Factors affecting cardiac frequency during self paced walking: body composition, age, sex and habitual activity [proceedings].
Explore the source record for details and available documents.
SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Energy expenditure during rest and self-paced walking was determined from early to late pregnancy either longitudinally or in a cross-section of women. The cross-sectional study was done with 16 women confined to a metabolic unit: six nonpregnant (NP), six early pregnant (EP 10 to 20 wk gestation), and four late pregnant (LP 30 to 40 wk gestation). In the longitudinal study, five of the six EP subjects from the cross-sectional study were studied at 5-wk intervals until parturition. Basal metabolic rate, measured by open circuit, indirect calorimetry, and expressed as kcal/min, was 13% greater (p less than 0.05) in EP compared to NP and was 28% greater (p less than 0.05) in LP compared to EP. Resting metabolism increased during gestation in the EP group from a value of 1.01 kcal/min at 15 to 25 wk to 1.15 kcal/min at 35 to 40 wk. When energy expenditure during rest is expressed as kcal/kg body weight/h, there were no significant differences due to stage of pregnancy. The time required for the women to walk 400 m at their own pace was measured. The pace of the LP women was 20% slower (p less than 0.05) than the EP women. But when the EP women were studied at 35 and 40 wk gestation their pace was only 4.5% slower than that at 15 to 25 wk. These data suggest that individual behavioral differences have a greater effect on pace than stage of gestation. A decrease in pace reduced the rate of energy expenditure per kilogram body weight for walking 400 m. But, body weight, rather than pace, was the major determinant of total energy expenditure for the walk (p less than 0.05). It is apparent from these data that body weight is the major determinant of energy expenditure during rest and self-paced weight bearing activity in pregnancy.
A treadmill exercise test is described that retains the advantages of self paced walking but allows the measurement of cardiorespiratory variables. A horizontal treadmill was modified to allow patients to control their own speed. During exercise continuous measurements of speed, distance, heart rate, arterial oxygen saturation, and stride length were made and subjective assessments of breathlessness were recorded on a visual analogue scale. Ten men with severe chronic obstructive lung disease performed a 12 minute corridor walk and a self paced 12 minute treadmill walk on the same day and repeat treadmill walks on different days. Six of them performed three walks or more. Six patients had ventilatory measurements during treadmill exercise. There was no significant difference (p greater than 0.1) in the distance covered during corridor and treadmill walks, and distances on the treadmill were repeatable after the first walk. Use of a mouthpiece significantly reduced the distance covered on the treadmill. The self paced treadmill walk is a simple repeatable test and has advantages over both a corridor walking test and standard progressive tests for assessment of breathless patients.
PURPOSE: This study: a) calculated the reproducibility (intraclass correlation coefficient, ICC) and precision (technical error of measurement, TEM) for VO2 during moderate paced walking, self-paced sweeping, window cleaning, vacuuming and lawn mowing; b) determined which of the five activities rated >or= 3.0 when exercise intensity was calculated in METs (1 MET or metabolic equivalent = VO2 of 3.5 mL.kg-1.min-1) and multiples of the measured resting metabolic rate (RMR); and c) expanded the limited database on energy expenditure during household and garden activities. METHODS: Twelve men and 12 women (mean +/- SD: 39.3 +/- 3.4 yr; 171.6 +/- 9.6 cm; 81.0 +/- 15.5 kg) were measured for RMR and VO2 during the five activities on two separate days via indirect calorimetry by using the Douglas bag method. RESULTS: The interday ICCs and TEMs for the five activities ranged from 0.81 to 0.97 and from 2.1 to 7.0%, respectively. The means were significantly (P < 0.001) above 3.0 for moderate paced walking (range = 3.3-8.7), sweeping (2.9-6.7), window cleaning (3.0-6.0), vacuuming (2.6-4.4), and lawn mowing (4.9-7.5) when VO2 was divided by measured RMR, but one and five subjects scored below 3.0 for sweeping and vacuuming, respectively. Division of exercise VO2 by the convention of 3.5 mL O2.kg-1.min-1 significantly decreased (P < 0.001) each mean, and lawn mowing (5.0 METs) was the only activity where all subjects scored above 3.0 METs (P < 0.001; 3.8-6.4); nevertheless, the means for walking (3.7 METs), sweeping (3.2 METs), and window cleaning (3.6 METs) were also in the moderate intensity category of 3-6 METs. CONCLUSIONS: These data: a) emphasize that the VO2 during self-paced moderate intensity walking and self-paced household and garden activities can be measured with reproducibility and precision, b) demonstrate that expressing energy expenditure in conventional METs yields lower values than when it is presented as a multiple of measured RMR, c) suggest that all activities except vacuuming are performed at moderate intensity when energy expenditure is expressed in conventional METs, and d) highlight the biological variability in energy expenditure when different people perform the same task.
Body weight, basal metabolic rate (BMR), and treadmill metabolic rate (TMR) (3.9 km/h, no elevation) were measured in 39 women at 12, 24, and 36 wk gestation and at 9 wk postpartum. Prepregnancy measurements were also made on 15 of the women. TMR at 36 wk (3.65 +/- 0.50 kcal/min) was significantly higher than at 24 wk (3.38 +/- 0.43 kcal/min) or at 9 wk postpartum (3.38 +/- 0.43 kcal/min). Net energy cost (TMR minus BMR) at 36 wk gestation (2.42 +/- 0.40 kcal/min) was not different from prepregnancy or postpartum values but was significantly higher than at 12 wk (2.28 +/- 0.39 kcal/min) and 24 wk (2.28 +/- 0.37 kcal/min) gestation. In eight women the energy cost of self-paced walking on a treadmill was measured. The absolute and net energy cost decreased sharply from 6 to 12 wk gestation (by 8% and 11%, respectively) but remained unchanged afterwards. The data suggest that in the energy requirements for pregnant women no additional allowance need be made for physical activity, even if a woman's activity pattern includes a substantial amount of externally paced work.
BACKGROUND: Intra-articular hyaluronate sodium is a relatively new therapy for the treatment of osteoarthritis of the knee. This randomized, double-blind clinical trial was conducted at a large primary care medical center to determine the impact of hyaluronate sodium vs conventional therapy on measures of pain, stiffness, and disability at rest and following functionally relevant walking and stepping activities. METHODS: A total of 120 patients (mean age, 67 years) with unilateral grades 1 to 3 medial compartment knee osteoarthritis were randomized to 1 of 4 treatment groups: group 1, 2 mL of hyaluronate sodium at a concentration of 10 mg/mL and placebo (100 mg of lactose); group 2, nonsteroidal anti-inflammatory drugs (NSAIDs) (75 mg of diclofenac and 200 microg of misoprostol) and hyaluronate sodium; group 3, NSAIDs and placebo (2 mL of isotonic sodium chloride solution [saline]); and group 4, placebo (lactose and saline). Intra-articular hyaluronate sodium or saline (2 mL) was administered once weekly over 3 weeks while NSAIDs or lactose were administered twice daily over 12 weeks. MAIN OUTCOME MEASURES: (1) Western Ontario McMaster Universities Index (WOMAC) global measure of pain, stiffness, and disability; (2) visual analog scale (VAS) scores for pain at rest and following functional walking and stepping activities (self-paced walking and stepping); and (3) functional performance (exercise time, heart rate, and predicted maximum oxygen uptake) at baseline and weeks 4 and 12. RESULTS: At week 4, significant improvement in WOMAC scores for pain and disability and VAS score for resting pain was observed in groups 1 to 3 compared with baseline measures. Groups 1 and 2 showed significantly lower self-paced stepping pain, while no change was observed in group 4. At week 12, groups 1 to 3 showed significantly greater improvement in WOMAC pain subscale score and VAS score for resting pain; however, these differences did not vary from week 4. Following self-paced walking and stepping, groups 1 and 2 reported significantly less activity pain, while group 1 showed significantly faster self-paced walking and stepping test results. Groups 1 to 3 improved self-paced walking and stepping time at week 12 compared with baseline measures, while predicted maximum oxygen uptake was significantly higher in the hyaluronate sodium groups 1 and 2 at weeks 4 and 12 compared with baseline measures. CONCLUSIONS: For resting pain relief, hyaluronate sodium seems to be as effective as NSAIDs. Further, for pain with physical activity and functional performance, hyaluronate sodium may be superior to placebo alone or NSAIDs alone.
Self-paced walking was used as a measure of the neuromuscular slowing observed with aging. The effects of age on the choice of speed of walking, stride length, and step frequency were described for 289 males and 149 females aged 19 to 102 yr. These subjects were asked to walk at three self-selected paces (slow, normal, and fast) over an 80-m indoor course. Sixty-two years coincided with an accelerated decline in speed of walking. Before 62 yr, there was a 1 to 2% per decade decline in normal walking speed. After 63 yr, females showed a 12.4% per decade decrease and males showed a 16.1% per decade decrease. The eldest group (63 yr and older) had a significantly slower speed of walking and smaller step length than the younger groups (19 to 39 and 40 to 62 yr) for all paces. Heart rate at the three paces was not changed across age. In a multiple regression analysis, the only significant independent variable for walking speed at all three paces was (age), which accounted for 19 to 38% of the variance. When the population was divided into two age ranges (19 to 62 and 63 to 102 yr), walking speed was associated with height before 62 yr and with height and age after 62 yr.
OBJECTIVE: Factors associated with impaired functioning in patients with lower extremity peripheral arterial disease (PAD) are not fully understood. The purpose of this study was to determine the relationship between depressive symptoms and objective measures of lower extremity functioning in persons with PAD. DESIGN: Cross-sectional. PATIENTS/PARTICIPANTS: Four hundred twenty-three men and women with PAD identified from 3 Chicago area medical centers. MEASUREMENTS AND MAIN RESULTS: PAD was defined as ankle brachial index (ABI) <0.90. The Geriatric Depression Scale short form (GDS-S) (0-15 scale, 15 = worst) was completed by all participants. A clinically significant number of depressive symptoms was defined as a GDS-S score >or=6. Six-minute walk distance and usual-and fast-pace walking velocity were determined for all participants. A GDS-S score >or=6 was present in 21.7% of participants with PAD. Adjusting for age, increasing numbers of depressive symptoms were associated with an increasing prevalence of leg pain on exertion and rest (P =.004). Adjusting for age, sex, race, ABI, number of comorbidities, current smoking, and antidepressant medications, increasing numbers of depressive symptoms were associated with shorter 6-minute walk distance (P <.001), slower usual-pace walking velocity (P =.005), and slower fast-pace walking velocity (P =.005). These relationships were attenuated slightly after additional adjustment for presence versus absence of leg pain on exertion and rest and severity of exertional leg symptoms. CONCLUSIONS: Among men and women with PAD, the prevalence of a clinically significant number of depressive symptoms is high. Greater numbers of depressive symptoms are associated with greater impairment in lower extremity functioning. Further study is needed to determine whether identifying and treating depressive symptoms in PAD is associated with improved lower extremity functioning.
BACKGROUND: A continuously paced shuttle walk test (SWTp) was developed to test the hypothesis that speed and rhythm could be more optimally imposed by an easier-to-follow sound stimulus at every step. The objective of this study was to assess the reproducibility of the SWTp and to compare the performance of patients with chronic obstructive pulmonary disease (COPD) on the conventional and optimally paced forms of the test. PATIENTS AND METHODS: The walk test results of 24 COPD patients were studied. All patients completed 2 SWTp sessions and a conventional SWT in random order, after an initial practice test for each. A portable device was used to measure peak oxygen uptake (VO2) in 6 patients. RESULTS: The intraclass correlation coefficient (Cronbach's alpha) was 0.95 for the STWp. The Pearson correlation coefficient between distance walked and peak VO2 in the SWTp was 0.86 (P < .02). Better performance was achieved during the SWTp (peak VO2, 3.30 mL/kg/min; P < .01; distance walked, 32 m, P < .001) than during the conventional SWT. The SWTp showed excellent reproducibility. CONCLUSIONS: COPD patients can achieve better performance with the stimuli provided in the SWTp than on the SWT.
The purpose of this study was to determine whether peripheral arterial disease (PAD) subjects had impaired temporal and spatial gait characteristics compared to non-PAD controls at preferred and rapid self-selected walking paces. A total of 28 PAD subjects with intermittent claudication (age = 71 +/- 1; mean +/- SEM) and 15 non-PAD controls with at least one cardiovascular risk factor but no ambulatory leg pain (age = 71 +/- 1) were recruited. Gait parameters consisting of velocity, cadence, stride length, swing time, stance time, single-support time, double-support time, and base of support were recorded at the preferred and rapid walking paces. At the rapid walking pace, velocity was 22% slower (p < 0.001) in the PAD subjects compared with the non-PAD controls (99.9 +/- 3.3 vs. 117.5 +/- 5.3 cm/s) due to an 8% (p = 0.019) slower cadence (99.9 +/- 1.7 vs. 103.3 +/- 2.4 steps/min) and a 14% (p < 0.001) shorter stride length (119.8 +/- 2.9 vs. 135.8 +/- 4.2 cm/stride). The PAD subjects spent 5% less of the gait cycle in the swing phase (p = 0.006) and 3% more in stance (p = 0.006) than their non-PAD counterparts. During the stance phase, the PAD subjects spent 5% less of the gait cycle in single-stance (p=0.004) and 16% more in double-stance (p = 0.007). Similar results were obtained at the preferred walking pace. In conclusion, compared with the controls, PAD subjects adopted an ambulatory pattern that favored greater gait stability at the expense of greater walking speed at either their preferred or rapid self-selected paces.
To gain further insight into the neural mechanisms for different forms of quadrupedal walking, data on postural orientation, hindlimb kinematics, and motor patterns were assessed for four grades of downslope walking, from 25% (14 degrees slope) to 100% (45 degrees), and compared with data from level and downslope walking at five grades (5-25%) on the treadmill (0.6 m/s). Kinematic data were obtained by digitizing ciné film, and electromyograms (EMGs) synchronized with kinematic records were taken from 13 different hindlimb muscles. At grades from 25 to 75%, cycle periods were similar, but at the steepest grade the cycle was shorter because of a reduced stance phase. Paw-contact sequences at all grades were consistent with lateral-sequence walking, but pace walking often occurred at the steepest grades. The cats crouched at the steeper grades, and crouching was associated with changes in fore- and hindlimb orientation that were consistent with increasing braking forces and decreasing propulsive forces during stance. The average ranges of motion at the hindlimb joints, except at the hip, were often different at the two steepest slopes. During swing, the range of knee- and ankle-joint flexion decreased, and the range and duration of extension increased at the ankle joint to lower the paw downward for contact. During stance the range of flexion during yield increased at the ankle joint, and the range of extension decreased at the knee and metatarsophalangeal joints. Downslope walking was also associated with EMG changes for several muscles. The hip extensors were not active during stance; instead, hip flexors were active, presumably to slow the rate of hip extension. Although ankle extensors were active during stance, their burst durations were truncated and centered around paw contact. Ankle flexors were active after midstance at the steeper slopes before the need to initiate swing, whereas flexor and extensor digit muscles were coactive throughout stance. Overall the changes in posture, hindlimb kinematics, and activity patterns of hindlimb muscles during stance reflected a need to counteract external forces that would accelerate angular displacements at some joints. Implications of these changes are discussed by using current models for the neural control of walking.
Long-term detraining results for individuals 75 years and older are needed. The purpose of this study was to assess long-term detraining effects on quadriceps strength and functional mobility in nursing home residents. Ten women (X = 82.8 years) who completed a strength training program were reassessed 1 year later. Clinical methods were used to remeasure dynamic and isometric quadriceps strength and functional mobility. One repetition maximum quadriceps strength declined 68.3% (p < 0.05) from trained values. Isometric strength losses were 29.8% at 90 degrees (p < 0.05), 28.7% at 60 degrees (p < 0.05), and 24.4% at 20 degrees (p < 0.05) of knee flexion 1 year postexercise. Fast-paced walking, self-selected paced walking, and timed up and go speed decreased 28.6% (p < 0.05), 19.5% (p < 0.05), and 54.1% (not significant), respectively, from posttraining. One year vs. baseline, isometric strength decreased 0-14.3%, dynamic strength decreased 48.9%, and functional mobility declined 16.5-20.7% despite an intervening training program. An increased strength loss rate beyond the age of 80 years may be a major factor influencing functional independence.
A prospective cohort study of London civil servants was used to examine the relation of physical activity to various causes of death. 6,702 men aged 40-64 y who participated in a baseline examination between 1969 and 1970 were followed up for 25 y during which time there were 2859 deaths. The association of two measures of physical activity (leisure time activity and usual walking pace) with cause-specific mortality was examined. Walking pace demonstrated inverse relations with mortality from all-causes, coronary heart disease (CHD), other cardiovascular disease (CVD), all cancers, respiratory disease, colorectal cancer and haematopoietic cancer following adjustment for risk factors which included age, employment grade, smoking, body mass index, and forced expiratory volume (P [trend]<0.05 for all). In analyses restricted to men without disease at entry, walking pace retained inverse associations with all-cause, CHD, other cardiovascular disease, and haematopoietic cancer mortality (P [trend]<0.05 for all). Leisure time activity was also inversely associated with mortality from all-causes, CHD, other CVD, and all-cancers following adjustment for risk factors (P [trend]<0.05 for all). Eliminating deaths in the first 5 and 10 y of follow-up did not greatly alter these associations. It is concluded that physical activity may confer protection against death due to some cancers, in addition to reducing cardiovascular disease risk.
ObjectiveThis study aimed to investigate the potential causal relationships between chronic pain and three key sarcopenia-related quantitative traits: (a) hand grip strength; (b) usual walking pace; and (c) appendicular lean mass, using bidirectional two-sample Mendelian randomization.MethodsWe conducted bidirectional two-sample Mendelian randomization using summary-level data from large-scale genome-wide association studies to assess the genetically predicted associations between chronic pain, including multisite chronic pain and chronic widespread musculoskeletal pain, and the aforementioned sarcopenia-related traits.ResultsMendelian randomization revealed that multisite chronic pain was significantly associated with an increased risk of low hand grip strength (odds ratio = 1.70; p < 0.001) and decreased usual walking pace (odds ratio = 0.81; p < 0.001); chronic widespread musculoskeletal pain was also significantly associated with decreased usual walking pace (odds ratio = 0.15; p < 0.001). Additionally, higher left hand grip strength was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.90; p< 0.001) and chronic widespread musculoskeletal pain (odds ratio = 0.99; p = 0.002); higher right hand grip strength was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.91; p = 0.002); and higher usual walking pace was significantly associated with a lower risk of multisite chronic pain (odds ratio = 0.49; p < 0.001) and chronic widespread musculoskeletal pain (odds ratio = 0.92; p < 0.001). No significant causal associations were detected for appendicular lean mass in either direction (all p > 0.05).ConclusionThis study provides genetic evidence supporting potential causal links between chronic pain and key phenotypic components of sarcopenia.
OBJECTIVE: To determine the role of peripheral nerve dysfunction (PND) in the disablement pathway. RESEARCH DESIGN AND METHODS: Vibration perception threshold (VPT) was measured in 894 women aged > or = 65 years, and those with normal peripheral nerve function and with mild, moderate, and severe PND were identified. Lower-extremity impairments included quadriceps strength (kilograms) and three progressively difficult balance tasks (able/unable). Functional limitations included rising from a chair (able/unable) and usual pace and fast-paced walking speeds (meters/second). Level of PND was related to impairments and functional limitations in linear and logistic regression models that controlled for potentially confounding factors, including reported diabetes. RESULTS: Level of PND was associated with impaired balance (adjusted odds ratios: 2.21, 1.95, and 3.02 for mild, moderate, and severe PND, respectively, relative to normal, P < 0.05). PND was also associated with decrements in both usual and fast-paced walking speeds (-0.08, -0.08, and -0.15 m/s for usual pace and -0.13, -0.12, and -0.24 m/s for fast-paced walking speed for women with mild, moderate, and severe PND, respectively; P < 0.01 for all). Reported diabetes was not associated with these outcomes in the presence of PND. Some, but not all, of the association between PND and functional limitations was explained by the relationship between PND and impairments. CONCLUSIONS: PND is significantly associated with both lower-extremity impairments and functional limitations in older women, and PND appears to have independent effects on functional limitations. The independent effect of diabetes on these outcomes may be limited when PND is considered. Further research is needed to determine if PND is causally related to disability in old age.
BACKGROUND: Reduced levels of physical activity have been found to be associated with an increased risk of osteoporotic fracture in a number of epidemiological studies, and intervention studies have shown beneficial effects of exercise regimes on bone mineral density. It is not yet established, however, which specific forms of customary physical activity are most strongly associated with bone mineral density in postmenopausal women. METHODS: A cross-sectional study was conducted in 580 postmenopausal women, aged 45-61 years, resident in Nottingham, England. The participants completed a detailed interviewer-administered activity questionnaire. Physical activity was assessed as total hours of participation per week in activities including housework, walking, gardening and sports. Stair-climbing and self-reported walking pace were also reported. Bone mineral density measurements were made using dual energy x-ray absorptiometry, measurements at five sites were used in analysis. RESULTS: The strongest associations between the activity measures and bone mineral density were for stair-climbing and walking pace, which both gave statistically significant positive associations at the trochanter hip site and the whole body. In women reporting a fairly brisk or fast walking pace, bone mineral density at the proximal femur was also significantly and positively associated with the frequency of walking at least a mile. There were no significant associations with aggregate measures of total customary physical activity. CONCLUSIONS: This study has identified two forms of physical activity, namely stair-climbing and brisk walking which are associated with increased bone mineral density at the hip and whole body in postmenopausal women. Both are feasible forms of activity for promoting to middle-aged women.