consequently, improve long-term effectiveness with respect to physical fitness and physical activity. In addition, we aim to compare costs of this strategy with centre-based cardiac rehabilitation.

Methods/design

This randomized controlled trial compares a 12-week telemonitoring guided home-based training program with a regular, 12-week centre-based training program of equal duration and training intensity in low to moderate risk patients entering cardiac rehabilitation after an acute coronary syndrome or cardiac intervention. The home-based group receives three supervised training sessions before they commence training with a heart rate monitor in their home environment. Participants are instructed to train at 70-85% of their maximal heart rate for 45–60 minutes, twice a week. Patients receive individual coaching by telephone once a week, based on measured heart rate data that are shared through the internet. Primary endpoints are physical fitness and physical activity, assessed at baseline, after 12 weeks and after one year. Physical fitness is expressed as peak oxygen uptake, assessed by symptom limited exercise testing with gas exchange analysis; physical activity is expressed as physical activity energy expenditure, assessed by tri-axial accelerometry and heart rate measurements. Secondary endpoints are training adherence, quality of life, patient satisfaction and cost-effectiveness.

Discussion

This study will increase insight in long-term effectiveness and costs of home-based cardiac rehabilitation with telemonitoring guidance. This strategy is in line with the trend to shift non-complex healthcare services towards patients’ home environments.

Trial registration

Dutch Trial Register: NTR3780. Clinicaltrials.gov register: NCT01732419

Heart rate and blood pressure response to exercise and recovery in subclinical hypothyroid patients

Background:

Exercise response of asymptomatic subclinical hypothyroid patients may aid in early diagnosis of cardiovascular morbidity.

Aim:

To study and compare the heart rate and blood pressure changes during exercise and recovery in subclinical hypothyroid patients and euthyroid controls.

Materials and Methods:

For the study, 30 each cases (mean age of 40 ± 7 years) of subclinical hypothyroidism and healthy controls underwent exercise as per Bruce protocol. Heart rate (HR) and blood pressure (BP) changes were compared every minute (min) till 3 min of stage II exercise, continued till maximum heart rate and thereafter on recovery, for 5 min after stoppage of exercise.

Results:

Both groups had normal HR and BP at rest, heart rate and BP increased with exercise and remained high even after 5 min of recovery from exercise. The increase in systolic blood pressure (SBP) with exercise was less in patients at the stage of exercise where maximum HR was achieved and up to 1 min of recovery. SBP at 5 min of recovery was higher in patients (P = 0.018). Diastolic blood pressure (DBP) increased with exercise and changes were similar in both groups during exercise and recovery. HR was higher in patients at 1 min of exercise. Changes in HR from 1 min of recovery to 2-5 min of recovery were significant in both groups.

Conclusion:

The present pilot study highlights that many parameters of HR and SBP during exercise and recovery in asymptomatic subclinical hypothyroid patients may differ from euthyroid, controls.

Does obstructive sleep apnea impair the cardiopulmonary response to exercise?

STUDY OBJECTIVES

The aim of this study was to evaluate cardiopulmonary exercise performance in lean and obese patients with obstructive sleep apnea (OSA) compared with controls.

DESIGN

Case-control study.

SETTING

The study was carried out in Sao Paulo Sleep Institute, Sao Paulo, Brazil.

PATIENTS AND PARTICIPANTS

INDIVIDUALS WITH SIMILAR AGES WERE ALLOCATED INTO GROUPS: 22 to the lean OSA group, 36 to the lean control group, 31 to the obese OSA group, and 26 to the obese control group.

INTERVENTIONS

The participants underwent a clinical evaluation, polysomnography, a maximum limited symptom cardiopulmonary exercise test, two-dimensional transthoracic echocardiography, and spirometry.

MEASUREMENTS AND RESULTS

The apnea-hypopnea index, arousal index, lowest arterial oxygen saturation (SaO2) and time of SaO2 < 90% were different among the groups. There were differences in functional capacity based on the following variables: maximal oxygen uptake (VO2max), P < 0.01 and maximal carbon dioxide production (VCO2max), P < 0.01. The obese patients with OSA and obese controls presented significantly lower VO2max and VCO2max values. However, the respiratory exchange ratio (RER) and anaerobic threshold (AT) did not differ between groups. Peak diastolic blood pressure (BP) was higher among the obese patients with OSA but was not accompanied by changes in peak systolic BP and heart rate (HR). When multiple regression was performed, body mass index (P < 0.001) and male sex in conjunction with diabetes (P < 0.001) independently predicted VO2max (mL/kg/min).

CONCLUSIONS

The results of this study suggest that obesity alone and sex, when associated with diabetes but not OSA, influenced exercise cardiorespiratory function.

Physical Activity and Long-Term Maintenance of Weight Loss

To examine the effect of exercise on the long-term maintenance of weight loss, two types of literature were reviewed--correlational studies of predictors of long-term weight loss, and randomized trials comparing diet, exercise, and the combination of diet plus exercise. Both literatures were striking in the consistency with which activity emerged as a determinant of long-term maintenance of weight loss. The benefits of exercise for long-term weight maintenance were observed with different types of populations, diets, and exercise interventions. Several possible explanations for these positive effects of diet plus exercise are presented, and suggestions made for future research on ways to maximize the benefit of this approach to weight control. Since adherence to exercise may ultimately prove to be the cornerstone for long-term weight maintenance, studying ways to improve exercise adherence is recommended.

A randomized, double-blind, placebo-controlled, crossover, dose-ranging multicenter study to determine the effect of sublingual nitroglycerin spray on exercise capacity in patients with chronic stable angina

BACKGROUND

Sublingual nitroglycerin increases exercise duration in patients with stable angina. Brief results from this study were published previously in German. Here, we more fully describe the study methodology, patient characteristics, and detailed results.

METHODS

This double-blind, crossover study enrolled 51 patients with stable angina. Patients were randomized to 1 of 5 treatment sequences and were administered placebo or nitroglycerin spray (0.2 mg, 0.4 mg, 0.8 mg, or 1.6 mg). Patients carried out 1 control exercise tolerance test (ETT) and 1 investigational ETT at each visit.

RESULTS

Dose-dependent increases in time to onset of angina, time to onset of moderate angina, and the occurrence of a minimum 1.0-mm ST-segment depression were seen following administration of nitroglycerin spray.

CONCLUSIONS

These results support the use of sublingual nitroglycerin spray in patients with stable angina who are being managed with medical therapy and in patients who have persistent angina post-revascularization.

Accuracy of peak VO2 assessments in career firefighters

BACKGROUND

Sudden cardiac death is the leading cause of on-duty death in United States firefighters. Accurately assessing cardiopulmonary capacity is critical to preventing, or reducing, cardiovascular events in this population.

METHODS

A total of 83 male firefighters performed Wellness-Fitness Initiative (WFI) maximal exercise treadmill tests and direct peak VO2 assessments to volitional fatigue. Of the 83, 63 completed WFI sub-maximal exercise treadmill tests for comparison to directly measured peak VO2 and historical estimations.

RESULTS

Maximal heart rates were overestimated by the traditional 220-age equation by about 5 beats per minute (p < .001). Peak VO2 was overestimated by the WFI maximal exercise treadmill and the historical WFI sub-maximal estimation by ~ 1MET and ~ 2 METs, respectively (p < 0.001). The revised 2008 WFI sub-maximal treadmill estimation was found to accurately estimate peak VO2 when compared to directly measured peak VO2.

CONCLUSION

Accurate assessment of cardiopulmonary capacity is critical in determining appropriate duty assignments, and identification of potential cardiovascular problems, for firefighters. Estimation of cardiopulmonary fitness improves using the revised 2008 WFI sub-maximal equation.

Exercise guidelines in pregnancy: new perspectives

In 2002, the American College of Obstetricians and Gynecologists published exercise guidelines for pregnancy, which suggested that in the absence of medical or obstetric complications, 30 minutes or more of moderate exercise a day on most, if not all, days of the week is recommended for pregnant women. However, these guidelines did not define 'moderate intensity' or the specific amount of weekly caloric expenditure from physical activity required. Recent research has determined that increasing physical activity energy expenditure to a minimum of 16 metabolic equivalent task (MET) hours per week, or preferably 28 MET hours per week, and increasing exercise intensity to ≥60% of heart rate reserve during pregnancy, reduces the risk of gestational diabetes mellitus and perhaps hypertensive disorders of pregnancy (i.e. gestational hypertension and pre-eclampsia) compared with less vigorous exercise. To achieve the target expenditure of 28 MET hours per week, one could walk at 3.2 km per hour for 11.2 hours per week (2.5 METs, light intensity), or preferably exercise on a stationary bicycle for 4.7 hours per week (∼6-7 METs, vigorous intensity). The more vigorous the exercise, the less total time of exercise is required per week, resulting in ≥60% reduction in total exercise time compared with light intensity exercise. Light muscle strengthening performed over the second and third trimester of pregnancy has minimal effects on a newborn infant's body size and overall health. On the basis of this and other information, updated recommendations for exercise in pregnancy are suggested.

Attenuated cardiovascular response to sympathetic system activation during exercise in patients with dialysis-induced hypotension

BACKGROUND

We wished to investigate potential causes of dialysis-induced hypotension (DIH), including the attenuated cardiovascular response to sympathetic system activation during exercise and myocardial dysfunction.

METHODS

This study included 26 end-stage renal disease (ESRD) patients with DIH, 30 ESRD patients without DIH (Non-DIH), and 30 control subjects. Each patient was evaluated with echocardiography and a symptom-limited treadmill stress test. The chronotropic index (CRI), heart rate recovery (HRR), systolic blood pressure response to exercise (SBP response), and tissue Doppler systolic myocardial velocities were calculated.

RESULTS

The HRR and velocities were reduced in dialysis patients compared to controls; however, they were similar in patients with and without DIH. Patients with DIH had the lowest CRI compared to the Non-DIH group (0.62 ± 0.15 vs. 0.73 ± 0.17, p = 0.020) and controls (0.62 ± 0.15 vs. 0.86 ± 0.11, p < 0.001). Similarly, patients with DIH had the lowest SBP response values compared to the Non-DIH (34.88 ± 15.01 vs. 55.67 ± 25.42, p = 0.002) and controls (34.88 ± 15.01 vs. 59.70 ± 23.04, p < 0.001).

CONCLUSION

Patients with DIH have inadequate sympathetic activity of the cardiovascular system during exercise and impaired left ventricular systolic function. Both factors could contribute to the development of hypotension during hemodialysis.

A Prospective Cohort Study on the Impact of a Modified Basic Military Training (mBMT) Programme Based on Pre-enlistment Fitness Stratification Amongst Asian Military Enlistees

Introduction: This study objectively evaluates the effectiveness of a 6-week Preparatory Training Phase (PTP) programme prior to Basic Military Training (BMT) for less physically conditioned conscripts in the Singapore Armed Forces. Materials and Methods: We compared exercise test results of a group of less fit recruits who underwent a 16-week modified-BMT (mBMT) programme (consisting of a 6-week PTP and 10-week BMT phase) with their ‘fitter’ counterparts enlisted in the traditional 10-week direct-intake BMT (dBMT) programme in this prospective cohort study consisting of 36 subjects. The main outcome measures included cardiopulmonary responses parameters ( O2max and O2AT) with clinical exercise testing and distance run timings. Results: Although starting off at a lower baseline in terms of physical fitness [ O2max 1.73 ± 0.27 L/min (mBMT group) vs 1.97 ± 0.43 L/min (dBMT), P = 0.032; O2AT 1.02 ± 0.19 vs 1.14 ± 0.32 L/min respectively, P = 0.147], the mBMT group had greater improvement in cardiopulmonary indices and physical performance profiles than the dBMT cohort as determined by cardiopulmonary exercise testing [ O2max 2.34 ± 0.24 (mBMT) vs 2.36 ± 0.36 L/min (dBMT), P = 0.085; O2AT 1.22 ± 0.17 vs 1.21 ± 0.24 L/min respectively, P = 0.303] and 2.4 kilometres timed-run [mBMT group 816.1 sec (pre-BMT) vs 611.1 sec (post-BMT), dBMT group 703.8 sec vs 577.7 sec, respectively; overall P value 0.613] at the end of the training period. Initial mean difference in fitness between mBMT and dBMT groups on enlistment was negated upon graduation from BMT. Conclusion: Pre-enlistment fitness stratification with training modification in a progressive albeit longer BMT programme for less-conditioned conscripts appears efficacious when measured by resultant physical fitness. Key words: Exercise capacity, Oxygen uptake, Recruits, Singapore

Cardiovascular Risk Factors among Career Firefighters

Sudden cardiac death is the leading cause of on-duty death among firefighters. Determining firefighters' risk of cardiovascular death or all-cause mortality, cardiovascular risk factor profiles, and energy demands while firefighting may aid in understanding why this occupational group is at risk for on-duty sudden cardiac death. A literature review conducted between 2006 and 2009 did not demonstrate that firefighters are at increased risk of all-cause death compared to the general population. In addition, cardiovascular risk profiles of firefighters are similar to those of the general population. Firefighters may be part of the national obesity epidemic; their hypertension and hypercholesteremia often are not diagnosed or are undertreated. The combination of personal cardiovascular risk factors and extreme physical work demands may contribute to sudden cardiac death in this population.

Suplementação proteica não aumenta a concentração plasmática de óxido nítrico em homens saudáveis

Suplementos nutricionais, supostamente, capazes de potencializar a produção endógena de óxido nítrico (NO) têm experimentado crescente popularidade entre os indivíduos fisicamente ativos. Diante da carência de informações sobre o assunto, o objetivo do presente estudo foi avaliar o efeito de um suplemento comercial à base de proteínas e aminoácidos sobre a produção endógena de NO. MÉTODOS: A amostra foi constituída de 12 homens sedentários, mas sem fatores de risco para doenças cardiovasculares. O protocolo de suplementação foi conduzido conforme o arranjo experimental duplo-cego cruzado. Os participantes receberam, aleatoriamente, placebo (PLA) ou suplemento proteico (SP), em dois momentos diferentes, separados por uma semana. Com o intuito de determinar a concentração plasmática de NO, amostras de sangue foram coletadas antes (24h e imediatamente antes) e depois (30 e 60 minutos) do consumo da substância PLA ou do SP. RESULTADOS: Não foi observada alteração na concentração plasmática de NO após a ingestão do SP em comparação com o PLA (pós-suplementação 30min - PLA: 19,3 ± 4,7µmol.L- 1 vs. SP: 18,9 ± 4,4µmol.L-1 e pós-suplementação 60min - PLA: 21,3 ± 6,5µmol.L-1 vs. SP: 20,3 ± 4,9µmol.L-1). Também não foi verificada alteração da pressão arterial. CONCLUSÃO: O suplemento nutricional à base de proteínas e aminoácidos, testado no presente estudo, não potencializou a produção endógena de NO.

Assessing the appropriateness of coronary revascularization: the University of Maryland Revascularization Appropriateness Score (RAS) and its comparison to RAND expert panel ratings and American College of Cardiology/American Heart Association guidelines with regard to assigned appropriateness rating and ability to predict outcome

BACKGROUND

Significant regional variation in procedural frequencies has led to the development of the RAND and American College of Cardiology/American Heart Association (ACC/AHA) guidelines; however, they may be difficult to apply in clinical practice. The University of Maryland Revascularization Appropriateness Score (RAS) was created to address the need for a simplified point scoring system.

HYPOTHESIS

The study was undertaken to compare revascularization appropriateness ratings yielded by the RAND Expert Panel Ratings, ACC/AHA guidelines, and the University of Maryland RAS.

METHODS

We applied these three revascularization appropriateness scoring systems to 153 catheterization laboratory patients with a variety of cardiac diagnoses and treatments. For each patient, appropriateness scores assigned by each of the three systems were compared with each other and with the actual treatment delivered. Concordance of care with appropriateness score was then correlated with outcome.

RESULTS

There were significant differences among all three scoring systems in their ratings and in the concordance of treatment with appropriateness rating. When treatment provided was concordant with RAND ratings, there was a lower occurrence of subsequent coronary artery bypass grafting (CABG), the composite end point of either CABG or percutaneous transluminal coronary angioplasty (PTCA), and the composite end point of death, myocardial infarction (MI), or revascularization. When treatment was concordant with the ACC/AHA guidelines, there was lower occurrence of all-cause mortality, PTCA, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization. When treatment provided was concordant with the RAS, there was lower occurrence of cardiac death, all-cause death, CABG, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization.

CONCLUSIONS

The RAS is a simple scoring system to assess revascularization appropriateness. When the RAND, ACC/AHA, and RAS systems are compared in a catheterization laboratory population, they rate the same patient differently and vary in their correlation of appropriateness rating with outcome.

Maximum oxygen uptake and body composition of healthy Hong Kong Chinese adult men and women aged 20 - 64 years

The aims of the present study were to assess the maximal oxygen uptake and body composition of adult Chinese men and women, and to determine how these variables relate to age. The cross-sectional sample consisted of 196 men and 221 women aged 20 - 64 years. Maximal oxygen uptake (VO2max) was determined by indirect calorimetry during a maximal exercise test on an electrically braked cycle ergometer. The correlations between VO2max and fat mass were -0.52 in men and -0.58 in women. Linear regression defined the cross-sectional age-related decline in VO2max as 0.35 ml kg(-1) min(-1) year(-1) in men and 0.30 ml kg(-1) min(-1) year(-1) in women. Multiple regression analysis showed that more than 50% of this cross-sectional decline in VO2max was due to fat mass, lean mass, and age. Adding fat mass and lean mass to the multiple regression models reduced the age regression mass from 0.35 to 0.24 ml kg(-1) min(-1) year(-1) in men and from 0.30 to 0.15 ml kg(-1) min(-1) year(-1) in women. We conclude that age, fat mass, and lean mass are independent determinants of maximal oxygen uptake in Chinese adults.

Reliability and validity of self-reported physical activity in the Nord-Trøndelag Health Study — HUNT 1

Background: A large health survey was previously conducted in 1984—86, the Nord-Trøndelag Health Study (HUNT 1), and another was conducted in 1995—97 (HUNT 2). A third, HUNT 3, started in 2006. However, the physical activity (PA) questionnaires have not yet been validated. Aims: To assess the reliability and validity of the self-reported physical activity questionnaire in the Nord-Trøndelag Health Study (HUNT 1). Methods: The HUNT 1 questionnaire was administered to a random sample of 108 healthy men aged 20—39 years. Repeatability was assessed with a repeat questionnaire after one week, and validity by comparing results with direct measurement of VO2during maximal work on a treadmill, with ActiReg, an instrument that measures PA and energy expenditure (EE) and with the International Physical Activity Questionnaire (IPAQ). ActiReg records the main body positions (stand, sit, bent forward and lie) together with the motion of the trunk and/or one leg each second. Results: The results indicated strong, significant agreement on test—retest (weighted kappa frequency, r=0.80, intensity, r=0.82, and duration, r=0.69). We found a moderate, significant correlation, r=0.48 (p≤0.01), between the index based on questionnaire responses and VO2max.Metabolic equivalent (MET) values of 6 or more from ActiReg and ``vigorous activity'' from the IPAQ most strongly correlated with the index (r=0.39, r=0.55, respectively). Associations of other measures obtained from ActiReg with questionnaire responses were weaker. Conclusions: Our results indicate that the PA questionnaire in HUNT 1 is reproducible and provides a useful measure of leisure-time PA for men. The questionnaire is very short, and compared favourably with much longer instruments for assessment of more vigorous PA. It should be an appropriate tool for use in further epidemiological studies, particularly when the interest is in aspects of PA reflected in fitness or METs greater than 6.